cognitive psychology exam 1

intro, neural basis, vision, recognition

introspection

observing and recording your own thoughts and experiences without interpretation

Wundt and Titchener

behaviorism

• created as a response to the limitations of introspection

• focused on observable behaviors and stimuli

• learning history is available and can be objectively studied

• less subjective

• measurable

watson, skinner, pavlov, thorndike

problems with introspection

• some thoughts are unconscious

• thoughts are not directly observable or measurable

• self reports may not accurately reflect the conscious experience

problems with behaviorism

• did not allow for the study of unobservable mentalistic notions (beliefs, expectations, goals)

• stimulus response accounts are not enough to explain behavior

• cannot accurately study and explain behavior without considering mental causes

blackbox

cognitive interpretation between input and output

beliefs, expectations, goal

the cognitive revolution was based on two ideas

1. the mental world cannot be studied directly

2. the mental world must be studied in order to understand behavior

transcendentalism

• reason backward from observations to determine the cause

• inference to best explanation

• helps make inferences about what happens in the blackbox

Kant

cognitive psychology

study of the acquisition, retention, and use of knowledge

mental processes underlying human behavior

focuses on understanding how individuals perceive, think, remember, learn, solve problems, and make decisions.

How do cognitive psychologists study mental events?

Indirectly --

• Measure stimuli and responses

• Develop hypotheses about mental events

• Design experiments to test the hypotheses

process of research in cognitive psychology

• form hypothesis

• derive predictions from hypothesis

• collect data to test predicions

• confirm, modify, or reject hypothesis

possible methodologies

• performance or accuracy

• response time (RT)

• cognitive neuroscience

• study of brain and nervous system to understand mental functioning

• cases of brain damage or impairments

• neuroimaging techniques

model predictions for RTs

• parallel model

• serial self-terminating model

• serial exhaustive model

(serial self exhausted is supported by the data)

paralel model

Search all of them at the exact same time

Doesn’t matter how big the list is you have the exact same reaction time

compare all at once, make decision

Flat line on graph

Tuning fork

serial self-terminating model

Stop once you find the match

serial exhaustive model

Two possibilities

Yes/no have same slope...

looking at everything before making a decision

supported by the data

capgras syndrome/delusion

difficulty with emotional analysis of faces

recognize that people look like their loved ones but believe they are imposters

Missing emotional evaluation

damage to amygdala (emotional)

damage to prefrontal cortex (logical)

principle structures of the brain

hindbrain

midbrain

forebrain

hindbrain functions

• Essential for survival

• controls key life functions

• unconscious

• Basic rhythms--heart beat, breathing

• Alertness

• posture and Balance

hindbrain structures

atop the spinal cord

• pons

• medulla

• reticular formation

• cerebellum

midbrain

sits above the hindbrain

• sensory relay

• Coordinates eye movement

• Includes parts of the auditory pathways

• Regulates the experience of pain

forebrain functions

Most cognition happens in the forebrain

forebrain structures

Cortex convolutions

Subcortical structures

4 lobes

• frontal lobe

• occipital lobe

• parietal lobe

• temporal lobe

forebrain: subcortical structures

• Thalamus: sensory relay and integration

• Hypothalamus: simple motivated behaviors (4 Fs: fight, flight, feed, fuck)

• Limbic system

  Amygdala: emotional processing

  Hippocampus: learning and Memory

cortex cerebral lobes

Thalamus, hypothalamus, limbic system (amygdala, hippocampus)

which side of the brain is the language center

left side

brocha area

wernick area

split brain

• Severed corpus callosum

o treatment for severe epilepsy

o limits communication between the hemispheres

• Evidence for some hemispheric specializations of functions

spatial/attentional neglect

deficit in attention

Neglecting events in the world as well as mental images

Not a sensation problem but a perception problem

ID: half daisy or half clock

3 different steps of attention

1. disengage

2. shift

3. engage

prosopagnosia

Patients cannot recognize familiar faces, maybe including their own.

