Cognition 1 Flashcards
Describe the Cornea
Curved transparent part of the eye that counts as ¾ of the ‘lens’ for the eye and lets light through.
Describe the Lens
This part focuses the light entering the eye onto the retina at the back of the eye.
Describe the Iris
The coloured part, provide adjustable aperture for the pupil.
Describe the Pupil
Hole in the centre of the iris which can contract and dilate depending on the amount of light entering the eye.
Describe the Retina
Made up of photoreceptors at the back of the eye, where the actual visual processing really begins
Name the two types of Photo receptor
Rods and cones
Describe the function of Rod cells
All rods are basically the same and they all contain the same photo pigment. Rods react well to dim light, making them almost completely useless in well-lit conditions
Describe the function of Cone cells
Cones come in three main types, long, middle and short wave cones. They work in well-lit conditions and are heavily centred in the fovea (centre).
Describe the path an image takes to get from the eye to the Primary Visual Cortex
Retina - Optic nerve - paths cross at Optic Chasm (50% split) - Optic Tract - LGN - Primary Visual Cortex (V1)
What does light do when it hits the ON region?
Increases the clicking rate
What does light do when it hits the OFF region?
Decreases the clicking rate
What is Luminance?
The amount of light energy something reflects - a physical property
What is Lightness?
How bright something looks - a perceptual property
Where is the primary visual cortex located?
The Occipital lobe at the back of the brain.
What did Hubel and Wiesel discover about the cells in V1?
That cells close to each other in VI have receptive fields close to each other on the retina.
What are the four types of cues?
Motion, Phsyical, Stereo, Pictoral
What does Euclid’s principle say?
Retinal image size halves as the distance to the object doubles.
Describe Stereo Cues
Binocular Disparity - the slight difference between the image on the right and left retinas
Describe Monocular Cues
Motion Parallax - when a person moves the images of the objects around them move across the retina, the closer an item is the faster it moves.
Physical Cues
Accommodation - this is how the eye focuses light to stop it being blurry, muscles moving in the eye signal distance.
Vergence - – Convergence of the eyes (cross eyed) is needed to fixate the image of a nearby object on both foveas. The angle of convergence gives the distance of the object. Is not very useful at telling us information about distance when objects are far away.
Pictorial cues
Occlusion – covering the image of a further object by the image of a nearer one.
Image size – A nearer object produces a larger image than a farther object of the same size.
Texture – a gradient of texture element size and shape provides a cue for distance over a surface.Shading – Gives clues as to the angle of an object
Where does object recognition happen?
In the lateral occipital complex
What happens if the Lateral Occipital cortex is damaged
Visual Form Agnosia
What are the two types of Visual Form Agnosia?
Associative and Apperceptive
What is Associative Visual Form Agnosia?
when a person cannot describe the content of visual input, people ca draw the item and categorize
What is Apperceptive Visual Form Agnosia?
Cannot process visual input, e.g. cant name and object in front of them.
Why can we recognise faces in every day objects?
Faces are a special sort of stimulus of which we have a cognitive bias towards
Fantz 1961
found that babies as young as young as 2 months old have a cognitive bias towards correctly configured faces
What is Prospagnosia?
Deficit in facial recognition where you cannot recognise any faces, even your own, sufferers describe the emotional feeling of recognition but cant, you can have it from birth (congenital) or acquire is gradually (developmental)
Capgras Syndrome
Patients believes familiar faces have been replaced by imposters, however they show normal autonomic nervous responses.
Yin (1969)
Showed that facial recognition is slower and less accurate in faces are inverted.
Bruce and Young (1986)
Proposed Holisitc Form Theory from a wealth of evidence suggesting faces are processed holistically, with emotional and semantic involved.
What makes a face attractive?
Averageness, Symmetry
What does Jeanneord (1997) propose?
That there are two separate components to graspig something, Reach trajectory and Grip aperture.
At what point does peak grip aperture occur?
70% through the reach
What is Cortical Blindness?
the total or partial loss of vision in a normal functional eye due to brain damage in the occipital cortex, can be aquired, congenital or even temporary
What is a Hemianopia?
