Cog Psych

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Research methods:

experimental methods

systematic manipulations of variables said to influence mental processing (IV)

behavioural measurements (DV) e.g.-response time, accuracy, counts -mostly quantitative

strengths

well controlled, good int validity

insights into how and why people process info in diff ways

led to theories of mental activity

limitations

ecological validity

expectancy effects

indirect measures: existence of mental representations and transformations must be inferred from beh (can't look inside brain

types of loss of function

Aphasias: speechlessness

Agnosias: usually visual- absence of knowledge

Apraxias: disorders of movement- 'without action'

Dissociations

single: when an injury to a specific location causes one type of loss of function and not another

double: characterised by opposite but complementary patient patterns- e.g- Broca's patient 'Tan' could not speak but could understand language, Wernicke identified cases where the patient could not understand lang but could still speak

MRI- magnetic resonance imaging

measure of brain structure useful for detecting lesions the brain and developmental changes

strong magnetic field- 3 Tesla (30,000Gauss)

safety considerations and compatibility checks- can't have metal in or on body

fMRI- functional magnetic resonance imaging

measure of brain function and activity

MRI/fMRI strengths/weaknesses

non-invasive, high spatial resolution, ability to measure structure and activity

safety issues, cost intensive, fMRI results are correlational so no causal effect

EEG- electroencephalograpy

measure of function, records electrical activity from electrodes placed on skull

high temporal resolution, spatial resolution less specific

TMS- transcranial magnetic stimulation

magnetic field temporarily inhibits or excites neural activity in region

provide causal r'ship, non invasive but non-specific effects associated with brain stimulation, discomfort

Sensation and perception

sensation: stimulation of sensory receptors and transmission of sensory info to the CNS

perception: mental process by which sensations are organised and interpreted to form an inner representation of the world

perceptual systems

exteroception- percep of external sitmuli

proprioeption- percep of our body including location in space/movement

interoception- percep of internal bodily signals such as heart rate/respiration

sensation: senses

absolute threshold- minimum stimulation needed to detect a particular stimulus- humans can hear sounds down to 20 hertz and up to 20,000 hertz

implications for mental health- e.g.-sensitivity-autism, hallucinations-Sz

perceptual constancy- perceived size stays the same even though the size of image on retina changes

sensory coding- from eye to cortex- converting important features of the environment into neural messages understood by brain (transduction)

transduction- converting one form of energy into another e.g.-visual- conversion of light into neural signals, physical signals from the environ go from thalamus then to areas in the brain

phase one- gathering light- height of wave=intensity, length=colour

phase two- getting light in the eye

phase three- transduction- optic nerve sends info to thalamus to area called lateral geniculate nucleus (LGN)- each LGN receives visual input only from the contralateral visual field, the optic nerves cross at optic chiasm, info then sent to primary visual cortex

phase four- in the visual cortex (striate)- functional specialisation theory- diff cortical areas code for the diff visual functions

V1 and V2- basic info- light and dark, some colour

V3/V3a- responsive to form but not colour

V4- sensitive to colour

V5/MT- responsive to motion but not colour

perception-bottom up or top down?

bottom up- ecological theories

percep is immediate and direct, no need for prev knowledge or mental reps

environ provides mass of info which is sufficient for the purposes of percep

top down- constructivist theories

percep is an active process of construction and interpretation

consists of stimulus input plus internal mental reps

percep is an informed guess and so not always reliable-prone to error (visual illusions)

Gibson and role of visual system

optic flow: as we move, the world appears to flow around us (global optic flow), as objects in world move they appear to flow (local optic flow)

environ affords us with unambiguous sources of info that we perceive directly- percep needs no further interpretation

affordances: action relevant properties of the environ- action opportunities offered by a particular object e.g.- the surface of stairs affords sitting but awkward step sizes of stairs can slow down walking -according to the direct view of percep we perceive affordances so as to control our beh/actions

separate visual pathways for percep and action

ventral and dorsal visual stream - parvocellular (ventral) and magnocellular (dorsal) pathway

dorsal visual stream determines 'where is it'

ventral visual stream determines 'what is it'

parvocellular pathway

relays info about colour and fine details, receives most info from retinal cones, high spatial freq and contrast sensitivity, shape percep, object vision

magnocellular pathway

analyses motion and spatial info, receives most info from retinal rods, low spatial freq and contrast sensitivity, steropsis (depth percep), spatial vision

evidence for the two visual streams

double dissociations with brain damaged patients

patient RV: stroke in parietal cortex (dorsal stream) causing optic ataxia

patient F: carbon monoxide poisoning in temporal lobe (ventral stream) causing visual agnosia

