perc dev exam 2 from lecture

Why do studies of infant perception require that state be taken into account?

Infants are differentially responsive to stimuli as a function of state

Examples of infant state

Calm, comfortable, asleep, awake, mad, tired

What sensory registers or input are ignored when asleep?

Visual and auditory

What input is not ignored in any natural state?

Pain

In what states do infants perform better at visual tasks?

Awake, alert, non-irritable

Why might infants who spend more time in awake, alert, non-irritable states perform better at visual tasks?

More engaged with the environment, getting the information in and processing it better, state impacts how well you can process information; this is why you want a research center to look like a safe environment for information processing (not a doctor’s office)

What were the findings of a study assessing infants’ attachment with their mothers and response to visual stimuli (particularly social stimuli) in home at 1 and 3 months and in the lab at 3.5 months?

3 month olds more alert and awake than 1 month olds. For infants who were more awake at 1 month, longer fixation on social stimuli at 3 months

What is a geometric pattern?

High-contrast pattern, usually related to shapes (not faces)

What do social patterns look like?

Face-like or natural kind/living thing-like

Boys who were more awake at 1 month…

Fixated more on social stimuli at 3 months

What are the findings on maternal assessment of infant temperament?

Boys (but not girls) whose mothers viewed them as more fussy or demanding spend less time looking at geometric designs. Boys who were quieted by visual stimuli looked longer at social and geometric stimuli. Parents who were sleep deprived were more likely to call children difficult.

Describe each type of photoreceptor

Rods: detect only light and dark, very sensitive to low light levels (night vision). Cones: detect color, fine detail and are concentrated near the center of your vision (fovea)

Three types of cones in humans and percentages

Short wavelength blue (10%), medium wavelength green (30%), long wavelength red (60%)

Is there an overlap in visual range of cones? Why or why not?

Yes, it helps the brain to integrate signals from different colors we see

How many types of cones are present in normal color vision?

3

What is lack of color vision called? Describe

Color vision deficiency, often incorrectly called color blindness, which is very rare and means a total lack of cones. Partial or complete lack of cones in retina. Mostly congenital, passed from mother to son. Some happens later in life (disease, trauma, toxic effects of drugs, metabolic disease, or vascular disease).

What are some ways to test color vision? Describe

Ishihara’s tests: most common method, show colored circles with numbers that a person with color deficiency would not be able to see (and some only people with color deficiency would see and some everyone can see). H.R.R. test: often used in eye clinics. Specialized “plates” used to detect specific types of color vision deficiency (specific types of cones). D15 and D100: task to put colored circles in “order.
Tests saturation as well as hues (rods and cones).

Which type of color vision deficiency is most common?

Red-green

How common is red-green color vision deficiency, and how is it usually acquired?

Worldwide 8% of men and 0.5% of women. Mostly genetic (congenital) acquired deficiency. Age-related deficiency increases after 65 (metabolic, cardiovascular, vascular). Up to 12% in areas that are not very diverse.

What is protanopia?

Common type of red-green color blindness. Usually congenital. No short- and medium-wavelength red cones. Only blue and green. Typically X-linked, so more likely for males. Big driving risk. Many shades of red appear black. Dark brown = dark green, dark orange, dark red, dark blue/purple and black. Many shades of blue = reds, purples and dark pinks. Mid-wavelength greens = orange.

What is deuteranopia?

Common type of red-green color blindness. Overrepresented in XY individuals. Colorblindness society calls it “green blind”. Mid-reds = mid-greens. Blue-greens = grey and mid-pinks. Bright greens = yellows. Pale pinks = light grey/white. Mid-reds = mid-brown. Light blues = lilac. Processing colors differently because of lack of cones.

What is tritanopia?

Rarest type (very rare). Blue-yellow color blindness. Usually no problems with everyday tasks. Can be caused by head trauma, cataracts, alcohol, solvents. Can be reversed.

Why is it important to diagnose colorblindness in children?

We label things in colors for children often. Confusion about color could look like inattention, leading to misdiagnosis of ADHD.

What is color constancy?

