Chapter 5B - Sensory and Perceptual Development Flashcards
SENSATION
SENSATION occurs when information interacts with sensory receptors—the eyes, ears, tongue, nostrils, and skin.
PERCEPTION
PERCEPTION is the personal interpretation of what is sensed.
RESEARCH METHOD in infants’ PERCEPTION
Scientists have developed research methods and tools sophisticated enough to examine the subtle abilities of infants and to interpret their complex action:
1) The VISUAL PREFERENCE METHOD;
2) HABITUATION and DISHABITUATION;
3) HIGH-AMPLITUDE SUCKING;
4) EYE TRACKING.
The VISUAL PREFERENCE METHOD
The VISUAL PREFERENCE METHOD is a technique employed in research on infants’ perception. It is based on children’s tendency to look at different things for different lengths of time. FANTZ placed infants in “looking chambers” and exposed them to different stimuli - he found that infants as young as 2 days old look longer at patterned stimuli, such as faces and concentric circles, than at patternless red, white, or yellow discs.
HABITUATION and DISHABITUATION
The HABITUATION and DISHABITUATION paradigm is employed in research on perceptual development.
A stimulus is presented a number of times. If the infant decreases its response to the stimulus after several presentations, this indicates that the infant is no longer interested in looking at the stimulus.
If the researcher now presents a new stimulus, the infant’s response will recover, indicating that the infant could discriminate between the old and new stimuli.
HABITUATION Is the name given to decreased responsiveness to a stimulus after repeated presentations of the stimulus, whereas DISHABITUATION is the recovery of a habituated response after a change in stimulation.
HIGH-AMPLITUDE SUCKING
HIGH-AMPLITUDE SUCKING is a technique employed in research on infants’ perception. To assess an infant’s attention to sound, infants are given a fake nipple to suck on, which is connected to a sound-generating system. First the researchers measures the baseline level of the sucking rate; initially babies suck frequently so that the interesting sound occurs often, but they soon lose interest in hearing the same sound so they begin to suck less often. Then the researcher changes the sound that is being presented. If the babies renew their vigorous sucking, the inference is that they have discriminated the sound change
EYE TRACKING
EYE TRACKING is a technique employed in research on infants’ perception. “Looking time” is among the most important measures of infant perceptual and cognitive development. Eye-tracking equipment allows for much greater precision than human observation in assessing various aspects of infant looking and gaze. Among the areas of infant perception in which eye-tracking equipment is being used are memory, joint attention, and face processing.
DEVELOPMENT of VISUAL PERCEPTION
At birth, the nerves and muscles and lens of the eye are still developing. As a result, VISUAL ACUITY is very poor and newborns cannot see small things that are far away.
Nevertheless, newborns show an interest in FACE PERCEPTION - infants spend more time looking at their mother’s face than a stranger’s face as early as 12 hours after being born. After a few months they can match voices to faces and distinguish between male and female faces.
FANTZ - employing the visual preference method he conceived - found that children prefer looking at patterned stimuli rather than non-patterned stimuli. The infant’s COLOR VISION also improves over time, being a product of both maturation and exposure to environmental experience.
At 3 months, infants start to develop PERCEPTUAL CONSTANCY, the ability to perceive an object as constant even though its sensory stimulation changes. There are two types of consistencies:
1) SIZE CONSTANCY, the recognition that an object remains the same even though the retinal image of the object changes as one moves toward or away from the object;
2) SHAPE CONSTANCY, the recognition that an object remains the same shape even though its orientation changes.
In the first 2 months of life, infants infants don’t perceive OCCLUDED OBJECTS as complete. They later acquire such ability through learning, experience and exploration via eye-movements of the environment.
DEPTH PERCEPTION in infants has ben studied in VISUAL CLIFF studies. Infants are placed on the edge of a fake cliff, which is actually covered by glass and they are called by their mothers, which stands on the other side of the cliffs. Most 6- to 12-months old infants do not crawl out on the glass, choosing instead to remain on the shallow side, sugesting that they can perceive depth. Since younger infants do not crawl, it is not possible to study depth perception in younger infants with visual cliff studies.
Perceptual development continues in childhood, as their visual expectations about the physical world continue to develop as they come to understand laws of the physical world (ball through opaque tube study).
DEVELOPMENT of HEARING
During the last two months of pregnancy, as the fetus lies in its mother’s womb, it can hear sounds: in a classic studies, newborns showed preference for nursery rhymes that their mother had read aloud during the last months of her pregnancy.
Development in hearing skills involve:
1) LOUDNESS - newborns cannot hear soft sounds quite as well as adults can; a stimulus must be louder to be heard by a newborn than by an adult;
2) PITCH - newborns are less sensitive to the pitch of a sound - the perception of its frequency - than adults are. They generally are less sensitive to low-pitched stimuli.
3) LOCALISATION - even newborns can determine the general location from which a sound is coming, but children are more efficient at localising sounds at 6 months of age.
Cochlear implants - which directly stimulate the auditory nerve - are used for children who are born deaf, which then proceed to show good progress in learning and understanding speech.
OTITS MEDIA
OTITS MEDIA is a middle-ear infection common in infants which, if it continues too long, can can interfere with language development and socialisation.
DEVELOPMENT of TOUCH and PAIN
Newborns do respond to touch - after all, it is the onsetting stimulus of many reflexes - and do feel pain.
DEVELOPMENT of SMELL
Newborns can differentiate odors - in one investigation, 6-day-old infants who were breast fed showed a clear preference for smelling their mother’s breast pad rather than a clean breast pad
DEVELOPMENT of TASTE
Sensitivity to taste is present even before birth - human newborns learn tastes prenatally through the amniotic fluid and in breast milk after birth.
INTERMODAL PERCEPTION
INTERMODAL PERCEPTION involves integrating information from two or more sensory modalities, such as vision and hearing - most perception is intermodal. Babies are born into the world with some innate abilities to perceive relations among sensory modalities, but their intermodal abilities improve considerably through experience.
