Cognitive Psychology

refers to all processes by which the sensory input is transformed, reduced, elaborated, stored, recovered, and used

the scientific study of the thinking mind

• What is it?
• What are the contents?
• Where did those contents come from?
• How does the mind interact with the world?

• Information from the senses is incomplete/imperfect (cave analogy)
• Most knowledge exists innately (accessed by rational thought , may need appropriate cues)

• The one thing that can be known for sure is that we are capable of thinking
• Ideas and sensations are real, thus the world likely exists

• Emphasized ideas as the product of logical reasoning
• Contents of the mind are endogenous
• Mistrusts senses as source of valid information

Contents of the mind based on sensory input, observation

• John Locke
• David Hume

• Tabula Rasa
• First input: sensations
• Subsequent ideas through association of sensations and ideas

• Ernst Weber
• Gustave Fechner

• How does sensation become an idea
• Absolute/Difference thresholds
• Remains a sub-discipline of cognitive psychology

• Along with the introspectionist
• Investigated consciousness by direct inspection
• Consciousness the object of focus
• Either its parts or its purpose and action
• What are the contents and operations of the mind

• Phenomenological experience is not solely a product of bottom up activity
• whole perception: sum (parts, relationships among them) - the importance of stimulus context
• Early examples included the "Gestalt Laws of Perception"

• Emphasized empirical data
• behavior, not introspection
• Early framework: S-R
• Later approaches incorporated S-O-R

• Behaviorism
• Latent learning (rats learned a maze without direct reward in the goal box)
• Cognitive maps (rats learned context, not just S-R associations)
• A forerunner of investigations of cognition

• Mathematical theory
• Modeled state, effect of organism, set of the mind

• Developed in 1950s and 1960s
• Strict behaviorism couldn't address interesting questions about mental operations
• "New Look" - attempted to explain psychodynamic phenomena in behaviorist paradigm

• The central concept in cognitive psychology
• Based on computer metaphor
• Classic version: cognition occurs as a sequential series of events in which info is encoded,
• computations occur, and results used to influence behavior
• Modern version: parallel processing is emphasized

• Representation of sensory information
• Held for short duration (<500 ms for vision)

• Combination of sensory elements into an object
• activates all or part of a previously stored representation

• Attention: filter only allowing a subset of info for additional processing
• Selection: a post-identification filter

• The goal of info processing is the adaptive control of behavior
• Output allows the selection of the next behavior (action, speech, thought).

• A method for investigating IP
• Central concept: mental processing takes time
• Assumes that each sequential processing step takes time
• Adding operations takes additional time
• Increasing the difficulty takes additional time

• Donders
• By subtraction, we can calculate the time taken in specific operations
• Time for signal to travel from ankle to shoulder level in the spinal cord

usually refers to a clinical focus, specialization

• Brain cells
• Consist of: soma, dendrites (input), and axons (output)

• Support cells
• 10x more glial cells than neurons
• Provide nutritive and structural support
• produce myelin

• Insulation for axons
• made from lipids and appears white
• nerve fibers are white matter, cell bodies are gray matter

Electrical Signals --> Axon --> Synapse --> Action Potential

• Neuron have a voltage
• 70 mV more negative inside than outside
• Electricity travel across dendrite and move in all direction
• Get smaller the further away they are from the source

• Special molecules produce the action potential
• electrical signal that travels in one direction
• always the same size

• At the end of axon
• Terminal button releases chemical neurotransmitters
• drift across synapse
• received by molecules on dendrite
• bind to specific molecules like a key in a lock
• NT reception produces AP in receiving neuron

• Receive input at thousands of junctions
• Combination of synaptic activity determines whether a neuron will or won't produce an AP

• NP: the material and efficient cause
• NA: the formal cause (structure and morphology)

The layer of cells on the surface of the forebrain

Frontal, Parietal, Temporal, Occipital

The hills and valleys on the brain surface

• Interhemispheric Fissure
• Central sulcus
• Sylvian Fissure

• Auditory - Temporal Lobe
• Visual - Occipital Lobe
• somatosensory - Parietal Lobe, behind the central sulcus
• Motor cortex - Frontal Lobe, in front of the central sulcus

• Motor cortex is in the front
• Sensory cortices are in the back
• Motor is ventral, sensory is dorsal
• Same throughout the nervous system

a fiber tract connecting left and right hemispheres

Primary Visual cortes

• Found in the center of the brain
• Sits atop the spinal cord/brainstem
• Sensory/motor relay between cortex and other areas

• Part of the motor control system
• PET and fMRI studies indicate it may be important for cognitive function, as well

