The Design of a Novel Digital Puzzle Gaming System for Young Children’s Learning by Interactive Multi-Sensing and Tangible User Interfacing Techniques

Abstract

In the fast-developing digital era, improving young children’s learning abilities by information technology has become a goal of early childhood education. Accordingly, a novel digital puzzle gaming system for young children’s learning is proposed, which is based on interactive multi-sensing and tangible user interfacing techniques. Three childhood education factors—digital learning, puzzle gaming, and interactive interfacing—are considered in the system design. Firstly, the needs in the development of the physical and mental functions, as well as the cognition and learning capabilities, of children aged 4–6 years are reviewed. Next, the existing studies of digital gaming for education are analyzed. Then, the proposed system was constructed to combine visual, auditory, and animation interfaces for easy uses by young children. The effectiveness of the system for young children’s learning was evaluated statistically using the SPSS based on the users’ and experts’ opinions collected from the methods of behavior observation, interview, and questionnaire survey. Several facts about young children’s learning have been found: (1) simple tangible interfaces can bring forth good gaming experiences to children; (2) rich visual and sound effects can enhance game-playing pleasures; (3) digital puzzle gaming have positive impacts on learning in early childhood education. In conclusion, the design of a digital puzzle gaming system like the proposed one with simple and physical interactive interfacing can bring forth a good gaming experience to children, and rich visual and sound effects can enhance the game-playing pleasure, indicating that digital puzzle gaming has a positive impact on young children’s learning in early childhood education.

1. Introduction

With the rapid development of science and technology, the world society has entered the digital age, and people’s living habits, like the use of cell phones and the Internet, are changing day by day. Accordingly, human cognition and interaction activities in learning are also changing. Educators began to create innovative teaching methods and versatile media tools for use in educational fields. Modern children grow up in the ever-changing digital age, and for preschool children, all experiences in their daily lives contribute to their knowledge learning and cognitive development [1]. Making good use of digital media and technology in teaching can enhance children’s learning in all areas, including language, math, and creativity. The combination of “digital technology” and “education” has also become the key to improving the quality and interactivity of early childhood education in the future, leading to the development of digital learning.

With the evolution of the times, interactive technology has been integrated into the learning process of early childhood education, stimulating many refreshing learning concepts and opening up a new path for traditional education. In this trend, digital game-based learning has been getting more and more popular in the past decade. In this type of learning, abundant multimedia is utilized to provide various kinds of learning situations for the students to practice multifaceted thinking and promote their interactions with society. In addition, both game playing and learning can be considered simultaneously to achieve the effect of “education via entertainment”. In such an educational approach, games can be designed to enhance the development of learning or cognitive skills, and simulation techniques can be adopted to allow learners to repeat the practice of specific skills in a virtual environment [2]. Silva, Rodrigues, and Leal [3] gave a review of gamification for use as a tool used to improve the quality and management of the teaching-learning process which can help both teachers and students reach their educational goals. Silva, Rodrigues, and Leal [4] also investigated how game-based learning can improve flow in accounting and marketing education, and found that by introducing games into the curriculum, students’ motivation and interest increased, and that games can be an effective way for students to learn.

Furthermore, for children’s enlightenment, puzzle games are the most popular because they have strong logic, mathematical rationality, and educational functions, and can bring pleasure feelings to young children. Therefore, the puzzle game plays an important role in early childhood education. In addition, in the way of communication between people and computers, tangible user interfaces are often used in various game systems, by which physical objects and digital information can be combined to create more friendly and simple interaction schemes for game players. Moreover, multi-sensing techniques via the use of audio-visual and tactile sensors can also be employed to improve the richness in the interaction process between the game system and the player.

In this study, it is aimed to design a digital puzzle gaming system by interactive multi-sensing and simple tangible interfaces for young children’s learning in early childhood education.

1.1. Literature Review

1.1.1. Developments of Early Childhood Education and Young Children’s Cognition

In the 21st century, early childhood education has become a hot spot in educational development and international competition and has received widespread attention from the international community. Jean Piaget (1896–1980), a well-known modern educational psychology scientist, divided children’s cognitive development into four stages, namely sensorimotor, preoperational, concrete operational, and formal operational, each of which exhibits intelligence differently [5]. After the sensorimotor stage, children’s cognitive development enters the pre-motor stage, which starts from the second year of life to the age of seven or eight and is the stage when the difference between children’s thinking and adults’ thinking is the greatest. Early childhood education is in the pre-operational thinking stage (2–7 years old), in which children start to use the mind to conduct rational thinking. This stage can be divided further into two substages, namely, symbolic function (2–4 years old) and intuitive thinking (4–7 years old). The intuitive thinking substage includes children between the ages of four and seven, in which the children become very curious and have interests in reasoning. It is believed that in the first two stages of cognitive development, children learn mainly through imitation and play [5].

Early childhood education has gradually attracted people’s attention with the trends of global development, technological progress, and low birthrates [6]. Kesäläinen et al. [7] studied how children’s play behavior was related to their cognitive skills and vocabulary development in integrated early childhood special education (ECSE) groups, and children with and without special needs were supported according to their diversity of individual needs by assessing children’s various learning paths. The research results indicated that all skills improved for all of the children during the research period, although there were differences in results between children’s status groups. Additionally, the National Association for the Education of Young Children (NAEYC) in the USA supports the appropriate development of related technologies for use in early childhood education. A necessary condition for successful learning is motivation and motivated learning does not stagnate, but in this day and age, many students must learn knowledge that does not directly stimulate their interests [8].

In addition, the two aforementioned major developments in the growth of young children, the cognitive function and the motor capability, can be cultivated through enlightenment games, among which the most popular are puzzle games that originated in the 1760s. In general, the puzzle game is a form of entertainment which can also be considered as a form of learning [9]. There are many types of puzzle games, such as word puzzle, logic puzzle, picture puzzle, and block puzzle [10], which allow young children to exercise their creativity, imagination, and exploration abilities through game playing. When the teaching content can be conveyed in the form of games, it attracts more learners’ attention and helps increase their learning motivations. Therefore, puzzle games can be said to play an important role in the educational process.

1.1.2. Education via Entertainment by Digital Technology

The 21st century is an era of digital learning, emphasizing the necessity of learning through games, because game-playing activities can reduce the boring feeling in the classroom [11], and in a digitalized environment, the use of games is also changing people’s learning styles in the different stages of education, creating a huge impact on the learning behavior of early childhood education. With the advent of multimedia storytelling, virtual environment creations, as well as wide applications of the Internet, the computer has become a tool for artistic creation today. Furthermore, through the uses of high-quality audio-visual and physical interactions, the computer has become a medium that is more expressive but more flexible for reinforcing and imitating the sensory qualities of other media [12]. In addition, with the help of interactive technology, the content of traditional teaching has also been greatly enriched. The combination and flexible uses of images, sound effects, color and light, and other multimedia elements have given a new look to the learning situation of early childhood education, making the originally static and flat learning content become more enjoyable. Following this trend, more and more kindergartens and families have begun to utilize the Internet and digital games in recent years, making interactive media a major tool used in the learning activities of children in modern times [13].

1.1.3. Digital Technology Development for Educational Purposes

The advancement of digital technology has made human–machine interaction techniques, which are the most indispensable for game playing, constantly updated or improved. Undheim [14] gave a literature review to identify patterns and discuss key perspectives from empirical studies published during the last decade that explore how young children and teachers together engage with digital technologies in early childhood education and care institutions. Nowadays, in addition to the traditional text input, as well as the use of the mouse, joystick, and drawing tablet, the techniques of speech and gesture recognition, somatosensory operation, and virtual reality have become the channels of communication between people and computers. By utilizing these intensively developing techniques, tangible user interfaces can be constructed, which combine physical and digital information to present various state expressions and manipulate digital contents [15]. Such tangible user interfacing techniques can be used further to develop more advanced applications like digital learning, display technology, and technology art.

In 2009, David Merrill, a graduate student at MIT, presented on the well-known American media TED an interactive learning device, “Siftables”, based on a physical user interface. Each building block is a modular computer that can sense the directions and adjacent building blocks through wireless communication, display the corresponding icons, and transmit digital contents like images and music [16]. In 2014, an American start-up game company, “Osmo”, launched an interactive puzzle game, “Osmo Genius Kits”, based on the use of an iPad. This product includes a computer vision system to analyze the placement of objects on a desktop. Traditional tangram, scrabble, and other educational games with learning value are displayed on the iPad screen through the game-playing styles of competition, cooperation, scoring, and level-challenging. The interactive feedback of physical objects is displayed on the iPad screen, so that the participants can enjoy playing the game, and strengthen their skills of language, space, exploration, and cognition in the meantime [17].