Long term memory

two types : declarative (cons) and implicit (uncons)

declarative:

episodic (personal events), spatial memory

semantic (facts and knowledge)

affected by amnesia

implicit:

priming effects

procedural memory

unaffected by amnesia

LTM depends on encoding storing and retrieving info

memory encoding is linked to the depth of processing of the info

Attention

'active' attention= top-down, voluntary, goal directed

'passive' attention= bottom-up, involuntary, stimulus directed

active attention has two components:

focused (selective) attention- attending to only one source of info while ignoring other stimuli

divided attention- two or more tasks are performed simultaneously (multitasking)

focused auditory attention

the cocktail party problem: there are many sounds at once, how do we pick out the relevant ones

Cherry: used dichotic listening task- a diff message is presented to each ear and ppts asked to attend to only one. verbal shadowing- repeating the attended message aloud as it is presented

findings: ppts efficient at screening out unwanted info, only physical characteristics (pitch, sex of speaker) were noticed, with physical diffs eliminated, task became harder based on semantics alone. Ppts did not remember the content of the unattended ear such as words being presented 35 times. The fact that only physical diffs were noticed and unwanted info didn't enter LTM suggests we have a processing bottleneck

early selection process:

Broadbent's filter theory: filtering occurs early in processing based on physical characteristics. Two stages of perceptual processing:

stage one- physical properties extracted for all incoming stimuli

stage two- more complex psychol properties such as meaning, limited capacity, serial

theory is bottom-up- info is filtered solely on the sensory analysis of physical characteri

however, sometimes subjects switch between listening to words and digits so this suggests people do shadow based on meaning not just physical - evidence of top-down attention

Treisman's attenuation theory- top down

subjects de-emphasise but not filter out the unattended message -based on findings that listeners engaged in verbal shadowing occasionally say words presented to the unattended ear and some ppts switched ears even when told not to following the semantic content -these occur when unattended messages are relevant to semantic context

late selection theory- Deutsch and Deutsch

the limitation is in the response system not at the level of perception, both messages are perceived in terms of meaning but only one can be shadowed at a time, all stimuli are fully analysed but there is a capacity limitation at the response end of the process, the person chooses to respond on the basis of what is the most important input

limitations: Treisman and Riley responsed by repeated the initial experiment but this time ppts were asked to stop shadowing and tap when they heard a target in either ear to reduce the importance of attending to a specific ear

results: 67% detection in attended ear, 33% detection in non-attended ear, evidence that late selection is unlikely

focused visual attention

two theories: space-based theory and object-based theory

space-based: spotlight metaphor- we attach attention to locations in space and process whatever is there- we move our eyes around to change the spotlight of attention. Zoom lens metaphor-attention to spatial locations can be broad or narrow- we flexibly adjust the spotlight of attention- broad areas less well processed, narrow focal point gives optimal processing but it takes time to move the focus to other areas of the visual field

object-based attention: focused on particular objects, even if field of view occupies a larger space

behavioural evidence for object and space based attention:

results: fastest response given for valid trials (demonstrates space-based facilitation), valid cue same object trials responded faster than invalid cue diff object trials - evidence that attention is predominantly object-based

neural evidence for object-based attention: ppts focused either on the face or house, both occupied the same spatial location, if attention is object based, selective brain areas for either house or face should be activated, if attention is space based, both face and house brain regions should be activated

Lavie- perceptual load theorya: attention is a limited capacity system but the amount that gets through the filter depends on how much work the perceptual system has to do

if cog load increases, distraction effects increase too, cog load requires additional processing mechanisms which reduce the ability to attend to a target, perceptual load and cog load involve diff processing mechanisms: perceptual load can enhance attention, cog load interferes with attention

visual search

feature integration theory: visual search involves processing object features and objects as a whole

two stages: 1) pre-attentive- rapid, parallel processing across a visual scene, single features pop out, bottom up detection. 2) attentive- slow, serial processing while searching for conjunctive features that make up an object

binding features together to form an object requires focused attention, in the absence of focused attention features are mis-combined resulting in illusory conjunctions

