MBB1 Flashcards
What is cognition?
to be acquainted with/to know
Two aspects of cognition?
Act of knowing
That which is known
What does the ‘act of knowing’ approach to cognition refer to?
Process
Comes by with actions (cognition as something learners do)
What does the ‘that which is known’ approach to cognition refer to?
- Product
- Mental re-presentations of what we perceive, reason, know - mental images (way mind encodes experiences we’ve had
- Construct representations of things I’ve encountered that are not present
- Memory is a constructive process
How did William James consider cognition
- That which is known
- Products/phenomena of knowing things
What was the significance of Ulrich Neisser?
-Led cognitive revolution (saw cognition as activity of knowing - something that can be studied as a science)
What are the cognitive processes
○ Perception ○ Attention ○ Memory ○ Decision-making ○ Reasoning ○ Problem-solving ○ Imagining ○ Planning
What is the lowest form of mental representations?
Sensorimotor representations
- all cognition starts here
- interact physically with world and people around us
What is the middle form of mental representations?
Mental images, visuo-spatial representations
-next level of removal from actual present
What is the highest form of mental representations?
Representing knowledge in abstract forms - ability to think about our own thoughts - metacognition - represent knowledge in language so we can label concepts in the world
-relating concepts
What is experience a product of?
integrating perceptual present and cognitive past
What is Neisser’s perceptual cycle?
○ Perceptual exploration (locomotion and action) as we sample actual present environment, makes us modify schema of present environment (cognitive map of the world and its possibilites) directions the perceptual exploration
What are the keys to becoming an effective learner
• Understanding key aspects of the functional architecture that characterises human learning and memory
• Knowing activities and techniques that enhance the storage and subsequent retrieval of to-be-learned information
• Knowing how to monitor the state of one’s learning and to control one’s learning activities in response to such monitoring
- Understanding certain biases that can impair judgements of whether learning has been achieved
What are the three approaches to learning?
- Surface
- Deep
- Strategic
What is surface learning?
○ Do not understand the concept
○ Not important things
What is deep learning?
○ Want to understand a concept beyond definitions
- Highly interested and motivated
What is strategic learning?
○ Combination of other two
○ Uses strategy based on situation you are faced with
-You choose strategy for how to approach
Why did Skinner introduce Operant condtioning?
- To explore how environment controls voluntary behaviour
- Behaviour that I produce generate consequences from the environment and they either serve to reinforce or punish the behaviour and that shapes me
- Nurture - environment shapes who you are (behaviourist approach)
What is the basic concept behind Operant conditioning?
- Behaviour is governed by the consequences that follow it - seek pleasure and avoid pain
- It is adaptive to learn associations between voluntary behaviours that reliably predict punishing or rewarding outcomes
- Behaviour is shaped by the learner’s history of experiencing rewards and punishments for their actions
When/why would we use reinforcement?
- Behaviour is reinforced whenever a desirable outcome occurs as a consequence of performing the behaviour
- If we want to see more of the behaviour: case of reinforcement
- Reinforced behaviours are more likely to be repeated
What was involved in the Skinner box?
○ Rat in a box - want the rat to press the lever in the box
○ Can’t reinforce until animal produces the behaviour itself
○ Keeps animal a little bit hungry so that it is active and exploring
○ When it does finally trip the lever, food pellet is introduced into the box (positive reinforcement)
○ Rat is more likely to press the lever
○ Therefore we can automate behaviour
○ Could also be reinforced by zapping the rat until he presses the lever (negative reinforcement)
What is positive reinforcement?
An animal will learn to produce a behaviour if the consequence of the behaviour is receiving something pleasant (adding)
What is negative reinforcement?
An animal will learn to produce a behaviour if the consequence of doing so is stopping something unpleasant (taking away)
What is the difference between continuous and partial reinforcement schedules?
○ Continuous reinforcement rarely occurs in natural environment
○ Behaviour usually reinforced on partial ‘schedule’
○ Partial reinforcement results in more persistent learning
What is a partial reinforcement schedule?
- Schedules when the learner only receives the reinforcement some of the time
- Creates more persistent learning than continuous
□ Gambling - pays off sometimes - just enough to think that maybe next time they will get the reward
□ Keeps learner looking for the next reward
○ Start with continuous reinforcement then drop to partial reinforcement
When does the extinction of reinforced behaviour occur?
○ Extinction occurs when reinforcement is withheld
○ Not immediate - may be brief increase in responding (extinction burst) followed by decrease in trained behaviour (eg tantrum)
○ Increase in more variable behaviour (ideal for shaping)
○ Responses that were reinforced partially are more difficult to extinguish than those reinforced continuously
What does ‘behaviour shaping’ refer to?