In 1932, Parten proposed a plan for children’s social activities which is widely used today. It is divided into four modules: single-player game, parallel game, associative game, and cooperative game, which have become the reference for designing subsequent game learning and experiencing activities [18]. Learning by digital gaming, which brings forth fun and engagement, and a fusion of serious learning and interactive entertainment, is an emerging and exciting medium for education [19]. The well-known sociologists Mildred Parten (1902–1970) and Sara Smilansky (1922–2006) both put forward relevant theories about children’s learning through play, and they encouraged teachers to put the theories into actions while teaching preschool children [18]. Hogle (1996) also suggested that games have related benefits to learning, including increased interest in learning, retention of memory, practice, and feedback, as well as cognitive thinking [20]. More recently, Amorim et al. [21] investigated the issue of adopting mobile games to foster the early literacy skills of children in poverty. Children were invited to play the learning games of Escribo Play to improve their word reading and writing skills. Compared with 104 reading interventions conducted in kindergartens, the Escribo Play effect size was 3.35 times stronger than a reading intervention benchmark.

With the development of technology, the interactive approach to childhood learning has prevailed widely, replacing the traditional static mode by the dynamic mode. Human interactions with learning-assisting devices are carried out through somatosensory operations, voice control, lime touches, or human movements. Therefore, the operational functions of interactive devices have also become more diversified. The application scope includes education, performance, and life [13,22]. The introduction of interactive technology in early childhood education can eliminate the traditional and boring teaching in classrooms. In the form of digital learning, puzzle games can be experienced through game playing with timely feedbacks and can also be designed to record data in the learning process so that the participants’ deficiencies in learning can be identified [10].

1.2. A Review of Existing Digital Games for Early Childhood Education

Through tangible user interfacing techniques, the effectiveness of children’s learning obtained in the learning process can be enhanced. In addition to making up for the lack of physicality of the graphical interface, the use of the interactive tangible interface (TUI) can also improve children’s enjoyment of learning. Several existing case studies of introducing TUIs into game learning were reviewed in this study and listed in

Table 1. Works of case studies of digital games using tangible user interfaces.

Work Title	TUI Form	Technology	Interactive Form	Description
A Cube to Learning (2005) [23]	structural device	miniature screen, accelero-meter, speaker	rotate and shake	A speaker, a three-axis accelerator, and a miniature screen are embedded in the system. When the user starts to answer a question issued through the speaker, the surface of a cube needs to be rotated to the answering side.
A Tangible Tabletop Game (2008) [24]	interactive surface, marking and control system	ESP with Arduino and electronic materials	scroll tap	This is an interactive table with a game made by ESP. The interactive tabletop surface is similar to an electronic chessboard. Users need to match the colors of a physical object interface with those on the tabletop to pass the game.
Storytelling through Drawings (2009) [25]	structural system, marking and control system	computer vision and projection screen	tap interface	The system grabs the position of a toothbrush by a webcam, and when the user holds the toothbrush to touch the bacteria, visual feedback will appear on the projection screen.
PuzzleTale (2010) [26]	structural device, marking and control system	computer vision and projection screen	multi-touch object manipulation	This is a learning system that combines multi-touch and graphic markers, and the user can interact with the system through the use of graphic markers.
AR Tangible Interface (2011) [27]	interactive surface, marking and control system	computer vision	object manipulation	The user places a marked interface card on the desktop, and after the camera captures and recognizes the image of the marked interface card, the screen displays the corresponding visual feedback.
Magic Sticks (2011) [28]	structural device	RFID and Bluetooth interface	tap interface	The system uses a magic wand with RFID as the interactive interface and cooperates with a Bluetooth device to allow the user to tap an area with a tag through the magic wand, and generate corresponding feedback.
TangiSense (2011) [29]	interactive surface and structural device	computer vision and projection screen	structural combination	The system uses computer vision technology to grab the images of objects on an interactive table to draw and interact with users. The chessboard-style desktop, LED colors, and a projection screen together are used to present visual feedback.
KidCAD (2012) [30]	interactive surface, marking and control system	computer vision	press the interface and object manipulation	Through the user’s pressing on a physical object and depending on the depth and strength of the manipulation of a brush, the corresponding visual effect of a 3D digital model is presented.
The Tangible Toy (2015) [31]	interactive surface, marking and control system	computer vision and mobile device	physical operations and visual feedback	Based on the use of computer vision technology to capture the position of a building block, when the position of the building block changes, the digital image also changes. Besides interacting with computers, the system also interacts with mobile devices.

as a reference for designing the proposed digital puzzle game system.

From the descriptions of the works of the case studies listed in Table 1, the following facts can be drawn for deriving the design principles for the proposed system.

(1)

The technical application of TUIs is often completed with aids from computer vision, for example, placing a webcam directly above or below the interactive surface to capture the user’s interaction with the TUI.

(2)

The interactive form of a TUI can be combined with electronic sensors to form a good interactive interface. The sensors so used include three-axis accelerators, speakers, Bluetooth elements, etc., which all can achieve the purpose of communication between the physical interface and the computer.

(3)

In addition to being game-like, the physical user interface of a game can also import learning content that children need, giving children extra value-added feedback when playing the game.

The TUI technique has been gradually integrated into various systems for use in modern early childhood education, and the advancement of technology and digital media has also created many distinctive interactive interfacing methods, most of which are interactive surfaces, symbols, and controls. However, games with themes are rarely introduced. Therefore, in this study, it is tried to introduce digital puzzle games with physical user interfaces into early childhood education, as described in the subsequent sections.

1.3. Proposed Principles for Digital Puzzle Game Learning in Early Childhood Education

In this study, a digital puzzle gaming system is proposed for young children’s learning in early childhood education. A tangible user interface was constructed to enhance the diversity of the game, so that children can get visual, auditory, and tactile interactive experiences when playing the game. The system was designed according to the following design principles drawn from the previously described literature reviews:

(1)

considering the four major factors for assessing the play performance of early childhood learning, namely, (a) child factors, (b) performance skills, (c) activity demands, and (d) context and environment, proposed by Zidianakis et al. [32] in the design of the proposed gaming system to offer a new type of learning experience;

(2)

using the TUI design model proposed by Wang and Kang [33], which includes the considerations of cognition, emotion, physiology, and social interaction, to design the operation mode and game procedure in the proposed system;

(3)

summarizing five indicators, namely, usability, enjoyment, experience, sociality, and richness according to the above literature surveys, and using them as the criteria for evaluating children’s learning effectiveness;

(4)

designing the interaction scheme of the proposed system according to the sensory-motor development of children, and combining the operations of the game interface, to achieve the effect of visual feedback, so as to allow children to feel the responses from the virtual and real worlds simultaneously;

(5)

introducing high-tech cloud network technology and electronic sensors, and cooperating with object projection, to make the connection between the gaming system and the peripheral interactive device more closely;

(6)

simplifying the physical interface and game-playing flow, and adding story-based game content that can stimulate children to think;

(7)

including lively, cute, and colorful elements in the visual design of the game, and using animations to present game situations, to enhance children’s willingness to participate and to increase their game experiences.

1.4. The Research Goal and Paper Organization

The main goal of this study was to construct a digital puzzle gaming system for use by young children with the aim of promoting their digital learning effect in early childhood education. Two major questions arise:

(1)

how to design a simple physical user interface for a digital puzzle game?

(2)

how to combine interactive technology and digital puzzle games to enhance the effect of children’s digital learning by playing the game?

The questions were answered in this study by constructing a digital puzzle gaming system by information technology that includes interactive multi-sensing and tangible user-interfaces, and conducting a statistical evaluation of the effectiveness of the system according to the opinion data of the users and several experts that were obtained by the system assessment methods of behavior observation, interviews, and questionnaire surveys.

In the remainder of this paper, the methods adopted for the construction and assessment of the proposed system are described in Section 2. Then, the details of the proposed digital puzzle gaming system and statistical evaluation of the system’s effectiveness are described in Section 3. Discussions and concluding remarks are given in Section 4.

2. Methods

2.1. Research Design

An illustration of the research design for this study is shown in Figure 1, which includes three major stages: survey, development, and assessment, as described in the following.

(1)

The survey stage—the reviews of relevant literature and case studies were conducted, with the topics including investigations of early childhood education, tangible user interfaces, digital puzzle games, etc.

(2)

The development stage—based on a prototyping method, the proposed digital puzzle gaming system was constructed according to a set of design principles derived from the literature and works reviewed in the last stage.

(3)

The assessment stage—the system was used in an exhibition space by a group of young children whose performances were recorded by the methods of behavior observation, expert interviews, and questionnaire surveys with the resulting dataset being used to evaluate the effectiveness of the proposed system by use of the statistical software packages SPSS.

In the aforementioned research design, the methods of prototyping, behavior observation, expert interview, and questionnaire survey were used. These methods are introduced briefly in the following. The details are described in the subsequent sections.

