Perception and memory

Question 1

4 main approaches to studying human cognition

Answer 1

1. cognitive psychology - involves trying to understand human cognition using behavioural evidence
2. cognitive neuropsychology - involves studying brain damaged patients to understand normal human cognition
3. cognitive neuroscience - using evidence from behaviour and the brain to understand cognition
4. computational cognitive science - involves developing computational models to further our understanding of human cognition, such models increasingly take account of our knowledge of behaviour and brain

Question 2

perception - outside in

Answer 2

1. what we know about the world we know from our senses
2. how does the energy of the outside world become a representation of the inside world
3. how accurate
4. humans have quite restricted perceptions of light and sound

Question 3

how does energy become a neural/signal representation

Answer 3

1. transduction - transforming energy from the outside world into a neural signal
2. sensation - picking up the raw signal
3. perception - recognising what the signal means
4. however much information is out there in the world, how a particular person sees it depends on how the world is represented in the brain

Question 4

point of contact - the eye

Answer 4

1. optic nerve to brain
2. different visual areas, v1-v5

Question 5

perception and sensation are not the same

Answer 5

1. top down processing - knowledge and expectation
2. bottom up - using sensory input

Question 6

theories of object perception

Answer 6

1. helmholtz’s theory of unconscious inference - a particular pattern of activation in the retina can be caused by a range of objects
2. likelihood principle - we perceive the object that is most likely to have caused that pattern, this judgement is a result of unconscious assumptions that we make about the environment and it happens automatically
3. we see objects in a 3D world, if there is a chance to interpret an object as 3D, we do
4. Gestalt principles (grouping) - similar things are grouped together, this law holds that objects in the environment are seen in a way that makes them appear as simple as possible, things that are near each other seem to be grouped together, law of continuity holds that points that are connected by lines are seen in a way that follows the smoothest path, according to the law of closure things are grouped together if they complete some entity, law of common fate states that humans perceive visual elements that move in the same speed and/or direction as parts of a single stimulus, using these laws we have now grouped bits in the environment into bits that belong together, bits that are an entity, next step is for the brain to figure out what is the object and what characteristics make it a member of that category of objects

Question 7

monocular cues of depth

Answer 7

1. perspective - placement and depth
2. occlusion - objects presented in front are perceived closer
3. shadow
4. arial perspective - because of scattering of blue light in the atmosphere, distant items seem more blue, on clear days mountains seem closer, scattering of light also creates a blur, blurry things seem farther away, contrast items seem closer
5. light and shade - we have the light-from-above assumption, perspective changes when this image is viewed upside down
6. monocular movement parallax - when the head moves close objects move fast, far objects relatively slowly

Question 8

but we have two eyes

Answer 8

1. binocular disparity - difference in the images of the two eyes
2. stereopis - disparity transformation into perception of depth
3. why two eyes - overlapping visual fields enable stereoscopic visions by blending slightly dissimilar views of an object, allows us to see farther into the distance with higher resolution

Question 9

interaction of perception and action

Answer 9

1. Held and Hein - is movement necessary to develop normal vision, all active kittens developed a visually guided paw placement response after 63 sessions, none of the passive kittens had, all active kittens avoided deep end of glass cliff, passive kittens went randomly to each side, self produced movement and concurrent visual feedback are essential for the development of visually guided behaviour
2. data coming in from our eyes only means something when we can reference it
3. we need feedback for what this information means, hence what we touch influences how we see

Question 10

cross cultural studies of perception

Answer 10

1. provide evidence that the way we perceive the world depends on what surround us
2. cultural influences can be due to factors
3. Segall, campbell and herskovits - western cultures are more susceptible to the Muller Lyer illusion and the Sander parallelogram illusion compared to cultures from rural Africa and the phillipines, people who live in urban environment which contains more rectangular shapes are more prone to these, people in rural areas experience more flat terrain and actual distance
4. Mayer and Rahmann - attentional blink paradigm where the second stimulus is difficult to process, greek and russian Ps were better at discriminating the light from the dark blue stimulus, no difference for green than german perception

Question 11

crossover in sensory modalities - synaesthesia

Answer 11

when presented with stimulation in one sensory modality, another modality can be simultaneously activated and a blending of the senses occurs