Patient is unable to see it the contralateral visual field
What is a Quadrantanopia
patient is unable to see in the upper or lower contralateral quadrant.
What is a scotoma?
any visual defect (can be smaller than a hemi or Quadrantanopia)
What is Blindsight?
Residual sensorimotor control following cortical blindness. Blindsight is the extraordinary phenomenon where people who have damage to parts of V1 and are blind to some parts of the world can actually describe objects placed in their blind field.
What is one explanation of Blindsight?
There is a secondary pathway that connects the retina to the parietal cortex via the superior colliculus meaning it bypasses V1 and is the likely pathway for Blindsight.
Evidence for Blindsight
Patient DB - - Left Hemianopia following surgical resection of the right occipital lobe however he could look towards and point at visual targets he could not consciously see
Milner and Goodale (1992)
concluded from research done on patient DF that there are separate brain systems for using information for perception and for physically controlling your actions (think about the posting task)
What is Optic Ataxia?
Caused by damage to left Parietal lobe which affects visually guided movement.
What is the Ventral Stream?
The ‘What’ stream, used for object processing, colour texture, size. Damage to this area causes perception problems such as visual form agnosia
What is the Dorsal Stream?
The ‘Where’ stream, used for spatial processing, location, movement. Damage to this area causes action problems such as Optic Ataxia.
What is Proprioception?
The bodies ability to sense where our body is in space without having to look.
What is Deafferentation?
Total loss of Proprioception
Describe Phantom Limb Pain
The sensation amputees often feel of unpleasent pains at the sight of their amputation. Treatment includes heat application, relaxation techniques, massage, nerve blockers, mirror box illusion
What is the Mirror Box Illusion?
Box with two mirrors placed back to back in the middle, amputee places good limb and amputated one in each side, the mirrors make it look like the limb is still in intact and getting the patient to do mirror symmetric movements can alleviate the ‘pain’ or ‘tension’ felt.
What is the Rubber Hand Illusion?
Botvinick and Cohen (1998) - Stimulation of a rubber hand at the same time as an actual hand can create the sensation of ownership of the rubber hand, to the point of galvanic skin response occurring when rubber hand is threatened with a hammer.
What is Embodied Cognition?
How the role of the environment around us plays a role in cognitive functioning.
Witt el al (2005)
Participants judged the distance of targets which were placed just beyond arms reach and asked to reach towards them whilst guessing, p’s judged the distance as shorter if given a baton (body extending tool)
What is Synaesthesia?
A harmless neurological condition in which stimulation in one sensory modality triggers simultaneous and involuntary sensory experiences in another unrelated modality, the condition appears to have a genetic link
Simner et al (2005)
propose around 1/23 experience some kind of synaesthesia
Baron-Cohen et al (2013)
synaesthesia seems to be more apparent in people on the autistic spectrum.
Nunn at al (2002)
fMRI scans showed that S’s have more activity in the region V4 (specialised for colour vision) when hearing a word spoken.
What is Selective Attention?
the process by where we focus mental processing on a limited range of events. Without selective attention we would not be ‘consciously aware’ of anything and we would be swamped with sensory overload of pointless information and unable to concentrate
What is Enhancement?
enables us to select some information for further processing
What is Inhibition?
enables us to set some information aside
What is Change Blindness?
surprising perceptual phenomenon that occurs when a change in a visual stimulus is introduced and the observer does not notice it. For example, observers often fail to notice major differences introduced into an image while it flickers off and on again
What is Covert Attention?
objects can be attended to covertly meaning we can process information to some extent even when our eyes are not directly focused on it
What are the two types of cues that can control covert attention?
Exogenous and Endogenous
What is a Exogenous Cue?
Sudden flashing light or movement, driven and reflexive, fat affect on attention with no competition from other stimuli?
What is an Endogenous cue?
Something that has to be internally interpreted in some way and is voluntary, long effect on attention and has to compete with other stimuli.