2.1.1. The Prototyping Method

Prototyping is a method for constructing and evaluating a system quickly with low cost before it is completely built for final uses [34]. Constructing a system according to the prototyping method needs the following steps in general:

(1)

conduct a survey of the literature about the relevant theories and existing studies related to the system to be constructed;

(2)

derive the principles for designing the system from the literature survey result;

(3)

construct a prototype system according to the derived principles;

(4)

carry out necessary field experiments or system exhibitions using the prototype;

(5)

evaluate the effectiveness of the prototype system by any system assessment methods;

(6)

improve the functions of the prototype system to finalize it; and

(7)

exhibit the system in public spaces to conduct field experiments and further modifications of the system.

2.1.2. The Behavior Observation Method

According to Wasson [35], behavior observation is a method for surveying the performances of the users of a system, which includes five parts as described in the following, named AEIOU, with each part focusing on one viewpoint about the use of the system:

(1)

activities (A)—what are the behavior patterns of people, and what are the processes in the activities?

(2)

environment (E)—what are the characteristics and functions of the space, and is it a personal or a public space?

(3)

interaction (I)—is there interaction between people and between people and objects?

(4)

objects (O)—what items and equipment do you have in the above environment?

(5)

user (U)—who is there, and what are the roles and relationships?

In addition, in the behavior observation method, the organization of the observation records is usually carried out directly using a form that can help the observer to focus on the concerned parts, the follow-up sorting, as well as the analysis on “what actually happened” rather than “the observer’s imagination”.

In this study, the behavior observation method was adopted to collect the data about the users’ performances on the proposed system. Specifically, a camera was set up in an exhibition area at the experiment field to record as video data the entire process of the children’s interaction with the system. In addition, the researchers of this study on the side carried out the task of recording the children’s performances with pen and paper by filling a form with focused items prepared in advance.

2.1.3. The Expert Interview Method

In the interview method, relevant persons were invited to respond to questions asked about topics related to a certain investigation, so as to find out facts about the investigation [36]. This method was adopted in this study for interviews with four invited experts who were invited to observe users’ performances on the proposed system. The aim is to collect their comments on the system as a reference for system improvement. The duration of each interview was 60 min. The questions asked in the interview include topics of three aspects, namely, introduction of interactive technology into early childhood education, digital puzzle game, and interactive experience of physical user interfaces applied to the digital puzzle game. The details and the result will be presented later in this paper.

2.1.4. The Questionnaire Survey Method

The questionnaire survey method is a means for collecting opinion data through sample surveys or censuses. The method can be conducted by telephone, paper, or the Internet. In this study, according to the developmental assessment principles of ICF (International Classification of Functioning, Disability, and Health) [37], the Denver II developmental test scale [38], and the media richness proposed by Daft and Lengel [39], questionnaire surveys of the children’s experiences of using the proposed digital puzzle gaming system were carried out for evaluating the effectiveness of the gaming system for children’s learning. Specifically, each child user, after completing performing the gaming system, was asked to fill out, possibly with the help of the parents or a researcher of this study, a questionnaire form that was designed according to the characteristics of the proposed digital puzzle gaming system and included questions about the user’s feelings of performing the proposed system and interactions with other players.

2.2. Participants

2.2.1. The Participating Young Children

In this study, a total of 58 young children were invited to the exhibition site to play the digital puzzle game on the proposed system. These children came from the Sun Moon Rise Kindergarten in Taichung, Taiwan. A summary of the participating children’s background data is shown in

Table 2. The statistics of the basic data of the participating young children.

Category	Item	Number of Samples	Percentage
Sex	Male	38	65.5%
	Female	20	34.5%
Age	4 years	8	13.8%
	5 years	16	27.6%
	6 years	34	58.6%
Interactive gaming experience	Yes	6	10.7%
	No	52	89.3%

, from which it can be seen that 35.7% of the children are female and 64.3% are male with an average age of 5 years, and more noticeably that 89.3% of them have no experience of using interactive gaming devices.

2.2.2. The Invited Experts

Four experts were invited to observe the young children’s use of the proposed system and interviewed to give their comments about their observations. One expert was in the field of digital learning, another was in the field of interaction design, and the other two were in the field of early childhood care, as shown in

Table 3. Experts were invited to observe users’ performances and accepted interviews in this study.

Code	Affiliation	Job Title	Expertise
T1	kindergarten	teaching staff	early childhood care, child welfare, early childhood education
T2	national university	associate professor	infant physiology, infant health, infant cognition
T3	national university	associate professor	digital learning, game education, information education
T4	national university	associate professor	interactive technology, human–machine interface, digital self-made

.

2.3. System Procedure

The construction of the proposed gaming system, based on the TUI design model [33] for developments of children’s learning and behavioral skills [32], called the “Tree of Wisdom—Color Matching and Touch”, is described in detail in this section, including the design idea, the system architecture, the adopted hardware and software, and the game-playing process.

2.3.1. Design of the Proposed System by Interactive Multi-Sensing and Tangible User-Interfacing Techniques

The design of the proposed gaming system, “Tree of Wisdom—Color Matching and Touch”, is based on the theme of playing around a “tree of wisdom” in a fantasy world, which yields wisely many kinds of “living fruits”. In order to transform a fruit grabbed from the tree into an “elf of a certain color” the player has to match correctly the color of the elf with that of the fruit for the fruit to show a vivid appearance with new vitality. The color appearances of the tree and fruits are presented by interactive technology on an interactive projection table, combined with electronic sensors and an animation projector. Furthermore, the physical user interface of the system is combined with a game-playing algorithm to provide visual feedbacks in the digital puzzle game, guiding children to go through the virtual and real worlds. It was expected that the proposed digital puzzle gaming system can strengthen young players’ sensory-motor development and promote their cognitive skills.

An illustration of the appearance of the proposed multiplayer cooperative puzzle gaming system with children players around is shown in Figure 2a. The system is composed mainly of the following parts:

(1)

an interactive projection table—of the shape of a cylinder as shown in Figure 2b, supposed to be the “tree of wisdom” of the proposed system;

(2)

a table screen on the projection table—for showing the game-playing graphics as illustrated in Figure 2c;

(3)

an animation projection unit—inside the projection table as shown in Figure 2d;

(4)

a tangible user interface unit—consisting of four “red” slide potentiometers attached on the lateral sides of the cylindrical projection table as well as four “colored” switch buttons on the tabletop.

The hardware and software used in the above parts of the proposed system will be described in detail later in this section.

2.3.2. Design of the Game-Playing Process

The “color matching and touch” games of the proposed digital puzzle game learning system, together with the switch buttons, the slide potentiometers, the projection animation unit and two audio speakers, constitute a multimedia environment in which the user interacts with the system. The game-playing process essentially goes in the following way.

• The game-playing process of the proposed digital puzzle gaming system—
• Part I: playing the color matching game
• Stage 1. Initialization—
• (1.1) Downloading the cloud database:

When the system is turned on, an initialization image with a large tray appears in the table screen on top of the projection table. After pushing any of the four switch buttons, an anthropomorphic orange shape and a progressive bar appear in the tray, indicating that the cloud database is being downloaded to the system.

(Note: Figure 3a shows the initialization image in which an anthropomorphic orange shape and a progressive bar appear.)

• (1.2) Entering the game-playing process:

A 6-second countdown of numbers 1 through 12 starts on the table screen, during which each player may press a switch button of the four on top of the projection table to enter the game with a tray filled with a colored fruit appearing in the personal interaction area. When the countdown stops, if two to four players have entered the system, then the color matching game is started.

(Notes: The six seconds for the countdown is called the standby time which is an adjustable parameter of the system. Figure 3b,c illustrate respectively the situation of a player pushing a button to enter the game, and that of four players having entered the game with colored fruits appearing in their respective trays).

• Stage 2. Color matching—
• (2.1) Adjusting fruit colors:

The initial color of the appearing fruit for each user might be incorrect, and in this case the user has to slide up and down the potentiometer on the lateral sides of the projection table to choose a correct fruit color from three ones provided by the proposed system. When the correct fruit color appears, the user has to push the switch button to confirm the selected color.

(Notes: a total of six fruit colors are used in the proposed system; an example of three colors of a fruit is shown in Figure 4 together with the corresponding positions and readings of the slide potentiometer for selecting the respective colors. Color 2 is the correct watermelon color. Figure 5 shows the real situation of a user using the slide potentiometer and the switch button for fruit color selection and confirmation).

• (2.2) Successful color pairing:

When the correct fruit color has been selected, the user has to push the switch button further continuously for a sufficient time duration to enlarge the fruit shape gradually and simultaneously increase the sound of accompanying music until the fruit “explodes” to become one with an anthropomorphic shape, indicating that the user has conducted color matching successfully and has given the fruit new vitality.

