Perceptual Development Exam 2

fixation

trichromatic

normal color vision using three cone types

monochromatic

total color blindness, uses only one or no cone types

chromatic adaptation

Exposure to light in a specific part of the visible spectrum. This adaptation can cause a decrease in sensitivity to light from the area of the spectrum that was presented during adaptation.

wavelength

present in cones - short = blue, medium = green, long = red

fNIRS

functional near-infrared spectroscopy; used to test infant color categorization, optical imaging that measures neural activity by looking for metabolic changes that lead to differential absorption of infrared light in brain tissue

visual exploration

used to maintain focus, change gaze, and follow objects

OKN (nystagmus)

fixate on point in large pattern, follow it with smooth eye movement until out of sight, eyes jerk back to center of visual field

Sapir-Whorf Hypothesis

the structure of a language influences the way its speakers think, perceive, and interpret the world

saccade

rapid ballistic eye movement that puts objects of interest into central focus , changes with age

tracking

smooth pursuit movements, develops by 6-8 weeks and continues to anticipatory pursuit

scanning

infants look at areas of high contrast

recognition

remembering when you've seen something before; infants preferred novel face in 10s to 2 weeks delay, indicating recognition!

recall

remembering a stimulus or event when it is not present

habituation

decreasing responsiveness with repeated stimulation. As infants gain familiarity with repeated exposure to a visual stimulus, their interest wanes and they look away sooner.

perceptual categorization

Quinn study found infants preferred the novel category - they're capable of perceptual categorization!

perceptual constancy

perceiving objects as unchanging even as illumination and retinal images change

subjective contour

visual illusion that evokes perception of an edge or figure (filling in missing parts)

shape constancy

you can stioll perceive the real shape/slant of objects regardless what's projected at the retina

Emmert's Law

the perceived size of an object (afterimage) increases proportionally as its perceived distance from the viewer increases

size constancy

knowing that an object isn't shrinking or getting bigger just because its moving further away or moving closer

size and nearness

bigger things of a familiar size must be closer and smaller things of a familiar size must be further away

objectification

knowledge of the self and external object as distinct entities, spatially segregated, persisting across time and space, and obeying causal constraints

spatial completion

filling in the box and rod as if its only two items - young infants think its 3

object perception

where does one object end and another begin

object segregation

the identification of separate objects in a visual array, motion, texture, color, pattern all aid this!

violation of expectation

used to see if infants expect partially hidden objects to be related or no

figure-ground relationship

organization of visual field into objects (figures) that stand out from their surrounding environment (ground)

proximity

groups nearby figure together

continuity (continuation)

smooth continuous patterns (ignore the 'broken')

inattentional blindness

depth cues

three classes:

- kinetic/motion-carried

- binocular depth

- static monocular/pictorial

kinetic depth cues

movement helps with perception of depth; using your movement and the objects movement (and the feelings in your eyes)

binocular depth cues

info from two eyes helps perception of depth

monocular (pictorial) cues

only need one eye to see depth (one kind is kinetic cues)

looming

takes up more of the visual field and see less background

zooming

takes up less of the visual field and see more background

optical expansion

movement-produced/motion carried depth cue, blink timing is important

motion parallax

kinetic depth cue using the difference you perceive in movement between near and far objects (closer objects look like they're moving faster than far objects), observed in 3.5-4 month olds

kinetic depth effect

as a viewer moves around stationary object, retina is presented with many images of the object (we see it as one 3D object)

binocular disparity

difference between the retinal image of an object coming from each eye (slightly different views from each eye)

stereopis

visual cortex fuses two different retinal images caused by binocular disparity into a single 3D image

convergence

the degree to which your eyes must turn inward to focus on an object (as it turns towards you)

interposition

if one object partially blocks our view of another, we perceive it as closer

linear perspective

parallel lines appear to converge in the distance, we see them as far away when they merge on the horizon

relative size

the larger an object appears, the closer the object is to the viewer

texture gradient

distant objects have blended/smoother texture than closer objects

shading/shadows

assumption of light from above (very powerful), and dimmer objects seem further away

reflections

nearby objects reflect more light into our eyes (assumption that light comes from above)

surface contours

2D image representations—lines, edges, or texture changes—that convey the 3D shape, curvature, and orientation of a physical object

