Sensation
Refers to the processing of basic information from the external world by
a) sensory receptors
b) brain
Perception
Process of organizing + interpreting sensory information about the world around us
Preferential looking technique
Method for studying visual attention in infants
–> two different visual stimuli are displayed on side by side screens
=> if the infant looks longer at one, one can infer the baby prefers this stimulus and can discriminate
(enables the researchers to asses the infants visual acuity)
Habituation
Procedure that involves repeatedly presenting a stimulus until the infants response to it habituates/declines
Contrast sensitivity
Infants can only detect a pattern when it is composed pf highly contrasting elements
–> this is due to the immaturity if infants cones, which are light sensitive neurons involved in detail vision
Structure of cones in infancy
- different size + shape
- spaced farther apart
- -> cones only catch 2% of the light striking the fovea
=> 8months: vision approaches that of adults
6y/o: full visual acuity
Visual scanning in infancy
- start scanning their environment right away
BUT: have trouble tracking moving stimuli because their eye movements are jerky
- 2/3months: able to track slowly moving objects
- ->visual scanning is restricted for complex shapes
- -> only outer edges are scanned ( concept conservation)
ex.: triangle –> only the corners are looked at
face –> only hairline or chin due to high contrast
Pattern (Face) perception in Infancy
<6months: are able to discriminate between individual faces
–> also monkeys/animals
> 9months: they rely on a detailed prototype of the human face to discriminate between people
–> this prototype is not applicable to animals
The other race effect
Individuals find it easier to distinguish between faces of individuals from their own racial group than between faces from other racial groups
–> features from the infants immediate environment drive this effect
Perceptual constancy
We perceive a constant shape and size
–> although our retinal image of the person changes in shape and size, we d not have the impression the person changes
Empiricist view on perceptual constancy
Perceptual constancy develops as a function of spatially experiencing our environment
Nativist view on perceptual constancy
Perceptual constancy stems from inherent properties if the nervous system
Object segregation
The perception of the boundaries between objects
–> motion is an important cue indicating the boundaries between objects
Optical expansion
Visual image of an object increases in size as the object comes toward us, occluding more and more of the background
–> infants blink in response, can’t attack
Binocular disparity
The retinal image of an object is never quite the same in both eyes
–> two slightly different signals are sent to the brain
Stereopsis
The visual cortex computes the degree of disparity between the eyes different neural signals and thus produces the perception of depth
Monocular depth
Depth cues that can be perceived by one eye alone
–> infants will reach for whichever object is nearer
Auditory perception in infancy
The auditory system is better developed relative to the visual system
Auditory localization
The perception of the spatial location of a sound source
–> to localize a sound, listeners rely on differences in sounds that arrive at both of the ears
=> infants have more difficulty using this information because head is smaller, thus the spacing of the 2 ears
(timing + loudness of info arriving at each ear is smaller)
Music perception in infancy
- infants have detailed memory of music including pitch, tempo, timbre
- preference for consonant music
–> with experience there is a process of perceptual narrowing which leads infants to loose the ability to make distinctions the he/she could make earlier
Smell in infancy
Smell helps infants to recognize their mothers
Touch in infancy
- Oral exploration dominates their first months
–> sucking fingers/objects to learn about their bodies
- Increasing manual control facilitates visual exploration
–> infants can hold objects to examine them more closely
Intermodal perception
Combining of information from 2 or more sensory systems
Piagets view on intermodal perception
Information from different sensory modalities is initially separate until after some months they can make associations between 2 or more senses
Spatial frequency
The number of cycles per degree of visual angle of the grating
–> A measure of how fine the bar pattern is on the retina
(one cycle = one light bar + one light bar)
–> finer bars = higher spatial frequencies
BUT: moving loser to the grating decreases this
Color perception in infancy
Perception of a light stimulus can vary on
a) chromatic color
b) brightness
–> color vision develops at 3-4 months
Binocular fixate
When both eyes are looking directly at the object, both foveas are directed at exactly the same place
–> Requirement for the operation of binocular disparity
Familiar size
Infants sensitive to a familiar size will perceive an object to be closer if they remembered from the familiarization period that this shape was smaller than the other one
–> response is based on what is perceived + what is remembered
Social referencing
Process of communication whereby people actively seek and use others’ perception and interpretations of ambiguous situations to form own interpretations of those situations
