Another experiment which supports the nativist view was conducted by Bower (1965). Looking again at depth perception in infants, Bower conditioned babies to associate sucking on a pacifier with the reward of an adult popping up saying ‘peek-a-boo’ which would excite the baby. The adult would only pop up however when the baby sucked on a pacifier in the presence of the original 30cm cube. Bower presented various different sizes of cubes at various distances and measured the amount of sucking each cube elicited. He found that, even when presented at a distance thus resulting in a much smaller retinal image, the original 30cm size cube generated the largest amount of sucking. Interestingly, a cube of a different size to the original but presented at a distance as to represent the original retinal size of the 30cm elicited little sucking. Such behaviours were found in babies as young as 3 months, showing that very young infants have some innate processing capacity to perceive depth and distance.
Another area of perception that has interested researchers is whether size constancy in babies is innate or not. In an innovative experiment by Slater, Matter & Brown (1990) 2-day-old babies were tested for an awareness of size constancy. The newborns were first shown a particular cube at a fixed distance until they were familiarized to it; it was expected the baby would soon lose interest in this cube. The researchers then introduced a second larger cube (of a similar pattern to the original cube) alongside the original cube but at a further distance so that both cubes produced the same retinal size as the original. It transpired that the babies preferred to at the second, less familiar cube showing that despite the cubes looking the same size the babies could differentiate between the two, thus displaying size constancy (Cardwell and Flanagan, 2009, pg 28)
Other evidence supporting the nativist position comes from Fantz (1963) who proved that infants as young as 10 hours old have an ability to perceive pattern – previously it had been thought that infants had little or no pattern vision until they gained enough learning (Fantz, 1963, pg 296). Fantz presented the newborns with a number of targets made up of black and white patterns. Some were plain, some were made up on concentric circles and others were constructed to resemble the basic features of a human face. Fantz found that infants looked longer at the patterns which resembled a human face and for the least amount of time at the plain targets. This lead him to conclude that there is an innate device in infants causing them to fixate on stimuli of social value (such as a face) and that its purpose is to facilitate the development of social responsiveness (Fantz, 1963, pg 297). Bower (1982) investigated this further and found that “even a crude mask will elicit a smile from a 6-week-old” (as cited in Mitchell and Zeigler, 2007, pg 95).
Despite the above evidence supporting nativist view, there are psychologists who argue that learning is largely involved in the development of perceptual abilities. Gregory is one such psychologist and he proposed an alternative position known as the ‘top down’ theory of perception. He argued that the sensory data received by humans cannot be fully processed without making use of previously stored knowledge in the brain to create an inference or hypothesis about incoming data (Cardwell and Flanagan, 2009, pg 24).
Evidence to support this view comes from research by Mitchell and Taylor (1999) who tested children between the ages of 3 and 7. They asked children to first look at a circular disk. The disk was then orientated at a slant so it would appear elliptical. The children were then asked to draw a replication of the elliptical shape they could see on a computer screen. The researchers found that children of all ages drew the elliptical disc as a more of a circle when they had been exposed to the disk in its circular form first (Mitchell and Taylor, 1999, pg 24). This finding supports the empiricist view of perception as it is clear that the children’s prior knowledge of circularity of the disk effected how they saw the shape. This therefore suggests, as Mitchell and Zeigler (2007) write that experiences influence perception and that it is not just an innate mechanism (pg 98).
Despite this, when reviewing the evidence it clear that infants and new born babies do have a number of perceptual abilities such as perceiving depth and size, as well as being able to distinguish between pattern and plain stimuli and of course, recognition of social stimuli such as the proclivity to look at stimuli which resembles a face. It is therefore possible say that the nature side of the debate is strongest when considering whether perceptual abilities are innate and argue that yes, many perceptual abilities are inborn in infants. However, the role of the environment cannot be ignored and it is clear from evidence that prior knowledge does have an effect on the subsequent perception of objects in children. It is therefore possible to conclude that it is an interaction of genes and environment that cause the development of perceptual abilities in children.
References
Bower. T. G. R. (1965) Stimulus variables determining space perception in infants. Science. 149, 88-89
Cardwell, M & Flanagan, C. (2009) Psychology A2: The Complete Companion. Oxford. Oxford University Press
Fantz, R, L. (1963) Pattern Vision in Newborn Infants. Science,New Series. 140, 296-297
Gibson, E.J & Walk, R.D. (1960) The visual cliff. Scientific American. 209, 64-71
Mitchell. P & Taylor, L.M (1999) Shape Constancy and Theory of Mind: Is There a Link? Cognition. 70, 167-190
Mitchell and Zeigler. (2007) Fundamentals of Development: The Psychology of Childhood. East Sussex, UK. Psychology Press
Slater, A., Matter, A. & Brown, E. (1990) Size Constancy at Birth: Newborn infants’ Responses to Retinal and Real Size. Journal of Experimental Child Psychology, 49, 314-322
Smith, P. S., Cowie, H. & Blades, M. (2003) Understanding Children’s Development (4th ed.) Cornwall, UK. Blackwell’s publishing.
Taylor, L. M. (2005) Introducing Cognitive Development. East Sussex, UK. Psychology Press.