The reinforcement of successive approximations to desired behaviour (reinforcing small steps)
How do you shape behaviour?
○ Start by reinforcing a high frequency component of desired response
- Since it won’t naturally occur at the start, start rewarding the behaviour that is closer and closer to the desired behaviour
- Build up to more sophisticated behaviour
○ Then drop reinforcement - behaviour becomes more variable again
○ Await response that is still closer to the desired response - reintroduce the reinforcer
○ Continue cycling through as closer and closer approximations to the desired behaviour are achieved
○ Enables moulding of a response that is not normally part of animal’s repertoire
When should punishment occur?
- Behaviour is punished whenever undesirable outcome occurs as a consequence of performing the behaviour
- Punished behaviours less likely to be repeated
What is a punisher?
any consequence of a behaviour that makes the behaviour less likely to recur in future
What is positive punishment
○ An animal will learn to stop producing a behaviour if consequence for producing behaviour is the presentation of an unpleasant stimulus (adding)
What is negative punishment
○ Animal will learn to stop producing a behaviour if the consequence of producing that behaviour is that something desirable is taken away (taking away)
When is punishment effective?
○ Three Cs:
- Contingency
□ Relationship between behaviour and punisher
must be clear
- Contiguity (timing)
□ Punisher must follow behaviour swiftly
- Consistency
□ Punisher needs to occur for every occurrence
of the behaviour
What are the disadvantages of punishment?
○ Rarely works for long-term behaviour - seems to suppress rather than eliminate
○ Does not teach a more desirable behaviour
○ If the threat of punishment is removed, behaviour returns
○ Produces negative feelings which do not promote new learning
○ Harsh punishment may teach recipient to replicate behaviour towards others
What are some alternatives to punishment?
○ Stop reinforcing problem behaviour (extinction)
○ Reinforce and alternative behaviour that is constructive and incompatible with undesired behaviour
○ Reinforce non-occurrence of undesirable behaviour
What is the theory behind classical conditioning?
• About predicting the future from past experience and using these predictions to guide behaviour
What was Pavlov’s approach to learning?
○ Need to recognise signals that preempt harmful creature being upon me rather than just the harmful predator itself
- Need to predict the future
What was involved in Pavlov’s dogs experiment
- Had dogs restrained in Pavlov harness
- Measured strength of salivation response in response to food stimuli
- Dogs started to predict when he was coming and started to salivate before he showed food
What does conditioning mean?
• Conditioning = associative learning
○ Important to learn associations between stimuli in
the environment that reliably predict other stimuli
○ Especially in relation to survival
What is classical conditioning?
○ Learning an association between a stimulus that reliably predicts another stimulus that is naturally associated with a defensive or appetitive reflex response
- Learning to produce a reflex response to a stimulus that would not naturally cause it
Are reflexes learned?
No
What is the process involved in classical conditioning?
• Before conditioning:
○ Unconditioned stimulus (UCS) and unconditioned
response (UCR) = reflex
- Unlearned
- Shown a treat –> salivate
○ A stimulus that does not produce a reflex = neutral
stimulus (NS)
• During conditioning
○ Preceding UCS with NS to get UCR
○ Establishing conditioned response
○ Need to do NS before UCS so that NS predicts the
UCS
○ Repeat a few trials in one session, and again after a
delay (days, a week)
• After conditioning
○ NS alone gets CR (conditioned response)
○ Reflex salivation response occurs at presentation of
formerly neutral stimulus on its own
○ NS becomes CS (conditioned stimulus)
○ UCR becomes CR
What is stimulus generalisation?
Classically conditioned response will generalise to other similar stimuli
What is stimulus discrimination?
- the extinction of stimulus generalisation
- eg Ring a number of other bells and not provide a UCS as well as the one bell that does
How do you achieve response extinction (with classical conditioning)?
○ Keep giving NS but without giving UCS
○ Learning remains but becomes suppressed
What does spontaneous recovery refer to (in terms of classical conditioning)?
○ Classically conditioned response can return after extinction
○ If there is a rest period after extinction trials and then present the stimulus again, conditioned response will return
○ Extinction will be stronger if extinction trials are spaced over multiple sessions
○ Each time the spontaneously recovered response will be decreased
What does rapid re-acquisition refer to (in terms of classical conditioning)?
○ Teaching the subject the CR again after sustained
extinction
○ Quickly relearn the response in fewer trials than initially
needed
- Learning was never fully lost
What was Watson’s theory in relation to behaviourism?
