Cognitive Psychology Flashcards
3/10/19 (106 cards)
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Cognition
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involves mental processes involved in perception, attention, learning and memory, language and communication, problem solving, reasoning, etc
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Cognitive psychology
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an approach that aims to understand human cognition by the study of behaviour
✳︎ cognitive processes include perception, attention, memory, language, decision making, among others
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Types of cognitive psychology
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- Experimental cognitive psychology
- Cognitive neuroscience
- Cognitive neuropsychology
- Computational cognitive science
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Cognitive processes - Perception
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receive information via sensory inputs
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Cognitive processes - Attention
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establish, maintain, and manipulate the focus on information
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Cognitive processes - Memory
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acquire, store, consolidate, and retrieve information
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Cognitive processes - Language
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main communicative process that, in addition to its own specific properties (words, grammar), needs to rely upon other processes
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Cognitive processes - Decision making
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make conclusions, selecting actions
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Key disciplines - Experimental cognitive psychology
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applies experimental methods to the study of behaviour and the processes that underlie it
- studies cognitive processes by measuring aspects of people’s behaviour
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Key disciplines - Cognitive neuroscience
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aims to understand human cognition by combining information from behaviour and the brain
- studies cognitive processes by measuring spatial and temporal aspects of the underlying brain activity
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Key disciplines - Cognitive neuropsychology
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involves studying cognitive functioning in brain-damaged patients
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Key disciplines - Computational cognitive science
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involves constructing computational models to understand human cognition
- Computational modelling: programming computers to model or mimic aspects of human cognitive functioning
- Artificial intelligence: constructing computer systems that produce intelligent outcomes
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Research methods
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- Reaction time (RT)
- Eye tracking
- EEG
- MEG
- PET
- MRI
- TMS
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Approaches to human cognition - experimental cognitive psychology
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- Focuses on experimental investigations of observable behaviour in its relation to underlying cognitive processes (e.g. perception, memory, etc.)
- General types:
∙ Bottom-up vs top-down
→ B.U processes result from the properties of the perceived stimulus
→ T.D processes results from the person’s intentions, i.e. by the what’s already in their head
∙ Serial vs parallel
→ Serial processes are “computed” one at a time
→ Parallel processes are computed in parallel
✳︎ T.D - internally driven attention
✳︎ B.U - externally driven attention - Serial processing - stimulus → attention → perception → thought processes → decision → response or action - one operation needs to finish before the next operation can take over
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Paradigm
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an accepted experimental task determined by a theory and common set-up
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Method
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∙ General: a scientific approach typical for a discipline e.g. observation, experiment etc
∙ Specific: experimental technique usually defined by the use of some apparatus e.g. MRI, eye-tracking
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Methodology: Eye-tracking
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Eye tracking helps to understand how people access information: 1) the point of gaze (where one is looking) and 2) gaze shifts (when/why people move their gaze)
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Experimental cognitive psychology: evaluation - strengths
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- a systematic approach to understanding human cognition
- control of experimental conditions: experiments are relatively “pure”
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Experimental cognitive psychology: evaluation - limitations
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- provides indirect evidence about underlying cognitive processes
- theories are often vague/hard to falsify
- findings often lack ecological validity (the extent to which experimental findings reflect “real” cognition)
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Bottom-up processes
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influenced by stimuli
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Top-down processes
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influenced by individual’s knowledge and expectations
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Serial processes
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sequential: one process needs to be completed before the next one can start
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Parallel processes
