Vocabulary Terms for Chapters 5, 6, & 7

Inverse Projection Problem

Similar image on the retina can be caused by an infinite number of objects.

Occlusions

When objects are hidden or blurred from our vision (such as when a notebook sitting on top of a pencil hides the pencil from view).

Viewpoint Invariance

The ability to recognize an object regardless of the viewpoint. (No matter what angle you're looking at an object from, you will still know what the object is!)

Perceptual Organization

The process by which small elements become perceptually grouped into larger objects. (Just like that example with spotting the dog in the black & white image in class, it looked like a bunch of random black and white spots, until our eyes and brain worked to put together a picture & identify/organize what we were looking at!)

Grouping

In perceptual organization, the process by which elements in the environment become perceptually "put together" (grouped) into units or objects.

Segregation

The process of separating one area or object from another.

Structuralism

Established by Wilhelm Wundt. States that perceptions are created by combining elements called sensations.

Gestalt

States that perceptions cannot be created by combining elements called sensations. "The whole differs from the sum of its parts".

Good Continuation (Principle of Continuity)

Connected points resulting in straight or smooth curves belong together. Lines are seen as following the smoothest path.

Pragnanz (Principle of Good Figure/Simplicity)

We prefer experiences that are simple & orderly, & that will simplify complexity. When you're presented with a set of ambiguous or complex objects, your brain will make them appear as simple as possible.

Similarity

Similar things are grouped together.

Proximity

Things that are near to each other are grouped together.

Common Fate

Things moving in the same direction are grouped together.

Common Region

Elements in the same region tend to be grouped together.

Uniform Connectedness

Connected region of visual properties are perceived as a single unit.

Closure

If presented with a stimulus that contains missing elements, the mind will fill in those gaps to create the perception of a completed image.

Figure-Ground Segregation

Determining what part of the environment is the figure so that is "stands out" from the background. The figure is more "thing like" & more memorable than the ground. The figure is seen in front of the ground. The ground is more uniform & extends behind the figure. (Basically, distinguishing what's the background and what's the figure we are seeing).

Objects

Compact & acted upon.

Scene

Is extended in space & acted within. A view of a real-world environment that contains background elements * objects organized in meaningful ways with each other in the background.

Gist of a Scene

Identifying important properties of a scene after viewing them for a specific amount of time. This is a general description of the type of scene.

Global Image Features

Information used by an observer which can be perceived rapidly & is associated with specific types of scenes.

Degree of Naturalness

Natural scenes, such as the ocean & forest have textured zones and undulating contours; man-made scenes (street) are dominated by straight lines & horizontals & verticals.

Degree of Openness

Open scenes (oceans) often have a visible horizon line & contain fewer objects. The forest is an example of a scene with a low degree of openness.

Degree of Roughness

Smooth scenes (low roughness) like the ocean contain fewer small elements. Scenes with high roughness like the forest contain many small elements & are more complex.

Degree of Expansion

 The convergence of parallel lines (e.g., looking down railroad tracks that appear to vanish in  the distance, or in a street scene) indicates a high  degree of expansion. 

Color

 Some scenes have characteristic colors (e.g., ocean: blue, forest: green, and brown.

Physical Regularities

Regularly occurring physical properties of the environment.

Oblique Effect

People perceive horizontals & verticals more easily than other orientations.

Light-from-Above Heuristic

Light in natural environment comes from above us.

Semantic Regularities

Patterns or rules that exist in how types of objects or concepts appear in the world. For example, semantic regularities can describe the typical contexts, properties, or interactions of objects or concepts. They are learned from experience & can help us understand & predict the world better.

Scene Schema

The knowledge of what a given scene typically contains. (EX: A kitchen typically contains knives, forks, ovens, etc. Our ideas of what they contain).

Likelihood Principle

Objects are perceived based on what is most likely to have caused the pattern.

Theory of Unconscious Interference

Established by Helmholtz. To explain why stimuli can be interpreted in more than one way.

Binocular Rivalry

Through colored glasses, one image is presented to the left eye, a different one to the right eye, & perception alternates back & forth between two things.

FFA

Fusiform Face Area. Responds only to faces.

PPA

Parahippocampal Place Area. Responds to places.

EBA

Extrastriate Body Area. Responds to bodies/body parts.

Neural Mind Reading

Using a neural response to determine what a person is perceiving or thinking, usually by fMRI.

Structural Encoding

Based in voxel activation & STRUCTURE of a scene (lines, contrasts, shapes, & textures).

Semantic Encoding

Based in voxel activation & the MEANING or category of a scene.

Amygdala

Activated by emotional aspects of faces.

Superior Temporal Sulcus (STS)

Responds to where the person is looking & to mouth movements.

Frontal Cortex

Activated when evaluating facial attractiveness.

Attention

The process of focusing on some objects while ignoring others.

Visual Scanning

Moving the eyes to focus attention on different locations on objects or in scenes. (Basically, scanning a scene with your eyes).

Fixations

The brief pause of the eye that occurs between eye movements as a person scans a scene. (Pauses while scanning a scene).

Saccadic Eye Movements

Rapid eye movement between fixations that occur when scanning a scene. (Basically, the eye moving really fast while scanning a scene).

Overt Attention

Attention that involves looking directly at the attended object.

Covert Attention

Attention without looking; (EX: seeing something "out of the corner of your eye").

Visual Saliency/Salience

Areas of stimuli that stand out/attract attention because of their physical properties. (EX: bright colors, high contrast, etc.).

Attentional Capture

When stimulus salience causes an involuntary shift of attention. (EX: Sudden movement or loud sounds can capture our attention to warn us of something dangerous like an animal or object moving rapidly toward us).

