PYB204 study guide Flashcards
williams syndrome
Patients with Williams syndrome have difficulty processing visuospatial information. However, they can learn repeated routes better than age-matched healthy individuals
early philosophy of cognitive psychology
nativism: knowledge is innate.
empiricism: knowledge s acquired through experience (aristotle, bacon, berkely, locke, hume, and mill)
Cognitive revolution
During world war 2, research on human performance was intensively conducted.
Information processing approach
theorises that humans actively process the information they receive from their senses, like a computer does.
input —> mind (where process of info occurs) —> output
two key principles of vision
- Perception is dynamic – we perceive change
- We perceive constancies in a changing environment
Fovea
at the back of the eye, focuses the light that we are directly looking at.
Saccades
spazzing wobbling to keep the eye moving. if the retina stabalises on an image, it will disappear as the photons stop firing and the brain fills the missing space.
ciliary muscles
they control the shape of the lens to accomodate for near or far targets. the ciliary muscles relax to focus near, and tighten to focus far. they sit on the top and bottom of the lens to stretch or relax the shape.
cones
High acuity, low dark sensitivity, fast dark adaptation
rods
Rods have low acuity, slow dark adaptation, high dark sensitivity
Vergende and stereopsis
the two eyes converge to produce two different, but aligned images of the same target.
duplex retina theory
Schultze proposed that rods and cones form two separate visual systems:
1. Photopic = bright light vision via cones
2. Scotopic = dim light vision via rods
ganglion cells
Act like a lens, capturing an image over an area of the retina (called the receptive field). This effect is due to a process of lateral inhibition between adjacent receptors using microelectrode recording
receptive fields
Ganglion cells have both excitatory and inhibitory connections within their receptive field. Some ganglion cells can be excited by light inside the receptive field.
the tectopulvinar system
purpose is to be the basic relay systems through the brain to respond to seeing things and acting on them. Van essen 1985, ungerleid and mishkin 1982 found several functions;
localisation of objects in space
guidance of eye movements
gross pattern perception.
some optic tract fibres project to the superior colliculi and then on the pulvinar and lateral posterior nuclei
where is the tectopulvinar system located
these structures are located in the thalamic region called the tectum. receiving back projections from the cortex.
blindsight
weiskrantz 1977, 1992 found that some people with damage to the focal system can still react to visual stimuli although they claim that they can not see them.
sensation
how our sensory organs (eyes, ears, etc) convert physical information into signals that our nervous system understands
perception
how we process environmental information to form internal representations of the environment
cognition
how we use internal representations to do more complex things
types of thresholds
difference thresholds: the smallest change in a stimuli can be detected. Weber’s law.
absolute thresholds: the minimum intensity of a stimuli that can be detected. Fechner’s law
absolute threshold
the minimum intensity of a stimulus that can be detected
the outer ear
pinna –> increases the sound amplitude. External canal provides protection and increases amplitude
ear drum –> tympanic membrane vibrating in response to sound waves, moves bones in middle ear.
the middle ear
ossicles –> the smallest bones in the body, transmit vibrations from the ear drum to the cochlea. provides protection from high amplitudes.
ossicles are made up of malleus, incus, and staples
inner ear
cochlear –> contains auditory sensory receptors
the inner ear contains the cochlear, with three canals: vestibular canal, tympanic canal, and cochlear duct
central auditory pathways
nerve fibres from each cochlea synapse in a number of sites on the way to the primary auditory cortex
The cochlear nucleus
The superior olivary nucleus
The inferior colliculus
The medial geniculate nucleus
The signal arriving at the cochlear nucleus splits and goes to each of the superior olivary nuclei. Beyond this point, input from both ears is present in both hemispheres.
frequency coding
sounds are made up of a mixture of sine wave components, the auditory system isolates and identifies the frequencies of these components. This is known as fourier analysis. The basilar membrane is about 30mm long and varies in stiffness and width alone its length. Travelling waves move along the basilar membrane and peak at a different point depending on the frequency of the sound.
cochlear implants
can do the maths of frequency coding for the ear and stimulate the cochlear based on the frequency of sounds
the auditory neurons
are arranged in an orderly manner in the primary and secondary auditory cortex.
