A fundamental limitation in infant perception is visual acuity and was investigated by Mohn & Van Hof-Van Duin (1985). Visual acuity is the resolving power of the retina, which, in infants is thirty to forty times poorer than in a normal adult. However, research has shown that there is a rapid development and by 6 months visual acuity is half that of adults, this was a result of the use of the spontaneous visual preference technique with patterned stimuli. It could be said that this limitation would result in a lack of visual perception of the world at birth, lending support to the empiricist view, however, according to Bremner this only limits the fineness of detail that can be resolved, infants can still perceive adequately.
Despite the limitations found in visual acuity psychologists have continued to investigate whether infants view the world as consistently as adults do by taking into account size and shape constancy. As a result of Piaget’s (1954) research it was assumed for some time that this was developed and not present at birth. However, evidence for both shape constancy (Slater and Morison 1985) and size constancy (Slater, Mattock and Brown 1990) has now been obtained with newborns. Research into size constancy resulted in the conclusion that infants respond to a change in true size but not to a change in retinal image size. This research clearly provides support for the nativist view that infants are able to perceive adequately before developing appropriate behaviours.
An area that has always been a key focus in research into infant perception is object unity. Kellman and Spelke (1983) found support for the nativist view when they conducted an experiment into object unity in infants. They habituated 4 month olds to a display of a rod that moved back and forth behind a box. They were then shown a complete rod and an incomplete rod; it was found that infants spent more time looking at the incomplete rod. From these results Kellman and Spelke concluded that infants had some understanding of object unity as they had become familiar with the complete rod in the display so the incomplete rod was a new and unfamiliar image. Slater, Johnson, Brown and Badenoch (1996) found support for this experiment. However Slater et al. (1990) concluded that unlike 4 month olds, newborns do not perceive object unity, they are limited to what is actually in view and Johnson & Aslin (1995) found that 2 month olds acted in the same way as 4 month olds. This research supports the empiricist view that there is a gradual emergence of object unity in the early months.
There has been a huge amount of research into infants’ perception of objects including experiments into subjective contours, object unity, shape perception and size perception. This research has resulted in the emergence of contrasting views and has attracted both positive and negative attention. It seems that the general conclusion is that infants are born with an innate capability to perceive objects, however this is limited and during the first 4 months infants develop very quickly and are able to fill in the gaps in perception in order to perceive object unity and subjective contours.
Another main area of study into infant perception is that of perception of people. In order for infants to form attachments it is paramount that they are able to distinguish between strangers and parents. Fantz (1961) conducted a study in which he presented infants with three examples of schematic stimuli. The first face presented had all its features in the right place, the second had all its features jumbled up and the third had the same stimulus brightness but had no specific features. Fantz found that even in the first month, infants showed a small but consistent spontaneous preference for the full face, it was concluded that even the youngest infants had the ability to perceive faces, therefore providing support for the nativist view of infant perception. However, there were several criticisms of this study, the main one being that the full facial arrangement contained more information around the edge of the stimulus and evidence has shown that infants tend to scan around the edge of complex pictures, therefore it is possible that infants may have looked longer at the full facial arrangement simply because there was more detail around the edge.
There has been extensive research conducted in this area as it has important implications for later development in infants. Wilcox (1969) estimated that the age for face perception was around four months; this was later revised to two months as a result of the work conducted by Maurer and Barrera (1981). This appears to provide support for the empiricist theory that perception is developed not innate. However it is possible that the negative results obtained with younger infants could be due to the experiments being unsuitable for infants that young. Goren, Sarty and Wu (1975) developed a more suitable method by using the visual preference technique. They moved the schematic stimuli back and forth within the vision field of newborns and found that they followed the full face further and for longer than the other two faces. It is possible that the movement of the stimuli was the reason for the different results; it could be argued that this method is more ecologically valid as faces are rarely static.
The second main area of research into face perception in infants is into whether infants are able to discriminate between familiar and unfamiliar faces. There have been several studies that have found support for the nativist theory that infants are able to distinguish between their mother’s and a female stranger’s face (Carpenter, 1974). The same results have been found with newborns that had only had a few hours contact with their mother (Bushnell, 2001). In all these experiments the infant showed a preference to their mother’s face. This is important evidence to support the theory that infants are able to perceive effectively before they know how to act appropriately.
However, one weakness found with this study is that it is possible that the infant will recognise the mother through smell rather than sight; therefore it is not possible to tell whether they are distinguished solely through visual recognition. Bushnell, Sai & Mullin (1989) tackled this problem by providing a strong smelling perfume to act as a kind of mask. Another problem is that when the mother looks at the infant they tend to have more pronounced facial expressions through familiarity, the infant could simply be reacting to this. Walton, Bower & Bower (1992) reduced this possibility by presenting video tapes of the mother and stranger to the infant, therefore it was clear that the infant stared longer at the mother due to visual recognition alone, this provides support for the nativist theory that infants are able to perceive adequately before knowing how to act appropriately.
Another area of face perception in infants investigated by psychologists is imitation. Piaget (1954) put forward the conventional view that imitation was impossible until infants were capable of representing self and other, a capacity thought to develop in late infancy. However, evidence has shown that even newborns are capable of imitating facial and manual gesture. Meltzoff and Moore (1977) were the first ones to report well-controlled studies of imitation in early infancy. The research into imitation provides strong evidence to support the nativist view as in order to imitate a facial gesture, infants have to be able to understand the method involved in making a particular gesture and match this to their own facial gestures. However, these findings were seen as highly controversial and still are. Investigating imitation is difficult as you are faced with two problems: you must ensure that the actions are simple enough for an infant to imitate but at the same time the gestures should not be those that can be confused with the gestures infants make spontaneously.
The research discussed in this essay provides evidence to suggest that many perceptual abilities are present in infants from birth or emerge very shortly afterwards. This suggests that many aspects of perception develop on innate, maturational factors rather than on learning from the environment. A main example of this would be face recognition; newborns become familiar with their mother’s face within a few hours of birth. The infant ability to perceive depth and distance and to apply visual constancies has also been investigated. It is not as clear in these areas whether the evidence provides support for the nativist or empiricist argument. The methodological difficulties involved in studying infants makes it difficult to form firm conclusions, however, it seems likely that babies need to interact with the environment at some level in order for their perceptual abilities to develop normally and effectively.
References
Cardwell, M., Clark, L., Meldrum, C. (2001) Psychology for A2 Level pp185-218
Slater, A., Bremner, G. (2003) An Introduction to Developmental Psychology pp117-139
Smith, P.K., Cowie, H., Blades, M. (2003) Understanding Children’s Development pp319-341
Sources
Cardwell, M., Clark, L., Meldrum, C. (2001) Psychology for A2 Level. Collins.
Carlson, N.R. Buskit, W. & Martin, G.N. (2000) Psychology: The Science of Behaviour (European Adaptation.) Harlow: Pearson Education Ltd.
Slater, A., Bremner, G. (2003) An Introduction to Developmental Psychology. Blackwell Publishing :Oxford.
Smith, P.K., Cowie, H., Blades, M. (2003) Understanding Children’s Development 4th Edition. Blackwell Publishing: Oxford.