They can describe the face and its expression but cannot recognize it.

structural brain imaging techniques

Wants to create 3D map

• CT

• MRI

functional brain imaging techniques

wants to measure activity

• PET

• fMRI

• EEG

Indirect brain behavior measurement techniques

• PET

• MRI

• CT

direct brain behavior measurement techniques

EEG and single cell recording

electrical measures measure neural activity directly

explicit memory

conscious recall of previously learned information

facts

implicit memory

unconscious

things you were not aware of (includes classical conditioning)

lateral inhibition

A pattern in which cells, when stimulated, inhibit the activity of neighboring cells. In the visual system, lateral inhibition in the optic nerve creates edge enhancement.

Computerized axial tomography CT

• Uses X-rays to take pictures of slices of tissue on an axis

• Radiation similar to what you get on a long flight

• Better for bones

• Lower resolution

detect brain structures, not activity

Magnetic resonance imaging MRI

• Uses magnetic fields and radio frequency pulses to produce pictures of organs

• Better for soft tissue

• No radiation

• Very powerful superconductor

detect brain structures, not activity

Positron emission tomography PET

measures metabolic or biochemical brain activity

If the brain is more active, it demands more glucose

Strength: spatially locating neural activity (where?)

Weakness: temporally locating neural activity (when?)

functional magnetic resonance imaging fMRI

observes and maps brain activity by detecting changes in blood flow

BOLD

blood oxygenation level dependent

Strength: spatially locating neural activity (where?)

Weakness: temporally locating neural activity (when?)

Electroencephalogram EEG

Records electrical communication within neuron

• Firing of action potentials in a neuron

• Millions of neurons create an electrical field

Strength: temporally locating neural activity (when?)

Weakness: spatially locating neural activity (where?)

subtraction method

Brain is always active

Find the difference between resting and active

III0I - IIIII = 000-I0

how to overcome limitations of neuroimaging techniques

combine techniques

use TMS for causal evidence

Transcranial magnetic stimulation TMS

• Magnetic pulses activate neurons

• Produces temporary lesions

• Provides causal data

does not measure brain activity or structure

spatial resolution

exactly where

the ability of a neuroimaging technique to distinguish between two separate points in space, effectively determining how detailed an image can be

the capacity a technique has to tell you exactly which area of the brain is active

temporal resolution

exactly when

the duration of time for acquisition of a single frame of a dynamic process

It is a measure of how quickly data is collected or how frequently images are captured over the same geographic location

ability to tell you exactly when the activation happened

primary projection areas

Regions of the cortex that serve as the brain's receiving station for sensory information (sensory projection areas) or as a dispatching station for motor commands (motor projection areas)

damage to association cortex results in

• Apraxia—movement

• Aphasia—language

• Prefrontal damage—planning, strategic thinking, inhibition

• Agnosia—identifying objects

associative agnosia

Recognition Issue: individuals can perceive the overall structure of objects but cannot associate this perception with stored knowledge about the object.

can describe the object

can perceive and bind basic elements but not

able to associate that representation with what they have in memory. Can copy drawings but not able to recognize them

appreciative/apperceptive agnosia

Perception Issue: Individuals have difficulty perceiving the overall structure of objects.

can perceive basic elements but cannot put

these elements together and identify the object. Drawing an

object will have all elements but will be a mess. Drawing from

memory is intact.

Two methodologies for assessing brain-behavior function

1. Impairments after damage to the brain (e.g., lesions), which we examine for loss of a function, compared to normal functioning brain.

2. Indirect (brain imaging) and direct (EEG) measurement of cognitive activities in intact brains

Glia

• Guide development of nervous system

• Repair damage

• Controls nutrient flow

• Electrical insulation speeds signal transmission (myelin sheath around some axons)

Neuron strucure

Dendrites: detect incoming signals

Cell body: contains the nucleus and cellular machinery

Axon: transmits signals to other neurons

all or none law

an action potential is fired only if the threshold is reached.