Perception of familiar objects as having a consistent color, even when changes in light and shadow filter the light reflected by the object

When do children use light/shadow information for depth?

By 7 months

What is the consequence of babies being born with an immature fovea?

Babies at first have poor color vision

What type of receptor is the fovea full of?

Cones

What is the fovea responsible for?

Daylight vision, fine detail, rich color vision

What does preference mean in the context of color sensitivity?

Look longer at/look at

How is infant color sensitivity measured?

Different colored stripes against (compared to) a gray background; not high-contrast, to avoid confound

What is the developmental trajectory of infant color vision?

Not very good very early, but develops rapidly in the next few months

At birth, do infants appear to perceive the difference between white and color?

No

When does infants’ contrast vision become similar to adult color vision?

By 2-4 months

What are infants’ color preferences?

Prefer (look more at) unique, simple (red, blue, e.g.) single hues over combinations

How does infant color sensitivity progress?

Birth: gray vs red (vivid, simple; might prefer in right lighting/circumstances, but generally not great); 1 mo: gray vs blue; 2 mo: yellow vs green; 3 mo: yellow vs red; 3-4 mo: color vision is almost adult-like

How does infant color categorization work?

Change within hues not noticed as much as change between

Right hemisphere’s characteristics for representing color

Language-free, present from infancy; category - no language needed

Left hemisphere’s characteristics for representing color

Language-dominant, language-based categories acquired throughout development, usually dominates right-hemisphere color representations

What are some key points about infant color perception?

We create categories very quickly. Forming categories is important to understanding and perceiving the world. By categorizing color, babies may have an easier time processing and learning from the world. Some categories don’t have a label yet.

What is the Sapir-Whorf hypothesis?

Linguistic relativity. Structure of a language determines a native speaker’s perception and categorization of experience. Grammar, language you speak, verbal structure of your language influences way you perceive the world. Grammatical gender influences how you perceive nouns.

What is the debate over the origin of color categories?

Adults can discriminate between thousands of different colors. Language uses only a small number of terms for colors. Categories differ across language. Is color perception affected by language?

Infants do not have words (yet) for the color categories, so how do we test this?

Functional near-infrared spectroscopy (neural activity when presented with different colors)

How does fNIRS work?

Non-invasive. Optical imaging that measures neural activity by looking for metabolic changes that lead to differential absorption of infrared light in brain tissue. Infrared light transmitted to brain and absorption detected by optical fiber skullcap or headband.

What were the findings from the Yang et al. (2016) color sensitivity study?

5-month-old brains (pre-production) responded to a change from a color in one category to a different category (categorized like adults). Infant brains represent some color categories before learning label for them.

What were the findings of the Skelton et al. (2017) study? What did they do?

Infants have categories for red, yellow, green, blue, and purple regardless of language. Color categorization is partly organized and constrained by biological mechanisms of color vision and not arbitrarily constructed by language. They systematically mapped infants’ categorical recognition for hue onto stimulus array.

What do the two types of eye movements do?

Maintain focus as object goes further away/closer to you. Change gaze/follow an object. Try to get the thing that’s most interesting where you can see it the best (usually center vision). Direct gaze, explore.

What is optokinetic nystagmus?

Fixation on a point in a large pattern (typically high contrast, black and white stripes), following it with smooth eye movement until it is out of sight, eyes jerk back to the center of the visual field. Not dramatic or big, not saccades but a different type of eye movements. Can also be used to assess acuity. Optokinetic drum: eyes are kinda floaty, most sensitive test for visual acuity.

What is a saccade?

A rapid, ballistic eye movement that puts the object of interest into central focus (jerky). Eyes dart in the direction of something interesting (detail, color on the fovea).

How do saccades change as a function of age?

Get better. Very young infants often over- and undershoot targets. Infants are born with it.

What is a problem with saccades?

Disconjugate movement: eyes not moving in tandem (problem - not normal)

What is the difference between tracking and smooth pursuit?

Tracking is anticipatory and seen in non-human animals. Smooth pursuit only exists in primates. Newborns track single moving objects in an arc of 90 degrees. It develops by 6-8 weeks and continues to anticipatory pursuit.