(Note: see Figure 6 for two examples of fruits with original, sliced, and anthropomorphic shapes, and see

Table 4. A list of four-season fruits and their respective realistic, sliced, and anthropomorphic shapes, as well as the corresponding textual introduction information (shown in the last column).

Season	Fruit Title	Fruit Shape			Introduction Information
		Original	Sliced	Anthropo-Morphic ***
Spring	Litchi
	Wax apple
	Tomato
	Guava
Summer	Watermelon
	Mango
	Passion fruit
	Cherry
Autumn	Pear
	Carambola
Winter	Orange
	Tangerine
	Strawberry

(*** Note: the anthropomorphic shape of each fruit shown here is just one of the two shapes shown in Table 5).

for all the fruits that will appear in the game-playing process, which are categorized by the four seasons and shown in three different shapes).

• (2.3) Failed color pairing:

If the color pairing fails, an error sound will be issued as a reminder for the user to continue trying.

• (2.4) Anthropomorphic shape selection:

After successful color matching, the anthropomorphic fruit shape, which was selected initially according to the slide bar position of the slide potentiometer, can be adjusted to become an alternative one provided by the system by sliding the potentiometer again to change the slide bar position.

(Note: the way to select anthropomorphic shapes for each fruit in Table 4 is illustrated in

Table 5. A list of the two anthropomorphic shapes of each fruit shown in Table 4 and the way to select them by the slide potentiometer.

Fruit Title	Anthropomorphic Shape 1		Anthropomorphic Shape 2
Bar position and reading value of the slide potentiometer (to select shape 1 or 2)	0~127		128~255
Litchi
Wax apple
Tomato
Guava
Watermelon
Mango
Passion fruit
Cherry
Pear
Star fruit
Orange
Tangerine
Strawberry

in which the two anthropomorphic shapes of each fruit and the way to select them by the slide potentiometer position are shown).

• Part II: playing the fruit catapult game
• Stage 3. Preparing fruit slices for the game—
• (3.1) Generating and popping up fruit slices:

After the desired anthropomorphic shape is selected, each user has to push the switch button once more to cut the fruit into a slice and pop it up onto “a slingshot with a spring underneath” which is located near the personal interaction area in the central tray of the table screen.

• (3.2) Adding textual introduction information of fruits:

With the original fruit still remaining on each user’ tray, a tag with extra textual information introducing the fruit (like the nickname, the alternative name, or a certain special property of the fruit) was shown additionally beside the anthropomorphic fruit shape to provide the player a better learning experience.

(Note: the introduction information of each fruit is shown in the last column of Table 4 and an example can be seen in Figure 6).

• Stage 4. Kicking fruit slices to get scores—
• (4.1) Bouncing the fruit slice:

With the fruit slice put readily on the slingshot, each user has to push the switch button for a sufficiently long time to catapult the fruit slice into the central tray area, which will then bounce randomly there.

• (4.2) Pushing the slingshot to hit incoming fruit slices into the other users’ slingshots:

Each user has to push the button continuously at the right times to kick any incoming fruit slice to go into the other users’ slingshots to get scores according to the following three rules:

(a)

a successful kick of any fruit slice into another user’s slingshot is given a score of two points;

(b)

the first scoring push is given specially a double score of four points;

(c)

a failure to push back a fruit slice coming from another user’s kick is given a negative score of one point.

• Stage 5. Ending the game playing by score ranking and player awarding—
• (5.1) Ending the catapult game:

The catapult game ends when all fruit slices are pushed into the slingshots of the users, i.e., when no more fruit slices exist in the central tray area for further pushing.

• (5.2) Score ranking and awarding:

The final scores obtained by the users are ranked finally, and the users are awarded accordingly crowns of different ranks: Rank No. 1 is awarded a golden crown, No. 2 is a silver crown, No. 3 is a bronze crown, and No. 4 is a silver laurel crown, as shown in

Table 6. Crowns are awarded to the users after score ranking.

Rank No. 1	Rank No. 2	Rank No. 3	Rank No. 4

.

• (5.3) Ending the game playing:

After the awarding step, the system shows an ending image and then returns to its initialization state as described in (1.1) above.

The previously described game-playing process of the proposed system can be presented more clearly by a flowchart shown in Figure 7 from the viewpoint of program execution by the computer.

2.3.3. Merits of the Proposed Gaming System for Early Childhood Education

As can be seen from the game-playing process described previously, at least the following merits of the proposed system seen from the perspectives of young children’s learning, as well as body and mind developments, can be identified.

(1)

Creating appropriate visual game contents for young children

In order to make the game-playing activity closer to the learning atmosphere for children aged 4 to 6 years old, the visual graphics of the game content were designed into two parts, namely, game characters and visual animations. In the game character part, the fruits played in the game were designed to have two kinds of visual appearance: realistic and anthropomorphic, both being in a cute and playful style. For the visual animation part, music was added to increase the audio effect.

(2)

Adopting simple decision-making steps in the game-playing process

In order to match the 4–6-years-old main users’ cognitive development, the game-playing process was not designed to be too complicated. Three colors out of six are used for each user in the color-selection situation, and for each color, there is only one decision-making event; the rest of the events are system-oriented so that the player does not have to conduct too many operations.

(3)

Helping motor development and enhancing eye-hand coordination ability

Besides using simple switch buttons for gaming control as conducted in many traditional games, the additional usage of slide potentiometers offers an opportunity for the children to practice “fine” operations that help the children’s sensory motor development as well as coordinated movements of eyes and hands (see Steps (2.4), (3.1), and (3.2), for example, in the above game-playing process).

(4)

Promoting development of audio, visual, and tactile response capabilities

The long-pressing action on the switching button required in the game-playing process offers a chance for the children to interact with the system in accordance with the visual, tactile, and auditory feedback. Specifically, the longer the time of pressing, the larger the fruit image becomes and the higher the sound effect of the accompanying music (see Step (2.2) in the above game-playing process), giving the gaming situation further increases of richness and pleasure.

(5)

Promoting children’s first cognition of virtual worlds

Projection animation is displayed, and electronic sensing elements are used in the game-playing process of the proposed system to achieve the effect of tangible user interfacing. In addition to achieving sensory-motor training in children’s cognitive development, such game playing also enables the children to receive feedbacks from the real and virtual worlds and get to know the conceptual essence of the metaverse developed in recent times.

(6)

Assisting children’s learning of the knowledge of fruits

The fruits introduced in the game-playing process of the proposed system are commonly seen in people’s regular life. In the first part of the game-playing process, the player has to select the correct color for a given fruit. Furthermore, in addition to providing the name of the fruit, additional textual information about the fruit was written on tags and shown in the game-playing process by the system. Therefore, the proposed system has the educational effect of providing in-depth knowledge of fruits to the young players in their early ages.

2.3.4. An Illustrative Example of Game Playing on the Proposed Gaming System

The game-playing process on the proposed system, “Tree of Wisdom—Color Matching and Touch”, includes mainly three types of interactions, namely, “physical operation”, “color recognition”, and “interactive animation”. To help in understanding the game-playing process of the proposed system, the intermediate results of an example of a four-children game-playing process on the system, which are shown on the table screen on top of the projection table, are depicted in

Table 7. An example of four-children game-playing results shown on top of the projection table.

Step No.	Interaction Result Shown on the Screen and Game Control	Explanation of the Players’ Interactions	Involved Devices and Technology	Tasks Completed by the System
1.1		None	The screen of the projection table	Showing an anthropomorphic orange shape and a progressive bar indicating cloud database downloading
1.2		Choosing a switch button to press	Switch buttons	Entering the gaming process by showing the initialization image
1.2		Judging the correct color according to the fruit displayed on the table screen	Animation projection	Providing three colors for each fruit for the player to choose
2.1		Sliding the potentiometer to change the color of the fruit	Slide potentiometer and animation projection	Processing the color-selecting signal coming from the slide potentiometer
2.1		Stopping sliding the potentiometer when the correct color appears	Slide potentiometer and animation projection	Changing the color of the fruit
2.2		Pressing the switch button to confirm the selected color and turn the fruit shape into an anthropomorphic one	Switch button and animation projection	After the fruit color is confirmed, changing the fruit shape into an anthropomorphic one if the button is long pressed
2.4, 3.1, and 3.2		Changing the anthropomorphic shape by sliding the potentiometer; and popping a fruit slice onto the slingshot by button pushing	Slide potentiometer, switch button, and animation projection	Changing the anthropomorphic shape selected by the player
4.1		Pressing the switch button to start bouncing the fruit slices into the central tray	Switch button and animation projection	Starting the catapult game by bouncing randomly all the fruit slices
4.2		Pressing the switch button to kick any fruit slice into other player’s slingshot	Switch button and animation projection	Carrying out the kicking actions done by the players until no more fruit slices exist in the central tray
5.3		Stopping pressing the switch button when no more fruit slice exists in the central tray	Animation projection	Showing a game-ending image on the table screen

.

