UCSD Psyc 102 Test 3

Perceptual organization

perceptual organization is how we group and perceive objects in our environment

What are two types of perceptual organization

grouping and segregation

Gestalt principles

Base organization principles by which our brain infers characteristics and processes visual information

List Gestalt principles

Good continuation: connected points resulting in straight or smooth curved lines are belong together

Pragnaz: Every stimulus is seen as possible

Similarity: similar looking things are grouped together.

Proximity: Things that are close together are grouped together

Common fate: things that are moving in the same direction are moving together

Common reigon: object segregated into specific reigons are grouped together.

Uniform connectedness: things that are connected are viewed as singular objects

Figure-ground segregation

The perceptual separation of an object from its background. depending on the organization of the object and background the brain prioritizes the object and views the background as the background.

Experiences can influence what is background and what is a figure, for example we associate sky blue colors with background as most external images have the sky as the background

Factors that determine figure-ground segregation

Color: lighter colors are associated with the backround

Position: Elements in the lower part of displays are more often viewed as figures of interest

Convex borders: shapes convex borders that are often viewed as the figure.

what did gestalt psychologists think experience and meaning contributed to perceptual organization

They thought it had low impact

What experiment showed that figure-ground can be influenced by the meaningfulness of the stimuli?

The gibson woman figure experiment

What does a scene contain

background elements, objects organized in meaningful ways with each other and the background

What is the difference between a scene and an object:

A scene is acted within, an object is acted upon

What did potter's research show about perception time for a scene

Average perception time is ~250ms

How did feifei ensure accuracy in detecting shorter that 250ms perception times in her experiment?

By using a mask shown after the test scene to ensure the afterimage of the scene did not remain on the retinas, giving the participants a longer time to perceive the image.

What was the shortest amount of time a person could percieve the roughest shapes of a scene as discovered by feifei?

27ms

What was the shortest amount of time a person could percieve the gist of a scene as discovered by feifei?

67 ms

List global features of scenes

Degree of naturalness

Degree of openness

Degree of roughness

Degree of expansion

Degree of color

What are the physical regularities people percieve the easiest?

Oblique effect: people perceive horizontals and verticals better than other orientations

Uniform Connectedness: Objects are defined by Areas of the same color or texture

homogenous colors and nearby objects have different colors

Light from above heuristic: generally assume lighting comes from the top and we group things together that way

What are sematic regularities?

Semantic regularities are internal heuristics we use to place things that make sense together, like a knife in a kitchen, which allows us to correctly identify correct groupings.

Theory of unconscious influence

Stimuli can be interpreted in more than one way, and by the likelihood principle: objects are perceived based on what is most likely to have caused the pattern.

What experiment used pictures of harrison fords face and control pictures to identify brain activity in the FFA

the Grill-Specter experiment, the neural processing was associated with the presentation and the response to the stimulus

Binocular rivalry

The competition between the two eyes for control of visual perception, which is evident when completely different stimuli are presented to the two eyes

Who created a brain activity decoder to estimate images based on brain activity

Kamitani and Tong

What were the two types of encoding used with kamitamni and Tongs experiment

Structural coding and Sematic coding

What are the parts of the brain that are associated with facial stimuli?

FFA: only reacts when a face is perceived

Amygdala (AG): activated by emotional aspects of faces

Superior Temporal Sulcus(STS): Responds to where the person is looking and mouth movements,

Frontal Cortex: Activated when evaluating facial attractiveness

Describe the visual clarity of infants

incredibly blurry, but as they age faces are some of the first things they identify.

What was the highest accuracy association infants had for faces

Top heavy configuration

Visual Scanning

Looking from place to place, fixating on specific things with saccadic eye movement

What is the difference between overt and covert attention

Overt attention is what you are directly looking at. Covert attention is what you percieve in the peripherals around what you are looking at

What characteristics of a scene direct our attention?

Stimulus Salience: areas of stimuli that attract attention due to their properties like color, contrast, orientatin, attentional capture,

What are cognitive factors that influence picture meaning?

Scene schema: Prior knowledge about what is found in typical scenes. What you fixate on is also influenced by this prior knowledge. Ex: Shinoda's experiment that determined that people are more likeley to detect stop signs at intersections because that is where we are used to seeing them.

Spatial Attention

the ability to focus on a particular position in space and thus to be better prepared for any stimulus that appears in that position

Task Demands

Task Demands override stimulus saliency

eye movements and fixations are closeley related to the action the person is about to take

Attention and cues

Information is most efficiently processeed when attention is being directed via cues

Elgy attention experiment

Showed observer two rectangles

cue signals where target may appear

task was to press button when target appeared

fastest reaction time at targeted position

enhancement for non-target in the same target rectangle

same object advantage

Carrasco experiment

Two grating stimuli showed to the left and right of a dot

target fixated on central point and was asked to identify which grating had higher contrast. cued object was often identified as higher contrast when the two were at the same contrast

Ocraven experiment

Attention to one part of mixed stimulus can influence what part of brain is activated more. Ex of overlapped face and house When overlapped images are shown,

Visual field attention and brain activity

As you attend to different parts of the visual field different parts of the brain are activated

What happens when we attend

increased perception

increased neurological response

Innatentional blindness

failing to see visible objects when our attention is directed elsewhere

change blindness

failing to notice changes in the environment; a form of inattentional blindness