Using examples from the infancy literature discuss how infants may be able to perceive adequately without knowing how to act appropriately. The development of infant perception has always been a focal point for developmental and cognitive psychologists. The focus of this essay is on the discussion surrounding whether infants are able to perceive adequately without being able to act appropriately. The work of Piaget (1954) is centre to this discussion, he stated that infants only develop object permanence around the age of 8 months. An important debate relating to infant perception is that between the empiricists and the nativists.
Empiricists, leading by the example of the philosopher John Locke believe that the newborn is a “tabula rasa” (Smith, Cowie & Blades (2003) p320) on which life experiences are recorded. The nativists claim that many perceptual abilities are present at birth; philosophers like Descartes and Kant argued that infants have an innate capability to perceive space. Over recent years there have been huge research advances as a result of new technology; developmental psychologists now have access to video filming and computer controlled stimuli.
Not only does this result in a higher quantity of research produced but as a result of the new methods available experiments predominantly have much greater objectivity and validity than before. This new technology has resulted in several new techniques particularly when looking at infants’ perception of objects. The spontaneous preferences technique is a main example as much of the evidence into infant perception has been obtained through this technique.
This example involves showing infants two stimuli side by side, psychologists look for a preference to one object in order to determine whether infants can discriminate between preferred and non-preferred stimuli. Although the results from this have supported the theory that infants are able to perceive before they can act, they may not be reliable as the infant may distinguish between the two stimuli but have no preference. Another technique used is the habituation novelty technique in which the infant is habituated to one stimulus in order to create a preference when another stimulus is introduced.
Slater, Morison and Rose (1983) used this method with simple shapes such as crosses, triangles and circles; they found that infants looked longer at the stimulus they had not been habituated to; this indicates that they were able to discriminate between the objects. However, the problem with this technique is that it cannot be said whether the infant is showing a preference or whether they are simply focusing in on the distinguishing features of the particular object.
Slater, Morison and Somers (1988) investigated this and found that newborns could discriminate between different line orientations. This evidence provides support for the nativist view that the “infants actively tries to create order and organisation in their perceptual world” (Smith, Cowie & Blades (2003) p320). 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.