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two or more cognitive processes occurring at the same time
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Ecological validity
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the extent to which experimental findings are applicable to everyday settings
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Cognitive neuroscience
is concerned with the scientific study of brain structures suppor cognitive processes
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Neuroimaging methods
- Single-unit recordings
- Electroencephalography (EEG)
∙ Event-related potentials (ERPs)
- Magneto-encephalography (MEG)
- Functional magnetic resonance imaging (fMRI)
∙ fMRI measures Blood Oxygen-Level-Dependent (BOLD) contrast
- Transcrannial magnetic stimulation (TMS)
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Spatial and temporal resolution
Neuroimaging methods vary in their measurement accuracy or resolution:
∙ Spatial resolution: how accurate the method is in measuring where the activity takes place
∙ Temporal resolution: how accurate the method is in measuring when the activity takes place
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Single-Unit Recording
- Electrodes inserted into the brain to record activity from a single neuron
- E.g. Hubel and Wiesel (1969;1972) primary visual cortex
- Exceptional temporal and spatial resolution
✳︎ Extraordinarily high spatial S.R
✳︎ Extraordinarily high T.R
- Limitations - invasive, expensive, many higher cognitive activities involve far larger populations of neutrons that aren't in the domain of this technique
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EEG: Electroencephalography
- Event-related potentials (ERPs) are averaged EEG responses that are time-locked to processing of stimuli
- Excellent temporal, poor spatial resolution
✳︎ ERP - Limited S.R, high T.R - providing a continuous measure of the time course of the response
- Limitations (ERP) - requires many trials, skull and brain tissue distort electrical fields, largely blind to subcortical activity
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MRI: Magnetic resonance imaging
- In MRI, radio waves are used to excite atoms in the brain leading to changes detectable by a large magnet
- MRI record brain's "BOLD" (Blood Oxygenation Level Dependent) signal. When a part of the brain is more active, there's an increased blood flow to that area; hence, stronger BOLD response
- Excellent spatial, poor temporal resolution
✳︎ High T.R. Voxel = 1mm x 1mm x 1mm
✳︎ Poor T.R (6-8s)
- Limitations - provides only an indirect measure of brain activity, distortions in some brain regions, noise from the scanner can be distracting, may be uncomfortable for claustrophobics, participants must remain still...limiting response types and experiment duration
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Transcranial Magnetic Stimulation (TMS)
- Brief pulse (or pulses) are emitted by a coil next to the skull
- Produces a magnetic field that can disrupt brain activity in the underlying cortex (∼1cm3) creating a temporary "lesion"
- Relatively good spatial resolution, excellent temporal resolution
✳︎ From about 7mm to several cm, depending on the coil and target area
✳︎ Milliseconds. TMS allows real-time modulation of brain activity
- Limitations - not clear how TMS changes brain activity, disruption may spread to connected regions, may cause painful muscle spasms, or (very infrequently) seizures
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PET
✳︎ Poor T.R. Detects regional blood flow changes on the order of 30-60s
- Limitations - PET provides only an indirect measure of neural activity and is an invasive technique
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MEG
✳︎ Excellent T.R
✳︎ V. good S.R
- Limitations - expensive to keep the SQUID cool, requires the participant to maintain a potentially uncomfortable body position for long durations, the technology and analysis are relatively new and complicated
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BASIC PROCESSES IN VISUAL PERCEPTION: History
- Abu Ali al-Hasan ibn al-Hasan ibn al-Haytham (965 in Basra – c. 1039 in Cairo).
- Principles of optics, physics, astronomy, mathematics, ophthalmology, philosophy, visual perception.
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Basic eye anatomy: CORNEA
the transparent “window” that covers the front of the eye and transmits light into the eye
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Basic eye anatomy: IRIS
the coloured part of the eye that helps regulate the amount of light that enters the eye
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Basic eye anatomy: PUPIL
dark opening in the iris. Together with the pupil determines how much light is let into the eye. It dilates (changes size) to accommodate for the amount of light that is available
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Basic eye anatomy: LENS
the transparent structure inside the eye that focuses light onto the retina
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Basic eye anatomy: RETINA
the layer of nerve cells that lines the back of the eye. The cells in the retina sense light and create impulses that are sent through the optic nerve to the brain
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Basic eye anatomy: OPTIC NERVE
the nerve that connects the eye to the brain. The optic nerve carries the impulses formed by the retina to the brain, which interprets them as images
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Retina
- 6 million Cones. Specialised for colour vision and sharpness.
- 125 million Rods. Specialised for movement detection and peripheral vision.
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From eye to the brain; From eye to cortex: 3 major processes
1. RECEPTION: light absorbed by receptors
2. TRANSDUCTION: light converted into electrical signals
3. CODING: properties of the perceived stimulus are reflected in the nervous system activity
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From retina to brain
✳︎ Optic chiasm
✳︎ LGN
✳︎ PVC
► Signals proceed along two optic tracts within the brain. One tract contains information from the left half of each eye and the other tract from the right half.