2.4. System Structure and Tools

The structure of the proposed digital puzzle gaming system is described in detail in this section.

2.4.1. The Hardware and Software of the Proposed System

As shown in Figure 8, the proposed system is mainly composed of three parts, as described in the following.

(1)

The tangible user interface (TUI)—this part is integrated with the interactive projection table through electronic sensors, and is composed of four switch buttons placed on the table top and four slide potentiometers attached on the lateral sides of the projection table as can be seen in Figure 2, as well as an Arduino Uno board embedded inside the projection table as shown in Figure 8. The players use the switch buttons and the slide potentiometers to communicate with the proposed system; signals generated by these devices are processed by the Arduino Uno unit, with the resulting signals sent to the computer for further processing to generate corresponding animation on top of the projection table.

(2)

The central processing unit—beside the computer, the central processing unit includes a cloud database in which system resources like the graphic and audio data for animation generation are kept. The graphic data of the game interfaces and the related elements of the fruit characters were created by use of the software package, Illustrator, and these data were taken as the input material into the software package, Unity, to carry out the production of animation and other game-playing content used by the proposed system.

(3)

The animation projection unit—the animation generated by the Unity is displayed on the table screen on top of the projection table via the use of the short-throw projector, as shown in Figure 2d. In addition, two audio speakers are utilized to yield music or sound accompanying the animation.

The major items of software and hardware equipment used in the proposed system are shown in

Table 8. The major items of software and hardware equipment used in the proposed system.

Software	Hardware
Unity 3D Adobe Illustrator Arduino Uno Solidworks *** KeyShot ***	Electronic sensors (switch buttons and slide potentiometers) PC computer Short-throw projector Audio speakers

*** The uses of these two software packages are described in Section 2.4.2.

.

2.4.2. Detailed Design of the Proposed System and Its Physical Interactive Devices

The operation of the proposed system is basically a combination of the major functions of the TUI supported by electronic sensors as well as the game animation supported by the animation projection unit. The two major functions are carried out on the screen on top of the projection table. The designs of the three major parts of the system, the interactive projection table, the electronic sensors, and the animation projection unit are described in the following.

(A) 

The Design of the Interactive Projection Table

In the design of the interactive projection table whose exterior shape looks like a tree, the animation projection distance and the height of the table for use by children has been taken into account and confirmed by 3D simulation in this study. Specifically, the body of the projection table was constructed by the use of dense boards obtained by laser cutting, as shown in Figure 9a. Additionally, clips were used on the wood to make the table more stable in structure, so that in the assembly of the table parts, no glue is needed to increase the mobility of the table.

Furthermore, the 3D software, Solidworks, was used for modeling the table structure, the software, KeyShot, was used to render the table appearance, and finally the construction of the table was completed by laser cutting, assembly, and painting, as shown in Figure 9b–e. For the construction of the top of the projection table, wood, acrylic boards, and projection film were used to compose the area required for animation projection on the tabletop, as shown in Figure 9f. Because the projection table may need be moved in the experiment field, the table bottom is equipped with rollers.

(B) 

The Design of the Electronic Sensors

The electronic sensor part of the proposed system is mainly composed of four switch buttons and four slide potentiometers. The players can control the switch buttons to communicate with the interactive content of the game. The switch buttons have different operating situations in different stages of the game, as presented in the aforementioned game-playing process and in the flowchart depicted in Figure 7. Specifically, pressing the switch button can carry out the actions of starting the game, confirming the selected color of the fruit, cutting fruit into a slice, and bouncing it onto a slingshot with a spring underneath, entering the catapult game, and pressing the slingshot to kick incoming fruit slices into others’ slingshots to get scores. In addition, sliding the potentiometer has the functions of selecting the correct color and the desired anthropomorphic shape of a given fruit. Three of these actions are illustrated in

Table 9. Three examples of actions carried out by pressing the switch buttons of the projection table.

Usage Context	Animation before Button Pushing	Visual Feedback after Button Pushing	Description
Entering the game			In the standby state with the initialization image shown on the table screen, press any switch button to enter the game.
Popping fruit slices up into slingshots			After the fruit color is decided, long pressing of the switch button will pop a fruit slice onto the slingshot in the central tray, if the color matching is correct.
Kicking fruit slices into other users’ slingshots			Press the switch button to kick away any incoming fruit slice into others’ slingshots to get scores; if it fails, the user will be out of the game.

.

The slide potentiometer module adopted in this study is a sensor that mainly relies on the brush in the module to sense the resistance. It can yield a total reading value of 1023 during sliding. After an experiment conducted in this study, in order to simplify the communication of the software Unity with the Arduino Uno unit, the total value of 1023 was converted into 225 in the Arduino Uno unit. This conversion also has the merit of making the reading value from the potentiometer more stable than the original reading which has an average error of ±4. Accordingly, the ranges for choosing a fruit color from the three given by the system are 0~85, 86~170, and 171~255, as shown in Figure 4; the two ranges for choosing an anthropomorphic fruit shape from the two provided by the system are 0~127 and 128~255, as shown in Table 5.

(C) 

The Design of the Animation Projection Unit

The visual animation shown during the game-playing process is presented on the top of the projection table through mirror reflection carried out by the short-throw projector, as shown in Figure 2d. The shortest distance that the short-throw projector can project is 80 cm, which was adopted as the height of the projection table. Additionally, the projection surface of the short-throw projector was placed horizontally, and the emitted animation content is reflected on the top of the projection table through the mirror surface.

(D) 

The Design of the Game-playing Process

After passing the first part of game playing, which includes color matching and anthropomorphic shape selection, the second part, namely the fruit catapult game, is started. By pressing the switch button, a fruit slice will bounce into the slingshot which appears in the central tray area. When firing the fruit slice by the slingshot for the first time, the button needs to be pressed for a longer time for the fruit slice to pop up randomly.

The speed for popping the fruit slices and the standby time for confirming the number of players (see Step (1.1) in the previously presented game-playing process) can be planned as external parameters of the system. In addition, the resource data for game animation stored in the cloud database (mentioned in Step (1.1) in the game-playing process as well) may also be changed. These parameters and the database content can be set in advance according to the different types of game requirements, like gaming theme, number of players, gaming situation, etc. This way of dynamic parameter or resource setting not only improves the flexibility of the proposed gaming system but also increases its novelty.

After the catapult game is over, the system will rank all the players’ final scores. The first place in the ranking results is represented by a golden crown, the second by a silver crown, the third by a bronze crown, and the fourth by a silver laurel crown, with all the crowns shown on the table screen at the end of the catapult game. This presentation of the ranking result is in line with the design criteria of children’s educational games, and the individual wins and losses are not the focus of the game, so the visual presentation of wins and losses through a ranking list is not adopted in this study.

3. Results

The main results of this study are described in this section, including those of the methods of observation, expert interview, and questionnaire survey. These results come from analyzing the data obtained from carrying out these methods in the experiments conducted in this study.

3.1. Exhibitions of the Proposed System for Field Experiments

The proposed gaming system “Tree of Wisdom—Color Matching and Touch” was publicly displayed at the Sun Moon Rise Kindergarten in Taichung city in Taiwan. The exhibition area mainly includes the interactive projection table and some posters. Each round of game-playing allows two to four players and lasts for 10 min. Each player can play two rounds of the game-playing process. In addition to the control of the visual animation and the physical interface, the game-playing process also includes auditory feedback to enhance the players’ sensory experiences. The behavior observation method was carried out during the game-playing process, and at the end, the parents or the researchers of this study gave oral questions to the players and filled in appropriate feedbacks on the questionnaire survey forms based on the children’s emotions and verbal answers.

A record of the experience process of four players of the proposed system in the exhibition environment is shown in Figure 10.

3.2. Analysis of Behavior Observation Results

In this study, the behavior observation method as described in Section 2.1.2 was applied in the exhibition environment for the aim of understanding the meanings and purposes of the children’s behaviors in the game-playing process. The observation of each player’s emotional performance was conducted from five viewpoints, namely, (1) activity, (1) environment, (3) interaction, (4) object, and (5) user, during the four major stages of actions in the game-playing process, namely, (a) fruit color adjustment, (b) anthropomorphic shape selection, (c) playing the catapult game, and (d) response to score ranking. The detailed observation items are listed in

Table 10. The items for behavior observation of the player’s emotions conducted in this study from five viewpoints.