The electrical signal is always of the same magnitude.

perception

how the brain interprets stimuli

• Transformation of physical energy into psychological experience

• What we see is not just determined by the stimuli in front of our eyes, but also our brains interpretation of that stimulus

perceptual system

Operates to generate hypotheses about what objects are being perceived, given the available data

sensation

what the body feels

Describing things in the most basic form

akinetopsia

unable to perceive motion

See “nothing” between locations

animation with low FPS

3 main layers of the retina

• Photoreceptors (rods and cones)

• Bipolar and ganglion cells, whose axons make up the optic nerve.

• Horizontal and amacrine cells, allow for lateral interaction

Cones

• mostly in the center (fovea)

• color sensitive

• higher acuity

• lower sensitivity

Rods

• periphery of the retina

• color blind

• lower acuity

• higher sensitivity

blindspot

There are no photoreceptors on top of the optic nerve.

This creates a blindspot ~18 degrees outwards from directly where you are looking

floaters

debris in your eye that are floating down toward the retina

Purkinje Trees

blood vessels become visible when light is shined in peripheral

used to the shadows on that side of the retina cast by the blood vessels but changes when the light is shined in your peripheral

sensory adaptation/stabilization

things that are usually fixed in our eye we “subtract out” of our vision

visual information in the eye

Photoreceptors

Bipolar cells

Ganglion cells and the optic nerve

visual information in the thalamus

Lateral geniculate nucleus (LGN)

visual information in the cortex

V1—the primary visual cortex, located in the

occipital lobe

single cell recording

• A neuron’s firing rate, or frequency of action

potentials, is recorded as various visual

stimuli are presented

• Investigators manipulate what is being shown

and then record how often the cell fires

• This allows us to determine what stimulus

characteristics influence the cell’s firing

receptive fields

size and shape of the area certain cells respond to

the what system

temporal

• identification of objects

• Occipital-temporal pathway

• What goes wrong: Visual agnosia

the where system

parietal

• Location of objects

• Occipital-parietal pathway

• What goes wrong: Problem reaching for seen objects

binding problem

parallel processing splits up the problem, but we do not see the world as disjointed

how our brain integrates different types of sensory information to form a unified perception of an object

When we perceive an object, our brain processes various features like color, shape, texture, and motion separately in different areas

factors that help solve the binding problem

• Spatial position

• Neural synchrony

spatial position

the visual areas processing features like shape, color, and motion each “know” the spatial position of the object

features detected in the same location are likely to belong to the same object

By mapping features to specific locations, the brain can keep track of which features belong together, helping to integrate them into a single perception

neural synchrony

the visual areas processing features of the same object fire in a synchronous rhythm with each other

The timing of neural firing helps bind features together, ensuring that the brain perceives them as a cohesive whole

conjunction errors

correctly detecting the features but making errors regarding how the features are bound together

top down processing

• relies on perception

• concept driven

• knowledge or expectation driven effects

• We already have an understanding of the whole and we go from the whole down to the specific parts

• Using an understanding of the big picture to reason about the individual pieces

• Memory knowledge prior experiences

• external

bottom up processing

• relies on sensation

• data driven effects

• Using individual pieces of information to make sense of the big picture

• identify the sensation before you start interpreting it

• simple visual features

• sensory input

optical illusions

a misperception (seeing something other than the truth)

demonstrate the gap between what exists and how our minds interpret it

evidence that our perceptual systems generate hypotheses about what objects are being perceived, given the available data

rare because our minds have

evolved to have interpretations that almost

always work in our environment

gestault principles

• Similarity

  • We tend to group like things together

• Proximity

  • Things close together are grouped together

• Good continuation

  • Even if you cant see what is happening in the background

• Closure

  • If the angles line up right

• Simplicity

  • General foundational principle

  • Simplest possible explanation

  • Least amount of items

constancy

Despite sensory information changing, object properties can appear as constant

perceptual constancy

• Shape constancy: We recognize an object as having the same shape even when viewed from different angles

• Brightness/color constancy: We see an object as having the same color under different lighting conditions

• Size constancy: We perceive an object as having the same size even when its distance from us changes

binocular disparity

each eye receives different stimuli

Two Eyes, Two Views: Because our eyes are about 6-7 cm apart, each eye views the world from a slightly different angle.