○ Said you could train infants to become any type of
specialist you might choose
- Nature dominates over nurture
What was found in the Little Albert experiment?
○ Testing to see if they could induce a phobia in an infant
by conditioning a fear response to a rat
○ After the instances they elicited an extreme fear
response to the white rat
○ Generalisation occurred to other furry animals and
Santa’s white beard that he had not previously shown
feared in
○ Did not get to extinguish the fear
○ NS –> CS = rat
○ UCS = loud noise
○ UCR = startle response
○ CR = fear of rat
What was Tolman’s take on cognitive learning?
○ Believed cognitive processes played important role in learning complex behaviours, even in non-human animals
○ Against hard-core behaviourism
What was involved in Tolman’s ‘rat in maze’ experiment?
- Food at end of maze
- Number of obstructions in maze that mouse needs to make it past
- If it makes wrong decision - punished
- Right decision will be rewarded
- After number of days rat knows how to run through maze most efficiently making minimal mistakes
- Didn’t just learn pathways that were rewarded, but also learned mental representation of maze (cognitive map) they would draw upon to get to the food
□ Sometimes rat would misbehave - learned much
more about spatial environment than what were
rewarded paths
What happened in Tolman’s adaptation of his original ‘rat in maze’ experiment - the sunburst maze?
- Altered the maze - sunburst maze (more pathways, and the original pathway does not lead to food anymore
- Which is the most likely path for rat to run down in new maze?
□ Most rats rans down alley 6 when they found out
that their original one had no food (brings them out
right where food would have been)
What is latent learning?
- Learning can occur in absence of rewards and punishments
How did Tolman demonstrate Latent Learning using the three groups of rats?
□ Group A was left to explore maze without reinforcement for 20 days
□ Group B was left for 10 days and then after 10 days was reinforced,
□ Group C was always reinforced
□ Learning becomes evident for Group B at day 11 - errors drops as soon as reinforcement was introduced, and mistakes made on day 12 was same as group C
□ Learning of group B was latent - couldn’t see it (it’s not that the rats hadn’t learned anything about the maze before reinforcement, but we just couldn’t see it because they had no reason to demonstrate it)
□ Therefore rewards affect whether learning is demonstrated, not achieved
What is Social Learning Theory?
- Humans and other animals can learn through observing
- Observational learning provides another example of how learning can occur indirectly without direct reinforcement or punishment
- Learning can take place socially and vicariously (through others) by observing others (models)
What was Bandura’s take on social learning?
○ Observational learning takes place through active judgement and constructive processes not just imitation
What happened in Bandura’s social learning experiment using children and the doll?
○ Experiment investigating children’s imitation of aggressive behaviour
- Four year-olds watched short film of adult playing
aggressively with bobo doll
- One group sees adults reinforced with treats after
performing aggressive actions
- Another group sees adults punished
(scolding/spanking by another adult)
- Third group saw same film but with no consequence
- After film, children played alone in a room with
several toys including a bobo doll
- When no incentive was given to the kids to imitate the behaviour, those who had seen the rewarding video reproduced same amount of actions as those who saw no consequence, whereas those who saw the punishing video were significantly less likely to reproduce the actions with no incentive
- Boys in general were more likely to reproduce the aggressive behaviours than girls
- When the children received incentive to reproduce the behaviours, all of them, no matter what video they watched, were equally able to reproduce the behaviours (still with gender difference)
- Demonstrated vicarious reinforcement and vicarious punishment
- Ties in with latent learning - children only performed the behaviour when reward was present but were much less likely to reproduce the behaviour when there was no reward - reward affects the demonstration of learning rather than the acquisition
What was the case study of Clive Wearing (with herpes encephalitis)?
- Caused bilateral hippocampal damage
- Results in pattern of memory deficits:
□ Recall of autobiographic episodes = poor
□ Recall of facts learned prior to illness = relatively
good
□ Capacity to learn new things = poor
□ Ability to attend to and understand current
conversation = fully preserved
□ Musical ability = fully preserved - Despite amnesia still retained his intelligence
- No longer had any episodic memory
□ Did not have brain parts necessary to recall anything that happened to him his whole life - Could remember general things (semantic memory)
□ Knew he was married (semantic)
□ Could not remember the wedding (episodic) - Lives in present moment
□ Represented by short-term memory and working
memory
What is memory?
- Set of systems for encoding, storing, and retrieving information acquired through our senses, and for relating this information to previously acquired knowledge
- Mental and neural representation of information we have experienced, imagined, and learned
What are the three main steps involved in memory?
