When does a child become conscious?
Physical and motor development in infancy and early childhood1
More recent research results on early childhood development have - at least in science - led to a greatly changed image of the toddler. While babies have long been considered passive, incapable of experiencing and acting, apart from the few essential services such as sucking and swallowing, it is now evident that babies already have amazing abilities (survival skills) immediately after birth. Not only are they naturally equipped for this, but they also show a pronounced need to familiarize themselves with the world in which they are born, to discover connections between their own behavior and environmental reactions and to influence the environment (Papousek 1989, p 113).
Although the innate reflexes dominate in the behavior of newborns, they are by no means exclusively "reflex beings"; ultrasound recordings have already shown spontaneous movements in embryos from the 10th week.
Elaborate studies have shown that the sensory systems for registering stimuli are astonishingly well developed at birth: newborns can hear, see and smell, they feel pain, touch and changes in position. And they show clear preferences for the human face (and for stimuli that at least resemble a face) and the human voice. A child can recognize the mother at an early age based on her physiognomy (Carpenter 1974), her voice (DeCasper & Fifer 1980) and her smell (MacFarlane 1975) (Papousek 1989, p. 113). It soon has some kind of conception of self and object: it can differentiate between itself and its environment in various sensory modalities, between self-contact and external contact, between self-generated sounds and sounds of the environment and between events that it causes itself , and which take place independently of him (Papousek 1989, p. 113).
In the following, the physical development will be briefly outlined and some findings on the development of selected perceptual skills and motor skills in earliest and early childhood will be presented. This seems obvious in view of the obvious and widely documented close connections between somatic, sensory and motor development. Naturally, however, cognitive performance - like all behavior - is linked to physical growth and maturation processes, and perception and motor skills are the basis for the development of intellectual abilities and thinking, especially language (cf. Piaget 1969). However, these psychological benefits will not be discussed in detail here.
The importance of movement for human development is obvious: only through movement can humans react to changes in their environment, affect them and deal with them. This applies to the most basic modes of locomotion and the simplest manual activities, but also to conveying the most subtle feelings and thoughts, e.g. B. by gestures or facial expressions and by speaking or writing. Targeted movements can only be carried out effectively if the necessary starting position of the body and limbs is guaranteed. The management and control of posture and movement is therefore one of the most important tasks of the central nervous system. The various sections of the central nervous system from the cerebral cortex to the spinal cord (the "motor centers") are responsible for this.
1. Physical development
The earliest childhood is characterized by rapid development processes, with body growth being particularly noticeable. However, the most dramatic development and growth processes take place before birth. From the fertilized egg cell a "new" person with more than 3 x 10 develops through cell division within 9 months12 Cells (written out 3,000,000,000,000), of which more than 2 x 1010 Neurons. Every minute of pregnancy, on average, more than 8 million new cells are created2 .
As impressive as this quantitative growth may be, what is much more fascinating is the fact that a multitude of different cells differentiate from a single cell, which arrange themselves in a meaningful way, form structures, interact with one another and ultimately form a viable organism. This extremely complex process is controlled by the genetic information of the genes, but is not independent of environmental influences. Environmental toxins, radiation, illnesses of the mother, her diet, drugs, medication and even the psychological state of the mother can affect the development of the unborn child - via the mother's organism.
Compared to other mammals, humans are born very "immature"; a normal course of pregnancy also leads to premature birth in humans. The human newborn is therefore particularly dependent on care. Nevertheless, the infant is by no means completely unprepared for its existence As soon as it is no longer supplied by the maternal organism via the umbilical cord, the infant has to breathe, take in food, excrete indigestible food residues and regulate its temperature (within limits) Register and use information about your environment, send signals to your environment, draw attention to yourself and make your first social contacts.
The newborn is approx. 52 cm long and weighs approx. 3.4 kg; there can be considerable deviations from these average values; on average, boys are slightly taller and heavier. The growth after birth is by no means continuous. The increase in length is 25 cm in the first year of life, 12.5 cm in the second, and slows down to 5 cm in the 6th year, but increases again at the beginning of adolescence and then comes to a standstill. The weight gain is approx. 6 kg in the first year of life, approx. 4 kg in the 2nd and approx. 2 kg in the 3rd. There are seasonal fluctuations in growth and it can be shown that stressors (e.g. illness, school entry) can lead to a slowdown in growth, which, however, are usually compensated by phases of increased growth.
At birth, the bones are still relatively soft and consist mainly of cartilage; the skull bones have not yet fully grown together. The storage of minerals solidifies the bones (ossification); this process is only completed by the age of 15. Bones are held together by ligaments and are connected by tendons and muscles; these must grow accordingly. The main function of the skeletal muscles is the contraction, i.e. the contraction or contraction while developing force. This consumes energy and generates heat. The contractions of the muscles that cause all of our movements are initiated and controlled by the central nervous system. Although all muscles are present at birth, they are by no means all functional, which is mainly due to the insufficient maturity of the nervous system.
The lower strength of bones in children means that their bones break less easily, while ligaments, tendons and muscles are more at risk.
The nervous system
The basis for controlling human behavior, performing voluntary movements, absorbing information and for all mental abilities is the nervous system, especially the brain. The brain and the spinal cord form the central nervous system (CNS), the rest of the nervous system, which ensures the connection between the CNS and the rest of the body, is called the peripheral nervous system (PNS). The most important functional building blocks of the nervous system are the nerve cells or neurons. But they are not the only building blocks that make up the brain and spinal cord. The neurons are embedded in a special supporting tissue made up of so-called glia cells. The glial cells are responsible for protecting and isolating the neurons from one another, and they appear to supply the nerve cells with nutrients and remove toxins. They also form the myelin layer that surrounds the larger axons and significantly increases their conduction speed.
The brain is made up of about a trillion (1012) Glial cells and 25x109 Neurons. Both types of cells each make up almost half of the brain's volume, 10-20 percent are filled by the extracellular spaces and the blood vessels.
Each nerve cell is connected to up to 10,000 others, which leads to an unimaginably high number of possible connections (1015), the length of the connections is estimated at 500,000 km - this with a volume of around 1650 ccm and a weight of 1.5 kg (for adults). In the cerebral cortex, which is characterized by a particularly high concentration of nerve cells, there are 100,000 neurons in every cubic millimeter3 . The human brain is considered to be the most complex structure in the world.