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P- and M-Cells
- Lateral Geniculate Nucleus (LGN) contain P-cells and M-cells
- Parvocellular cells (P-cells) - sensitive to colour and fine detail.
- Magnocellular cells (M-cells) - sensitive to motion and coarse outlines.
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Two pathways
- P pathway → sensitive to colour → input comes from cones
| - M pathway → sensitive to motion → input comes from rods
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In the brain: visual cortex; primary visual cortex
- V1
- V2
- Neurons from P and M pathways mainly project to V1. P (ventral) pathway proceeds via V4 involved in colour processing. M (dorsal) pathway proceeds via V5 involved in motion processing.
- Areas V1 and V2 are involved in early visual processing, they respond to colour and shape.
- The receptive field for a given neuron is the corresponding retina region from which it receives input.
- V1 neurons are organised as a retinotopic map: They have the same positions relative to one another as their receptive fields in the retina.
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Visual pathways in the brain
- Dorsal ("where"/"how") stream
| - Ventral ("what") stream
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Two specialised visual streams
- The VENTRAL stream: involved in the recognition of objects (what things are) and representing their features (colour, shape). Receives input from the parvocellular pathway. Stretches from V1 to the temporal cortex.
- The DORSAL stream: involved in the recognition of actions and recognizing where objects are. Receives main input from the magnocellular pathway. Stretches from V1 to the parietal cortex.
✳︎ However, information processing in the two pathways is by no means totally or cleanly segregated.
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Ventral ("what") stream: colour processing (V4)
- V4
- IT
- Evidence that V4 is involved in colour processing comes from:
1. Neuropsychology: Patients with achromatopsia have damage in V4. They show deficits in colour perception with normal perception of form, shape, and motion (Bouvier & Engel, 2006).
2. Neuroimaging: Viewing of coloured objects activates a pathway from V1 to V4 (Zeki & Marini, 1998).
3. Single-unit recording: Neurons in V4 that respond strongly to colour (Conway, Moeller, & Tsao, 2007).
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Ventral ("what") stream: form processing (IT)
- IT (inferotemporal cortex) Neurons in IT differ along two dimensions:
∙ Object selectivity: neurons that respond mainly to a certain type of objects (e.g., a circle)
∙ Change tolerance: neurons that respond to differences in changes in object’s position, size, illumination, etc.
✳︎ Several visual areas are involved in form processing (V1, V2, V3, V4, ICT). However, the cognitive neuroscience approach has focused mainly on the inferotemporal cortex (IT)
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Dorsal ("where") stream: motion processing (MT (middle temporal)/V5)
- Evidence that MT area (middle temporal) is involved in motion processing:
1. Neuropsychology: Patients who suffer from akinetopsia have damage in MT. They find that objects in motion become invisible.
2. TMS: Beckers and Zeki (1995) used TMS to produce a temporary lesion in MT, which resulted in complete akinetopsia.
✳︎ Human V5 is located near the occipito-temporal border below the superior temporal sulcus.
✳︎ Another area that is involved in motion processing is area MST (medial superior temporal), which is adjacent to V5. This area is thought to be involved in the visual guidance of walking.
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VISUAL CORTEX: Summary
► Primary visual cortex (V1 and V2): initial visual processing
► Receptive field: the corresponding retina region from which VC neurons receive input
► Retinotopic map: VC neurons occupying the same relative positions as their respective receptive fields on the retina
► Ventral Stream: specialised for “what” information: object’s shape, colour, orientation
► Dorsal Stream: specialised for “where and how” – information about object’s location and motion
► V4: colour processing
► IT: form processing
► V5(MT): motion processing
► Achromatopsia: a condition following damage to V4 with impaired colour perception but intact form and motion perception
► Akinetopsia: a condition following damage to MT with impaired motion perception but intact shape and colour perception
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Functional specialisation in visual cortex
→ V1 and V2: Form, shape and orientation
→ V3 and V3a: Form of moving objects
→ V5(MT): Motion
→ V4: Colour
✳︎ The importance of V1 is shown by lesions at any point from retina to V1, which cause virtually total blindness in the affected part.
∙ V1 and V2 are involved at an early stage and respond to colour and form.