Posner (1980)
developed an experimental cueing task, which involved valid, neutral and invalid trials with participant’s reaction times being recorded. Participants had to hit a button whenever they saw a target on the screen and there would be one of the three cues on the screen beforehand hinting at where the target might appear. It was shown that the response time was longer in the invalid trials (where the target appeared somewhere other than where the cue would have suggested). This research suggests that invalid cues are of cost to the brain as they require more attention than valid cues.
Describe Bottom Up control.
Saliency (the amount an object stands out), edges, colours, brightness, evolved for survival as can signal dnager. Saliency is difficult in cluttered environments
Descirbe Top Down control.
Attention is directed by some internal mechanism or decision, i.e. the brain directs eye movements to help us see better, i.e. focusing the fovea (are of highest acuity) on the target area, as well as keeping the image centred should the body be moving around
Yarbus (1967)
showed us that when 7 people were free viewing a photo they all had different patterns of eye movement however all concentrated mostly on the faces in the images. The human eye voluntarily fixates on the areas containing useful information. People who ‘think’ differently also, to some extent, ‘see’ differently
Dicks et al
P’s focused on the legs of the kicker but in the real world version that they focused on the ball more proving that there really is a difference between lab experiments and real world experiments.
What is a Fixation?
when the eye stays almost still on an area of interest for 200-300ms, this is when visual information is captured and sent to the brain, these are usually not random locations but points of interest in a scene.
what is Saccade?
Fast and short eye movements between fixations (~20ms)
what is RSVP?
Rapid sequential visual presentation, allows for the reading of nearly 12 words per second
What is Perceptual Span?
the number of letter simultaneously processed, normal readers can read around 12 letter forwards and 3 or 4 letter backwards indicating the perceptual span is centred asymmetrically around the PoF. This effect is reversed in readers of Arabic or Hebrew where text is read right to left
what are the three stages when learning to read?
when learning to read, pictorial, a brief period where children photograph a few words, phonological, where they learn to decode graphemes into phonemes, and the orthographic stage where word recognition become fast and automatic.
Describe Dyslexia
linked to impaired ability to process phonemes, the brains of dyslexic children present a number of characteristic anomalies, anatomy of the left temporal lobe is disorganised, the brains connectivity is altered and there are several regions that are insufficiently activated.
Describe Atkison and Shiffrin’s (1971) model of memory.
Stimuli enters our through our senses and is briefly encoded in the form in which it enters in the sensory memory store, in the store auditory stimuli can be held for around 4 seconds and visual stimuli about 1/4 of a second. As long as the stimuli has your attention then it will enter into the short term memory store which can hold around 7 items (+/- 2), and lasts for around 18-30 seconds, through the process of rehearsal stimuli can enter into the unlimited capacity of the long term memory store where the information becomes semantically encoded and stored.
Describe the Primacy/recency effect?.
Murdock (1962) showed us that when given a list of 20 similar word to remember we are more likely to remember the words at the begining ofthe list (primacy) and at the end of the list (recency)
Sperling et al (1960)
asked p’s to remember rows of letters, 3 rows of four letters, 12 in total, after flashing the letters for just 1/20th of a second. When asked to recall all 12, they usually remembered less than half, however if a low high or medium tone was played just after the image they could more often than not recall all the letters on the corresponding row.
What is Iconic memory?
fast decaying store of visual information
What is Echoic memory?
fast decaying store of auditory information
Describe Baddeley and Hitch’s model of Working Memory.
Is a more sophisticated understanding of the short term memory consisting of 4 main components. The Central Executive (controller) which coordinated the operation of the other components with a limited capacity. The Visuospatial sketchpad (inner eye) handles non-phonological information and is a temporary store for visual and spatial information. The phonological store which is responsible for processing sound based information and is made up of two components, the articulatory loop (inner voice) and primary acoustic store (inner ear). Lastly there is the Episodic Buffer which was only added in 2000 and is a limited capacity store which that can access and integrate information from the other components.