Disparity: This difference in the images is called binocular disparity. The brain uses this disparity to calculate the distance to objects.

Depth Perception: By comparing the two images, the brain can create a 3D perception of the world, allowing us to judge depth and distance accurately

monocular distance cues

depth cues that can be perceived using just one eye

• Interposition/overlap: When one object overlaps another, the overlapping object is perceived as being close

• linear perspective: Parallel lines appear to converge as they recede into the distance, like railroad tracks meeting at the horizon

• texture: Textures become denser and less detailed as they move farther away.

• shading: The way light and shadows fall on objects can give us clues about their shape and distance

• Motion Parallax: When we move, objects closer to us move faster across our field of vision than objects that are farther away

• Relative Size: Objects that are farther away appear smaller than those that are closer, even if they are actually the same size.

• Relative Height: Objects positioned higher in our field of vision are perceived as being farther away.

depth through motion

• Motion Parallax: When we move, objects closer to us move faster across our field of vision than objects that are farther away

• Optic flow: Future seeing hypothesis

• Multiple cues provide information across different circumstances

form perception

carving up the world into objects, foreground and background

cues to depth

We need to know distance to be

successful at size, shape, and

brightness judgments

objectivist view

Our senses precisely, and accurately, reflect

the physical world

subjectivist view

there is no inherent organization to the world,

but rather, our brain organizes our

perceptions, and we therefore believe the

world is, itself, organized

synthetic/constructionist

Perception is transformation of physical energy into

psychological experience

What we see based on the stimuli, but also our brain’s

interpretation of the stimuli

benefits to recognition beginning with features

• Building blocks

basic features combine to form more complex patterns

allowing a single object-recognition system to deal with a variety of targets using the same building blocks

• commonalities within variable objects

focus on common features makes it easier to recognize objects quickly and accurately, even when they vary in appearance

• generalization across different objects

The common features detected in bottom-up processing can be shared across many different objects

allowing the recognition system to be flexible and adaptable, recognizing objects in different contexts and variation

features

the small elements that result from the organized perception of form

visual search

suggest that unique features have priority in perception

word superiority effect

It is easier to perceive letters together than in isolation

frequency effect

More likely to recognize high frequency words

Recognize words that we encounter more often

repetition based priming

if you have encountered it recently you are more likely to recognize it

well formedness

the more representative a string is of the regular patterns of spelling in that language then the easier it is to recognize the string and the greater the context benefit produced by the string

More likely to recognize real words than gibberish

And more likely to recognize gibberish that follows common spelling conventions than gibberish that does not

feature nets

explain how the brain recognizes patterns, such as letters and words

Feature Detectors: These are the lowest level and detect basic visual features like lines, curves, and angles.

Letter Detectors: The next level up, where combinations of features are recognized as specific letters.

Bigram Detectors: These detect common pairs of letters (bigrams), helping to recognize familiar letter combinations.

Word Detectors: The highest level, where combinations of letters and bigrams are recognized as whole words.

feature nets consist of

Nodes pass along activation through links.

The activation from multiple nodes sums up at higher levels.

If the summed activation exceeds the decision threshold, the node at that level is activated, leading to recognition.

This process helps explain how we can recognize complex patterns, like words, from simpler visual features efficiently and accurately

nodes: different levels of detectors (features, letters, bigrams, words)

links: connections between nodes

Activation sums: Each node has a certain activation level. When a node receives activation from multiple sources, these activations sum up

decision thresholds: The node will only trigger recognition if this summed activation exceeds a certain decision threshold. This threshold ensures that only sufficiently strong and consistent patterns are recognized, reducing errors.