Cog Psych 2, 3, 4, 5, 6, 7,8, 9

Absolute Threshold

Minimum stimulus intensity detected 50% of the time.

Difference Threshold (JND)

 Smallest detectable difference between stimuli.

Weber’s Law

The ratio of JND to stimulus intensity is constant.

Fechner’s Law

Perceived intensity follows a logarithmic scale.

Signal Detection Theory (SDT)

Differentiating signals from noise, considering both sensitivity and decision bias.

Psychophysics

Studies the relationship between physical stimuli and perception.

Thresholds

Establish limits of perception.

Functional Imaging

Measures brain activity associated with cognitive tasks.

Decision-Making Models

Explain how we process uncertain information.

Trichromatic Theory

The theory that human color vision is based on three primary colors.

Opponent Process Theory

The idea that color perception is controlled by opposing retinal processes (e.g., red-green, blue-yellow)

Binocular Disparity

The difference in images between the two eyes, provides depth perception.

Affordance

The concept that objects suggest their use directly through perception (e.g., a chair affords sitting)

Bottom-up vs. Top-down Processing

Sensory-driven vs. knowledge-driven perception

Gibson's Direct Perception Theory

Suggests perception is immediate and does not require inference.

Gregory's Constructivist Theory

Perception is an active process of hypothesis testing.

Mental Representation

The way information is encoded, stored, and processed in the mind.

Analogical/Pictorial Representations

Resemble real-world objects (e.g., mental images)

Propositional Representations

Abstract and language-based (e.g., "The cat is on the mat").

Picture-like Representations

Function in their own spatial medium

Propositional Code

A different form of representing knowledge

Functional Significance

Images aid memory and cognition (e.g., pictures are recalled better than words)

Mental Rotation

Images behave like real-world objects in space

Image Scanning

The time to scan a mental image correlates with distance

Computational Model (Kosslyn)

Images exist in a spatial medium with defined limits and resolution.

Image generation, interpretation, and transformation are structured processes.

Cognitive Penetrability (Pylyshyn)

Definition: If beliefs/goals alter perception, then perception is not purely functional.

Example: "Imagining something means considering what it would look like if you saw it."

Evidence from Brain Studies

PET and fMRI show overlapping activation for perception and imagery.

Damage to the occipital cortex affects both perception and mental imagery

Double Dissociation

Some patients have imagery deficits but intact perception and vice versa

Aphantasia

The inability to form mental images (Zeman, 2010)

Embodied Cognition

Basic Premise: Cognitive processes are shaped by bodily states and interactions with the environment.

Embodied cognition studies

Handling rough objects affects perceptions of social interactions.

Sitting in a hard chair makes people less likely to compromise.

Holding a warm drink leads to perceiving others as more generous.

Functions of Vision

Object recognition (identifying what is in the environment)

Guiding action based on visual input

Perceptual Organization

How sensory units (lines, spots, etc.) form coherent objects

Gestalt Principles

Figure-ground

Proximity

Similarity

Symmetry

Good continuation

Closure

Pragnanz

Models of Object Recognition

Template Matching

Feature Analysis

Recognition by Components

Computational Model

Template Matching

Comparing perceived images to stored templates

Feature Analysis

 Breaking down objects into elemental features

Recognition by Components

Objects are constructed from primitive shapes called "geons"

Computational Model

Primal sketch (basic structure)

2.5D sketch (depth and spatial relations)

3D model (full object representation)

Bottom-Up Processing

Stimulus-driven perception

Top-Down Processing

Expectation and context-driven perception

Agnosia

The inability to recognize objects, people, or sounds despite functioning sensory organs

Apperceptive Agnosia

Failure in shape discrimination despite intact visual functions

Occipital lobe damage (e.g., CO poisoning, head trauma)

Associative Agnosia

Failure to attach meaning to objects despite adequate perception

Temporal and occipito-temporal damage

Prosopagnosia

face blindness

 Right hemisphere lesion, particularly in the occipito-temporal region

Pure Alexia

letter-by-letter reading

Capgras Delusion

Emotional recognition disruption despite intact face recognition

Types of ADHD

Inattentive Type

Hyperactive/Impulsive Type

Combined Type

Combined Type ADHD

Features of both inattentiveness and hyperactivity/impulsivity

Hyperactive/Impulsive ADHD

Excessive movement, difficulty waiting, impulsivity

Inattentive ADHD

Difficulty sustaining attention, forgetfulness, distractibility

Continuous Performance Tasks (CPTs)