○ Encoding
○ Retrieval of non-consolidated memory
-Retrieval of consolidated memory
What is involved in encoding?
- Experience an event (with audio, spatial and visual information) - as we experience that event it sets off activation in the cortex in areas dedicated to receiving that sensory input
- Interplay - back-and-forth between the activation occurring in the cortex and the process going on in the hippocampus where each stream of sensory information is being put together into a single representation that matches the input that’s occurring
- Process of encoding leaves and imprint on brain
What is involved in retrieval of non-consolidated memory?
- Something causes that event to come to mind - retrieval cue (something that shares some of the same sensory components as original event)
- Causes activation of that partial information in hippocampus
- Sets off retrieval process that brings to mind other associating information (brings to life connections that have been formed and sends that information back out to the areas of the brain that were originally activated by past experience –> not only the sensory components present in retrieval cue but also other sensory components of original event come to mind
- Consolidation occurs through process of retrieval
- Storage is strengthened by retrieval
What is involved in retrieval of consolidated memory?
- At point of consolidation of a memory, retrieval cue in environment doesn’t need to trigger hippocampus - input is sufficient to regenerate entire network of connections originally experienced
- Retrieving can occur either inadvertently - retrieval cue, or with internal intention to retrieve the memory
What is visual sensory memory?
• Temporary, sensory-based representation of input received through sensory channels
○ First stage of acquisition of sensory input
○ Opportunity for encoding to occur
• Allows sensation to persist long enough that we have time to attend to it and store it
• Provides buffer (‘holding area) between early sensory processes and later cognitive processes
• Only some of information stored in sensory memory will be retained
• Iconic (visual) and echoic (auditory) memory
○ Brief duration (decays quickly)
○ Large capacity (relative to STM)
What did Sperling’s experiment on the capacity and duration of iconic sensory memory show?
○ Letters flash on screen for 50ms - how many can you remember
○ Conclusion of iconic memory capacity
- Capacity Is about 4 items
○ Sperling thought method he used was flawed because participants said they could recall everything but it disappeared too quickly to say them all aloud
○ Addressing problem
- Modified approach
□ Instead of full report of what was seen, asked
participants for partial report
- Initial set of letters displayed for 50ms
- Then auditory tone indicated which line to
retrieve from (high tone = top line etc)
- Participant repeats cued line
□ Findings:
- Participants were able to recall most of line
cued
What is the multi-store model for memory?
-Information goes into sensory register, moves into short-term memory - moves into long-term memory if we rehearse it enough
○ Short-term sits between sensory memory and long-term memory - role is to mediate transformation of sensory input into meaningful content that can be transferred into long-term memory
- Thought of as a temporary storage site - structural account
○ Information kept active in short-term memory (STM) through process of active rehearsal mediated by verbal representations
○ Rehearsal results in transfer from STM to LTM (long-term memory) storage site
According to the multi-store model for memory, what is the STM capacity and duration?
○ Capacity = 7 +/- 2 items, about the amount of verbal information that can be rehearsed for 2 seconds
○ Duration = seconds to minutes, depending on ability to maintain attention to stimulus
What are the limitations of the multi-store model?
-only gives one-directional flow - doesn’t give us a clear mechanism for how information from long-term might be retrieved
○ Need more than just the ability to maintain sensory input to get into long-term memory - need to integrate information that is currently active in consciousness with things from cognitive past
How is the verbal STM capacity assessed?
Digit-scan task
Using the digit-scan task, what is STMs capacity for verbal information?
○ Recall random sequence of verbally presented digits in the order they were present
- Test of immediate serial recall
○ Systematically increased length of sequence to determine the span
○ Average span is 7 +/- 2
What is an argument against the digit-scan task?
overestimates pure short-term memory although useful measure of verbal memory capacity
How do you measure the STM capacity for visual information?
• Change-detection task
What is the change-detection task?
○ Briefly displays a sample array
○ After a brief retention interval (small break) a test array is presented
○ Participants compare the test array with their memory representation of the sample array to determine if there are any differences
○ Results showed that if the size of the sample array changed while the time of the retention interval remained the same, participants could readily make stable judgements about test array up to about 3 or 4 items - then performance accuracy gets worse rapidly
What is Miller’s theory on ‘Chunking’?
-a strategy to group the input events, apply a new name to the group, then remember the new name rather than the original input events
○ Don’t merely retain information but try and
make sense of it
• Capacity limit on STM should be viewed in relation to the number of meaningful chunks rather than meaningless bits of information
• Method that can be used to increase our STM capacity by chunking in groups of 3 or 4 - compatible with capacity of STM
• Recent studies that reduce the potential for chunking estimate the pure capacity of STM at 3 +/- 1 units of information rather than 7
What is the Brown-Peterson task in measuring STM duration?