central auditory pathways
the cochlear nucleus
the superior olivary nucleus
the inferior colliculus
the medial geniculate
agnosia
the impairment of object recognistion. they can identify elements of the object but not the object as a whole
two cortical pathways for processing visual information
ventral pathway: ocipital lobe to the temporal lobe, processing information about identity and appearance
dorsal lobe: ocipital lobe to parietal lobe, processing information about objects, important for guiding action.
optic ataxia
intact object recognition but inability to use visual information to guide action (impairment to the dorsal stream)
theories of pattern recognition - gestalt principals
similarity, closure, good continuation, and proximity
theories of pattern recognition - template matching
comparing a shape/pattern to something we already know. matching the pattern to a template. this does not always work at we do not have every template
theories of pattern analysis - feature analysis
a visual pattern is perceived as a combination of elemental features. Known as Selfridge’s pandemonium model. This is a hierarchy of elements that recognise things. Initially the pattern is broken down to simple elements that are perceived first, then this becomes more complex and the brain reconstructs them to recognise the pattern.
theories of pattern analysis - recognising by component theory
An object is first segmented into a set of basic sub-objects (called geons) and then recognised in the brain by a composition of geons.
neural mechanisms of pattern recognition
neurons in higher-order visual areas respond to increasingly complex patterns. ight detection neurons firing information at the neuron in the primary visual cortex. The combination of this information allows the visual cortex to identify patterns. All this information is combined to recognise an object, reconstructing information in the brain. this process is bi-directional as we solve problems the more we look and reconsider it.
grandmother cell hypothesis
that the neural pathways are so specific that there is a specific cell that recognises a specific object/light pattern. lacking evidence but seen in the jennifer aniston neuron that fires when we look at her.
word superiority effect
superior recognition of letters in a word context rather than letters alone. Indicates top-down influence on pattern recognition. We can identify the letter D easier when presented in a word rather than alone when presented for a short period of time.
visual vs verbal representation of information
inability to notice salient changes in a visual scene. standing 1973 study finding that participants will recognise a zoomed out image of a scene as the exact same image they were shown prior.
early selection theories of attention - the filter theory
sensory information has to pass through some bottleneck. Only some of the sensor information is selected for further processing. seen in the dichotic listening task
early selection theories of attention - the attenuation theory
salience of unattended stimuli is reduced, but they are not filtered out entirely.
late selection theories of attention
the filter blocking unecesary stimuli happens after the perceptual stimuli has undergone analysis for its semantic content
voluntary attention
top-down and goal directed. Focus of attention is usually the same as the focus of the eyes. But not always, this is known as posner’s cueing paradigm. Similar processing enhancement is observed when reflexive cues are used. An arrow or a flash on the screen will draw your attention to the stimulus that it is pointing to or flashing over.
reflective attention
bottom-up and stimulus-driven. When more time passes between a reflexive cue and a target, response to the target becomes slower. The reflexive attention system has build in mechanisms to prevent reflexivity directed attention from being stuck at a location for too long (inhibition of return).
feature integration theory
people must focus attention on a stimulus before they can synthesise its features into a pattern, in essence, attention works as glue with which various features are combined into an object. We scan each letter, one at a time until we find the letter, but this will be harder in some environments where the surrounding patterns are similar
dual task performance
attention deficit in dual tasks can be seen in Stroop effect. this is reporting the colour of the word you are reading, when the words read the names of colorus but are coloured in a different colour, there is a difficulty.
sensory memory
less than one second memory, this is iconic (visual), or echoic (auditory). can hold 3-6 items
short-term / working memory
1-10 second of memory, this can be central executive, visiospacial sketchpad, phonological loop, or episodic buffer. can hold 7 (+or- 2) items
long term memory
longer than 10 seconds, declarative explicitly memories or non-declarative implicit memory
types of long-term memory
declarative memory: memories for facts and events, you can explicitly remember
non-declaritive memory: implicit memory (motor skills), you can not explicitly remember
memory encoding
the way information is processed affects how well it is encoded in long-term memory. Depth (levels) of processing and information is processed in a deeper and more meaningful manner will be better encoded.
