PSY 2105 Chapter 7
Sensory and Perceptual Development
October 17 2012
Issues in the Study of Perceptual Development
All sensory systems are operative from birth, and all achieve close to adult levels by the end of infancy.
Detection of sensory information
Interpretation of sensation
Organization and understanding of meaning of sensations
Focus on certain stimuli while ignoring others
Theories in Sensory-Perceptual Development
o Emphasizes the role of experience in organizing complex perceptions from simple sensations
o Emphasizes the innate aspects of perception that allow a baby to understand the world
o Emphasizes the impact of knowledge on perception
Theories of Perceptual Development
o states that perception is a cognitive construction based on sensory input plus information retrieved
Perception, is a representation of world that builds up as infant constructs an image of
experiences (Piaget, Vygotsky)
o states perception has functional purposes of bringing organism in contact with environment and of
increasing adaptation (Gibson)
Making Sense of the Infants Sensory and Perceptual Experiences (Some Approaches)
The Preference Method
o Simple procedure in which at least two stimuli are presented simultaneously to see whether infants will
attend more to one of them than the other(s).
One major shortcoming
If an infant shows no preferences among the target stimuli, it is not clear whether he or
she failed to discriminate them or simply found them equally interesting.
1 PSY 2105 Chapter 7
The Habituation Method
o Process whereby a repetitive stimulus becomes so familiar that responses initially associated with it no
Simple form of learning. As infants stop responding to familiar stimuli, they are telling us that
they recognize them as old hat- something that they have experienced before.
o Way of determining what infants can sense is to present them with a stimulus and record their brain
Electrodes are placed on the infant’s scalp above those brain centers that process the kind of
sensory information that the investigator is presenting. This means that responses to visual
stimuli are recorded from the back of the head, at a site above the occipital lobe, whereas
responses to sounds are recorded from the side of the head, above the temporal lobe.
o Provides infants with a special pacifier containing electrical circuitry that enables them to exert some
control over the sensory environment.
After the researcher establishes an infant’s baseline sucking rate, the procedure begins.
Whenever the infant sucks faster or harder than he or she did during the baseline observations
(high-amplitude sucking), the infant trips the electrical circuit in the pacifier, thereby activating a
slide projector or tape recorder that introduces some kind of sensory stimulation.
o Babies react with cries and heart rate changes to skin damage (pin prick)
The infant’s nervous system is definitely capable of experiencing pain
Receptors for pain in the skin are just as plentiful in infants as they are in adults.
Babies’ behavior in response to a pain-provoking stimulus suggests that they experience pain.
o Sensitivity to touch can be demonstrated in the womb
Tactile stimuli elicit a variety of reflexes in the newborn
rooting, palmar reflexes
Recognition of objects by touch
o Babies react with facial expressions
Rotten eggs, fish
6-day-olds turn more frequently toward mother’s breast pad than another woman’s
o Various tastes will either elicit a facial expression or change the rate of sucking
Example: sweet tastes
2 PSY 2105 Chapter 7
o Sensory feedback from vestibular organs maintain balance and body posture
Posture can alter alertness in babies (more alert in vertical than horizontal)
Development of vestibular sensitivity and posture is a necessary scaffold for the development of motor skills
Visual cues can outweigh vestibular cues
As the wall moves toward the infant, the
visual system signals movement, while
the vestibular system does not; the infant