∙ V3 and V3a respond to form (especially in motion) but not to colour.
∙ V4 responds to colour and line orientation.
∙ V5 is specialised for visual motion.
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Two pathways: perception and action
∙ Milner & Goodale: Vision-for-perception system based on the ventral pathway
Vision-for action system based on the dorsal pathway
∙ Norman’s (2002): Dual-process approach: Ventral pathway for “knowing” the environment and dorsal pathways for guiding behaviour.
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Evidence for pathway independence: double dissociation
- Patients with optic ataxia have damage to the dorsal pathway. They have problems with visually-guided movements but not with object recognition.
- Patients with visual agnosia have damage to the ventral pathway. They have problems with object recognition but not with visually-guided movements.
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Object perception
- “…the ability to rapidly (<150 ms viewing duration) discriminate one visual object from other visual objects …” (DiCarlo & Cox, 2007).
- Object recognition is effortless and effective allowing us to have an efficient and rapid control of visual environment.
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Object perception: purposes
```
- Object perception serves a number of purposes:
►Recognition
►Identification
►Categorisation
►Naming
►Matching
```
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Object perception: basics
- Primates are very good at object recognition even in the situations of:
►object transformations
►violations of visual boundaries
►at various distances, viewpoints, and in different lighting conditions
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Object categorisation: invariance
Object categorization is possible even when there is infinite number of category members.
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Object categorisation: generalisation
Object categorization is efficient even if we have never seen similar objects before
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Object categorisation: perspective and missing parts
- We can recognise objects that are only partially visible.
| - And the same objects from very different angles (although certain orientations can take effort)
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Gestalt psychology
- a school of psychology founded in Germany in early 20th century. Main purpose – explain perception in terms of gestalts (holistic object representations)
- Holistic perception: perceiving objects as a whole rather than via a decomposition into several parts.
- As a result, we tend to order and group our perceptual experiences in a holistic, regular, and orderly manner (is it a bottom-up or a top-down process?).
- The Law of Prägnanz: “Of several geometrically possible organisations that one will actually occur, which possesses the best, simplest, and most stable shape” (Koffka, 1935, p. 138)
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The Law of Prägnanz
- Reality is organised or reduced to the simplest form possible
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Gestalt's principles: emergence
- Emergence: complex patterns emerge as a whole instead of being recognized by identifying constituent parts (e.g., feet, ears, nose, tail, etc.).
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Gestalt's principles: reification
- Reification – the principle of “filling in the blanks”. The experienced percept contains more spatial information than the sensory input, on which it is based.
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Main Gestalt principles: multistability
- Multistability - the tendency of ambiguous perceptual experiences to alternate between available interpretations.
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Main Gestalt laws
1. The law of proximity - elements tend to be grouped together if they are close
2. The law of similarity - elements tend to be grouped together if they are similar
3. The law of good continuation - elements requiring the fewest changes or interruptions are grouped
4. The law of closure – tendency to perceive objects as a whole even when they are not complete.
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Gestalt psychology: evaluation
- Advantages: Offers a good intuitive description of certain properties of perceptual organisation
- Limitations: More descriptive than explanatory
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Modern theories of object perception: Recognition-by-Components Theory: Biederman, 1998
- Objects consist of combinations of geons (geometrical icons) - 36 basic geons
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Modern theories of object perception: Viewpoint-Dependent-Theories: Tarr, 1995
- An image is not always easily decomposable.
- Changes in viewpoint reduce the speed and accuracy of object recognition
- Canonical views of objects (mental images) are stored. New input is recognized by finding the closest match in memory.
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Viewpoint-dependent vs Viewpoint-independent theories
►Biederman (1987): The ease of object recognition is (typically) not affected by the observer’s viewpoint
►Tarr (1995): Changes in viewpoint can reduce the speed and accuracy of object recognition
►Recent evidence suggests both mechanisms are used at different times:
∙ viewpoint-independent for easier between-category decisions
∙ viewpoint-dependent for harder within-category decisions.
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Objects and faces in the brain: Object recognition in the brain
- Ventral stream is important for object recognition.
| - Area IT (inferotemporal cortex) is sensitive to different object categories.