Observation Viewpoint	Major Actions in the Game-Playing Process
	Fruit Color Adjustment	Anthropomorphic Shape Selection	Playing the Catapult Game	Response to Score Ranking
Activity	Select the fruit color by sliding the potentiometer and lock the color by a long press of the switch button where the longer the press, the bigger the fruit.	Change the anthropomorphic shape of the fruit by sliding the potentiometer.	Get scores by kicking fruit slices onto other players’ slingshots by pressing the switch button.	Show the score points with the ranking crown at the end of the game.
Environment	A public learning classroom where the proposed system was exhibited for invited children to share the game-playing activity in a joyful and pleasant atmosphere.
Interaction	Issue a sound effect if the selected color is wrong; else, enter the next game stage.	Choose a favorite anthropomorphic fruit shape and press the switch button to lock the shape.	Pop out incoming fruit slices to keep them out of one’s own slingshot.	Identify the score points of one’s own side by the color and splendor of the awarded crown.
Object	Table screen, slide potentiometer, and switch button	Table screen, slide potentiometer, and switch button.	Table screen and switch button.	Table screen.
User	Multiple players in a “mutual aid” relationship.		Multiple players in a “competing” relationship.

. The total observation time of each player’s was five minutes in which 1.6, 1.4, 1.2, and 0.8 min were allocated to the observations of the four stages of actions of (a) through (d), respectively, as shown in

Table 11. Allocation of times for observing the four major game-playing actions.

Major Game-Playing Action	Fruit Color Adjustment	Anthropomorphic Shape Selection	Playing the Catapult Game	Response to Score Ranking
Allocated time in 5 min	1.6 min	1.4 min	1.2 min	0.8 min

. A total of six different types of emotion were observed and recorded for each player in the 5-min observation period, as shown in

Table 12. Symbols representing the six types of emotion of each player.

Emotion Type	Excited	Pleasant	Surprised	Distressed	Frustrated	Nervous
Symbol

, in which each emotion type is represented by a distinct symbol.

In addition, a total of 58 children came to the exhibition site to play the games on the proposed system. Their emotions expressed during the game-playing process were observed and recorded by the researchers of this study using the symbols shown in Table 12. With the participating children being labeled as C1 through C58, part of the recorded data for children C1 through C6 are shown in

Table 13. The recorded observation data of 58 children’s emotions by the symbols in Table 12.

00.00			01.00					02.00					03.00					04.00				05.00
Time (5 min)
Game-Playing Action	Fruit Color Adjustment								Anthropomorphic Shape Selection							Playing the Catapult Game						Response to Score Ranking
C1
C2
C3
C4
C5
C6
. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .
C58

. Additionally, for each player, his/her emotional expressions represented by the symbols were counted and listed, resulting in

Table 14. The statistics of the recorded observation data of 58 children’s emotions.

Emotion Type	Excited	Pleasant	Surprised	Distressed	Frustrated	Nervous
Symbol
C1	7	13	3	2	0	0
C2	8	7	4	3	0	3
C3	11	10	4	0	0	0
C4	4	8	4	2	0	7
C5	6	14	3	2	0	0
C6	5	11	8	1	0	0
. . .	. . .	. . .	. . .	. . .	. . .	. . .
C58	6	8	8	0	0	3
Sum	443	425	264	109	50	151
Average	7.64	7.33	4.69	1.88	0.86	2.60

.

From the statistics shown in the recorded observation data of 58 children’s emotions listed in Table 14, as well as the textual records of in-field observations of the players’ mutual interactions during the game-playing process, the following conclusions can be drawn.

(1)

Among the statistics of the six emotion types, the sums of the first three positive emotions (i.e., the excited, pleasant, and surprised ones) are higher than those of the three negative emotions (i.e., the distressed, frustrated, and nervous ones), indicating that the children have played the games with positive emotions on the proposed system.

(2)

The average values of positive emotions are between 4.69 and 7.64, and those of negative emotions are between 0.86 and 2.60, indicating that the proposed system brings forth good gaming experiences to the participating children.

(3)

In the game process, children will remind and help each other when selecting the fruit colors and the anthropomorphic shapes, showing “mutual aid” relationships; during the catapult game and the scoring ranking step, they have “mutually competitive” relationships, and this kind of switching the children’s relationships through the game-playing context is thought to have a positive impact on their cognitive development.

(4)

In the meantime, the visual, auditory, and tactile interactions that the children experienced during the game-playing process promoted the children’s willingness to join the game, and the hands-on operations required to play the games brought forth more game exploration experiences to the children.

(5)

The children have positive emotional feedback on the dynamic selection of the anthropomorphic shape for the fruit in the game-playing process, which is similar to role switching encountered in people’s daily life.

3.3. Analysis of Results of Interviews with Experts

In this study, the questions asked in the interviews with the invited experts (introduced in Table 3 in Section 2.2.2) fall into three aspects, namely, (1) introduction of puzzle games into early childhood education; (2) adoption of interactive technology and experience activities in early childhood education; and (3) promotion of game learning for children, as shown in

Table 15. The summary of the results of the interviews with the experts.

Aspect	Questions	The Experts’ Opinions
Introduction of puzzle games into early childhood education	Why are puzzle games important for early childhood education?	The training brought by puzzle games can strengthen young children’s thinking. Puzzle games not only can retain the meaning of learning, but also can bring educational game content to young children. Puzzle games can reduce children’s feeling of boredom in learning by game-playing, thereby improving their willingness to learn.
	How should the play mode of the puzzle game be planned?	Game-playing experience of different senses may be added by incorporating lively, cute, or colorful elements in the game. Hands-on game-playing varieties such as puzzles, tangrams, and magic cubes may be incorporated into puzzle-related games.
Adoption of interactive technology and experience activities in early childhood education	What are the effects for learning by engaging children in interactive technology-related experience activities?	Young children at this age are very interested in video games, and so the content of the games can be diversified. Products with “interactive technology” elements, from the perspective of young children, will bring forth a “magic” feeling to children and stimulate their imagination.
	How should interactive technology-based experience activities be planned?	The design of device operation and game content should be as simple as possible, and it would be better if instructions could be added to each step of the game. It is necessary for children to reduce the psychological feeling of confusion when they first come into contact with games; therefore, the game screen should be presented in a simple way, and the content is planned to be rich.
Promotion of young children’s game learning	What do you think about the content of games for young children at this stage?	Too many sensor parts are included in game-playing, so the device configuration and the game-playing process may be reconsidered. Contextual or narrative game themes may be added.
	Do you have any suggestions for designing or modifying the game learning works for young children?	The visual presentation of the proposed system can be more embellished to make the game screen more vivid. It is suggested to make good use of animation to present the situation of the game and add more cute and moving things that are attractive to young children. It can be tried to understand the development of children at this age for a better design of the operation method and experience content of the game.

.

The first aspect mainly covers questions about the importance of educational games for early childhood education, and the means to improve the attractiveness of game content to young children; the second aspect includes questions about the effects for learning by engaging children in interactive technology-related experience activities and how such activities should be planned; the third aspect covers questions about how to take game learning as the main axis to construct or modify gaming systems suitably for children.

Based on the experts’ opinions expressed in the interviews as described in Table 15, the design of the structure of the proposed digital puzzle gaming system has been adjusted in this study. After the interviews, it was also confirmed that the introduction of interactive technology combined with puzzle game playing into early childhood education and learning is of positive significance. Compared with traditional textbooks, the learning content brought forth to children through game playing can enhance their willingness to learn, and the lively and vivid visual animation can also promote children’s motivations to participate in the gaming activity. The experts’ opinions obtained in the interviews as described above were integrated to draw the following conclusions.

(1)

Introducing digital puzzle games into young children’s learning can not only maintain the meaning of education, but also can reduce the children’s bored feelings that often arise during the traditional static learning process.

(2)

The game content should be simple to understand, and the game-playing process should be easy to operate without unnecessary steps.

(3)

Incorporating lively, cute, or interesting animation contents into digital games can enhance children’s willingness to participate and experience game-playing activities.

(4)

Integrating various sensory activities into the game design to create audio, visual, and tactile experiences can improve children’s game-playing experiences.

3.4. Statistical Analysis of Questionnaire Survey Results

Each of the 58 invited young children, after completing game playing on the proposed gaming system, was asked to fill out, possibly with the help of the parents or the researchers of this study, a questionnaire form about his/her background and feelings of the game-playing process.

3.4.1. The Design of the Questions for the Questionnaire Survey

The questionnaire survey conducted in this study includes 19 questions as shown in

Table 16. The questions asked in the questionnaire in this study and the statistical data of the Likert-scale scores of the answers to them.