Of all the organs, the brain is that which, in terms of mass, corresponds most closely to the adult state, possibly with the exception of the eye (Tanner 1970, p. 119). At birth, (almost) all the nerve cells in the brain and most of the necessary connections are already in place. Nevertheless, at the time of birth, the brain mass of 300 to 400 grams is only about 1/4 that of adults. At 6 months the brain weight is almost 50%, at 2 1/2 years 75% and at 5 years 90% of the adult brain. For comparison: the total body weight at birth is 5% and at 10 years 50% of the weight of an adult.
The growth of the brain is due to the fact that the nerve cells grow and many of their processes and connections are only formed after birth - under the influence of the sensory stimuli flowing into the brain, but also the neuronal activities of the brain itself. - However, many of the already existing connections between nerve cells broken down again in the course of development; the number of links appears to be greatest among two-year-olds. The greatest increase, however, is based on the formation of new glia cells, which increase the efficiency of the brain without being directly involved in the ongoing information processing processes.
2. First activities and reactions of the infant
Sleeping, screaming and eating are the most essential and obvious "activities" of the newborn. First of all, it sleeps most of the day, it can scream from the beginning to draw the attention of its caregivers, very emphatically, to itself. and he can take liquid food (breast milk or bottle-fed food). But in addition to these ostensible and essential behaviors, the newborn already has a multitude of abilities that enable him to grow into a person who is increasingly able to live his life In the course of the first two years of life, these are primarily the ability to take in information about the environment (perception) and to learn to control one's posture willingly, to grasp and manipulate objects and to move on one's own.
Newborns sleep about 16 to 17 hours a day, spread over 7 or 8 sleep periods. The sleeping and waking phases are evenly distributed between day and night and follow a roughly four-hour rhythm (with three hours of sleep and one hour of being awake). In the course of development, the states of sleep and wakefulness concentrate on fewer periods of correspondingly longer duration, whereby the daily sleep time is generally shorter (Zanden 1985, pp. 128-131). If the duration of the sleep phase is around four hours at the age of two weeks, it increases to seven hours towards the end of the first year of life (Anders & Keener, 1985, quoted from Maier, Ambühl-Caesar & Schandry 1994, p. 55) . The total sleep duration at this point in time - with large individual differences - is approx. 13 hours, at the end of the second year of life 12 hours per day.
Most physiological parameters in humans (and animals) are subject to diurnal fluctuations for which clear 24-hour rhythms can be demonstrated (so-called circadian rhythms). In newborns there is little evidence of the presence of such circadian rhythms, not even for the sleep pattern; only at eight weeks there is a tendency to solidify sleep periods at 25-hour intervals. From 16 weeks onwards, the onset of sleep is set to around a 24-hour period (the child now falls asleep at around the same time every day) (Kleitman & Engelman 1953, Mills 1974, quoted in Maier, Ambühl-Caesar & Schandry 1994, p. 57).
In the first few months, the infant's behavior can be described according to the following categories (see also Rauh 1983, p. 85):
- Sleep / wake and agitation and calm states. First of all, at least three stages of activity can be distinguished: wakefulness, active sleep and peaceful sleep (Maier, Ambühl-Caesar & Schandry 1994, p. 54). Other authors differentiate further and differentiate between six levels of activity (from deep sleep to screaming, Rauh 1983, p. 85). Right from the start, there are considerable differences in the distribution and characteristics of the various forms of condition between individual children.
- Sleep / wake and arousal and calming cycles. The sequence or alternation of the various arousal phases is also characterized by large inter-individual differences. In the first few weeks, the processes begin to stabilize and change under the influence of external clocks.
- Motor reactions. Random, undirected movements, which are interpreted as signs of motor restlessness (kicking), spontaneous but (apparently?) Intended movements (lifting of the head) and clearly structured vegetative and motor reflexes can be distinguished.
- perception and learning. Recent studies of the newborn's ability to perceive and learn have led to astonishing results. These achievements can be interpreted as proto-social perception and learning processes, because they serve almost exclusively to attract the attention of the caring adult (and thus to ensure his or her survival). Alertness and optimal viewing distance (approx. 20-25cm) provided the newborn reacts intensely to human faces and the slightly raised human voice and the human speech rhythm; it can localize speakers (primary coupling of hearing and looking) and it reacts to objects approaching but not receding; it calms down through absorption (touch, warmth), but also through vestibular stimulation (carrying around, rocking, rocking).
- Socially interpreted signals from the infant. Many of the infant's behaviors are interpreted by adults as social signals and ensure the beginning and continuation of social interaction. These include: eye contact, smiling, snuggling up to, screaming, turning away, searching and grasping reflexes, but also the child's appearance.
- interaction and communication games. Right from the start there have been approaches to interactive behavior between caring adults and the infant. This shows a synchronization of the infant's rhythmic and facial movements with the adult's speaking rhythm and the infant "imitates" certain adult behaviors (e.g. sticking out the tongue), which, however, differs from the later imitation behavior. But adults also imitate the behavior according to the infant, she changes voice and language and "instinctively" chooses the optimal eye relief for the child - without being aware of it.
Characteristic of the newborn is its "closed" posture, all joints are curved, arms and legs are drawn, the fists are closed, the toes are also drawn. In the prone position, the pelvis is raised, the knees are drawn under the stomach, the arms are drawn Next to the head. Extension movements in the hips and joints are rare, but become more frequent in the first few weeks. The upper and lower extremities are also curved in the supine position. This position is a result of the greater tension in the flexors compared to the extensor muscles. In the abdomen - and in a supine position, the child spontaneously turns his head to the side, in the prone position some newborns manage to lift their head a little, but generally the head cannot be held at first.
If the baby is lifted up by the arms from the supine position, the head is initially balanced a little, but then falls back. The arms are slightly bent at the elbows, and in a healthy child you can feel an equal amount of resistance in both arms. The symmetry in posture and movements is considered a sign of healthy development.
If the child is held seated, the entire back of the newborn is rounded (the child "sags"). In the following weeks, the upper part of the back is initially held more straight.The head is first balanced briefly in this position, but then tilts forward.
3. Motor development in the first months of life
In the beginning there is the reflex
Although the newborn is more passive in its behavior and spends most of the time sleeping, it is by no means immobile. The first noticeable movements observed in newborns can be divided into two types:
- Random, undirected movements that are interpreted as signs of motor restlessness and discomfort (kicking) and
- Purposeful, clearly structured vegetative and motor reactions that represent purposeful but involuntary responses to certain stimuli; these are the so-called innate reflexes.