Saliency Map

A "map" of a visual display that takes into account characteristics of the display such as color, contrast, & orientation that are associated with capturing attention.

Scene Schemas

Observer's knowledge about what is contained in typical scenes.

Task-Related Knowledge

An observer's knowledge of the goals & the task at hand used to guide the eyes during a visual task.

"Just in Time" Strategy

Eye movements occur just before we need the information they will provide.

Spatial Attention

Attention to a specific location.

Same-Object Advantage

The faster responding that occurs when enhancement spreads within an object.

Attention Maps

Created by Datta & DeYoe (2009). Show how directing attention to a specific area of space activates a specific area of the brain.

Local Field Potential (LFP)

An electrical response recorded with electrodes placed on the surface of the brain, which measures electrical signals from thousands of neurons near the electrode.

Coherence

Indicates the degree to which two signals are synchronized.

Binding

The process by which features are combined to create our perception of a coherent object; can also occur across senses, as when sound & vision are associated within the same object.

Binding Problem

The problem of how neural activity in many separated areas in the brain is combined to create a perception of a coherent object.

Feature Integration Theory (FIT)

A theory proposed by Anne Treisman to explain how an object is broken down into features & how these features are recombined to result in a perception of the object.

Preattentive Stage (of Perceptual Processing)

An automatic & rapid stage of processing, during which a stimulus is decomposed into individual features. Occurs before we focus attention on an object.

Focused Attention Stage (of Perceptual Processing)

The stage of processing in which these independent features are then combined into a coherent perception.

Inattentional Blindness

People can be unaware of clearly visible stimuli if they aren't directing their attention to them.

Change Blindness

Difficulty in detecting differences between two stimuli that are presented one after another, often with a short blank stimulus interposed between them, or short temporal gap (EX: blinking/looking elsewhere). Also occurs when part of the stimulus is changed very slowly.

Task-Irrelevant Stimuli

Stimuli that don't provide information relevant to the task at hand.

Load Theory of Attention

Lavie's theory that the amount of perceptual capacity that remains as a person is carrying out a task determines how well the person can avoid being distracted by task‐irrelevant stimuli. If a person's perceptual load is close to perceptual capacity, the person is less likely to be distracted by task‐irrelevant stimuli.

Perceptual Capacity

The resources a person has for carrying out perceptual tasks

Perceptual Load

The amount of a person's perceptual capacity needed to carry out a particular perceptual task.

Ecological Validity

An ecologically valid experiment matches its stimuli, conditions, & procedures to those present in the natural world.

Ecological Approach to Perception

Focus on the moving observer & identifying information in the environment that the moving observer uses for perception. Called ecological approach because they focus on perception in NATURAL contexts.

Optic Flow

Appearance of objects as the observer moves past them. AKA, Optic Flow Field.

Gradient of Flow

Difference in flow as a function of distance from the observer. Provides information about HOW FAST the observer is moving.

Focus of Expansion (FOE)

Point in distance where there is no flow.

Invariant Information

Information that remains constant regardless of what the observer is doing or how the observer is moving. Together with FOE provides information about how fast you are moving & where you are heading (part of depth perception).

Self-Produced Information

When a person moves, that movement creates information, & this information, in turn, is used to guide further movement. (EX: Somersaulting/Backflip)

Visual Direction Strategy

A strategy used by moving observers to reach a destination by keeping their body oriented toward the target. (EX: Walkers correct when target drifts to left or right.

Spatial Updating

Process by which moving observers keep track of their position within a surrounding environment when they move.

Wayfinding

The process of navigating through the environment to distant destinations that aren’t visible from our starting point. Involves perceiving objects in the environment, remembering objects & their relation to the overall scene, & knowing when to turn & in what direction (EX: When we walk across campus from one class to another or drive to a destination miles away).

Landmarks

Objects on a route that serves as a cue to indicate where to turn; a source of information for wayfinding.

Decision-Point Landmarks

Objects at CORNERS where the subjects had to decide which direction to turn.

Non-Decision-Point Landmarks

Objects located in the MIDDLE of corridors that provided NO critical information about how to navigate.

Topographical Agnosia

A condition associated with brain damage (in the parahippocampal gyrus) in which patients are unable to recognize landmarks in real-world environments.

Cognitive Map

A mental map of the spatial layout of an area of the environment.

Place Cells

Neurons that fire only when an animal is IN a certain place in the environment.

Place Field

AREA of the environment within which a place cell fires.

Experience-Dependent Plasticity

Experience impacts the biological organization of the brain.

Affordance

The information specified by a stimulus pattern indicates how the stimulus can be used (EX: seeing a chair as something to sit on or a flight or stairs as something to climb).

Ventral Pathways (WHAT)

Processing stream for perceiving objects.

Dorsal Pathways (WHERE/HOW/ACTION)

Processing stream for acting on objects.

Partial Reach Region (PRR)

A network of areas in the parietal cortex that contains neurons that are involved in reaching behavior. Contains neurons that control reaching & grasping.

Mirror Neurons

Neurons in the premotor area of the monkey’s cortex that responds when the monkey grasps an object & also when the monkey observes someone else (another monkey or the experimenter) grasping the object.

Mirror Neuron System

Network of neurons hypothesized to play a role in creating mirror neurons.

Traditional Approach to Perception

Focused on how the environment is represented in the nervous system. Purpose of perception is to create a mental representation of something in the environment.

Action-Based Approach to Perception

Purpose of perception is to guide our actions in the environment, enabling survival.

Action‐Specific Perception Hypothesis

Turn around from “action depends on perception” to “perception depends on action”.