By Elizabeth S. Spelk, Massachusetts Institute of Technology.
Source: Introduction to Psychology book. Authors — R.L. Atkinson, R.S. Atkinson, E.E. Smith, D.J. Boehm, S. Nolen-Hoeksema. Under the general editorship of V.P. Zinchenko. 15th international edition, St. Petersburg, Prime Eurosign, 2007.
People have an amazing ability to learn from each other. This ability is noticeable already in a one-year-old child who is able to understand the meaning of a new word or the function of a new object, simply by observing how another person uses this word or object. The rapid and extensive learning that occurs in early childhood suggests that many of the knowledge and beliefs are acquired through interaction with external objects and people. But isn’t our very ability to perceive objects and people the result of learning? Or does perception come from internally generated processes of growth and develop relatively independently of experience?
For nearly 2 years, most scientists who have pondered this question have concluded that humans learn to perceive, and that development proceeds from unthought, unstructured sensation to conscious, structured perception. In studies of newborns, however, data have been obtained that contradict this view. For example, we now know that newborns, just like adults, perceive depth information and use it to estimate the true size and shape of objects. Infants pick out the same sound patterns in the speech stream as adults, focusing in particular on the set of sound contrasts used in human languages. Newborns distinguish human faces from other images and mainly pay attention to them. Finally, newborns are sensitive to many of the features of objects that adults use to distinguish one thing from another, and they integrate information about these features in the same way that adults do.
How does perception change in infancy? As babies develop, they begin to perceive the depth of space, objects and faces with increasing accuracy. In addition, infants begin to focus on the speech features of their native language rather than other languages. (Interestingly, this seems to be due primarily to a decrease in sensitivity to the features of foreign languages, and not an increase in sensitivity to the features of the native language). Finally, infants are more sensitive to new sources of information about the environment, such as stereoscopic depth information, the shape of objects, and new frames of reference for estimating the location of objects and the order of events. All this increases the accuracy and richness of perception in infants, but does not make the world of the child, which is a stream of sensations, more meaningful and structured.
The results of neonatal studies are increasingly being confirmed in studies of the development of perception in other animals. Since the early work of Gibson and Walk, we have known that depth perception develops in animals independently of visual experience. The innate ability to perceive depth of space allows newborn kids to avoid falling from cliffs, and rat pups and kittens with newly opened eyes to avoid collision with approaching surfaces. Recent studies show that newly hatched chicks perceive the boundaries of objects in the same way as adults do, and even visualize hidden objects. The study of the developing animal brain shows that both genes and intrinsically structured neural activity play an important role in the development of normally functioning perceptual systems, while the experience of perceiving objects — objects and events — is less important. As with newborn babies, normal visual experience enriches and fine-tunes the perceptual systems of young animals, and its absence can cause various disturbances. Like infants, animals do not need visual experience to transform their perception from a stream of unstructured experiences into a structured visual schema.
As a result, we can say that perception is quite structured at birth and consistently in its development. This sequence may help explain why babies learn so well from other people. Just look at an infant watching an adult unscrew the lid of a jar while saying, «Let’s open it.» If the infant could not perceive the lid and jar as moving objects that could be manipulated, he would not understand the meaning of the adult’s actions. If he could not distinguish the sounds that distinguish the word «open» from other words, he could not learn to pronounce it. And if he could not perceive a person as a subject similar to himself, watching the actions of this person and hearing his speech would not allow the baby to learn to do or say anything. Thus, infants’ amazing learning abilities may depend heavily on an equally amazing, but as yet unexplored, capacity for perception.