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Cog ability/intelligence

7 metaphors of intelligence

geographical metaphor

notion that certain brain areas have localised, specific functions

'map out' people's abilities = modelling 'ability factors' that underlie the range of diff abilities

identifying ability factors (e.g. memory) helps to understand which factors give rise to overarching abilities

Spearman believed that specific abilities do not capture the essence of intelligence, proposed one overarching factor causes indiv diffs in intelli

However, Thompson said Spearman's 'g' actually consists of many diff intellectual skills, he suggested multiple factors make up intelligent beh (e.g. driving seems like a single skill but is actually made up of sub-skills

Thurstone argues there are multiple intelle capacities and people have diff patterns of strength and weakness in these abilities: comprised of 7 diff but interrelated factors: verbal comprehension, verbal fluency, number, memory, perceptual speed, inductive reasoning and spatial visualisation

multiple-factor theories

human intelli comprises many distinct abilities

Gilford- up to 180 diff factors

hierarchical theories: 9 abilities at the top (not just g) including common crystallised and fluid abilities. Crystallised=accumulation of knowledge and skills. Fluid=flexibility of thought and abstract reasoning capability

Working memory and g

WM has both a storage and a processing component, provides an explanation of what intelli or an ability might be, emphasises cog load as a measure of intelli

cog studies

Jensen found faster, more consistent responding was associated with higher IQ

speed of same/diff judgements have also been related to IQ- Deary and Caryl

emphasises perceptual fluency as a measure of intelli

epistemological metaphor

origin, nature and limits of human knowledge

Piaget- 4 stages of dev. of knowledge and intelli

sensori-motor stage (0-2)- refine and eleaborate innate reflexes

pre-operational stage (2-7)- language acquisition

concrete operational (7-11)- conservation-milk in tall or short glass, same volume

formal operational stage (12-adult)- systematic problem solving skills

also assimilation and accomodation of new info to dev. rich knowledge structures (schemas)

sociological metaphor

Vygotsky- people use psych tools- these tools are language, imagery and thinking styles of a society, influence of more knowledgeable other (MKO's) on knowledge acquisition through scaffolding, tools enhance mental capacity

intelli is considered to be diff for diff communities and families

anthropological metaphor

culture is central to defining intelli

Australian Uni students value academic skills and ability to adapt to new events as critical to behaving intelligently

Malay students value practical skills as well as speed and creativity

but there must be consideration of universal cog processes e.g. memory and deduction

the systems metaphor

intelli is viewed as consisting of several interdep parts

notion that a single metaphor of intelli is not sufficient

a functional system e.g. intelligence must integrate multiple perspectives

theory of multiple intelligences: integrates bio, geographic and anthropological metaphors - 8 or poss more intelligences

Sternberg's triarchic theory of successful intelligence

intelli is the balancing of analytical, creative and practical abilities within particular environment

capitalising strengths and correcting weaknesses

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Indiv diffs in cognition

synesthesia: 'blending of the senses' -stimulation of one sensory modality leads to additional perceptual experiences e.g. grapheme-colour syneasthesia the synaesthete perceives black letters or digits as inherently colours

demonstrates indiv diffs in percep

other types: sequence-space, sound-colour, lexical-gustatory

sound-colour and lexical-g show altered perceptual experiences between sensory modalities

causes:

distal/ultimate causes: 1)genetic- runs in families, x-linked chromosome more prevalent in females. 2)environ- acquired, e.g. repeatedly looking at colourful refrigerator magnets

proximal cause: neural basis- brains are wired diff, greater connectivity between areas that link the inducer and the concurrent

neural basis of GC-synaesth: increased white matter connectivity in temporal cortex and parietal lobe, enlarged volume in the fusiform gyrus (contains word and colour areas)

how do we assess whether someone has grapheme-colour (GM) synaesth

stroop task- indiv letters are shown in colours different from the synaestetes experience

characteristics: letter G printed in black may trigger experience of blue while the percep of blue does not trigger the cons experience of the letter G (inducer (G) >>> concurrent (colour)). However, inducers are perceived unconsciously following colour percep- detected by (e.g.) faster naming of graphemes or skin conductance responses