Question 12

components of memory

Answer 12

1. memory - process involved in retaining, retrieving and using information of the past which affects the present and possibly the future
2. memory storage model - Atkinson and Shiffrin - sensory input persists very briefly, passively in modality, specific temporary buffers, only attended items are identified and represented in a short term store, where they can be operated on or transferred into LTM, STM is very limited in capacity, contents decay or are overwritten/displaced by new input or by information retrieved from long term storage unless deliberately maintained by rehearsal
3. STM - Baddeley and Hitch - phonological loop holds info in speech based form, episodic buffer, central executive, visuospatial sketchpad holds visual and spatial info
4. LTM - explicit/declarative induces episodic events and semantic, implicit/non declarative includes procedural and emotional conditioning

Question 13

reasoning for the separation of STM and LTM

Answer 13

1. introspection - primary vs secondary memory
2. physiology - info stored in current neural activity vs changes in synaptic strength, something must hold new information during initial consolidation, reverberating circuits, cells in monkey prefrontal cortex show sustained activation in delayed response and delayed match to sample tests
3. complex information processing systems use temporary work spaces - keep information being operated on readily available, temporarily store information that is not worth storing permanently

Question 14

working memory (STM)

Answer 14

1. experiments on normal subjects and effects of brain damage also show that STM is distinct from long term memory
2. to test whether our mind do have this type of temporal storage we need tasks that measure memory for very recent information
3. Brown Peterson distraction paradigm - P reads a short list of 3 letter, tries to retain it while counting backwards by threes until cued to recall, retention interval varies from trial to trial but rapidly declines over time then levels off
4. free recall - P sees/hears a long sequence of items, at end of list tries to recall as many as possible in any order, if they are asked to recall the last items first they are relatively well remembered - recency effect

Question 15

explaining the pattern of short term forgetting

Answer 15

1. single trace theory - memory trace decays rapidly to start with, then more rapidly
2. dual trace theory - retrieval after a short interval mediated by temporary rapidly decaying memory trace, retrieval after longer interval mediated by a more permanent memory trace
3. dual trace theory supported by retention over short interval influenced by factors that don’t influence retention over a long interval, retention over a long interval influenced by factors that do not influence retention over a short interval

Question 16

factors selectively impairing free recall

Answer 16

1. list length - the longer the list the fewer items are recalled but recency effect is unchanged
2. Glanzer and Cunitz - faster presentation rate reduces recall of items presented earlier but not of recent items, same for longer list, old age, alcohol, so far a single dissociation - consistent with a single memory trace whose decay rate is changed by these manipulations, double dissociation needed, counting backwards after the end of the list eliminates the recency effect but does not influence the probability of recall of early items
3. sperling - partial report superiority effect, report of the whole grid was poor, cued report of single row was good, the difference because for whole report it takes time to say all the letters and after about 1 second the sensory memory is lost, reporting the single row is quick but the partial report superiority is also lost when they cue comes after 1 sec, same reason sensory memory trace has faded

Question 17

visual working memory and change direction

Answer 17

1. brief interpolated blank frame produces transients all over the visual field - attention no longer automatically attracted to region of change
2. only way to detect a change is to compare the present display with memory for the objects in the previous frame
3. under these conditions we don’t easily detect changes - unless we happen to have just attended to the region of the change
4. very limited memory for the objects in the previous frame - change blindness

Question 18

change blindness and the transition from iconic to visual working memory

Answer 18

1. different attributes of objects presently in the visual field are represented local activity in multiple visual cortex maps - separate maps for features such as orientation, movement, colour
2. this sensory activity persists beyond the stimulus offset (sensory memory) unless overwritten by a new retinal image but not for long
3. while it remains available, binding of features by focal attention creates object files in visual working memory
4. unless you have attended to an object in the previous frame and its file is made into visual working memory, you wont detect the change
5. VSTM can hold only about 3 or 4 objects in one shot

Question 19

is visual STM distinct from long term visual memory

Answer 19

1. sequence of 8 philips checkerboards, followed by a sequence of test checkerboards same as/different to each pattern in the first sequence reverse order
2. P decides same/different for each pattern
3. recency effect final item remembered better
4. recency effect eliminated by 5s of mental arithmetic
5. slower presentation rate improved memory for all but the last item
6. so the most recent complex array seen is held in visual STS, previous patterns recovered if at all from distinct long term visual memory