Keywords

1 Introduction

‘Do not let children lose at the starting line of life’ expressed most parents’ expectation for their children. Therefore, they would like to grasp any opportunity that may make children grow, even ‘playing’. They hope that playing ‘toys’ can allow their children to explore the world and develop their intelligence. ‘Toys’ are important partners that accompany children’s growth and are indispensables that comfort children and promote their sensory and mental development. The so-called ‘educational toys’, which emphasize that they can enlighten intelligence, stimulate brain development and develop intelligence, have been advertised in recent years. In fact, the selection of toys is highly correlated to development stages of babies and young children. Appropriate toys selected according to the development needs at different stages can not only inspire babies’ intelligence, train visual, auditory, tactile and other sensory functions and stimulate creativity, but also help physical growth and intellectual education. On the contrary, toys not in compliance with children’s stages of physical and mental development are not beneficial to their development and may do harm to them.

In babyhood and childhood, the physical and psychological developments of babies and young children experience rapid changes. Although their sensation and perception systems are not mature, there is significant progress in their development every month (Shaffer and Kipp 2013). From the perspective of toy design and intellectual education, since babies develop rapidly in babyhood, it is very important to learn about their perception and motor development and provide appropriate toys for stimulation in correct development months. For example, 1-month-old babies are at an early stage of visual development when their visual angle is only 15°, they are only interested in black and white pictures, they can only slightly raise their heads, and their heads move with their eyes. Only upon learning about this can designers design effectively according to such human factors and achieve the purpose of educational toys. However, it can be seen from baby toy design practice that most relevant design studies are only for school-age children; there are few studies on human factors for baby toy design. According to the Theory of Multiple Intelligences and Physical and Psychological Development in Babyhood of Gardner (2011), a professor at Harvard University and a developmental psychologist and education scientist, the intellectual education on babies at this stage mainly focuses on visual and auditory aspects, such as spatial vision, language, body kinesthetic, natural observation and music; since babies and young children are not yet fully developed, advanced intelligence aspects, however, are relatively uncorrelated. To conclude, the objectives of this study are to ensure that visual and auditory design is based on academic and theoretical basis and make toy design more rigorous to have more positive value to the physical and mental development of babies and young children. Therefore, this study attempts to obtain the related human factors in babyhood from the perspective of intelligent toy design and that human factors can be effectively grasped during corresponding toy design, so as to achieve useful and effective design. The following questions are studied: (1) What is the process of physical development at different stages of babyhood? (2) What are the characteristics of visual development at different stages of babyhood? (3) What are the characteristics of auditory development at different stages? (4) Any suggestions for toy design based on physical and mental development at different stages?

2 Literature Review

2.1 Overview of Stages of Human Development

The course of human life begins at the moment of conception and ends with death. In this process, there are changes in quality and quantity at physical, psychological and social levels. Such changes are not temporary or incidental, but a directional and structural continued progress to maturity; and such changes are interrelated (Santrock 2006). Scholars Shaffer and Kipp (2013) further divided each stage into six stages according to developmental changes as shown in Table 1. The babyhood from birth to 18 months is a stage with the fastest rate of physical development. Babies get to know the concept of things in the world to establish schema.

Table 1. Stages of human development
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2.2 Physical, Visual and Auditory Development in Babyhood

The physical development in babyhood mainly includes two aspects: (1) physical development - development of all body parts; and (2) motor development - brought about with physical development (Shaffer and Kipp 2013; Skelton 1997; Stoppard 2007). Newborns have basic sensory functions upon birth. They can perceive surrounding visual, auditory and olfactory stimulations and can response to such stimulations. However, the relevant physical and perceptual abilities in ‘babyhood’ may gradually get matured with the accumulation of experiences in physical development and learning process. Perception is the meaningful sense formed from the physical and sensory information integrated by the brain. The development of perception, together with physical development, memory and experiences, is closely correlated to individuals’ growth (Shaffer and Kipp 2013).

The cornea and crystalline lens in eyes are of transparent structure, thus light can be focused on the retina via the light-gathering effects of the two structures, stimulating photoreceptor cells to produce vision. Vision is the sense by which individuals distinguish the Light and shade, color, shape and other characteristics of external objects (Eysenck and Keane 2015). Babies’ visual functions begin to promote visual development with visual exploration in the process of growth and mechanisms that rely on experience. Therefore, mechanisms of innate abilities and experiences will jointly promote the development of babies’ visual system. The auditory sense is one of the most primitive sensory perception of humans and can be divided into three forms: language, music and noise (Shaffer and Kipp 2013). The auditory sense has developed to a certain extent in the fetal period. Especially at the end of pregnancy, the fetus is already sensitive to the sound of its mother’s voice and some external sounds and even feels that the sounds heard in its mother’s womb have a certain stabilizing power. Babies have some degree of auditory ability, including responding to sounds and trying to find the sound source (Shaffer and Kipp 2013). Therefore, when babies cry or are unhappy, they will gradually calm down when their mothers play some music often heard during pregnancy. See Table 2 for relevant concepts of sounds and music. Physical development and perception are necessary conditions influencing motor development. Therefore, it is important to learn about babies’ perception and motor movement and providing appropriate toys for stimulation.