synaesth and attention

faster in detecting congruent and slower in detecting incongruent coloured targets relative to non-syns

paid more attention to congruent vs incong coloured targets during visual search, non-syns paid equal attention to both

synaesthesia and memory

enhanced memory and associative memory

dual coding theory- explaining the memory advantage in syns: visual and verbal info is represented by diff stores, dual coding of info (making verbal and visual associations) increases the chance for later recall

indiv diffs in cog styles

visualiser-verbaliser cog style questionnaire (VVQ) defines our tendency to think more in pictures or words

representational diffs of visual/verbal strategies in the brain

stroke patient- lesion to left inferior frontal gyrus (Brocas area- speech production), benefitted from using a visual strategy, capitalising on strengths (visual) rather than weaknesses was most effective for recognition memory

strategy preferences

verbalisers activated a language-comprehension area (supramarginal gyrus) during the picture-based condition

visualisers acitivtaed a visual region (fusiform gyrus) during the word-based condition

strategy prefs are stable and not automatically altered to accommodate stimlus type

effects of cog style on learning

visualisers and verbalisers differed in term of gaze behaviour while learning

best learning outcome is acheived by multi-modal learning and may require the learner to learn additional strategies

however, strategy effectiveness on learning outcomes depends on several factors: type of material to be learned, prior knowledge, ease of connections that can be formed between text and images

Can braining training enhance cog performance?

experience-dependent plasticity: neural connections that are created and reorganised throughout life as a result of an indiv's unique experiences. When indivs experience substantial and sustained demands on their cog system plasticity will manifest itself

Draganski et al: 38-second year medical students were scanned at three time points, 3m before major exam, 1-2 following exam, 3m after exam. grey and white matter were assessed at each time point testing for learning-induced structural plasticity

signif grey matter volume increase in lateral parietal regions and hippocampus

signif grey matter volume decreases in middle occipital regions, but coupled with white matter, increase

explaining the hippocampal grey matter increase beyond exam period

stress relief may have reduced elated cortisol levels during study and facilitated dendritic arborisation, synapse density and neurogenesis

study shows that exp-dep neural plasticity leads to regional structural increases and decreases in the brain

why cog training?

aging population, more appealing than medication and delay mental illnesses/cog decline in general

age related decline: posterior to anterior shift in aging (PASA)- older adults increasingly rely on functions of their prefrontal cortex when engaged in cog tasks to compensate neural dedifferentiation

scaffolding theory of aging- older adults maintain cog function despite neural decline by using compensatory neural activity >> scaffolding=recruitment of additional neural activity to support declining brain areas

cog reserve- experiences and behs that protect us from cog decline (educ, work, active lifestyle)

measuring training-related changes

structural changes

increased volume of neural structures following training

grey matter increase

study suggests platform games may induce structural changes and improve navigational strategy

functional changes

intrinsic neural reorganisation- altered connectivity between brain areas following training

valid way of seeing whether intrinsic neural reorg has taken place is to examine the default mode network(DMN)

DMN is a set of brain areas that are active when the brain is at rest (although awake), it deactivates when we focus on external stimuli or tasks. DMN is altered during old age and disease, reduced de-activation ring task performance

transfer effects

near transfer=improvements limited to the trained ability

far transfer=training shows broad changes in processing abilities that transfer to other unrelated tasks

far transfer effects- evidence of improved working memory following updating training in young, but not older adults, striatum mediates transfer of learning after updating training in young but not older adults. Findings suggest older adults may not always show signif improvement transfer to other tasks, but show slowing of cog and neural decline following cog training

alternative interventions

engagement: projects aim to identify more practical training schemes for older adults -ppts in productive engagement conditions learned quilting, digital photography or both: improved episodic memory following intervention relative to control group

physcial exercise- older adults learned to juggle- increased grey matter in gyrus, hippoC, nucleus accumb in jugglers but neural/beh effects receded after 6m

Summary

in young adults: cog training can improve cog func and show transfer effects, induce structural and func brain changes

in older adults: cog training can slow neural and cog decline (transfer less freq than in young adults)

alt interventions to cog training show encouraging transfer effects in older adults