Question	Content	Min.	Max.	Avg.	S. D.	(A)	(B)	(C)	(D)	(E)	(F)
						Strongly Agree (5)	Agree (4)	No Opinion (3)	Disagree (2)	Strongly Disagree (1)	% of Agreements (F = A + B)
Q1	I can play with switch buttons	2	5	4.66	0.71	77.6%	13.8%	6.9%	0%	1.7%	91.4%
Q2	I can operate the slide potentiometer precisely	3	5	4.72	0.61	81%	10.3%	8.6%	0%	0%	91.3%
Q3	I feel that the playtime flies quickly	3	5	4.78	0.53	89.7%	6.9%	3.4%	0%	0%	96.6%
Q4	When I encounter a difficult problem, I discuss it with my peers	2	5	4.26	0.94	58.6%	13.8%	22.4%	3.4%	1.7%	72.4%
Q5	When my peers encounter difficulties, I will take the initiative to help	2	5	4.43	0.95	70.7%	6.9%	13.8%	5.2%	3.4%	77.6%
Q6	After the game, I discuss with my peers the mistakes I encountered during the game-playing process	2	5	4.43	0.88	65.5%	15.5%	15.5%	3.4%	0%	81%
Q7	I like the way the anthropomorphic fruit moves	3	5	4.84	0.41	86.2%	12.1%	1.7%	0%	0%	98.3%
Q8	I can easily select a color to match that of the fruit	3	5	4.78	0.53	82.8%	12.1%	5.2%	0%	0%	94.9%
Q9	After the game, I can remember the color, name, and introduction of the fruit	2	5	4.66	0.76	91.4%	5.2%	0%	3.4%	0%	96.6%
Q10	I was able to play without guidance	1	5	4.31	1.09	67.2%	6.9%	17.2%	6.9%	1.7%	74.1%
Q11	I can finish the game on my own	2	5	4.60	0.81	77.6%	8.6%	10.3%	3.4%	0%	86.2%
Q12	I think the game is simple	3	5	4.74	0.51	77.6%	19%	3.4%	0%	0%	96.6%
Q13	I can understand the description of the game content	3	5	4.76	0.47	77.6%	20.7%	0%	0%	1.7	98.3%
Q14	I can feel that color is the main axis of the game	3	5	4.88	0.37	89.7%	8.6%	1.7%	0%	0%	98.3%
Q15	I am clear about how I play	4	5	4.79	0.40	79.3%	20.7%	0%	0%	0%	100%
Q16	I can push out other kinds of fruits from the game I played	3	5	4.84	0.45	87.9%	8.6%	3.4%	0%	0%	96.5%
Q17	I love the digital images in the game	4	5	4.95	0.22	94.8%	5.2%	0%	0%	0%	100%
Q18	I love the hands-on operations in the game-play process	3	5	4.91	0.38	94.8%	1.7%	3.4%	0%	0%	96.5%
Q19	I prefer to play with friends because I have played interactive games	3	5	4.88	0.42	91.4%	5.2%	3.4%	0%	0%	96.6%

. Furthermore, a five-point Likert scale [40] was adopted to design the answers to the questions, i.e., the five choices of “strongly disagree”, “disagree”, …“strongly agree”, with scores 1, 2, …, 5, respectively.

More specifically, after completing the game-playing process, the parents or researchers read the questions of the questionnaire to the children, and then filled in the appropriate options according to the children’s body movements, emotions, and facial expressions. A total of 58 valid questionnaires were collected, and the Likert-scale data of the answers to the questions are also shown in Table 16. The statistical analysis results will be described later in this section, including the reliability and validity of the questionnaire answers, as well as the evaluation of various perspectives of the effectiveness of the proposed gaming system for young children’s learning.

3.4.2. Adopted Methods for Analyzing the Reliability and Validity of Collected Data

In this study, the IBM software package SPSS (Statistical Product and Service Solutions) version 22 was used for analyzing the reliability and validity of the collected questionnaire survey data.

Reliability is about the consistency of the data, in spite of repeated measurements [41]. The reliability analysis in this study was based on Cronbach’s alpha value α [42] computed by the SPSS. When the computed Cronbach’s alpha value α is close to 1.0, the consistency of the collected data is nearly the greatest; when α ≥ 0.8, the data are usually considered to be sufficiently consistent; when α ≥ 0.5, the data are just acceptable in consistency; and in all of these cases, the data are regarded as reliable [43].

Validity is about the accuracy of a dataset, indicating the degree that the data express appropriately the concepts under consideration [41]. In this study, two methods were used for measuring the accuracy of a dataset, i.e., the Kaiser–Meyer–Olkin (KMO) measure of sampling adequacy and the Bartlett’s test of sphericity [44,45,46,47,48]. A KMO measure value larger than 0.7 in general indicates the acceptability of the accuracy of the collected data, while a significance level value smaller than 0.05 yielded by the Bartlett’s test of sphericity indicates generally that the dataset is accurate. When the results yielded by both of the two methods indicate the accuracy of the collected data, the dataset is regarded to be adequately related and suitable for further structure analysis [49].

3.4.3. Statistical Analysis of the Adequacy of the Collected Data for Structure Analysis

At first, the SPSS was used to analyze the collected questionnaire survey dataset presented in Table 16. The results are shown in

Table 17. The measured values of the KMO test and the significance values of Bartlett’s test of the collected questionnaire survey dataset.

KMO Measure of Sampling Adequacy		0.765
Bartlett’s Test of Sphericity	Approx. chi-square	564.617
	Degree of freedom	171
	Significance	0.000

where the KMO measure value is seen to be 0.765, and the significance value of the Bartlett sphere test is seen to be much smaller than 0.05 (specified as 0.000 by the SPSS). The two computed index values both show the acceptability of the accuracy of the collected questionnaire survey dataset listed in Table 16. In other words, the collected data are adequately related for further structure analysis.

3.4.4. Structure Analysis of the Collected Questionnaire Survey Data

The technique adopted in this study for structure analysis of the collected questionnaire survey data is to combine the uses of “the method of exploratory factor analysis (EFA) via the principal component analysis (PCA)” and “the varimax method with Kaiser normalization” [44,45]. Again, the SPSS was adopted to carry out the computations required by the two methods. The result is a set of groups of related questions, with each group of questions having a common property, called latent dimension or scale.

Accordingly, with the data in Table 16 as the input, the result yielded by such a technique of structure analysis is a rotation matrix as shown in

Table 18. The rotated component matrix resulting from the structure analysis of the questionnaire survey dataset.

Question	Factor 1	Factor 2	Factor 3	Factor 4	Factor 5
Q5	0.843	0.334	0.083	0.125	0.135
Q6	0.823	0.012	0.129	0.139	−0.076
Q10	0.707	0.080	0.350	0.140	−0.018
Q4	0.663	0.266	0.030	−0.228	0.356
Q12	0.504	−0.111	0.477	0.396	0.087
Q18	0.086	0.838	0.218	0.242	0.201
Q17	0.059	0.806	0.060	0.234	0.120
Q19	0.155	0.662	0.374	0.088	0.024
Q8	0.364	0.504	0.217	0.349	0.088
Q13	0.274	0.266	0.780	−0.027	−0.222
Q15	0.079	0.189	0.747	0.161	0.315
Q14	0.071	0.165	0.612	0.595	0.138
Q7	0.336	0.358	0.517	−0.147	0.178
Q9	−0.084	0.117	0.184	0.714	0.184
Q11	0.209	0.298	−0.078	0.652	0.078
Q3	0.167	0.431	−0.030	0.560	−0.091
Q1	0.354	0.041	0.341	0.052	0.718
Q2	0.338	0.112	0.042	0.394	0.697
Q16	−0.179	0.128	−0.029	0.033	0.671

, which shows that the 19 questions (regarded as variables) of the questionnaire survey can be divided into five groups G1 through G5 (i.e., can be categorized to belong to five factors) as follows:

G1 = {Q5, Q6, Q10, Q4, Q12};

G2 = {Q18, Q17, Q19, Q8};

G3 = {Q13. Q15, Q14, Q7};

G4 = {Q9, Q11, Q3};

G5 = {Q1, Q2, Q16},

where for every question in each group (i.e., for every variable on each factor), the corresponding absolute factor loading value (highlighted Table 18) is larger than 0.5, therefore, no question need be removed (i.e., no variable need be deleted after this way of structure analysis). Furthermore, the five factors labeled 1 through 5 in Table 18 yielded by the SPSS are just the aforementioned latent dimensions or scales, which are given the titles of (1) social development; (2) affective cognition; (3) information communication; (4) organizational thinking; and (5) interactive experience in this study, as shown in

Table 19. The structure of the questions grouped into five dimensions (scales).