○ Remember three consonants
○ To prevent rehearsal - required to count backwards in 3’s until given a signal to stop
○ Retention interval was manipulated systematically
○ Memory probed (tested) after 3, 6, 9, 12, 15 or 18 seconds
○ Ability to retrieve three letters in their order dropped rapidly
○ After 3 seconds - participants got the letters right on about 50% of trials
○ By 9 seconds performance dropped to about 20%
○ By 12-18 seconds performance dropped to 0
○ Suggests memory trace seems to fade half strength after 3 seconds and down to nothing after 12-18
What are some issues with the Brown-Peterson task in assessing STM duration?
- Forgetting occurred due to interference
□ Retroactive interference from subsequently
attending to the backwards counting task
□ Proactive interference from consonant strings
studied on previous trials
- Even after 12-18 seconds on first few tasks
results were quite accurate - only got worse
the more trials done
What are the aspects of Badley’s model of working memory?
- Three-part model
- Working memory is multi-component model of short-term memory that expands on original idea of multi-component model
- Top-tier = central executive process
- connects to subsidiary systems:
- visuospatial sketchpad
- Phonological loop
- Episodic buffer
- connects to subsidiary systems:
- all fluid systems
Describe the visuospatial sketchpad
- Previous accounts left this part out
- Images and spatial representations
○ Visuo-spatial working memory system temporarily holds visually based representations such as faces, objects, and written words
- Mentally manipulate visual information
□ Mental rotation of objects
□ The use of mnemonics
□ Mental arithmetic
□ Cognitive maps for navigation
Describe the Phonological Loop
- Attkinson-Schiffman’s model of short-term memory
- Verbal memory processes and mechanism of maintenance rehearsal for verbally-coded representations of memory
- Capacity for amplifying verbal and sound input and retaining that input through a loop/rehearsal mechanism
○ Working memory involves not just maintenance of information in a phonological store, but active manipulation of the information
○ digit-span backwards task
- Considered a test of phonological
working memory
□ Need to not only hold in mind the number sequences in order, but then also present them backwards - manipulation
- In contrast to standard digit-span task which measures maintenance only and does not nvolve manipulation
Describe the Episodic buffer
- Combines information from visuospatial sketchpad and phonological loop together into a bound representation
- Combined in multisensory episodic trace
- Workspace and experience we have of consciousness - sound and vision work together to give integrated experience
- Holds integrated episodes and it’s a buffer in that it provides a temporary place for representing the current contents of consciousness
Describe the Central Executive Process
- attentional processes
- Higher-level control system that allows us to focus attention on any of the representation areas (the subsidiary systems), and ability to do so simultaneously
○ Executive processes are used in planning and coordinating complex behaviour (attentional system not memory system)
- Goal orientation
- Focus attention
- Control of social behaviour
- Switching between tasks, updating memory, inhibition of distracting information
- Planning and problem solving
○ Executive processes are governed by circuitry in the pre-frontal cortex
Where are the Executive Processes based
Pre-frontal cortex networks
Where is the Phonological Loop based?
left-hemisphere fronto-temporal lobe network
Where is the Visuo-spatial sketchpad based?
right occipital-parietal network
Where is the Episodic Buffer based?
parietal network
What are the two major divisions of long-term memory
- Declarative memory (explicit)
- Non-declarative memory (implicit)
What is declarative memory?
○ Knowing what, why, when, where ○ all of the information that we can talk about ○ Facts, events, locations, ○ Hippocampal-dependent ○ 2 Sub-divisions - Episodic □ Remember personally-experienced events □ Contextualised □ Ability to mentally time travel □ When/where memories □ Tulving - said it is particularly human - Semantic □ What/why □ Abstract □ General knowledge about the world □ Not personal □ Conceptual knowledge ○ Type of declaritive memory can be revealed through explicit memory tests
What is non-declarative memory?