How does scanning develop in infancy?

It gets better as a function of age. From 2 to 12 weeks, infants spend more time looking broadly at info presented to them. Very young infants look at areas of high contrast (hairline, eyes). At 1 month, infants scan perimeter of shapes, begin to refine to high contrast and eyes. By 2 months, infants scan perimeters of shapes and interiors (including eyes, high contrast) of shapes; “triangle” (important information: mouth, eyes).

What is attention?

Evolved brain processes. Some sensory input is selectively processed over other information. You can’t pay attention to everything. What’s important changes as a function of other stuff.

What are the two types of attention?

Overt attention: move eyes or perk up ears to focus on a particular object or location or a bit of information. Covert attention: shift attention without moving eyes.

What is the result of covert attention?

Neither thing is properly attended to. People are not good at multitasking (something has to give).

What is visual salience, and how does it influence attention?

Visual salience is when things stand out against a background. For example, a man in a red shirt stands out when surrounded by a lot of people in a white/light shirt.

What is attentional capture, and how does it influence attention?

Attentional capture is what stands out the most. Green circle is not as capturing as a red diamond, for example.

What does the painting memory task show about attention?

The observer’s interest and goals influence attention

What does the sandwich-making task tell us about attention?

Interaction with the environment/task demands influences attention.

Can we look directly at something and not see it? Explain.

We miss things that are out of our visual field, but we can also miss things we are looking directly at. Attention filters information, sometimes to the point where something is not encoded or does not reach the level of conscious awareness. For example, when asked to attend to the intersection of two lines, we might not notice squares appearing in the background at all.

What is inattentional blindness?

A failure to perceive fully visible objects or events that are unexpected or because your attention is directed toward another task

Why does inattentional blindness occur?

High cognitive load (keeping track of lots of things)/multitasking, narrowed attention, low base rate (unlikely in specific circumstances) of unexpected object or event

What does the invisible gorilla study tell us about inattentional blindness?

We can miss things we are looking directly at

What is change blindness?

Failure to notice significant changes in a visual scene because your attention is focused elsewhere or interrupted. Difficulty detecting a difference even though it is obvious when you know to look for it/where to look.

Why does change blindness happen?

Human visual perception, cognitive resources are limited. We rely on selective attention; do not capture every detail.

What are some ways to measure to measure change blindness?

Spot-the-difference scenes and person swap studies

What are the findings of research on infant object name learning with head-mounted eye tracking?

Older social partners name the object and look at it. Sustained attention: both people looking at an object >3 seconds. Joint attention: infant and parent looking at the same object at the same time.

How does the novelty preference method work?

Infants prefer (look longer at) novel over familiar stimuli. Show stimulus until familiar. Pair familiar and novel stimuli. If prefer novel, if they can distinguish (tell the difference).

Why is it important for infants to tell the difference between objects?

If infants cannot see similarities among objects, then they spend a lot of time studying the same thing over and over. Not very adaptive. But if can see similarities between things, then can focus attention on new things.

What are the developmental outcomes of faster habituation time in infancy?

Learning more later on, academic/cognitive achievement, higher IQ

What is the recognition method of memory testing?

Multiple choice questions are an example. Noticing whether identical/similar to a previously experienced stimulus.

What did Strauss & Cohen do in their study?

Habituated 5-month-olds to objects with particular size, color, form, and orientation. Tested on an alternative object with one of those attributes being different.

What did Strauss & Cohen find from their study?

Immediate test (no delay post-habituation): all four attributes remembered. 15-minute delay: color and form remembered. 24-hour delay: form remembered.

What are some characteristics of the recall method of memory testing?

Essays are an example. Remembering a stimulus or event when it is not present. Retrieval of information from memory. Requires more mental effort than recognition. More difficult memory task. Harder to test in infants.

What does habituation tell us about memory?

Recognition of stimulus: subsequent habituation trials decrease in duration. Can last for days to weeks, depending on stimulus. Only perfect practice makes perfect. Practice makes permanent.

