Task 2 Flashcards
Sensation
The processing of basic infromation from the external world, by oursensory receptors.
Perception
The proccess of interpreting and organizing sensory information about objects, events and the spatial layout of the world around us.
Visual acuity
How well can infants can perceive details
High visual constract
Infants prefer to look at patterns of high visual contrast
Poor constract sensitivity
Cone fovea
Infants can only detect a pattern when it has constrasting elements.
That is because all cone fovea contains widely spaced and poorly ddveloped cone receptors
Contrast sensitivity
How do we measure it
Thanks to measuring contrast sensitivity we can determine how an infant perceives objects of different sizes.
Measured by the determining the smallest difference between dark and light bars of grating, at which an observer can still detect the bars.
Spatial frequency
Measure of how fine the bar pattern is on the retina. Determined by number of cycles of the grating per degree of visual angle.
Contrast sensitivity function
CSF across ages
Plot of contrast sensitivity vs spatial frequency
1 month- infants cannot see fine details and can only see large objects with high contrast.
– Undeveloped state of fovea forces it to see with rod-dominated peripheral retina.0
2 months Infants contrast perception has improved
3-4 months Infants can dofferentiate happy faces an surprised angry neutral faces as well as a cat and a dog.
fovea
a small depression in the retina of the eye where visual acuity is highest. The centre of the field of vision is focused in this region, where retinal cones are particularly concentrated.
Perceiving color
Color vision is determined by the action of three types of cone receptors. It develops early, and appreciable color vision is present within first 3-4 months of life.
Two dimensions perception of light stimulus can vary
4 months and color
Its chromaic color
Its brightness
4 months infants categorize colors the same way adult trichromats do
Optical expansion
Depth cue in which an object occludes increasingly more of the background, indicating that it is approaching
Binocular disparity
Depth cue in which difference between retinal image of object in each eye results in two slightly different signals being sent to the brain.
Pictoral cues
Familiar size
Depth cues that depend on experience with environment and development of cognitive capabilities. These include overlap and familiar size.
Infants familiarize with two objects of small and large size. It is predicted that infants perceive object to be closer if they remember it.
Newborns and infants perceiving faces
Newvborns and infants can distinguish between different faces and very young infants prefer to look at face-like stimuli.
Disagreement- Whether preference for faces is caused by special mechanism or same mechanism for perception of objects.
Prosopagnosia
Area responsibe for object perception cannot take over the task of identifying faces.
Object perception
When a person moves our image of the person changes in size and shape but the person itself doe not
Perceptual constancy
Perception of objects as being of constant size, shape and color, even if there are differences in the retinal image of the object.
Object segregation
Perception of boundaries between objects. So, identification of separate objects in a visual array
Thershold for hearing a tone
Newborns can hear and are capable of crude sound localization
3 6 month old infant and adult audibility function similarily
6 months infants threshold is within 10-15 dB of the adult threshold.
Mothers voice
New brons can recognize sounds they have heard before
Speech perception
The ability to discern meaning through words and sentences emrges before the infant can produce speech
Phonemes
Smallest unit that when changed, changes the meaning of a word. Each language is constructed from these units
Voice onset time (VOT)
Time delay between when a sound begins and when the vocal cords begin vibrating.
Speech segmentation and 1 month olds phonemes
1 month olds are capable of categorical perception of phonemes even with no experience in producing or hearing speeching sounds.
Speech segmentation is the ability in infants to determine where in a string of sounds one word ends and another begins.
Language and child
Infant posses mechanisms for perceiving all speech sounds early in development, but during the first year of life they become tuned to the language the child hears
reason they loose it after a year? They become sensitive to distinctions between sounds that are important in their language
Intermodal perception
Combination of ear and eye into a perceptual whole
Examples of intermodal perception
Hearing mothers voice helps newborn recognize her face
recognition can be achieved by other means: odor and other cues
2 experiments with intermodal perception
Experiment 1 Kaye and Bower:
Sucking behavior of infants determine what image appears on the screen.
result: 1 day old infants are able of matching a shape they feel to a shaoe they can see
Experiment 2 Kuhl and Meltzoff
Baby sees two women faces each repeting different vowel sounds that match the lip movement of only one of the faces.
Result children tend to look at sound lmatching face.
Olfaction in infants
newborns can smell and can discriminate between different olfactory stimuli
Taste
Newborns discriminate sweet, sour and bitter stimuli
