<P> A well known study used to show early signs of recall memory, examines 3 month old infants behavior with mobiles . The experiment entailed tying a string on a colourful mobile to the infant's foot, so that kicking would cause the mobile to move, pleasing the baby . After the initial training, it was shown that a week later the infants kicked in order to produce movement . Two weeks later the infant resumed the kicking behavior after a short reminder session where they watched the mobile moving (unattached to their foot). This experiment showed a recognition of the mobile, as well as recall (after one week), and cued recall (after 2 weeks). Recognition and recall are two essential aspects of memory; these are particularly useful in children since verbal reporting of memory may not be available yet or as reliable when testing very young participants . At the age of approximately 9 months some infants are able to reproduce some simple actions they observe up to 24 hours after witnessing them . The reproduction of behaviors such as choosing one object over another or repeatedly placing an object in a certain spot is a type of situational memory test used to identify the child's level of memory capability . Deferred imitation, the ability to reproduce behaviour without cuing, can be seen and tested near the age of 18--24 months . Children become able to replicate more complex events with greater detail, from memory . </P> <P> Jean Piaget, a child development psychologist, conducted a study testing the cognitive and memory abilities of children around 2 years of age . These tests were conducted using objects presented to the child followed by their removal from sight . This causes very young infants to believe the object no longer exists . At approximately 8--12 months, children will look for the missing object and this display shows memory, as well as a comprehension that it still exists when it is not directly seen . This led to the theory of object permanence which demonstrates the stage at which memory and cognitive development have reached the level of mental representation . </P> <P> A child as early as 7 days old can shows signs of facial expression imitation such as tongue or lip protrusion and opening of their mouth . There is some debate as to whether this is a voluntary or reflexive action though the ability to imitate demonstrates the infants ability to encode the image and imitate it . Evidence of facial memory over longer delays can be seen in children as early as 2--3 weeks old . Changes in behavior such as crying less and smiling more shows evidence for recognition of a familiar face . </P> <P> Recognition can also be shown with habituation, the process of attending a familiar stimuli less in preference for a new one . This can be seen as early as 5 months of age in several forms including auditory and visual identification . In a study of 8 - 10 month infants, both familiar objects / faces and newly presented ones were introduced at different intervals and time delays . Looking time and first looks were recorded, and the results indicated habituation and memory recall . </P>

Who attempted to find the exact spot in the brain where learning occurs