Measure sustained attention and impulsivity

Visuo-Spatial Orienting Tasks (VOTs)

Assess spatial attention control

Conflict Resolution Tasks (CRTs)

Measure inhibition of automatic responses

Flankers Task

Evaluates attention network efficiency

Attention Network Test (ANT):

Alertness: Reaction time difference between cued and non-cued trials

Orienting: Responses to spatial cues

Control: Ability to manage competing stimuli

Inhibition Model (Barkley)

Core deficit: Poor response inhibition

Impact: Poor executive function, leading to inattention and impulsivity

Filtering out distractions

Interference control

Stopping an ongoing response

Delayed decision making

Inhibition of prepotent responses (Barkley)

Impulse control

 Cognitive-Energetic Model (Sergeant, 2005)

ADHD symptoms stem from dysfunction in energy regulation:

Key Insight: ADHD is linked to an inability to regulate energy and maintain task engagement

 Dopamine Transfer Deficit (DTD) Model (Tripp & Wickens)

Impaired dopamine response transfer to predictive cues

Weaker anticipatory dopamine release

Treatment for ADHD according to DTD model

Stimulants (e.g., methylphenidate) amplify dopamine responses to predictive cues

Behavioral Effects in DTD model

Difficulty sustaining effort

Poor delayed gratification

Impaired reinforcement learning

Normal Dopamine Process

Initial dopamine response to unexpected rewards

Over time, dopamine shifts to cues predicting rewards

Helps maintain motivation and behavior

Basic categories of attention

Alertness & Arousal

Vigilance

Selective Attention

Alertness & Arousal

Level of information extracted from surroundings

Vigilance

sustained attention over time

Selective attention

Filtering relevant stimuli while ignoring others

Models of Attention

Broadbent's Filter Theory (1958)

Treisman's Attenuation Theory (1960)

Deutsch & Deutsch Late Selection Model

Feature Integration Theory (Treisman)

Broadbent's Filter Theory (1958)

Early selection based on physical properties

Treisman's Attenuation Theory (1960)

Partial filtering with priority processing

Deutsch & Deutsch Late Selection Model

Selection at the response stage

Feature Integration Theory (Treisman)

Attention required for complex feature binding

Spatial Attention

Posner's Paradigm

Object-Based Attention

Posner's Paradigm

Spotlight metaphor, cueing paradigm

Object-Based Attention

Attention can follow objects rather than just spatial locations

Inhibition of Return

Harder to re-attend to previously attended locations

Inattentional & Change Blindness:

Perceiving without attention vs. failure to detect changes

Reticular Activating System (RAS)

Regulates arousal and alertness

Superior & Inferior Colliculi

Eye movement control, visual/auditory attention

Pulvinar Thalamus

Selective filtering and relay of information

Parietal Cortex

spatial attention, hemineglect syndrome

Cingulate Cortex

Conflict resolution, response selection

Executive Control Networks

Dorsal: Goal-directed attention

Ventral: Stimulus-driven attention

Hemineglect Syndrome Characteristics

Ignoring stimuli from one side (typically left neglect from right hemisphere damage)

Affects perception, reading, drawing, and even bodily awareness

Types of Neglect (hemineglect syndrome)

Egocentric: Based on body position

Object-based: Ignoring one half of an object regardless of spatial location

Neuropsychological Tests for hemineglect

Line Bisection Task

Cancellation Tasks

Copying and Drawing Tests

Recovery & Interventions for hemineglect

Sensory stimulation

Awareness training

Motivation-based therapies

Feature Integration Theory (Treisman):

Features detected automatically but need attention for binding

Explains visual search tasks and illusory conjunctions

Inattentional Blindness:

Failure to perceive unexpected stimuli due to lack of attention

Example: Own name detected but similar-sounding words are ignored