Ames (trapezoid) window

optical illusion of a two-dimensional trapezoidal shape used to measure depth cues in infants

moro reflex

startle reflex when arms of baby thrust outward, then embrace as fingers curl - peaks at 1 month, begins to disappear at 12 weeks

deuteranopia (lack of green cones)

an inherited form of defective color vision in which red and green hues are confused; "green" cones are filled with "red" cone opsin

protanopia (lack of red cones)

an inherited form of defective color vision in which red and green hues are confused; "red" cones are filled with "green" cone opsin

tritanopia (lack of blue cones)

an inherited form of defective color vision in which hues with short wavelengths are confused; "blue" cones are either lacking or faulty

X-linked

A gene carried on the X chromosome. If a male inherits an X-linked recessive trait from his mother, he expresses that trait because the Y from his father has no counteracting gene. Females are more likely to be carriers of X-linked traits but are less likely to express them.

congenital

present at birth

Gestalt

broader name for the principles of perception (proximity, similarity, continuity, closure, and figure-ground)

deletion

covering of the farther object (motion-produced cue)

- ex. gradual occlusion of your moving hand as it passes behind the other hand

accretion

uncovering of the far object (motion-produced cue)

- ex. gradual reappearance of the moving hand as it emerges from behind your other hand

decibel

level or emplitude of an auditory stimulus

frequency

aspect of a wavelength that makes up pitch

resonance

A phenomenon that occurs when two objects naturally vibrate at the same frequency

timbre

harmonic structure of a tone that makes a sound unique among other sounds of the same pitch/loudness

ampiitude

one aspect of loudness of an auditory stimuli

approval

more frequency variation in pitch (goes higher)

disapproval

dull, more stagnant and lower frequency in pitch

pitch

high to low, fundamental frequency of a wavelength

localization

figuring out where sound sources are; infant reflex to turn head towards sound - disappears around 2 months, then re-emerges at 4 in a more sophisticated way

Why is it important to cognitive development whether an infant can perceive, categorize, and recognize a

visual stimulus? And auditory one?

infant perception, categorization, and recognition of stimuli is important for efficient learning (adaptation!), because then they're able to focus attention on new things.

What evidence is there to suggest that infants are capable of perceptual categorization? Color

categorization? phoneme categorization?

Quinn et. al cats vs dogs categorization experiment found that infants preferred the novel category!

Are infants capable of visual recognition? How does this ability develop?

yes, Fagan study from 1970s using habituation of human faces with varying delays (10s to 2 weeks) found preference for novel face at all delays for 5-6 month olds!

- same findings with patterns, cartoon drawings, and abstract drawings

What are motion-carried/ kinetic depth cues? When do they emerge?

when you use perceived relative motion (difference you perceive in movement between near and far objects) to identify depth; emerges around 3.5-4 months

Do infants have preferences with respect to voices? language? Music?

Infants prefer mom voice in native language, and have a preference for musical sounds (respond to rhythm in music, sensitive to melody)

What are binocular depth cues? When do they typically emerge?

when info from two eyes aids depth perception, emerges 3-4.5 months

What are monocular/ pictorial depth cues? When do they typically emerge?

pictorial depth cues are static and monocular (you only need one eye to perceive them); emerges between 5-7 months or later

What information about an object helps infants to understand object unity and object segregation?

color, texture, size, shape, and movement

What is the role of movement in an infant's understanding of object unity and object segregation?

movement helps represent objects as coherent and complete across time and space, making object unity/segregation easier than static objects.

What are the characteristics of Infant Directed Speech? Adult Directed Speech?

infant directed speech is characterized by a higher pitch, bigger pitch range (and octave), smoothed and connected pitch contours/more melodic; adult directed speech is more flat

U shaped curve

development isn't linear; usually skills are present, then disappear, then reappear at a more sophisticated level

color constancy

perception of familiar objects as having consistent color even when changes in light/shadow filter light reflected by object

color perception

ability of the brain to interpret differences in wavelengths as differences in color

color categorization

infants perceive and categorize color; organized and constrained by bio mechanisms of color vision and not just language

attention

when some sensory input is selectively processed over other information

overt attention

move eye to focus on a particular object/location

covert attention

shift attention without moving eyes

change blindness

difficulty detecting a difference even though it is obvious when you know to look for it

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