• Part of the 'limbic system'
• Important for motivation

• A set of structures deep within the forebrain
• Motor control

• In the temporal lobe
• Important for the formation of memory

• Arousal
• Sleep /wake cycles
• But also general alertness

• Phrenology
• Language localization: Broca and Wernicke
• Motor functions: Fritsch & Hitzig

• Flourens
• Lashley
• Mass Action
• Equipotentiality
• Hebb

Removed parts of dog brain and did not observe the changes predicted by phrenologists

Had rats learn a complex maze following removal of parts of cortex - looking for the engram (memory trace)

• Deficit depended upon the amount of cortex removed
• Specific location of the lesion was not important

• Each segment of cortex is capable of functioning like any other
• Differentiation is the result of experience, not intrinsic qualities

• Suggested that memory is a function of large parts of cortex
• The engram is a network of cells that re-wire themselves
• Memory is a function of a mass of cells
• A memory is spread across a network of cells
• A given cell may participate in many memory networks
• Cell Assemblies

• Many functions can be localized (sensory and language)
• Distributed networks control many functions (Perception, ID, Language, Attention)
• Within a given area, mass action and equipotentiality are valid
• Memory (Agnosia with lesions of ITG
• Perceptual encoding

• Oldest method for studying brain functions
• Problem: removal does NOT mean that the area was the 'center' of a particular function

• Nerve cells produce small electrical fields
• The sum of these fields is the EEG

• EEG may be time locked
• Random fluctuations average out over trials
• producing ERP
• Positive voltage peak at about 300 ms is called P300

• ERPs have excellent temporal resolution
• ERPs have poor spatial resolution

• An X-ray image of the brain assembled from multiple individual images
• Cons: Poor spatial resolution, doesn't show function well
• Pros: cost effective for diagnosing strokes, tumors, etc.

• Nerve cells need a lot of oxygen and glucose to function
• radioactive oxygen or glucose is injected and when atom decay they emit rays
• detectors compute location of decay by timing rays
• Use subtraction method to compare multiple conditions
• Pros: decent spatial resolution, shows functional changes
• Cons: high cost, spatial resolution still not great, low temporal resolution (30s)

• Pros: excellent spatial resolution, decent temporal resolution
• Large magnet causes alignment of molecules
• Second magnetic field is applied to cause some atoms/molecules to shift fields by 90 degrees
• scanner measures change in magnetic field
• different atoms/molecules/ return at different rates

• Computer uses field changes to construct a picture of the densities of different atoms/molecules
• Specifically mesures changes in oxygenated blood cells
• specifically de-oxygenated hemoglobin
• where is the brain using the most oxygen
• BOLD-blood oxygenation level dependent image

• Receptor cells - location of transduction
• Via thalamus
• Cortical project area
• mapping of receptor organ
• environment in represented in contralateral
• Primary cortex projects to secondary, association areas

• Receptor organ: Retina
• Receptor cells: Photoreceptors --> tranduce photons
• To thalamus: through RGC (retinal ganglion cell axons) in optic nerve
• Where in thalamus: Lateral Geniculate Nucleus (LGN)
• Coritcal Projection: V1, secondary corticies (dorsal: where and ventral: what paths)

• Retina: Network of neurons on back wall of eyeball
• Cones: central
• Rods: peripheral
• Fovea: (only cones)
• Blind spot: ganglion cell axons exit, blood vessels access eyeball

• Visual field centered at gaze fixation
• Each retina is mapped across V1
• left/right of gaze is processed in contralateral hemisphere
• above/below mapped around calcarine fissure

• Figure- Ground Perception
• Proximity
• Similarity
• Continuation

• Figure-Ground
• Proximity: reduction of horizontal differences = see as series of rows, reductions of vertical differences = see as column
• Similarity: if see patch of color tend to think of as one whole shape or that they belong together
• Continuation: if edge continues uninterrupted see as one object

• Sine wave:Based on how quickly object reflects/absorbs light
• Complex wave
• Properties:
• Spatial frequency: Cells in V1 are sensitive to different levels of spatial frequency
• Phase: distinguishes different stimuli based on what phase its in
• Contrast: amplitude of wave determines contrast

Cells in V1: there are more cells that respond to vertical and horizontal edges than oblique edges

• Retinal Ganglion Cell (RGC)
• Simple cortical cell
• Complex cortical cell
• Hypercomplex cell

receives info from lots of photoreceptors in a cricular patter

Converge on cell in V1 that responds to sequence of circular patterns = edge

responds to simple sine wave with horizontal, vertical, oblique orientation

Rows of circular field that responds to moving edge with particular orientation

In V2 oriented edge that's moving but it stops --> corner

• Spectrum -- Trichromaticity
• Cortical area V4
• Color constancy, Context Effects
• Color and After Effects, Pop-Out