Table 2. List of relevant concepts of sounds and music
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2.3 Educational Toys

Such toys promote, by edutainment, players’ sensory exploration and cognition of the world, including inspiring the development of language, music, logical/mathematical, visual/spatial, bodily/kinesthetic, curiosity, imagination and intellectual achievement (Frost et al. 2001; Ogata 2004). Besides, such toys also bring about joy, companionship and autonomy and improve memory, aesthetic ability and concentration (Goldstein and Goldstein 1994), thus are recognized by most educators.

3 Method

The objective of this study is to obtain the human factors for the design of educational toys for babyhood to make such design suitable for 0–18-month-old babies and ensure that the design of receive audio-visual stimuli is based on academic and theoretical basis. Since the objects in this study are not yet mature in mind and body, there are a lot of limitations compared with general study objects. Therefore, first of all, this study obtains the ‘physical and psychological development progress for babies in different months’ by document analysis and by widely collecting, reading and concluding from medicine, physiology, cognitive science and anthropology and other fields. Next, the deficiencies in the review results and toy design thinking are taken as the material source of ‘semi-structured’ interviews (expert interviews), which are carried out with four experts respectively, with interview results sorted out; finally, the ‘policies and suggestions for toy design’ are proposed on the basis of the ‘human factors for the design of educational toys for babyhood’ and toy design thinking as shown in Fig. 1 (Table 3).

Fig. 1.
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The research method used

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Table 3. List of experts
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4 Results

Since relevant contents are complex, we obtained the following results and suggestions by widely collecting, reading and concluding more than 100 pieces of relevant literature from medicine, physiology, cognitive science and anthropology and by expert interviews.

4.1 Physical Development Process for Babies in 0–18 Months

This paper sorts out the Physical Development Process for Babies in 0–18 Months (Table 4) according to babies’ physical and psychological development. The physical development of most babies is regular and can be used as the reference basis for babyhood toy development. However, every baby has a different constitution, thus there are still individual differences in physical development.

Table 4. Physical development process for babies in 0–18 months
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4.2 Arguments for the Characteristics of Visual Development at Different Stages of Babyhood

Babies’ visual functions begin to promote visual development with visual exploration in the process of growth and mechanisms that rely on experience. Therefore, mechanisms of innate abilities and experiences will jointly promote the development of babies’ visual system. Since various visual abilities in babyhood have different development in different growing periods, in order to help to understand such development and further apply such development in the development and design of toys, we further conclude and sort out the ‘visual ability processes in babyhood’ in this study. See Table 5.

Table 5. Visual ability processes in babyhood
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Since the wave length of soft yellow-green light is long, eyes are highly sensitive to yellow-green light and are not easy to be fatigue. In terms of colors, in the first 3 months after birth, babies can only recognize white and black; 3–4-month-old babies can recognize red, green and blue. Later, with the accumulation of life experiences, babies may have different color preferences in different periods. This cannot be judged according to physiological factors. With regard to shapes, 3–4-month-old babies can only recognize the basic contour of objects. Later, they will begin to recognize details and are especially absorbed in moving objects.

4.3 Arguments for the Characteristics of Visual Development at Different Stages of Babyhood

Normal newborns have auditory sense immediately after birth (Shaffer and Kipp 2013) and can ‘stare at the person who speaks’ (Rheingold and Adams 1980; Rosenthal 1982); and are most focused on high frequency sound (Ecklund-Flores and Turkewitz 1996). Thus, babies can quickly learn to recognize the words that they often hear. 4–5-month-old babies can turn their heads when someone call their names but have no response to other names (Mandel et al. 1995); when they are 7 months old, they can generalize the patterns learned from language to other sounds, such as pitch, the timbre of an instrument and the sound of an animal (Marcus et al. 2007). Therefore, from the perspective of cognitive learning, repeating simple nursery rhymes, singing sweet songs and saying loving words will be highly favorable to the development of auditory sense, emotion and movement. On the contrary, excessively loud, sharp, irritating or unpleasant sounds may scare babies. Their brain and auditory system will repel these sounds, which is extremely detrimental to brain development (Karmiloff and Karmiloff-Smith 2004; Stoppard 2007).

It can be concluded that babies’ auditory sense starts in the fetal period. In the process of auditory development, babies can recognize multiple sounds in surrounding environment and master human languages. Babies’ auditory susceptibility has significant individual difference. Some have higher susceptibility and that of others is lower, but such individual difference is not unchanging. In fact, babies’ auditory sense keeps developing under the influence of living conditions and education. Lastly, in order to help to further understand auditory development processes and apply them in toy development and design. We further conclude and sort out auditory development processes in this study. See Table 6.