○ Knowing how
○ Motor skills (eg riding a bike)
○ Cognitive skills (eg reading)
○ Non-hippocampal dependent
○ This kind of memory is revealed when previous experience facilitates (improves) performance on a task
- Reveals itself through behaviour
○ Does not require conscious recollection
○ Type of memory is revealed through implicit memory tests
○ 5 Subdivisions:
- Procedural memory
□ Ability to learn and perform motor and
cognitive skills (‘how to’ memory)
- Priming
□ Demonstrated by change in ability to
identify a stimulus as a result of prior
exposure to that stimulus or a related
stimulus
□ Repetition priming
- For example, prior exposure to a word in a lexical decision task will make the word easier to respond to the next time it is encountered
□ Associative/semantic priming
- Example - the prior presentation of
the word ‘nurse’ facilitates
subsequent identification of the word
‘doctor’
- Classical conditioning (associative
learning)
□ Learning to attend a neutral stimulus
because it has become associated with a
meaningful stimulus
- Operant conditioning (associative learning)
□ Learning to produce/avoid a behaviour
because it has become associated with
rewarding/punishing consequences
- Non-associative learning
□ Habituation
- Earning to ignore a stimulus because
it is trivial (eg screening out
background noise)
□ Sensitisation
- Learning to attend to a potentially
threatening stimulus
What is amnesia
• Deficits in memory caused by brain damage, disease, drug abuse, or psychological trauma
• The selective deficits in memory processes seen in cases of amnesia provide support for the proposed division between the declarative and non-declarative memory systems
-Two types:
-retrograde
-anterograde
What is retrograde amnesia?
○ Inability to recall things that happened prior to problem causing the amnesia
○ Usually temporally graded
- Oldest memories are less susceptible to amnesia
- Temporal gradient
- Clive Wearing did not have a temporal gradient -
did not remember any of it
○ Usually rare or temporary
What is anterograde amnesia?
○ An inability to recall anything since the time of the brain injury
○ Inability to learn new information
○ Much more common
What is the case of H.M.?
• Developed severe epileptic seizures in his youth
○ Rendered him unconscious every time
• Through teens and early 20s seizures became more frequent
• Experimental surgery proposed to treat the seizures
○ Removal of the medial portion of both
temporal lobes, including hippocampi
• H.M. acquired a severe and permanent inability to acquire any new information
○ Both episodic and semantic
○ Anterograde amnesia
• very precise damage to brain - precision of surgeon’s knife rather than general damage
○ Very pure case of what happens when the medial temporal structures are removed
• Did stop seizures
• Experienced both retrograde and anterograde amnesia
○ Retrograde:
- Couldn’t remember hospital staff or his way to the bathroom
- Did not remember death of favourite uncle three years previously
- But early memories vivid and intact (temporal gradient)
○ Severe Anterograde:
- Could recall nothing of his day-to-day events of his hospital life
- Could not form, retain, or retrieve new episodic memories
- Severely impaired ability to learn new semantic facts
• Normal sensory and working memory (STM)
○ Normal digit span ability
What was Fergus Craik’s contention to memory and retention?
Said they were merely outcomes of the normal processes of perceiving and comprehension
• Brenda Milner challenged this:
○ Her amnesic patients had no trouble comprehending events, they were clearly capable of processing deep semantic levels, but they don’t remember things
- How can that be explained by Craik’s theory?
What is the role of the hippocampus in consolidation of memories?
- The temporal gradient of retrograde amnesia tells us that memories cannot be stored permanently in the hippocampi
- Severe anterograde amnesia that results from the removal of the hippocampi bilaterally indicates that these structures must be crucial for the consolidation of new information
- Craik conceded that cases like H.M. forced him to adjust his account of elaborative encoding to include not just the process of interacting meaningfully with information in working memory, but also an additional process of consolidation, mediated by the hippocampus
- Memory can be fully consolidated at the point at which it can be retrieved through cueing where memories are now independent of hippocampus and can self-activate in their own network
Are the phonological loop and visuo-spatial sketchpad dependent on one another?
no:
○ Concurrent performance of a visuo-spatial task and a phonological recall task does not impair the performance on either task
- Eg a visuospatial task such as recalling the pattern of coloured squares on a checkerboard does not interfere with verbal digit-span task
○ Operate independently from one another
○ Two tasks of the same nature (ie two phonological loop or two visuo-spatial sketchpad tasks) when performed together will have interference
○ Contrast with the effect of non-attended speech in the auditory channel while trying to complete an auditory memory task - the non-attended speech effect occurs when performance on a verbal memory task declines in the presence of irrelevant speech
Are anterograde amnesiacs capable of new procedural learning?
Yes
What does the mirror-tracing task show about anterograde amnesiacs and learning procedural learning?
○ Given piece of paper with double-outline of a star on it
○ Need to trace a third line in between the two lines trying not to take new line outside boundaries of other two
○ Do this with a barrier up so you can’t directly see what hands are doing - only have a mirror to reference your performance
○ Need to adapt to following movements of your hands mirror-reversed
○ Difficult to do the first time but will adapt with practice
○ Would H.M. show equivalent mirror tracing performance if he practiced the task over a few days?
