Perceptual Abilities in Babies

As a species, human beings have a truly remarkable capacity for perception. We are able to see and interpret visual stimuli, and process this information in a way that is meaningful to us. We can also perceive the location of a sound, transform pressure changes in the air into meaningful sentences, and create myriad tastes and smells from our molecular environment. But are these perceptual abilities innate or learned? 19th century psychologists believed that newborns and young infants experience a confusing perceptual world, either perceiving nothing or making very little sense of the stimulation they are exposed to. However, research carried out over the last 30 years has changed the traditional view of the young infant's perceptual world from one of "incompetence" to one of "competence". This essay will discuss the capacities of newborn infants in terms of visual, auditory, olfactory and taste perception.

One of the most basic questions we can ask about infant visual perception is how well infants can perceive details. Using the preferential looking technique and the visual evoked potential method, researchers have determined that the perception of details is poorly developed in infants at birth. Generally speaking, visual acuity for infants tends to be between 20/400 to 20/600 at one month. This increases rapidly over the first 6 to 9 months, with full adult acuity being reached some time after 1 year of age. The explanation for this is the result of a poorly developed visual cortex, and poorly developed cone receptors in the fovea. The shape of the cones in the fovea are vastly different from those of an adult, with newborns having comparatively fatter inner segments and smaller outer segments. The small outer segment cannot absorb light effectively, because they contain less pigment than that of adult cones. Additionally, the fat inner segment creates a coarse receptor lattice with large spaces between each cone. This means that most of the light entering