• Consists of photons at various wavelengths
• Visible: 400-700nm

Three color receptors: cones, long-, medium-, short gama sensitivity and rods

• rods = respond to green and brightness/dimness
• cones = have long and short sensitivity

• V1 cell can respond to color --> blobs
• V4 = located along collateral sulcus, 1st major convergence of color info, output to ventral and dorsal streams, basic color processing goes to dorsal and ventral streams

• Reflected light depends upon light source
• Clothing matches when you dress indoors, but not outdoors
• Mutual inhibition of color-responsive cells

• Activation of a subset of cells by image (yellow, blue-green, rods in both locations)
• Blank screen - relative increased activation of other cells
• Can be observed with color and orientation sensitive cells

• Colorblindness
• X-linked effect
• Protonomaly
• Deuteranomaly

• X-linked effect
• Protonopia - no red
• Deuteranopia - no green
• Tritanopia - no blue

• Oculomotor cues : distance
• Binocular cues: two eyes
• monocular: organization

• Convergence: direction of each eye
• Accomodation: lens focus
• Increased muscle strain is a cue to proximity

Two different views: focus beyond the image, separate images on retina, perception of depth

• Interposition: One object in front of another
• Size: large is usually closer
• Perspective: distances converges on a vanishing poing
• Motion parallax: near items/far items move in opposite directions

V6 Flow fields vs. object movement, detects self moving v. object moving

Hair cells bend --> voltage change in membrane --> NT release --> spiral ganglion cells transport message to MGN of thalamus --> auditory cortex in temporal lobe

• Air pressure wave to motion tympanic membrane, ossicles, fluid in cochlea
• Displacement of basilar membrane bends hair cells

• Primary Auditory cortex
• Belt Region
• Parabelt region: anterior/posterior

Responsive to pitch

responds to combos of sound, complex stimuli

• analogous to ventral 'what' stream in vision
• sound recognition and identification

analogous to visual dorsal 'where' stream

• Pitch
• Intensity
• Timbre
• Location
• Masking

• Defined by frequency of sound
• Cochlea has labeled line place coding approach

frequency and rate coding

• place coding
• speech occurs where the overlap of place and rate coding is

The more cells that are firing the louder the sound

phase is the reason why we hear it as one sound and not multiple sounds

• Interaural Time Difference
• Interaural Intensity

• Most important cue
• Processed in the superior olive where circuits of cells respond to relative arrival time
• Broader bandwidth = better localization

Shadowing: a decrease in intensity on the opposite side of localization, most effective for high frequencies

head or the sound source to be moving

• Arrival times only give direction in one dimension
• equal arrival means source is at the midline
• Ambiguity is reduced by the pinna

• A 2nd auditory stimulus makes the 1st stimulus harder to detect
• Task is segregating two simultaneous stimuli
• Frequency overlap, similarity, and critical band increase masking (2 octaves)

• Is there a stimulus or not
• Has the stimulus changed or not

Auditory and Difference

Minimum stimulus magnitude which can be reliably detected

• Minimum change in magnitude detectable as a change
• The 'just noticeable difference' (JND)

• Pros: moderately quick
• Cons: can have considerable error due to bias in responding

• Pros: the most precise measurement of the threshold
• Cons: the slowest method

• Pros: Very quick
• Cons: most subject to error, very imprecise

Sensitivity and Bias

Goal is to determine when an actual signal occurs against the background noise

There is always a tendency to respond positively or negatively and that can be affected by experience

• Prosopagnosia
• Pure Word Deafness
• Luria's Pure Alexic Pt.

• Cannot recognize faces
• Can recognize voice and components of face

• Cannot recognize, comprehend speech
• Hearing otherwise intact

• Sudden onset acquired alexia
• Could see, comprehend speech

Context and relatedness to study scene

• Early computer model for visual perception/recognition
• Primary concern: identifying 3D objects despite variation in 2D shape
• 4 levels of representation:
• Retinal (image) level
• Primal sketch
• 2 1/2-D
• 3-D

• Pixels code level of brightness
• Flat image
• Like b/w TV picture
• Resolution: 8 bit (0-255)
• This is the info available to photoreceptor matrix

• Pixels coded as -127-0 and 0 - +127
• Algorithm searches for zero crossings
• edge
• line segment
• Contrast = magnitude of difference at edge
• Primal objects, 'blobs' are patches of light or dark w/border of zero crossings