What is Elaborative encoding?
the process of actively relating new info to knowledge that is already in the memory
What is Organisational Encoding?
the act of categorising new information by noticing the relationships between items
What is Explicit Memory?
the act of consciously retrieving past experiences
What is Implicit Memory?
the influence of past memories on later behaviour and performance, even though people are not trying to recollect them or even aware that they are
What is Procedural Memory?
the knowledge of practical memory such as how to ride a bike or drive a car.
What is Semantic Memory?
the memory of facts and general knowledge
What is Transience?
forgetting things with the passing of time
what is Retroactive Interference?
where newly learned things interfere with the memory of older things
What is Proactive Interference?
when earlier learning affects the ability to remember newly learned things
Describe the tip of the tongue phenomenon.
the temporary inability to retrieve information from your LTM accompanied by the feeling you will soon recover it
What is Blocking?
a failure to retrieve information that is available in memory even when you are actively trying to remember it
Describe Absentmindedness
a lapse in attention that results in a memory failure
What is Divided Attention?
situations where individuals have to simultaneously monitor more than one source of information
What is Retrograde amnesia
inability to retrieve information that was acquired before a particular date
What is Anterograde Amnesia?
the inability to form any new long term memories, things don’t progress form short term to long term
What is Source Monitoring?
recall of when, where and how information was acquired
What is Consistency Bias?
altering the past to fit the present
What is Change Bias?
exaggerating differences between the past and present
What is Egocentric Bias?
altering the past to make us look better
What is Persistence?
the intrusive recollection of events that we wish we could forget.
What is Episodic Memory?
the memory of personally experienced events
What is a Flashbulb Memory?
the memory of a particularly emotional or unusual event were the person can remember seemingly small irrelevant details exactly to a degree miles above that of normal long term memories.
What is the NOW PRINT! mechanism
this is a mechanism that acts like a camera to record details in certain emotional situations, however it could just be the amount of rehearsal that becomes involved in the retelling of shocking memories.
What factors affect the reliability of Eye Witness Tesitmony?
Stress, Weapon focus, post event contamination such as witness discussion, police questioning other than the cognitive interview.
Loftus et al 1987
Found that when a scene involves a weapon people are less likely to be able to identify the culprit than if no weapon is seen.
Godden and Baddeley 19751
Found that people are more likely to remember information if they are recalling it in the same context as it was first learned.
Describe the method of Loci
imagine a series of places that have a specific order to them, imagine the items you have to remember in each of these locations
define learning
a relatively permanent change in behaviour or mental processes as a result or practice or experience
Describe Classical Conditioning
learning that occurs when a NS becomes paired with an US to elicit a CR
What is Stimulus Generalisation?
learned response to not only the original stimulus but also other similar stimuli
What is Extinction?
gradual weakening or suppression of a previously CR
What is Stimulus Discrimination?
learned response to only the specific stimuli but not similar stimuli
What is Spontaneous Recovery?
reoccurrence of a previously extinguished CR
what is Higher Order Conditioning?
when an NS becomes a CS using a previous CS
What is Operant Conditioning?
pairing voluntary responses with negative or positive consequences, really complex skills can be achieved in both humans and animals through operant conditioning
What is Shaping?
• Reinforce increasing close approximations of desired behaviour, happens in small steps and very useful when leaning complex behaviour
Skinner 1948
Superstitious Pigeons
Describe Fixed Interval Reinforcement
– reinforcement will become available when a fixed time period has elapsed following the previous reinforcement. The first response after this interval will produce the reinforcer. For example, someone who gets paid every two weeks and knows when the reinforcement is coming
Describe Variable interval reinforcement
reinforcement will become available when a time period has elapsed following a previous reinforcement however the length of time of the waiting period differs. Reinforcement regardless of performance at unpredictable intervals. E.g. pressing a button for a lift is 100 times is not going to make it arrive any faster
Describe Fixed Ratio reinforcement
Reinforcement will be delivered after a specific number of responses have been made, for example getting paid for every 100 letters you post.
Describe Variable ratio reinforcement
reinforcement will be delivered after a specified average number of responses have been made – e.g. slot machines, sometime you only put a few coins in and get the reward, sometimes you have to put loads in.