In addition, spontaneous but (apparently?) Intended body movements (lifting the head, eye movements) can be observed, which are initially very weak and only gain importance later. - However, the reactions mentioned are not the first movements of the child, rather motor development begins before birth; From the 10th week of pregnancy onwards, spontaneous movements of the embryo can be detected using ultrasound recordings. From the 5th month of pregnancy onwards, movements of the fetus can occur4 are clearly felt by the mother and they become increasingly intense as the pregnancy progresses.
Some of the reflexes that can already be triggered at birth have lost their importance in the course of human development (grasping reflex), others are still essential for the survival of the newborn, e.g. sucking reflex, inspiratory reflex and swallowing reflex. The child must bring these skills with them, there is no time to learn them, without these skills they would starve or suffocate.
Most of these reflexes disappear again after a few weeks or months, as the cerebrum and cerebral cortex increasingly gain the upper hand over the innate automatisms and take control of the movements. Now the child can learn to plan and control his movements at will. Without a weakening of the earliest reflexes, further advances in movement possibilities would be hard to imagine. How should the child practice grasping and manipulating objects when they reflexively grasp an object as soon as it touches the palm of the hand?
However, not all reflexes are eliminated in the course of development; some accompany and benefit us for a lifetime, e.g. coughing, sneezing and blinking reflexes.
Reflexes are essential indicators of the maturity and functionality of the child's nervous system. As a matter of routine, the physical condition of the child is checked immediately after delivery at the initial examination of the newborn (U 1) and the reflex strength is assessed in the so-called APGAR test (see Table 1). During the preventive medical check-up U 2 (between the 3rd and 10th day), the state of health and the reactions are examined again in more detail, including checking the sense of balance. - Further preventive examinations are in the 4th-6th Week (U 3), 3-4. Month (U 4), 6.-7. Month (U 5), the 10th-12th month (U 6), and between the 21st-24th month Month (U 7) planned. The last preventive examinations U 8 (43.-48 months) and U 9 (60.-64 months) take place in the 5th and 6th year of life.
If necessary, however, significantly more reflexes can be checked, e.g. using the Brazelton Neonatal Behavior Assessment Scale, which includes 20 reflexes. The moment of stepping up and the strength, the evenness on each side of the body (e.g. in the case of an asymmetrical tonic neck reflex) and the extinction of the respective reflex are of diagnostic importance. In the event of deviations from the "normal" course of development, there is a suspicion of neuronal disorders.
Table 1: APGAR index (according to Oerter & Montada 1987)
The newborn is assessed in the first, the 5th and the 10th minute after birth according to three assessment levels (0 = not present, 1 = weakly present, 2 = normal) with regard to:
1. Skin color
2. Uniformity and type of breathing
3. muscle tone
4. Reflex triggering
5. Heart activity
A maximum value of 10 means: healthy child with regular heartbeat, strong screams, well-developed cough reflex and pink skin color.
In view of the large number of known reflexes, we can by no means describe all or most of these reflexes here; in addition, the number of reflexes described increases steadily with intensive research into the behavior of the newborn. A description of the essential reflexes and indications of their diagnostic relevance can be found in Scheidemann 1974 (p.547-552) and Scholbach 1974 (678-688), an overview in Hellbrügge et al. 1978 (p. 24f). A distinction is made between tonic reflexes, spinal reflexes, adjusting reflexes, statokinetic reactions and balancing reactions to maintain balance. Tonic reflexes are brain stem reflexes and cause a sustained contraction of certain muscle groups (e.g. grasping reflex). Spinal reflexes are controlled via the spinal cord and coordinate the movements of mutual extremities (e.g. walking reflex, flight reflex).
Set reflexes are tied to a functional midbrain and enable normal posture to be regained (labyrinth set reflex LSR). Statokinetic reactions are complex automatic movement reactions that are triggered by stimulating the organ of equilibrium (Moro reflex). Balancing reactions to maintain balance are also triggered by irritation of the organ of equilibrium, but result in balancing movements of the body (support reaction of the arms when threatening to tip over).
We want to limit ourselves here to the exemplary description of a few reflexes and reactions that can be triggered in the newborn, which can also be easily observed in everyday contact with the infant. The period in which these reflexes can normally be triggered is specified in each case.
Search reflex: If the child's cheek is touched (with the mother's nipple or with the finger), it turns its head in the right direction with the following suction movement. The search reflex can be triggered up to the 3rd month, after which the child is able to perceive, recognize and consciously control the food source.
Sucking reflex: Touching the lips or the oral mucosa triggers suction movements followed by swallowing. If a child did not manage to do this in the past, they had to starve to death; today they can be fed through a tube if necessary. The sucking reflex is detectable up to the 3rd month.
Grasping reflex: When the palms of the hands or the soles of the feet are touched, the fingers or toes are bent and an object can be grasped. In some newborns, the grasping reflex is so strong that they cling to the fingers of an adult so tightly that they can be pulled up for a short time. This spectacular performance is also known as the Darwin reflex. The hand-grasping reflex disappears in the 3rd to 5th month and is then replaced by (willful) grasping, the foot-grasping reflex can be demonstrated up to the 9th month.
Creep reflex: If the child lies on its stomach and pressure is exerted on the sole of the foot, the child begins to crawl as if it were trying to flee. This reaction can be triggered up to the 2nd or 3rd month.
Moro reflex (Clutching reflex): This reflex is triggered by shaking (strong knocking on the surface), abrupt change of position (briefly letting the head fall back), and fright. Arms, hands, fingers are brusquely spread apart and immediately brought back to the body while bending at the same time (as if the child wanted to cling to). Under certain circumstances, a first phase (which is very short in the mature newborn) can be distinguished in which only the spreading movement is shown without a subsequent movement of the clamps. As a vestibular reaction, the Moro reflex can be clearly triggered up to the 3rd month and weakly triggered by the 6th month.
Standing reflex: The upright newborn baby stiffens his legs when touching the surface with his feet. This tonic form of the support reaction is gradually replaced in the 4th month of life, so that from the 8th month onwards, the legs bear the weight of the body with full load on the soles of the feet when the trunk is supported.
Crying reflex: If the newborn is held in an upright position and one foot touches a flat surface, it lifts the other foot, as if to stride, and sets it down again forwards past the other foot if one follows the trunk. The walking reflex subsides in the 2nd month. - This could possibly be related to the fact that the head and legs are too heavy to perform the striding movements. The walking movement can also be triggered later by means of suitable experimental arrangements. The walking reflex can therefore be seen as an early “rhythmic behavior pattern” that also triggers the kicking movement in the supine position and from which free walking develops (see Rauh 1998, p.237).