What did Quinn et al. (1993) do for their study on infant perceptual categorization? What did they find?

They randomly assigned 3- to 4-month-old infants to one of two different conditions (cats, dogs). For six familiarization trials, they showed the infants side-by-side photos of different cats or dogs (depending on condition). Then they showed the infants two photos, one of a novel cat and one of a novel dog. Infants looked longer at the novel category (dog if they were familiarized with cats, cat if they were familiarized with dogs).

What are some examples of categories used in experiments that found that infants are capable of perceptual categorization?

Dogs and cats, dogs and birds, horses and giraffes, chairs and couches

Why is it important that infants remember and recognize things they’ve seen?

They can create a prototype, process it, and move on to learn about new things. Being able to recognize something = efficiency in learning about the world.

What have studies by Fagan (1970) shown about infants’ ability to recognize stimuli after a delay? What were their methods?

Five- to 6-month-old infants were familiarized with two side-by-side identical faces. After a delay ranging from 10 seconds to 2 weeks, they were shown a familiar face next to a novel face. They looked longer at the novel face at all delays. There were similar results with abstract drawings, patterns, baby faces, and cartoony drawings. Infants are capable of long-term visual recognition.

Infants and children who struggle with the figure-ground relationship have difficulty…

learning to read

What is the figure-ground relationship?

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

What are some ways we tend to organize things?

Proximity: group nearby figures together. Continuity: smooth continuous patterns (ignore the “broken”). Closure: fill in gaps to create whole objects (illusory triangle).

How do we know that infants can organize objects via closure?

Infants can habituate to shapes with missing pieces as if they are full shapes.

What are some milestones in the development of pattern perception?

2-month-old infants can analyze and integrate separate elements of a visual display into a coherent pattern. 7-month-olds see an illusory square.

What is subjective contour?

Visual illusion that evokes perception of an edge or figure

How old are infants when they respond to subjective contour? What other species can do this?

7 months. Cats can also do this.

True or false: subjective contour can make a figure “look” brighter than the background

True

In the Berthenthal study, how old were the infants when they could perceive coherence among moving elements?

3 and 5 months.

What are the two types of perceptual constancy?

Shape: you can still perceive the real shape and slant of objects regardless of what is projected on the retina. Size: an object is perceived as having a constant, stable size, regardless of changes in its distance from the observer or the size of its image on the retina.

What is Emmert’s Law (1881)?

If retinal images of two different objects at different distances are the same, the physical size of the object that is farther away must be larger than the one that is closer

What do looming and zooming mean in terms of size constancy?

Looming: moving closer to us. Zooming: moving farther away from us. An object is not shrinking or getting bigger just because it is zooming or looming.

What did Granrund do in the physical vs. retinal size study? What was found?

Habituated one group of 4-month-olds to a 6-cm-diameter disk at a distance of 18 cm. Habituated another group of 4-month-olds to a 10-cm disk at 50 cm. So one was smaller and closer, and one was larger and farther. For the test trials, both types of disk were presented side by side at a distance of 30 cm. For each infant, one object had a novel physical size but a familiar retinal size, and the other had a familiar physical size but a novel retinal size. They looked longer at test objects with novel physical sizes. This suggests that infants understand the relationship between physical size and distance when they view objects at different distances.

What did Slater et al. (1990) do for their study on size constancy in newborns? What did they find?

They showed newborns a large or small cube at varying distances. The size remained the same throughout, but the size of the retinal image changed from trial to trial. In the test trial, the infant is presented with the original cube or another cube that is twice as large and twice as far away. They looked longer at the new cube. This suggests that they could tell the difference in spite of the cubes having the same retinal size.

What is the most familiar object to infants?

Faces

Why is the reaching/grasping paradigm used for studies of infant depth perception?

Infants reach for things they think they can grasp or touch

What was the procedure of the mother’s face study? What was found?

The infant was shown an image of their mother. Lighting in the room was arranged such that it appeared that the infant was looking at the actual mother’s face and it was far away. Then the image was made larger. The infant then reached to touch the face.

What was the procedure of