- Despite thinking he had never done the task before, his results did show improvement over time
- Showed completely normal acquisition of the skill
- Demonstrates that procedural learning can proceed independently of the brain systems required for declarative memories
- First evidence of a clear dissociation between devastated declarative memory ability and his fully preserved non-declarative performance
What are other types of preserved non-declarative memories in anterograde amnesiacs?
○ Intact classical conditioning
○ Intact priming effects seen in word-stem completion tasks
○ Normal habituation and sensitisation
• Both H.M. and Wearing show these effects
• Also patients with Korsakoff’s syndrome (anterograde amnesia caused by binge-drinking), depressed patients undergoing bilateral ECT, patients with anoxic encephalopathy who all suffer anterograde amnesia
What is attention?
The ability to preferentially process some parts of stimulus at the expense of processing other parts of the stimulus
Why do we need attention?
○ Perceptual system has limited capacity
○ Can’t process everything in visual scene simultaneously
- Helps us avoid becoming overwhelmed by limiting processing
What are the two types of attention?
Overt attention
Covert attention
What is overt attention?
Looking directly at an object
What is covert attention?
- looking at one object but attending to other objects
○ Could be used in sports to make people think they are going to move one way but actually move another way
How can you tell where someone is attending?
Tracking eye movements
-Unless purposely try not to, you generally look at the object to which you attend
What are eye movements called?
saccades
• Eyes do not move over scene smoothly - they jump from point to point
Jumps are known as saccades
What are fixations?
Rests between the eye jumps where eyes stay looking directly at object
What determines what you fixate on?
Your goals and expectations
How do eyes move between saccades and fixations?
Ballistically (fast)
What are the two processes involved in directing attention?
○ Initial involuntary process (mediated by attentional capture)
○ Subsequent voluntary process (guided by goals and expectations)
What is the general process of directing attention?
• When scene is first presented fixations are captured by salient parts of a scene
○ Known as ‘attentional capture’ - involuntary
• After first few fixations can then direct your fixations according to your goals
○ Voluntary
What captures our attention?
○ Contrast
- Regions of colour contrast or luminance contrast - Regions of size contrast - Regions of orientation contrast - Regions of motion/flicker contrast
What directs our attention?
○ Observer’s goals and expectations
- If an object is unexpected you will fixate on it
longer and more often
□ Syntactically inconsistent = an expected
object doing something unexpected
(something that violates the fundamental laws
of nature)
□ Semantically inconsistent = unexpected
object
What are the effects of attention?
-Attention speeds responses
-Can influence appearance
• Attention can change apparent contrast of an
object
• Attention can also make objects appear bigger,
faster, more richly coloured
• Makes perception more vivid
-Can influence physiological responding
What was Posner’s experiment of attention’s effect on response speed?
○ Shown a box with an arrow above it to indicate which side an ‘X would appear on
○ Valid trials = X appeared on side indicated by arrow
○ Invalid trials = X appeared on other side than implied by arrow
○ Neutral trials = no arrow appeared
○ Participants had to press button as soon as X appeared (only had to respond to indicate the X appeared, not on which side it appeared on)
○ Found that Invalid trials produced the slowest response times
What was Carasco’s experiment of attention’s effect on contrast?
- Participants were shown two gratings of different contrast and had to record which one had higher contrast
- Sometimes there was a peripheral cue (a dot drawing the attention to one side)
- When there was a peripheral cue and the contrasts were the same participants recorded the grating on the side of the cue to be of a higher contrast
- Suggests that cued grating appeared to be higher contrast
How does attention affect physiological response to stimuli?
Neurons in the brain respond more strongly to attended stimuli than to unattended stimuli
What is the Binding Problem?
The issue of how an object’s individual features are combined (bound) to create a coherent percept is known as the binding problem
What is the Feature Integration Theory (FIT) in explaining the Binding Problem?
○ Suggests that binding problem is solved by attending to only one location at a time
○ Crucially, only features associated with that location are processed - only these features are bound together
○ This avoids binding features from different objects
What are Illusory Conjunctions?
○ A prediction of FIT is that if attention is inhibited features from different objects will be incorrectly bound together
○ Treisman and Schmidt - illusory conjunctions occur
- Presented character strings very briefly (95-168ms)
followed by a noise mask
- Primary task was to report the two numbers
- Observers were asked to report coloured letters
- Observers often associated the wrong colour with
the wrong letter
- Incorrect bindings = illusory conjunctions
What is RM’s case regarding illusory conjunctions?