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Objects and faces in the brain: visual agnosia
- Impairment of object recognition despite otherwise preserved visual abilities.
- Visual Agnosia Subtypes:
►Achromatopsia - inability to distinguish between colours.
►Prosopagnosia - inability to recognize human faces.
►Orientation Agnosia - inability to judge object orientation.
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Objects in the brain: evidence from visual agnosia
- Object-related responses reduced in regions surrounding IT area.
- Impairments to ventral stream and the corresponding cortical areas affect object recognition
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Face recognition
- Face processing is an example of holistic specialized object recognition process
- Part–whole effect: Memory for a face part more accurate when presented within the whole face (Farah, 1994)
- Fusiform area (FFA):
►Found in the lateral fusiform gyrus. Part of ventral stream.
►Often damaged in prosopagnosia.
►More responsive to faces than to other objects.
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Prosopagnosia
- Face blindness
| - Damage to FFA
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Faces and objects: double dissociation
```
- Prosopagnosia:
►Object recognition - yes
►Face recognition - no
- Object agnosia
►Object recognition - no
►Face recognition - yes
```
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Visual imagery: Do the same brain areas support seeing objects and imagining them?
- Kosslyn & Thompson (2003): “Visual mental imagery occurs when a visual short-term memory representation is present but the stimulus is not actually being viewed; visual imagery is accompanied by the experience of ‘seeing with the mind’s eye’”
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Visual imagery and visual perception
- Perceptual Anticipation Theory (Kosslyn):
►Close relationship between imagery and perception
►Predicts that perception and imagery should influence each other
- Propositional Theory (Pylyshyn):
►Little relationship between imagery and perception
► Predicts that perception and imagery should not influence each other
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In support of perceptual anticipation
- Sheperd & Meltzer (1971): Research on mental rotation shows that the human mind maintains and manipulates mental images similarly to perceived objects.
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In support of perceptual anticipation
- Kossyln (1978): It takes longer to signal “mental travel” between the imagined landmarks that are farther apart than those that are closer together
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ATTENTION: Sensory modalities
1. Visual (seeing)
2. Auditory (hearing)
3. Olfactory (smell)
4. Haptic (touch)
5. Gustatory (taste)
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ATTENTION: Sensation
Refers to physical stimulation of the sensory receptors
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ATTENTION: Perception
Refers to interpreting sensory information
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Attention
Is a “highlighter” system that (1) selects information for processing and (2) helps us ignore information we don’t want/need to process
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Why study attention?
1. Access to information.
2. Gating of information access.
3. Inhibition of information access.
4. Multitasking.
5. Mind wandering. Inattentiveness
6. Attention and memory consolidation
7. Etc.
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Attention: definitions
1. "...withdrawal from some things in order to deal effectively with others” (James, 1890).
2. "...a spotlight..." (Posner et al, 1980).
3. "...select stimuli..." (Corbetta, 1998).
4. "...selectively concentrating on one aspect...ignoring other things...processing resources" (Anderson, 2004).
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Attention: main concepts
1. Selective attention
2. Divided attention
3. Sustained attention
4. Bottom-up (involuntary) attention
5. Top-down (voluntary) attention
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Attention: basic categories
- Top-down attention: voluntarily directing attentional “searchlight” and allocating cognitive resources to the task
- Bottom-up attention: involuntary attending to stimuli that are salient (stand out compared to other stimuli)
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Attention: basic features
- Selectivity – attending to a limited subset of information while ignoring (inhibiting) the rest. Focusing.
- Limited capacity – limited ability to handle different tasks at once (divided attention). Multitasking.
- Sustainability – limited ability to engage in protracted thought, especially on the same subject (sustained attention). Vigilance, Alertness.
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Selective attention: The Cocktail Party Effect (Cherry, 1953)
- The “cocktail party” effect: Ability to follow a conversation at a cocktail party in a very noisy environment.
- Attention needs to select one input channel for processing and inhibit the rest.
- As a result, you become “deaf” (unaware) to the info outside of the focused channel.
- In the lab:
✳︎ Shadowing task: overt repetition of the info presented in one channel:
►Content of the unattended channel – unnoticed
►Change in language – unnoticed
►Hearing your name in the unattended channel – noticed!