incidental vs intentional learning and memory
Depth of processing not whether one intends to or not, can determine the amount of material remembered.
theories of forgetting
decay theory: memory traces decay over time
the inteferance theory: memory traces becomes less accessible due to interferance from competing memories
memory storage / retrieval
We make inferences at the time of memory retrieval, sometimes we are not even aware that we are making inferences rather than remembering what was actually studied.
false memory
sometimes we are required to clearly separate what we actually learned from our inferences. this is seen in inaccurate eye witness testimony
deleting memories
when cues memories can undergo reconsolidation. This is a brief liable stage where the memory can be reinforced or altered. Opportunities for therapy can be seen in part of the basis of modern therapies for anxiety and trauma.
conditioning and extinction of memory
repeated presentations of a conditioned stimulus without the unconditioned stimulus creates a competing memory trace that can supersede the conditioned memory. Called extinction learning. Basis for modern exposure therapies, such as PTSD and anxiety.
problem space
is the term describing the various states of the problem
problem state
is a representation of the problem in some degree of solution.
three ways to acquire operators - problem solving
discovery, direct instruction, analogy/imitation
three criteria for selecting operators - problem solving
backup avoidance, difference reduction, and means ends analysis
difference reduction - problem solving
the tendency in problem solving to select operators that eliminate a difference between the current state and the goal state. it is a useful method but not always optimal. it only considers whether the next step is an improvement and not whether the larger plan will work
means end analysis
creates a new subgoal to enable an operator to apply, an operator is not abandoned even if it cannot be applied immediately.
incubation effects - problem solving
the phenomenon that sometimes solutions to a particular problem come easier after a period of time in which one has ignored trying to solve the problem.
retina physiology
Receptor cells synapse with bipolar cells.
Bipolar cells synapse with ganglion cells.
Horizontal cells connect different receptor or different bipolar cells.
Amacrine cells connect different bipolar or different ganglion cells.
These connecting cells allow events at one location to influence events at another.
hearing
Sound is caused by changes in air pressure. These pressure waves are characterised by amplitude, frequency, and phase.
The human hearing range is between 20-20000 Hz
pitch perception
Perception of a missing fundamental – when higher-order harmonics are present in the absence of the fundamentals, the missing fundamental is filled in. A missing fundamental is perceived even when harmonics are presented to different ears
loudness perception
Generally, high-frequency sounds are perceived to be louder (up to about 5000 Hz)
—> Around 3000-5000 Hz, sounds are perceived to be loudest
—> as the amplitude goes up, the effect of frequency becomes smaller
factors that affect loudness perception:
- Sound duration (longer = louder)
- Frequency
auditory space perception
determination of a sound’s horizontal and vertical direction as well as how far away a sound is
interaural time difference
unless a sound is directly in front of or behind you, it reaches two ears at different times (onset difference)
the onset difference can be detected by a simple ‘delay line’ mechanism in the brain
the same sound will most likely be in different phases when it reaches each of the two ears (phase difference). But the phase difference is less useful for localising high-frequency sounds
interaural intensity difference
the energy of a sound decreases as it travels farther. the head works as a barrier that reduces the intensity of the sounds (sound shadow) –> this effect is more pronounced for high-frequency sounds.
visual capture (hearing)
when we visually perceive where a sound ‘should be’ coming from, it tends to override our auditory localisation. when we have some visual information about how a stimulus ‘should’ sound, it strongly affects how we hear the stimulus
change blindness
the inability to notice salient changes in a visual scene
the cocktail party effect
you can hear your name mentioned in a crowded bar, even when you are talking to someone else.
early vs late selection
Treisman and Geffen’s (1987) dichotic listening task:
participants had to shadow one message from one ear. at the same time, they had to detect a target word, which was heard by either ear.
Predictions:
the attenuation theory: the target will be less frequently detected in an unshadowed ear
late-selection theories: the target will be detected equally well in either ear
Results (detection accuracy)
- in the shadowed ear: 87%
- in the unshadowed ear: 8%
plausible retrieval
much of recall in real life involves plausible inference rather than exact recall
