Infant cognitive development

Development is typically considered to be something progressive, as we age we move from more simple to more complex structures or behaviours. This causes us to interpret early or immature forms of cognition as incomplete forms of the adult model. This does not always hold true. Immature forms of development can serve some function of their own, as it adapts for the current environment of the infant. For example, infant's relatively poor perceptual skills protect their nervous system from undergoing sensory overload. The fact that infants have slow information processing prevents them from establishing intellectual habits early in their lives that would cause problems later in life, as their environments are significantly different. From this it could be argued that infants and young children's cognitive and perceptual abilities, might be designed to be suited to their needs at that particular time in their lives rather than incomplete versions of the more sophisticated models possessed in adults. Hanus Papousek (1977), looked at the concept that learning at an early stage of development may not be beneficial to the infant if it creates overstimulation. In an experiment he conditioned infants to turn their heads to the sound of a buzzer. The training for the task, began either at birth or at 31 or at 44 days. He discovered that infants took many more trials and days to learn the task if they learned from birth than the infants who learned later. Infants need stimulation, however, if stimulation is too great than it could distract infants and young children from other tasks, and replace other, more crucial activities to their development such as social interaction.[11]

The development of memory in children becomes evident within the first 2 to 3 years of a child's life as they show considerable advances in declarative memory. This enhancement continues into adolescence with major developments in short term memory, working memory, long-term memory and autobiographical memory.[12]

Research on the development of memory has indicated that declarative, or explicit memory, may exist in infants who are even younger than two years old. For example, newborns who are less than 3 days old demonstrate a preference for their mother’s own voice.[13]

The perception of causality was initially studied by Albert Michotte where he presented adults with animated images of moving balls.[14] By manipulating the direction and timing of the moving balls (spatial and temporal dimensions) he was able to influence participants’ perception of causality. There is contradicting evidence on whether causal perception is innate and present at birth or whether it is a result of perception development. Through research with very young infants, many studies have shown support for the theory that humans are born with the mechanisms needed for the perception of causality .[15][16][17] Recent research has even shown this ability in newborns only a few hours old.[18] However, other studies have shown similar results received by Michotte (1976) in infants as young as 6 months, but not younger .[19][20] These studies support a more developmental progression of abilities required for the perception of causality.

Object permanence is the understanding that an object continues to exist, even when one cannot see it or touch it. It is an important milestone in the stages of cognitive development for infants. Numerous tests regarding it have been done, usually involving a toy and a crude barrier which is placed in front of the toy, and then removed repeatedly (peekaboo). In early sensorimotor stages, the infant is completely unable to comprehend object permanence. Psychologist Jean Piaget conducted experiments with infants which led him to conclude that this awareness was typically achieved at eight to nine months of age. Infants before this age are too young to understand object permanence, which explains why infants at this age do not cry when their mothers are gone – "Out of sight, out of mind". A lack of object permanence can lead to A-not-B errors, where children look for an object at the location where they first discovered it rather than where they have just seen it placed.

Studies in psychology[21] also suggest that three dimensionality and depth perception is not necessarily fully intuitive, and must be partially learned in infancy using an unconscious inference. The acquisition of depth perception and its development in infant cognitive systems was researched by Richard D. Walk. Walk found that human infants is able to discriminate depth well from an "innate learned" point of view, they are able to discriminate depth from the age at which they can be tested. However, their visual mechanisms are still maturing. Walk discovered that infants are better able to discriminate depth when there is a definitive pattern separating the deeper and shallower areas, than if either one is at all indefinite, and the depth and distance must be of a certain level of distance in order to be successfully distinguished by the infant. According to Walk there is a clear development of perceptual behaviour, as with increasing age it is shown that children are able to discriminate between depths more accurately, and gauge more subtle differences between depths.[22]

Largely thanks to the innovative strategies developed by Renee Baillargeon and her colleagues, considerable knowledge has been gained in the about how young infants come to understand natural physical laws. Much of this research depends on carefully observing when infants react as if events are unexpected. For example, if an infant sees an object that appears to be suspended in mid-air, and behaves as if this is unexpected, then this suggests that the infant has an understanding that things usually fall if they are not supported. Baillargeon and her colleagues have contributed evidence, for example, about infants’ understanding of object permanence[23] and their reasoning about hidden objects.[24]

From birth, babies are learning to communicate. The communication begins with crying and then begins to develop into cooing and babbling. Infants develop their speech by mimicking those around them. Gestures and facial expressions are all part of language development. In the first three months of life babies will generally use different crying types to express their different needs, as well as making other sounds such as cooing. They will begin mimicking facial expressions and smiling at the sight of familiar faces. Between the ages of 4–6 months infants have a greater response towards different tones in voices, and greater engagement, watching the speaker's face. The child's own language skills develop with larger variation in babbling sounds, and elicit responses in conversation through babbling. From 7 months to the end of their first year babies are able to understand frequently heard words and can respond to simple requests. Their babbling becomes more complex and they communicate with it as if they are making sense, they use babbling to express their desires. Non-verbal communication also develops and actions such as waving goodbye are produced. This is also the period in which babies often say their first word, an important milestone in the child's life.[25]

The most common technique used in research for testing self-awareness in infants is a mirror test known as the "Rouge Test".[26][27] The rouge test works by applying a dot on an infant’s face and then placing them in front of the mirror. If the infant investigates the dot on their nose by touching it, they are thought to realize their own existence and have achieved self-awareness. A number of research studies have used this technique and shown self-awareness to develop between 15 and 24 months of age.[28][29] Some researchers take language such as "I, me, my, etc." as an indicator of self-awareness.[30]

Rochat (2003) described a more in-depth developmental path in acquiring self-awareness through various stages.[31][32] He described self-awareness as occurring in 5 stages beginning from birth.

Symbolic thought refers to the ability to use words, images, and other symbols to represent words or feelings. During the preoperational stage a child's capacity for symbolism increases, this is shown by their increase in language use during this stage. This can also be seen by the way children play with objects, a stick becomes a sword and a box becomes armor. Children in this stage still might not understand that a map represents a real place, and that a picture of food does not have a smell.[36]