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Selective attention: Inatentional Blindness Effect (Simmons & Chabris, 1999)
- Didn't see bear moonwalking in the middle
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Early selection theory (Broadbent's 1958)
- Parallel inputs are filtered before accessing one of them: ►Filtering prevents overloading of the limited capacity mechanism
- Accounts for Cocktail Party effect:
►We are unaware of the unattended info because it undergo sensory but not semantic processing before being filtered
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Challenges to early selection theories
- Some information from the unattended channel is noticed during dichotic listening (Treisnam, 1960; Allport, et al., 1972).
- So, some monitoring of the unattended channel must occur!
- It matters what information is in the unattended channel!
- Also…shadowing becomes easier with experience (people learn to multitask!) (Underwood, 1974).
- Individual differences (some are naturally better at multitasking!) (Conway et al., 2001).
- Implicit learning from the unattended channel (meaning processing without awareness) (Von Wright, Anderson, & Stenman, 1975)
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Late selection theory (Deutsch and Deutsch, 1967)
- Try to explain why some unattended info is accessed
►both channels are semantically analyzed to a degree during sensory processing
►filtering happens later in STM (rather than in during perceptual access) and only relevant information is processed deeper; hence, late selection model of attention.
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Attenuation theory (Treisman, 1960)
- Unattended information is not fully inhibited (as in early selection models) but attenuated after initial sensory processing.
- Typically, unattended information does not reach semantic processing threshold, but the detector remains sensitive to some types of information (e.g. familiar or very relevant information) leading to occasional “breakthroughs”.
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Limited capacity: central processing bottleneck
- Driving while talking on a mobile phone causes:
►missing red lights
►increase in reaction time
- These deficits result from a central processing bottleneck of attention and reflect serial (rather than parallel) processing.
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Processing bottleneck: psychological refractory period
- In serial processing models, Psychological Refractory Period (PRP) is the period of time during which the response to the second stimulus is delayed because the first stimulus is still being processed (Pashler, 1994).
►The processing bottleneck occurs because only one stimulus can be processed at a time.
►Makes it impossible for two decisions about the appropriate responses to two different stimuli to be made simultaneously.
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Visual attention: Endogenous vs Exogenous attention
- Endogenous Attention:
►Voluntary attention. Controlled by the individual’s intentions and expectations
►Supported by a goal-directed (top-down) dorsal network, involved in prediction.
- Exogenous Attention:
►Involuntary attention. Automatic shifts of attention.
►Supported by a stimulus-driven (bottom-up) ventral network, involved in recognition.
= TOP-DOWN vs BOTTOM-UP
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Covert vs Overt attention
- In overt attention, gaze shift accompanies shift of attention.
- In covert attention, attentional shifts occur in the absence of eye movements.
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Explicit vs implicit attention
```
- Explicitly processed stimuli:
►Are noticed and consciously accessed
►Duration > ~70 ms
- Implicitly processed stimuli:
►Are unnoticed and unreported
►Duration < ~70 ms
= ATTENTION and AWARENESS
```
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Attention networks in the brain (Posner & Petersen, 1990)
- Alerting network: maintaining vigilance over a period of time
- Orienting network: directed attention, 3 operations: disengage, move, engage
- Executive network: Target Detection, Supervisory Control
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Basics of visual attention: main points
- Endogenous vs exogenous attention
- Overt vs covert attention
- Explicit vs implicit attention attraction
- Alerting, Orienting, and Executive networks
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Theories of visual attention
- Spotlight Model (Posner, 1980): Unattended information undergoes limited processing.
- Zoom-Lens Model (Eriksen & St. James 1986): Attentional scope is expandable.
- Multiple Spotlights Model (Awh & Pashler, 2000): Several spotlights are possible but little processing in “blind spots”.
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Attentional spotlight: evidence (Posner, 1980)
- Attentional facilitation (RT speed-up in valid condition) in the absence of eye movements (covert attention).
- Attentional focus (spotlight) and visual focus are partially independent
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Zoom-lens model: evidence (La Berge, 1983)
- 5-letter words presented centrally.
- The probe appears in the location of either letter.
- Letter task: Attention is focused on the central letter.
- Word task: Attention is focused on the entire word.