Although the course of the reflexes is largely fixed, at least rudimentary exercise or learning processes seem to play a role even with such automated movement sequences. If the infant wants to ingest food, at least three activities must be balanced: sucking, swallowing and breathing. The child can do this best if he has the opportunity to suckle in the first few minutes or hours. If this experience is delayed for more than 6 to 24 hours, everything will not work out that easily. Only 48 hours after birth is the child able to suckle as skillfully as in the first hours of life. Later on, food intake becomes more and more successful and the child is more and more sure to find the mother's breast or the bottle. - Sucking, as inherited physiological mechanisms that functions excellently and runs as unchangeable automatisms, also requires a certain amount of practice; reflex behavior is also capable of gradual adaptation to external reality (Piaget 1969, pp. 39-52).
In addition to the reactions described so far, infants are capable of another amazing achievement: They try to mimic behavior. If you stick your tongue out to a baby who is about a week old, it reacts - by sticking out your tongue too! In such "attempts" it is advisable to hold the child upright and support the buttocks and head firmly and securely; this is the posture in which the child can observe his surroundings most attentively and shows the greatest willingness to react. His own face should be about 20 cm from the child's face, the distance at which the newborn's visual acuity is optimal. The fact that infants are already able to mimic the behavior of others has until recently been disputed by scientists as well; this must be done the child first perceives the behavior of the adult, interprets what has been seen and converts the visually recorded information into motor behavior, which is difficult to imagine without the assumption of an at least partially functional cerebral cortex.
The fact that the infant is able to perceive that the person opposite is sticking out his tongue is astonishing enough - not to mention the reaction he then shows. - It is difficult to understand how this coordination of equivalent information in the visual and motor system succeeds in the first week of life, for which the visual information has to be converted into a corresponding motor action program. It is therefore assumed that the two systems (the visual and the motor memory) are not yet separated, so that a (still imprecise) common coding can take place and thus the visual information immediately triggers a motor program (Conolly & Jones 1970, after Oerter 1989 , P. 49). With this assumption, however, it needs to be explained why most visual input apparently does not trigger any motor output.
Before we describe the further development of the voluntary motor performance of the child, the question of how well children are able to absorb information from their environment should first be discussed.
4. Perceptual development
The knowledge about our environment and the processes in our body that is necessary for survival is provided by special sensory organs, which, however, can only ever grasp a certain section of the information available. This information is passed on to the central nervous system, there “processed” and ultimately integrated into the image of the world that is accessible to us and into our conception of ourselves 5. The sense organs can be divided into exteroceptors, which provide information about the outside world, proprioceptors, which register the position and movement of our body, and enteroceptors, which provide information about mechanical and chemical events in the intestines.
The most well-known sense organs are the eye, the ear, the taste organ of the tongue, the olfactory organ of the nose, the tactile and temperature organ of the skin and the nociceptive system (the "pain organ"). In addition, the sense of balance provides us with information about gravity, ( above-below) and via linear acceleration and rotational acceleration. We receive information about movements of the body and body parts and the position of body parts through the so-called "depth sense", whose sensors are in the muscles, joints and tendons, but also in the skin.
When researching the performance of the sensory organs, two approaches can be distinguished:
Objective sensory physiology examines which stimulus affects a certain sensory organ, which changes this stimulus causes in the special receptor cells, how these changes are converted into a neuronal impulse pattern and how this impulse pattern is processed in the sensory areas of the brain. Subjective sensory physiology or perceptual psychology, on the other hand, examines the sensations and perceptions that trigger the activities of the sensory organs in human consciousness (e.g. which wavelength creates the impression "red", from which temperature water is perceived as "painfully hot").
In the last few decades, research in the field of perception has taken a tremendous boost, with - according to its importance for humans - the main interest is visual perception, followed by studies on hearing; on the other hand, there are only a few studies on the sense of touch, smell and taste (which, however, are of the greatest importance for newborns in particular). A number of methodological problems arise from such investigations, particularly for very young children. On the one hand, the waking phases, in which the sensory performance of infants can be checked, are very short. Because of the restricted behavioral possibilities (you cannot ask the children what they see), complex research methods have to be used. Visual acuity, which is defined as the limit of the eye's ability to resolve two closely spaced lines as such, is determined in infants by the fact that they are offered a black and white bar pattern and a uniform surface at the same time. If you look at the bar pattern significantly longer than the homogeneous surface, it can be assumed that your visual acuity is sufficient to perceive the bar pattern. Only in this case do these patterns appear more interesting to them and attract their attention more than a homogeneous gray surface. This approach assumes - quite rightly - that infants concentrate on more interesting things.
We cannot go into the individual methods used to determine sensory performance here (Pieper 1979, pp. 21-24 for a general overview, detailed information from Maier, Ambühl-Caesar, Schandry 1994) limit material results; we are essentially referring to the reviews by Nickel (1972), Pieper (1979), Zaichkowsky, Zaichkowsky & Martinek (1980), Banks & Salapatek (1983) and Maier, Ambühl-Caesar & Schandry (1994).
It is currently considered certain that all human sensory systems are fundamentally functional even in the newborn. Biological structures that are still immature (e.g. retina and optic nerve) improve rapidly in the first few months of life, and the sensory thresholds approach those of adults in the first year of life (Kaufmann-Hayos 1989, p. 410). The close connection between perception and motor skills becomes clear when an infant - long before he is able to move forward independently or to grasp an object - moves his eyes, head and upper body in order to fixate on a face or an object and to look after them .
The visual perception performance is presented separately for the different qualities or categories of perception such as "brightness", "color", "shape", "depth" and "movement", since these perceptual qualities are processed by different neurological systems in clearly separated brain regions takes place that become functional at different times.
The distinction between different brightnesses is one of the basic services of visual perception, without which no perception of contrast or shape is possible.More recent research results suggest that the eye is able to perceive differences in brightness immediately after birth and that the perception of brightness increases sharply in the first 20 days after birth and then approaches that of adults by the 60th day; the development of the perception of brightness is therefore completed in the course of the first two months.
Even at the age of two months, children can correctly distinguish the colors red, orange, green and blue from white, regardless of the luminance, but this is not yet possible for the colors in the yellow-green and purple areas. By the age of three months, children can also distinguish white light from blue-green color lights, and the conclusion is that children already have normal color vision at this age.