Latent Dimension (Scale)	Label	Question
(1) Social development	Q5	When my peers encounter difficulties, I will take the initiative to help
	Q6	After the game, I discuss with my peers the mistakes I encountered during the game-playing process
	Q10	I was able to play without guidance
	Q4	After the game, I discuss with my peers the mistakes I encountered during the game-playing process
	Q12	I think the game is simple
(2) Affective cognition	Q18	I love the hands-on operations in the game-playing process
	Q17	I love the digital images in the game
	Q19	I prefer to play with friends because I have played interactive games
	Q8	I think the game is simple
(3) Information communication	Q13	I can understand the description of the game content
	Q15	I am clear about how I play
	Q14	I can feel that color is the main axis of the game
	Q7	I can finish the game on my own
(4) Organizational thinking	Q9	After the game, I can remember the color, name, and introduction of the fruit
	Q11	I can finish the game on my own
	Q3	I feel that the playtime flies quickly
(5) Interactive experience	Q1	I can play with switch buttons
	Q2	I can operate the slide potentiometer precisely
	Q16	I can push out other kinds of fruits from the game I played

.

3.5. Analysis of the System Effectiveness by the SPSS According to Questionnaire Survey Results

In this section, the effectiveness of the proposed gaming system for young children’s learning is evaluated. For this aim, first the reliability of the collected data should be verified before the data can be used. By the SPSS, Cronbach’s alpha values of all the collected questionnaire data as well as those of the questions covered by each of the five above-mentioned latent dimensions (scales) are computed and shown in

Table 20. The reliability of the collected questionnaire survey dataset and the respective reliability of the data of the questions belonging to each latent dimension.

Latent Dimension (Scale)	No. of Questions	Cronbach’s Alpha Value
(1) Social development	5	0.824
(2) Affective cognition	4	0.778
(3) Information communication	4	0.765
(4) Organizational thinking	3	0.580
(5) Interactive experience	3	0.666
Overall	19	0.871

. As can be seen from the table, the alpha values are all larger than 0.5, and that of the overall questionnaire dataset is 0.871. This means that both the consistency, or equivalently, the reliability of the overall dataset and that of each of the five datasets belonging to the five latent dimensions are confirmed. Therefore, they can now be used for evaluating the effectiveness of the proposed system from the perspectives of the five latent dimensions.

The details of such evaluations are too lengthy to be described here, and so are included in the appendix (named Appendix A) at the end of this paper.

From the evaluations of the system effectiveness from the five perspectives of social development, affective cognition, information communication, organizational thinking, and interactive experience shown in Appendix A, the following conclusions can be drawn.

(1)

Most players thought that the proposed games were easy to understand and simple to play.

(2)

The children’s feelings of the interactive games played on the system were positive.

(3)

The children enjoyed the rich audio-visual experience and the multimedia feedback of the proposed gaming system.

(4)

The children had positive experiences with regard to the design of the gaming process and the cognition of the game content.

(5)

Most children were confident that they could complete the gaming process and understand the basic structure and rules of the game.

(6)

The children are satisfied with the overall interactive experience obtained on the gaming system.

3.6. The Findings Derived from the Four Methods Adopted in This Study

For the evaluation of the effectiveness of the proposed gaming system, four methods, namely, prototyping, behavior observation, expert interview, and questionnaire survey, have been applied in this study. The evaluations of the four methods have been presented in the previous sections, from which the following findings can be drawn.

(1)

Through the behavior observation method, it was found that game playing on the proposed system makes the participating children feel excited, surprised, and happy with a positive emotional experience, that the children wanted to play more rounds after the gaming process is over, and that they could get familiar with the game content quickly, showing that the system is interesting and attractive to children.

(2)

Through the interviews with the invited experts, it was found that the proposed system is rich for children to experience hands-on operations in games, and that educational training brought forth to children by game playing has positive impacts on their cognitive development.

(3)

Through the questionnaire survey, it was found that the interactive gaming system with tangible user interface combined with animation has good usability for young children, and that after the children finished experiencing the game-playing process, they can clearly describe the interactive process and game content, showing that the children had a positive cognition and experience of the gaming system.

4. Discussions and Conclusions

4.1. Discussions

The aim of this study was to design a digital puzzle gaming system by interactive multi-sensing and simple tangible interfaces for young children’s learning in early childhood education. The gaming system was publicly displayed at a kindergarten, and a total of 58 children were invited to play the games on the system. The evaluations of the system have also been conducted, reaching some positive conclusions about the system that are described in the next section.

Most of the previous studies like those listed in Table 1 [23,24,25,26,27,28,29,30,31] emphasized the uses of interactive surfaces, symbols, and controls, and lacked the introductions of “games with themes”. In more detail, in several of the systems of the studies mentioned in Table 1, namely, Storytelling through Drawings [25], PuzzleTale [26], AR Tangible Interface [27], TangiSense [29], KidCAD [30], and The Tangible Toy [31], the computer vision technology was adopted as an interactive form, in which manipulations of additional objects were used. In contrast, in this study simple tangible interfaces are used, and the proposed digital puzzle gaming system can be played by just touching simple interfacing sensors (switch buttons and slide potentiometers) with two hands instead of manipulating additional objects.

Furthermore, in the other systems mentioned in Table 1, namely, A Cube to Learning [23], A Tangible Tabletop Game [24], and Magic Sticks [28], interfacing sensors were adopted for uses in playing interactive games, the designs and utilizations of diverse sensors were carried out, which create less rich audio-visual outputs. In contrast, more vivid audio-visual outputs were generated by the proposed gaming system, making the participating children feel excited, surprised, and happy with positive emotional experiences, showing that the system is more interesting and attractive to children.

In conclusion, including the comparisons mentioned above and the findings about the effectiveness of the proposed system, the following merits of the proposed system can be drawn.

(1)

The games of the proposed system are story-based with themes that are simple for the young children to understand.

(2)

A tangible user interface has been constructed to enhance the diversity of the game so that the young children can get visual, auditory, and tactile interactive experiences from playing the game.

(3)

The system has an interesting game-playing flow with lively, cute, and colorful elements in the visual design of the games.

(4)

The system was designed to include interactive multi-sensing techniques for the participating children to learn digital technology in their early childhood period.

In addition, some limitations on this study are as follows.

(1)

The proposed system was designed for use only by preschool children aged 4 to 6.

(2)

The operation mode of human–computer interaction with a tangible use interface was explored in this study.

(3)

The digital puzzle game was selected as the main topic for investigation, and physical operations were taken as the basis for system development.

4.2. Conclusions

A novel digital puzzle gaming system, named “Tree of Wisdom—Color Matching and Touch”, based on the techniques of interactive multi-sensing and tangible user-interfacing has been proposed for young children’s learning in early childhood education. The use of the tangible user-interface (TUI) in the proposed system creates a bridge for the children to communicate with the virtual world. The interface facilitates manipulation of multimedia objects via interactive technology. In this aspect, the idea of using an interactive projection table in the proposed system combined with tangible user interfaces has proven to be effective for strengthening children’s motor development and cognitive skills.

The methods adopted in this study include “literature review” and “prototyping” for constructing the proposed system, as well as “behavior observation”, “expert interview”, and “questionnaire survey” for assessing the effectiveness of the constructed system. Specifically, through literature reviews, relevant principles for designing the digital puzzle gaming system were derived, based on which digital puzzle gaming via an interactive projection table using TUIs as interactive media to add novelty of the game-playing process was implemented successfully in this study. The presentation of animation on the table screen and the dynamic uses of the switch buttons and slide potentiometers have created a gaming situation suitable for young children to gain multi-sensory experiences and learn useful knowledge.

The assessment of the system’s effectiveness through the methods of behavior observation, expert interview, and questionnaire survey as conducted in this study came up with the following major conclusions.

(1)

The design of a simple and physical interactive interface can bring forth a good gaming experience to participating children.

(2)

Rich visual dynamics and sound effects can enhance the users’ game-playing pleasure.

(3)

The introduction of digital puzzle games has a positive impact on young children’s learning in early childhood education.

Furthermore, the proposed interactive gaming system developed in this study, which is implemented by various digital technology techniques for multiplayer gaming situations, offers a novel experiencing platform for preschool children to play digital puzzle games that can improve the children’s abilities of cognition and hand-eye coordination. In particular, the digital audio and video content of this system can be easily replaced according to different game plots, and so can easily be expanded to implement other puzzle games for different applications.

Taking into consideration the conclusions and findings obtained through the expert interviews and the questionnaire survey of the users’ feelings about their performances on the proposed system, the following improvements on the proposed system are suggested for future studies:

(1)

strengthening the content of the game-playing process and combining more educational significance into the design to increase the richness of the system;

(2)

simplifying the vocabulary used in the game-playing process and improving the human factor in the system design to meet the learning need of early childhood education;

(3)

increasing the richness and diversity of the interactive interface design for the system;

(4)

expanding the system to include more forms of learning for early childhood education in urban and rural areas;

(5)

using more media information to provide young children with experiences of manipulating interactive technology with both entertainment and educational significance.