Table 6. Auditory development processes in babyhood
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If babies are exposed to music early, the music elements in music tunes that vary in height, speed, and strength can better inspire the development of children’s sensory perception and music ability (Karmiloff and Karmiloff-Smith 2004). Babies’ musical ability first is that their auditory sense hears music and generates feelings. Then such delighted feelings drive them to find ‘sounds’ and make ‘sounds’ by themselves to experience the relationship between sounds and people, things, objects, time and space. Thus, such interests increase with time, leading to the music ability cultivation and skill learning. For this point, Moog (1976a, b) pointed out on the basis of a study on babies cognitive abilities: 0–4 months: babies are sensitive and feel safe to high frequency music and noise, thus women’s and children’s voices can make babies calm down; after 4 months: babies like ‘delighted music’ and ‘beautiful voices’: after 6 months: strong sounds cannot make babies physically move with music, but ‘delighted music’ and ‘beautiful voices’ can; 18 months: 10% of babies can physically move with music rhythm (Moog 1976a, b). Besides, relevant studies also proved that when babies are 2 months old, they can lie still and listen to music; when they are 2–3 months old, they can preliminarily distinguish ‘pitches’; when they are 3–3.5 months old, they can distinguish ‘timbres’; 5–6-month fetuses have music perception; when they are 6–7 months old, they can distinguish simple ‘pitches’.

Sinor (1980), an American scholar of music education proposed, according to the ‘cognitive-developmental theory’ of Jean Piaget, a developmental psychologist, the ‘musical development of children’, which shows that 0–1-year-old babies begin to develop the dynamic and timbre of perception, and listening and moving abilities of response. The musical activities before 1 year old emphasize tunes and intonation related to music, rather than linguistic speech on the rhythm of music. Babies can also distinguish different rhythms.

It can be concluded that music does soothe emotions. The frequency of music is very important in soothing music. Low frequency is for comfort. However, this does not mean always playing low frequency music to fetuses. The music should have some changes, such as the changes in tone and cadence. A cradlesong is soothing, but it should be accompanied by the hug from adults. A cradlesong should be slow with stable pitch, such as the stability of Baroque music, the rhythm of which is close to heart rate. The mind-inspiring music should be diversified, not too long, highly comparative and repetitive. Music for mental development should have design lesson plans and music with meaningful guidance. Babies’ audition is very sensitive, thus the volume of toys with sound should be below 50 dB.

4.4 Suggestions for Design of Acousto-Optic Toys Based on Physical Development of Babies and Young Children

For visual sense, although light can easily attract their attention, hurts can be easily caused. Therefore, light should be carefully designed. Please use indirect light. Among lights, blue light is terrible, thus do not apply it. It is suggested not to develop the visual sense of 0–3-month-old babies. Hanging toys can be added to babies above 4 months. Toys may not be dynamic and in black, white and warm colors with high saturation, such as red, yellow and orange. For babies above 5 months, toys may be dynamic to allow babies and young children to practice eyeball tracking.

For auditory sense, the sounds of music should be from real instruments with stable melody and range, for example, there are a total of seven tones, the range of which should not be too wide. The melody should be within one range without large fluctuations. The speed of music should be one beat in one second, that is, sixty beats in one minute. Generally speaking, such speed is in line with heart rate. For voice, mothers’ voices can be used (for example, when clicking the pictures of cars, “car” will be said) to enhance babies cognition. The adding to motherese to the sound feature of products can increase babies’ preference. Such motherese can also be interspersed in different paragraphs by playing motherese first to lead babies stare on left and right sides to promote their visual development. Since sounds have the synesthesia of colors and visual perception, the match of sounds and colors can be used to train the synesthesia of babies and young children. Meanwhile, the match of visual features with sounds, such as the match of a dog shape with barking, should be taken into account when designing toys for babies and young children above 12 months.

Finally, we propose the following summaries and suggestions for different stages:

  1. (1)

    0–3 months: this stage emphasizes the soothing sound rather than the soothing light/visual objects.

    For 0–3-month-old babies, since their visual sense has not been fully developed, the staring distance increases from 20 cm to 7 m, and the staring can last as long as 10 min, the stimulation development for this stage should be based on sound, rather than visual ability.

  2. (2)

    Above 4 months: addition of object space concept

    Babies above 4 months begin to develop synesthesia and 3D concept. At this stage, the combination of sounds and objects can be used to train babies’ sense of space.

  3. (3)

    5–12 months: learning of music and training of perception

    Babies and young children above 5 months can identify timbres, pitches, tones, melodies and simple tunes in music. Therefore, it is suggested to train babies’ music perception, including different timbres, rhythms and melodies.

  4. (4)

    Above 12 months: emphasis of the interaction between sound and movement

    Babies and young children above 12 months begin to have body movements, thus different music or sounds can be used to guide the learning of body movements of babies and young children at this stage.

5 Conclusions and Suggestions

This study enriched the relevant human factors for baby toy design by different academic literature review and expert interviews and proposed design suggestions for different stages. The results can be applied to the development of educational toys for babies. Therefore, it can be concluded from this study that the design of the educational toys for 0–18-month-old babies should be focus on the development of sound senses. If visual lights are used, please use indirect lighting; blue light is prohibited. Mothers’ voices are important for children. However, the design of few products on the market has applied mothers’ voices. It is suggested to apply such voices during design.