By the age of five to six, children can easily distinguish between colors of different brightness and saturation. The inability to correctly name colors, which can still be observed in kindergarten age, is therefore less related to color vision,
but rather with whether or not corresponding terms are available.
The child can already perceive shapes and patterns in the first month of life; with medium brightness, the optimal distance from his eye, in which he can see quite clearly, is around 20 cm. - Interestingly, this is the distance between the faces of mother or father and child that they create when they turn to their child and make eye contact with him (this is the so-called optimal dialogue distance, Papousek 1989, p. 116). It does not matter whether the parents shake the child up or whether it is lying down, they always choose this distance, which is optimal for the child, but by no means for the adult. When caring for the child, on the other hand, adults are about twice as far away, which corresponds to the reading distance. Incidentally, both parents, but also other caregivers, try hard to make eye contact with the child from the first contact.
In addition to faces, vertical contours in particular initially attract the attention of newborns; the size of the form elements is particularly decisive for the child's attention, then the number of form elements and their arrangement become important. At two months, the perception of shape changes: Now the children begin to pay more attention to features within the contours of the shape. Faces are no longer fixed in the area of the hairline or chin, but mostly in the area of the eyes. Obviously, this change takes place very suddenly. At six months of age, children can recognize the identity of a form in various presented positions; however, children up to pre-school age have difficulties distinguishing the same shapes due to different spatial positions (e.g. the same triangles either on the top or on the base line); it is particularly difficult to distinguish between a shape and its mirror image. - Even at school age, the letters b, d, p and q are often mixed up.
Four to six year olds are not able to recognize lines of certain angles of inclination; this only works with horizontal and vertical lines. However, this is more of a memory problem, since when presented at the same time, differently inclined lines can very well be distinguished from one another.
There is a close relationship between shape perception and visual acuity. In the older literature one usually finds the statement that newborns can only differentiate between very rough shapes. In contrast, more recent research results show that babies between one and seven days old have around 1/8 of the visual acuity of adults and at six months their visual acuity is approximately the same as that of adults. This is at least true if the distance between the eye and the object is within certain limits. However, Pick & Pick (1970, p. 792) refer to results according to which visual acuity reaches its maximum around the age of ten.
These findings for differentiating between shapes and colors are in agreement with anatomical studies, according to which the structure of the retina in 7-month-old infants largely corresponds to that of adults (Maurer 1975, after Pieper 1979, p. 25).
Some things are more likely to catch newborns' attention than others. We have already indicated the interest of babies in human faces or images of faces, including schematic ones. Accordingly, z. For example, it can be shown (according to Vander Zanden 1985, p. 139) that newborns turn more to patterns than colors, more facial-like than other shapes, more "complex" than "simple" shapes. Fantz 1963 also found that newborns at the age of Looking at a schematic black and white picture of a face 10 hours to 5 days longer than a piece of newspaper, a piece of newspaper longer than a black and white target, and this target longer than a solid red or white or yellow target - It could be natural that color vision at this early age is not yet sufficiently developed to perceive the colors used.
In the case of older children, the question of whether they are more oriented towards shape or color characteristics can be checked by asking them to select the one of two figures that corresponds to a comparison figure. One of these figures corresponds to the comparison figure in terms of color and the other in terms of shape. In the age groups four to nine years, the form is usually preferred as a criterion, this preference increases with age.
Perception of moving objects
As early as two days of age, the eyes of babies follow e.g. a moving face or a white card over a short distance. With a month, the gaze follows a moving object over an angle of 90 degrees. Later the child also begins to observe the movements of his arms and legs. In the first 3 months, babies look at moving objects longer than they look at stationary objects. If a moving object behind a screen first disappears and then reappears on the other side (e.g. a toy train), children after a few demonstrations show anticipatory eye movements to the point in question as early as the second month of life. These observations are regarded as early signs of the constancy of the object, but can also be used as an indication that the children grasp the structure of the course of events (Kaufmann-Hayos 1989, p. 411).
By means of suitable test arrangements it can be shown that already 3 year olds intuitively know quite well about the trajectory of thrown objects (Wilkening, F, Huber, S. & Cacchione, T. 2006). Correctly anticipating movements of objects and reacting accordingly - e.g. if a ball is not thrown directly at the child and he wants to reach the ball - only succeeds at the age of six to eight and is initially only very imperfect. Only ten year olds are able to do this (cf. Zaichowsky, Zaichowsky & Martinek, 1980, p. 72). - However, our own observations suggest that with sufficient experience, even younger children can coordinate their own movements well with those of moving objects, e.g. B. in tennis, soccer or basketball.
Distance vision, depth vision and space perception
Distance and depth vision are closely related to binocular vision, especially at close range, whereby the information about the differences between the two retinal images is used. Whether distance and depth vision is innate, developed or learned as the nervous system matures, is still controversial.
The results of empirical studies indicate that at around 20 weeks, children’s deep vision is already sufficient to distinguish whether an object is inside or outside of their reach. At this age, children also show reactions when an object comes towards them; such a reaction cannot yet be observed at 14 weeks of age.
At around six months of age, children’s deep vision is sufficient to recognize an abyss as dangerous and to avoid it. This can be shown by investigations on an apparent abyss ("visual cliff"). This test arrangement simulates an ecologically significant environmental situation (Gibson 1969): Half of a table with a glass plate is underlaid with a chessboard-like pattern, the other half lets you see the patterned floor at a depth of one meter. This creates the impression of an abyss. It is checked whether children crawl from the "safe" side to their mother, who lures her child with a toy on the "deep" side Of course, this experimental set-up only allows statements if the children are already able to move around independently. However, it can also be tested whether children show fear reactions when they are placed on the "deep" side. Interestingly, children avoid that too Abyss, if you can convince yourself of its strength by tapping the glass surface above the abyss e are guided by their visual impression that signals danger and not by their tactile perception. - Or they do not take any risks with contradicting information and prefer to stay "on the safe side".
At the latest with the ability to crawl around independently, the child develops an idea of space, ie it learns to judge its location in the frame of reference "space". When locating objects, the point of reference is one's own body; this "egocentric attitude" to space dominates for a longer period of time Time. Piaget & Inhelder (1971) found that children do not develop a full understanding of perspectives until the age of nine to ten. Before that, it is very difficult for them to put themselves in someone else's position, e.g. when looking at a model of a landscape. Other authors, on the other hand, report that this already succeeds four-year-olds if the framework conditions of the experiment are changed, e.g. by covering one's own perspective. - The results of the spatial conception are definitely dependent on the complexity of the stimulus material, the relative position of one's own viewing angle to the required viewing angle, the type of performance required (arranging objects, selecting images) and the person of the experimenter.