• Algorithm computes edges, contrast ratios, and blobs
• probabilities for shading, contrast
• Builds image (proababilities for 3-D on a 2-D surface)

• Volumetric images are computed
• uses 'geon'-like template-elements to construct objects
• Incorporates Gestalt principles to estimate object shape

• Template Theories
• Feature Theories
• Structural Theories

• Feature (bottom-up approach)
• Examine letter for feature properties and compare those features
• Feature examples: edges, orientations, locations

• Concept driven
• Compare perceived objects with template

• Task is to indicate if letters are same or different
• Physical appearance
• Name
• Vowel/Consonant: vowels quicker than consonants

• Task, name the letter
• Tachistoscopically presented
• Subjects respond by voice

• Combines feature and template analysis
• Four levels of analyzer modules (daemons)
• Image, Feature, Cognitive, Decision

• Encodes the visual signal
• Extracts features: contrasts, edges, borders
• Each feature excites corresponding daemons in stage 2

• Analyze/Recognize features in the image
• Each daemon reports the strength of evidence for its feature
• Lines at a given orientation
• Curves
• Corners at a given orientation
• Combinations of features excites corresponding daemons in stage 3

• Daemon reports strength of its particular combination of features
• Lines meeting at oblique angle excite cognitive daemons representing A, Y, K
• Parallel lines excite cognitive daemons representing E,F,H,N,M,U
• Horizontal lines excite cognitive daemons representing A,E,F,H

• Listens to the pandemonium of shouting cognitive daemons
• Loudest daemon wins

• If the initial info processing involves
• sensory storage, filtering, pattern recognition, then reporting the output for awareness

• Pre-cuing: 10 items
• Simultaneous: 9 items
• Matches historical estimates of span of apprehension

• Letter recognition is affected by context
• implies data-driven processes are sensitive to top-down modulation

• Developed as explanation for WSE
• Letter ID/detection better in words than nonwords
• Better in words than for letters alone
• Combines top-down and bottom-up processing

• The bottom up activation of all compatible nodes at the next higher level
• The inhibition of other nodes at that level
• The inhibition of incompatible nodes at lower levels

• Developed as an alternative to IAM
• Explains acquired dyslexia
• speech/reading comprehension
• Primarily feed forward activation/ processing

• Formants
• Vowels
• Consonants

• Bands of sound energy
• Change across time = speech
• Lowest formant is principal pitch of voice

Relative position of formants

Rapid changes in formant positions

• Phonemic decoding - words, lexical nodes
• Parallels dual route model of reading

• Phonemic decoding
• Activates motor patterns for speech
• Mirror neurons
• Viewing speaker- biases perception = ventriliquism

• Phoneme units activated
• Inhibits lexical units of other phonemes
• Syntax and semantics modulates baseline activation of lexical units

• Structural Theory
• View Based Theory

• Pragnanz
• Proximity
• Similarity
• Common Fate
• Good Continuation

Perceived objects tend to be as simple as possible

Perceived objects tend to have components near to each other

repeated features are grouped into large 'objects'

Things moving in the same direction are grouped together

Points that, when connected, for straight or simple curved lines are perceived as belonging together

• Utilizes a shape alphabet
• Geons
• RBC proposed for recognition of "basic category level"

• Recognition of incomplete objects depends on geons
• Complex objects are more resistant to the removal of individual geons
• The relationship among geons is critical

Cues to shape obscured

Failure because of uncommon perspective

View

• Difficult to define...but you know when you are paying it
• What happens at the points of rest in the stream of consciousness

Difficulty organizing tasks and sustaining attention

• Ignores info from left side
• dressing, shaving, cancellation task, flower drawing, clock drawing
• Not poor sensory response, lack of attending

• Excessive scanning
• Hyper-aware of possibility of danger
• Easily distracted

• Unable not to stop thinking about depressing topics
• Concentrates well, but on one or one set of items
• Cannot disengage attention

• selectivity
• shiftable
• divisible
• a finite resource

• focuses processing and awareness on subset of sensory info
• when another focus is possible

Subject could only provide info about the speaker they were told to attend to, and only surface things (gender) in the other

• Selective Filter
• Limited capacity channel
• Detection-ID device

• All info analyzed for
• physical properties
• linguistic properties

• All info processed to the level of ID
• selection occurs after ID, info not passed to working memory decays quickly

• Paying Attention requires effort
• Attention functions like a spotlight
• Some things automatically attract attention: they "pop-out"
• There is a limited-capacity route to attention
• Different characteristics describe attention attracted automatically and attention directed by volitional control (controlled v. uncontrolled)

Attentions a limited resource