○ RM is a patient with parietal lobe damage
○ Has Balint’s syndrome
○ When multiple objects are present, RM has difficulty focusing attention on a single object
○ When shown two letters, each with a different colour, reported the wrong letter-colour combinations on 23% of trials, even when allowed to view the letters for 10 seconds
○ RM is very prone to illusory conjunctions because he could not focus attention on single object
What is the FIT prediction of visual search?
○ Some forms of visual search require binding to occur
○ Eg binding is required is the target contains the same features as the distractors
○ If the target differs from the distractors only by its particular conjunctions of features - conjunction search
○ FIT predicts that in conjunction searches attention needs to be applied to each object in turn (one at a time) to determine whether or not the attended object is the target
○ These searches are predicted to be very slow
○ Other types of visual search can occur without solving the binding problem
○ If the target contains a feature that the distractors do not - feature search
○ FIT predicts that because binding does not need to occur, attention does not need to be applied to each item in turn
- Searches are predicted to be fast
What is change blindness and why does it occur?
• Attention can determine what we remember
• If you don’t attend to it , you probably won’t remember it
• Change blindness = changes that are obvious when attention is drawn to them and are missed when attention is not drawn to them
• You can only notice a few parts of a scene at a time
• If one of those parts change you will notice it
• If another part of the scene changes you will not notice it
• Doesn’t only happen in static pictures - can also happen in real world
○ Simons and Levin
- Experimenter asks someone on the street for directions
- People carry a door pass between them and the experimenter changes
- 50% of people giving directions did not notice the change in person
What are the three factors that make perception difficult?
-Stimulus on the retina is ambiguous
○ Objects can be hidden or blurred
- Machines have difficulty recognising objects if the
whole object is not seen or is blurry
○ Objects look different from different viewpoints and in different poses
- Machines find it hard to recognise an object when
they appear in unexpected poses or angles
What are the competing to solutions to the problem of perception?
- Structuralism
- Gestaltism
What is structuralism?
○ Distinguishes between sensations and perceptions
○ Sensations = elementary processes occurin response to stimulation
○ Perceptions= = conscious awareness of objects and scenes
○ Structuralism claims that sensations combine to form perceptions
○ According to structuralism conscious awareness is sum of these elementary sensations
§ Contains nothing that was not already present in these elementary sensations
What is Gestaltism?
○ Directly contradicts structuralism
○ Conscious awareness is more than just the sum of the elementary sensations
○ Conscious awareness can have a characteristic not present in any of the elementary sensations
○ Two pieces of evidence for this claim:
- Apparent motion
□ Observer sees two stationary dots flashed in
succession
□ Although each dot is stationary observer sees
motion
□ Conscious awareness has a character
(motion) not present in elementary sensations
□ Conscious percept of motion was constructed
and was not present n the elementary
sensations
- Illusionary contours
□ Seen in locations where there are no physical
contours
□ Conscious awareness of the illusory contour
is constructed
What are the two mechanisms of Gestalism?
-Grouping
□ Process by which parts of an image are
perceptually bound together to form the
perceptual whole
-Segregation
□ Process by which parts of a scene are
perceptually separate to form separate
wholes/objects
-Together, grouping and segregation allow a scene to be perceptually organised into its constituent objects thereby allowing observers to make sense of the scene
What are the 6 key principles that govern Gestalt Grouping?
• The more of these principles that apply, the more likely components of an image will be grouped together to form a perceptual object
• Original principles
○ Good continuation
- Aligned or nearly aligned contours are
grouped together to form a single object
○ Pragnaz
- AKA principle of good simplicity
- Essentially groupings occur to make the
resultant figure as simple as possible
○ Similarity
- The more similar objects are, the more likely
they will be grouped together
○ Proximity
- The closer objects are together the more likely
they will be grouped together
○ Common fate
- Things that move together are grouped
together
• Additional 2:
○ Common region
- Elements that are in the same region of space
are grouped together
○ Uniform connectedness
- Connected regions with the same visual
characteristics (eg colour) tend to group
together
What are the principles of Gestalt Segregation
• Much of perceptual literature focuses on figure-ground segregation
• Objects are normally perceived as figures and the background is typically perceived as the ground
• If you can identify the figure you can identify the objects
• Regions of image are more likely to be seen as the figure if:
○ They are in front of the rest of the image
○ They are at the bottom of the image
○ They are convex
○ They are recognisable
• The more factors that combine, the more likely that it will be seen as a figure