Constancy performance is essential for finding one's way around in the environment and for developing the concept of an object. The child must recognize that an object is the same despite a changed distance, lighting and perspective (object constancy) and that it also exists when it cannot be perceived (object permanence).
Although the retinal image changes when we move our head, we do not have the impression that the environment is moving. We still recognize objects that change their position and distance and thus their image on the retina as the same objects. We recognize a cube as a cube, no matter from which angle we look at it, an elephant appears large to us, even if it is far away (and its image on the retina is smaller than, for example, that of a mouse that is close in front of us). Even if the lighting changes, the color of an object appears to be the same - a piece of coal is black to us, regardless of whether we look at it in bright sunlight or at dusk. This stability of our perception is made possible by a number of correction programs, the most important of which are called constancy of shape, size, brightness and color.
Evidently, indications of constancy of shape can already be found in children between the ages of 50 and 60 days, but performance of constancy of shape improves even between the ages of seven and 18. On the other hand, there are no indications for the existence of size constancy in the first half year of life, between two and ten years the size constancy performance increases steadily, other results suggest that from the age of eight no improvement in size constancy can be demonstrated.
Various observations can be used to develop the concept of an object in the child. If you show a two-month-old child a toy, hide it behind a screen, remove the toy first, then the screen, the child shows signs of astonishment that indicate that he "expected" to see the toy, but it will not At six months of age, the signs of object persistence are stronger; the child looks after an object that has fallen and looks for an object that is partially obscured. Between eight and twelve months of age, the child begins to find hidden objects Thus, by the age of one year at the latest, almost all children have understood that an object is there even if they do not see it.
The child's ability to recognize familiar objects or people in images is closely related to the concept of an object. Sometimes even the one-year-old succeeds in doing this. However, it often behaves as if it were real objects or people. The symbolic character of images is usually only recorded in the course of the second year of life, i.e. in the time in which the symbolic character of language is also recorded. As expected, a higher number of points is required for four-year-olds than for ten-year-olds to recognize schematic outline figures in the form of dotted lines.
The notion that newborns are deaf for days was refuted early on. The fetus can hear noises as early as 3 months before birth (Birnholz & Benacerraf 1983, quoted from Vander Zanden 1985, p. 141). Correspondingly, infants react to noises from birth, but the type and strength of the reaction depends on the child's condition (awake, asleep, hungry, full) as well as on the type of noises and the volume.
The sensitivity of the human ear to sound and the associated nervous system are evidently particularly well suited for the perception of the human voice. The sensitivity is highest for the frequency range from 500 to 2000 Hertz, i.e. vibrations per second, this is the frequency range of human speech.
This also applies to newborns: their sensitivity to broadband noises, e.g. human speech sounds, is significantly better than to pure tones, and infants between four and 14 weeks are able to differentiate perfectly between vowels, but not between tones of different frequencies .
The mother's voice can be distinguished from other voices within the first 12 hours. Overall, low notes seem to have a calming effect, whereas high notes tend to cause shock reactions.
Generally speaking, the sensitivity to sound is significantly reduced compared to adults in the first few weeks, but it soon increases. A study covering the age range from five to 14 years showed that sound sensitivity increased, albeit only slightly, up to the age of 13. From this age, however, the upper frequencies that can still be perceived shift steadily downwards; If the ten-year-old child still perceives frequencies above 20 kilohertz (KHz), then it is only 19 KHz for a 20-year-old adult and 17 KHz for a 30-year-old.
Directional hearing (as the primary coupling of hearing and looking) is functional just a few minutes after birth, as evidenced by eye movements to the source of the noise.
Various studies show that even newborns perceive human voices and are very willing to react to language: Based on the analysis of video recordings, it was possible to show that newborns already react to the language of adults and synchronize their movements with the sound patterns of language (Condon & Sander 1974a, 1974b, quoted in Vander Zanden 1985, p. 141). The analysis of the vocal communication between mother and two to five-month-old children showed that even at this age vocal imitations by the child are often and regularly found in all dialogues (Papousek 1989, p. 476).
Annotation: Because of the importance of hearing for language development (without adequate hearing ability, "natural" language acquisition is not possible) parents should pay particular attention to whether their child reacts to (hidden) sources of noise and, if there is any doubt, point this out to the pediatrician.
4.3 Broad sense
The sensitivity of the sense of balance is already well developed at birth, and the newborn usually reacts to changes in position with movements of the whole body (positioning reflexes). The sense of taste and smell are also functional immediately after birth. Based on the sucking behavior, different reactions to sugar, salt, citric acid, quinine and water can be detected from the 2nd week onwards. Obviously, sweets already taste good in newborns. Even a preference for sucrose (fructose-vegetable sugar) over glucose (grape sugar) could be demonstrated (Engen, Lipsitt & Peck 1974). Even children as young as two days old react to strong smells by initially moving their arms and legs, increasing their breathing rate and increasing their heart rate. With increasing duration, however, you get used to it, and the reactions become weaker. The sensitivity to odors increases significantly within the first days of life; Interindividual differences with regard to sensitivity could also be demonstrated (cf.Vander Zanden 1985, p. 142).
Newborns are initially relatively insensitive to temperature, but they are irritated when they are presented with milk in the bottle at more than 50 degrees and less than 22 degrees Celsius (Jensen 1935, quoted from Vander Zanden 1985, p. 142).
A sensitivity to pressure can be seen from the fact that certain reflexes can be triggered by touch immediately after birth, e.g. the grasping reflex.
Any stimulus can lead to pain sensations if it exceeds a certain intensity. In contrast to earlier views, there is no longer any doubt that there is a sensitivity to pain in infants, although it is initially reduced, but increases significantly in the first few weeks of life. The head is more sensitive than the extremities; Girls seem to be more sensitive to pain stimuli than boys.
4.4 The integration of different sensory modalities
The perceptions of the various sensory channels are integrated into a complex perception, this is an important and great achievement that works better with increasing age. Immediately after birth, the visual and acoustic perception are already coordinated, and the child "seeks" a source of noise with the eyes (Maier, Ambühl-Caesar & Schandry 1994, p.16) B. the imitation of mouth and tongue movements, “reaching” for an object (“prereaching”) are considered to be an indication that the various sensory impressions are integrated early on World that “what is visible can usually also be felt and tasted, or that where something sounds, something can usually be seen” (Kaufmann-Hayos 1989, p. 413).
The assumption that newborns show a developmental sequence from tactile to visual perception could not be confirmed. Recent studies have shown that visual perception dominates in all age groups when visual and tactile information is available at the same time, e.g. when recognizing shapes. The dominance of the visual perception system is also evident in conflict situations. In the case of contradictions between the information of different sensory channels, the visual information is trusted most.
5. The development of voluntary motor skills
Compared to the ability to perceive, motor skills are only very inadequately developed in the first months of life. First of all, the child can absorb much more information than it can apparently utilize and convert into (recognizable) motor reactions. The sensor system is ahead of the motor system6 .
In the course of the first year of life, however, as the central nervous system matures, the child succeeds increasingly better in consciously controlling his movements. It learns to hold its head, lift its head off the surface, grab objects, prop up, turn around, sit, crawl, stand and finally run. To what extent the existing reflexes are integrated and used, or whether they are completely extinguished and replaced by new movement patterns, is currently controversial.
When acquiring these new movement patterns, the following rules of development apply (cf. Herzka 1973, p. 13):
- Biological dependence: The development of behavior is linked to physical development; only the maturation of the nervous system and muscles enables progress (not only) in the motor area.
- Progressive differentiation: The movements are initially coarse, imprecise and prolonged, but become increasingly refined and effective. The baby often misses an object that he wants to grasp, soon his movements become more and more precise.
- Centralization: The interaction of the individual movements is improved and increasingly coordinated with one another. This so-called coordination ability improves decisively in the first year of life and in early childhood, but increases in performance can be observed into adulthood.
5.1 Getting around
The development of movement in the first year of life can be understood as an effort by the child to explore the environment, first by looking, then by grasping and finally by "experiencing" through its own locomotion. In the first few months, the infant increasingly gains control over himself Posture: he first manages to hold his head, prop up himself, roll over and sit up and sit down. All these activities make it easier for the child to increasingly visually control his environment. As soon as he succeeds in grasping, manipulating and grasping objects at will examine objects from all sides, assess the weight and surface quality. This is initially only possible within the reach of his hands, but changes as soon as the child manages to move forward independently. Now it can also move further away Look for objects lying down. At the same time, his “Weltb ild "is crucial if it can perceive familiar rooms and objects from different perspectives. This is also the case when it learns to straighten up.
If the child begins to move independently, these efforts to explore the immediate environment (first of all the home) should in no way be restricted more than is absolutely necessary. Now at the latest, the apartment must be made "child-safe" under the aspect of safety for the child (and to prevent anger and frustration for the parents), which means above all:
- Securing stairs, balconies and windows
- Secure shelves, cupboards, etc. against tipping over
- Attach safety bars to cabinet doors and drawers
- Secure sockets
- Place "valuable" objects and devices inaccessible, lock them up.
5.2 Gripping / hand motor skills
The importance of using the hand, i.e. grasping it, cannot be overestimated for the child's overall development. It is not for nothing that we use the term "comprehension" in the sense of understanding a state of affairs. - Without a doubt, grasping for objects and manipulating with objects under the control of the eye represent an essential element of cognitive development in early childhood (Oerter 1989, p . 45).
The term grasping refers not only to the ability to take perceived objects in hand, but also to the ability to hold onto objects and let them go, to handle objects skillfully and appropriately, for which the coordination of visual perception and hand movement is required (hand dexterity). The hand also enables the use of tools and also fulfills perceptual functions, e.g. when assessing the properties of an object such as weight, hardness, temperature, texture, and contact functions, e.g. B. waving or stroking.
Although children can perceive objects very early, specific grasping movements only take place from 4 months. Before that, objects are already grasped and held, but this is initially done reflexively (grasping reflex) and later an object that accidentally comes into contact with the hand is held.
Bower (1979, quoted in Oerter 1989, p. 45) reports that even in the first 4 weeks the sight of an object can trigger arm movements in the direction of this object and the hands are closed when the arms are stretched out. Likewise, in the first 20 weeks - even in the dark - noises trigger directed arm movements. Both arm movements after a seen object and after a source of noise gradually cease in the 2nd month. At 3-4 months, the child looks at his own hands, follows his moving hand with eye and head movements and reaches for the hand he has seen. At 4-5 months, as in the first 4 weeks, arm and gripping movements occur again when looking at an object, but even now the movement is not controlled with the eyes. At 5-6 months, the control of the hand movement by the eye succeeds so well that the object can always be grasped. The open hand closes only after touching the object, so it seems to be controlled by tactile means. Reaching for a sound source no longer occurs.
Targeted hand-eye coordination is achieved at the age of 4 to 7 months. When looking at a coveted object, both open hands are usually moved towards this object, the object is usually also touched, grasped and often brought to the mouth. The movement is increasingly refined; later, the object is usually gripped, viewed and touched with one hand, whereby the gripping is initially done palmar, i.e. the object is pressed against the palm of the hand with the fingers. At this age, the hand, which is actually uninvolved, usually still moves. Later, the child grabs a smaller object with all five fingertips and the interplay of the fingers works so well that the palm of the hand no longer has to be used. At the age of 9-10 months, the child uses the so-called tweezer grip to pick up a raisin, for example, while holding the object between an extended index finger and an extended thumb. Only later does the child learn the so-called pincer grip, in which at least the index finger is bent and the thumb - as in adults - is opposite (from 11 months).
Obviously, letting go of an object is by no means easy; consciously relaxing the muscles of the hand in order to let go of an object is by no means successful straight away (cf. Zaichkowsky, Zaichkowsky & Martinek 1980, p. 39). Around the 9th month of life, the child "actively" drops objects, practices grasping and letting go, observes where the released object falls, gets a feel for the speed and the distance to the ground, hears the impact on the ground. The child has obviously taking pleasure in this achievement and turning it into a game (which can be very tiring for adults).
5.3 The "timetable" of motor development in the 1st and 2nd year of life
The available, mostly older studies on the development of the so-called basic forms of movement in infancy such as holding the head, sitting, turning around, crawling, standing and walking consistently show that the age at which certain forms of movement occur can vary considerably, the sequence of forms of movement but is constant; a child can first roll over from prone to supine position and vice versa before it can sit down without assistance, and only then will it crawl (e.g. Bayley 1935, Gesell 1971, McGraw 1969, Shirley 1931). The following times for the occurrence of certain elementary movement patterns are therefore only approximate values; A rapidly developing child takes its first steps as early as 10 months, another can take it almost twice as long without this having to be a cause for concern. When asked when a deviation from the "normal" developmental course should be viewed as noticeable, not only a certain skill has to be considered in each case, but the overall development of the child. In addition to the individual variation in development, it must also be taken into account that the Development obviously depends on population and time: African children show a developmental advantage over European and North American children and today's American children are ahead of those 40 years ago in their development (cf. Appleton, Clifton & Goldberg 1975, pp. 135 ff).
- During the first month the child succeeds in increasing control of his head posture. This enables him to look better and better at his surroundings and to turn to interesting phenomena. In the supine and prone position, the child begins to lift his head for a short time. If it is held seated, it can hold its head upright for a moment at the end of the first month and lift its head from the prone position for a short time. Arms and legs are mostly drawn up, hands closed in fists. If they come into contact with the mouth, the child sucks on them. An object brought into the plane of vision is followed with the eyes.
- In the 2nd month If the back of the child is increasingly less rounded when it is held in a sitting position, the head can be held upright for a short time, but then still falls forward. In the supine position, the face is mostly turned to one side. The child is already kicking both legs vigorously and moving his arms vigorously. The hands are opened more often. In the prone position, the legs are no longer so strongly drawn, the stretching movements in the hips become more frequent.
The child follows vertically moving objects with their eyes and looks for sources of noise with their eyes. It reacts differently to different auditory stimuli.
- In the 3rd month in the prone position, the head and shoulders are lifted off the surface. The child leans on their forearms. The head can be held up for a minute, the face forms an angle of up to 90 degrees to the base. If you lay the child on its side, it rolls over onto its back.
The child follows a horizontally moving object with his eyes. It pays attention to its hands and fingers, especially their movements. It briefly holds an object that is placed in its hand and tries to bring it to its mouth. It begins to repeat actions on purpose. If it causes a small bell hanging above it to ring through an initially accidental hand movement, it repeats this movement many times ("experimental movements").
- In the 4th month the child lifts their head from the supine position. From the prone position, the child succeeds in supporting himself on both forearms and lifting his head and chest off the surface. If it has enough freedom of movement in this position, it moves arms and legs violently. Sometimes there is the forearm support and briefly lifts the head, chest and arms off the surface and stretches the legs abruptly. The shoulders are pulled back, the arms bent and the hands open. Due to the violent movements, the child rocks on its stomach.
If you hold it in a sitting position, your back is now stretched and you can already control your head. The child can now grasp and hold on to suitable objects, but sometimes only when they are placed in his hand. The hands perform "groping" movements and increasingly touch each other (the child plays with his fingers).
An object is now "scanned" with the eyes, new surroundings are carefully observed. A source of noise is sought with the eyes and by moving the head. If an acoustic stimulus and an optical stimulus are presented at the same time, the child usually turns to the optical stimulus.
- At the age of 5 months In the prone position, the child continues to lean on their forearms, but also increasingly on their hands. Some children manage to just lean on one arm and reach for things with the other. It sometimes happens that it rolls onto its back from this position, especially when its head is turned upwards at an angle; however, this rotation takes place passively and involuntarily, the child loses its balance to a certain extent.
If it is pulled from the supine position by the hands into the seat, it lifts the head and shoulders. It tries to straighten up further. The child can reach for an object, but is still clumsy and cannot hold on to it. It handles toys, looks at it carefully and often brings it to its mouth. It tracks people walking around with eye and head movements.
- In the 6th month the child can sit with support, in the prone position it supports itself on the hands, the entire chest is lifted from the surface and the weight rests on the stomach and hands. At the same time, he is already able to lean on one hand for a short time, for example when he is reaching for a toy. If it wants to reach a toy in front of it that is out of the reach of its hands, it starts to move, but this usually does not succeed. The hands are now mostly open. It now reaches for objects quite purposefully and examines them in detail. It does not like to let go of objects in its hand, and it reacts displeasantly when something is taken away from it. It looks after a falling object.
- At around 7 months of age the child can roll over from prone to supine position; from the supine position it first moves to the side position, later it can also roll into the prone position. This active turning requires movement coordination between the pelvis and shoulder girdle, the turning requires a helical movement of the entire body with the support of movements of the extremities. Now the child can change his body position himself, which is important for the further development of sitting and crawling.
If the child has the opportunity, it takes hold of its feet and plays with them. If it is held under the armpit, the child crouches and pushes itself off again by stretching the hips, knees and ankles (springs). The child likes to hit the mat with toys, it changes an object from one hand to the other. For example, they can hold a piece of bread in their hand and eat themselves. It can now grab and hold two objects with its hands at the same time.
- In the 8th month the child begins to move on its stomach.Since the movements of arms and legs are not yet well coordinated, he usually does this only imperfectly. But it can rotate on its own axis. In the supine position, it takes hold of the offered fingers and pulls itself up like a pull-up to sit, lifting its legs. It may already be gripping so tight that it can be lifted up. When seated, it can sit freely for a short time. It tries to maintain the sitting posture by holding on. It is already standing with little support and - if it is held upright - places one foot in front of the other as if it wanted to go.
The child shows great interest in the details of his environment. He plays with objects frequently and persistently, increasingly grasping them with his fingertips.
- At 9 months If the child is seated, they can sit freely for a few minutes and bend forward a little without losing their balance, but not to the side. If you hold it by the upper arm and lean it to one side, it supports itself with the other hand in order to protect itself from falling over to the side. Held by the hands, it stands firmly on its feet for a few seconds and takes over its entire body weight. He is also able to pull himself up on a chair and hold on to a stand. Lying on its stomach, it tries to move forward, but sometimes slips backwards. Some children lean on their forearms and drag their bodies ("seals", without significant leg involvement). This seal phase is quite short and is soon followed by crawling (with the child moving forward on hands and knees).
- At 10 months If the child slides forward in the prone position by moving the arms and legs, it increasingly lifts the body off the surface. The technology used in the individual case can be quite different. The child has mastered the ability to sit up from the prone position. It sits stable with straight back and legs and can play for so long without losing its balance.
It pulls itself up - mostly from its four-legged position - on furniture to stand. The gripping is more and more precise and it is possible to contrast the index finger and thumb. This means that the child can now also grasp very small objects with the thumb and index finger, but still with the "tweezers grip", i.e. with the index finger and thumb extended. The coordination of both hands is so advanced that the child can hold two objects (e.g. building blocks) The child no longer just drops objects randomly, but also throws them away with swing, although it is not yet able to throw them in a directional manner, which is probably due to the lack of coordination between the throwing movement and letting go.
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