Cognition In Clinical Contexts Flashcards
What is cognition?
All processes by which sensory input is transformed, reduced, elaborated, recovered and used. E.g- perception, language and memory
What is perception?
The ability to extract meaning from sensory input
How does the visual system work?
The distal stimulus is an object in the environment which is registered by sensory receptors to form a proximal stimulus (the image created on the retina). The proximal stimulus is transmitted to the primary visual cortex located in the occipital lobe of the brain.
What are illusory contours?
The ability to see boundaries/edges even though they are not physically present in the stimulus - This is a rational strategy that help make sense of disorder in everyday life.
What is template matching theory of object recognition?
Recognition results from comparing a stimulus to an internal representation stored in memory, each object requires a didferent template for each rotation or slant of an object.
What are the weakness of template matching theory?
It cannot account for the complexity of human visual processing, e.g being able to recognise objects when only being able to see a portion of the stimulus as the visual system cannot include templates of every fragment of every object.
What is feature analysis theory of object recognition?
Objects composed of a number of characteristics called a distinctive feature which are stored in memory along with the the physical relationships among features. E.g both letters T and L have a vertical and horizontal line (distinctive feature) but also have different physical relationships.
What are the weaknesses of feature analysis theory?
Most shapes in the real world are too complex to be able to store all the physical relationships and distinctive features they are composed of.
What is semantic priming?
The recognition of a face/object when the name of the objects/individuals is preceded by a semantically similar word. This is a form of covert recognition.
What is the fusiform face area?
Part of the brain associated with face recognition in which Kanwisher et al. Used fMRI and found that the right fusiform gyrus ridge responded differently to faces compared to objects.
What is Bruce and Young’s model of face recognition?
8 component modular model with different subfunctions processed independently. Pathways for familiar faces vs recognising expressions. Parallel processing dealing with visually derived semantic info such as sex, age, and race.
What is McClelland’s Interactive activation and competition model of face recognition?
Parallel distributed networks in which semantic information is pooled with relationships between info is represented as a connection. Connections within a pool are mutually inhibitory, connections between pools are mutually facilitatory. Person identity nodes can be partially activated and semantic priming facilitate node activity to spread across modalities.
What are face selective neurons?
Located in the superior temporal sulcus and the inferior temporal cortex. They form gnostic units which are selective to complex stimuli. Outputs are combined to form detectors of higher order features (colours and shapes are combined to form faces)
What is agnosia?
The impairment of visual object recognition in people who possess sufficiently preserved visual fields.
What is apperceptive agnosia? What are the behavioural symptoms?
An inability to perceive form. Patients cannot draw objects, match similar objects or even describe objects, but they can move about and negotiate obstacles without difficulty.
What is associative agnosia?
An inability to use a mental representation of an object to access stored knowledge about the object.
What are the causes of agnosia?
Bilateral lesions that form blind spots called scotomata across visual fields
Failure to group characteristics which produce a formless representation
Damage to memory itself and so meaning cannot be retrieved.
What is prosopagnosia?
The inability to recognise faces that cannot be explained by problems with visual fields. Though unable to recognise faces via visual input other modalities such as voice can be used.
What is capgras delusion? How is it different to prosopagnosia?
Capgras delusion eecognises a face yet denies the identity of the individual (often believing theyre an imposter) but prosopagnosia is an inability to recognise or identify a face at all.
Loss in ventral stream can cause prosopagnosia, whilst loss in dorsal stream can result the in capgras delusion.
What is multi-sensory perception?
The process by which info from different senses is brought together.
What is the McGurk illusion?
The auditory component of a sound is paired with the visual component of another sound forming a third sound.
E.g ‘ba’ is presented to ears, ‘ga’ is presented to eyes, subject perceives ‘da’
What is synaesthesia?
The automatic production of a sense relating to one part of the body by stimulation of another sense relating to a different part of the body.
How can synaesthesia be acquired?
Sensory deprivation, pharmacologically triggered (LSD)
How do we know that synaesthesia is real?
Empircal research with high internal consistency, functional imaging studies and synaesthetic stroop effect support that it is a genuine phenomena and are not hallucinations
What is attention?
A multidimensional concept that describe ways of responding in the cognitive system.
What is Cherry’s cocktail party effect?
Humans can (selectively) attend to one conversation even though there may be many other conversations going on around them.
What are dichotic listening tasks?
Pps simultaneously receive one message in one ear and a different message in the other and are asked to record what they heard. Pps attend to one message and are unable to identify the language or any specific words on the unattended channel.
What is the problem of the cocktail party effect?
It does not reflect human experience because it suggests individuals do not extract meaning from the unattended conversation when in everyday life, individuals attend to unattended conversations when something relevant is talked about such as your name or a related theme.
What is broadbents filter model?
The cognitive system is seen as a series of info processing channels. A selective filter identifies what info is processed and passes it to a limited capacity channel at which it is said to be the focus of attention. A response is then generated.
What are the properties of Broadbents selective filter mechanism?
Selection is based solely on the physical info (explains dichotic listening tasks-identifying voice/noise/pitch, but not the contents of message)
Info on unattended channels undergo no further processing
The filter is consciously controlled.
What are the problems with Broadbents model?
Broadbents filter does not focus on the contents of unattended messages but by alternating connected words between channels in a dichotic listening task, pps are able to process meaning before and not after the filter suggesting it doesn’t adequately describe human experience.
What is Treismans attenuation model?
Replaced broadbents filter with an attenuator which semantically analysed info to an extent so that relevant and meaningful info can be attended too, with some sources such as an individuals own name and ‘help!’ Become permanently facilitated.
Whats the problem with triesmans attenuation model?
The way in which attenuation processing is poorly specified and the model does not explain how this processing occurs.
What is Feature integration theory?
Features of a visual search such as colour with attention acting as a glue that combines the different features to form a coherent percept.
What is Posner’s cueing paradigm of visual attention?
Cues can enhance attention without eye movements. Pps focus on a centre point and press a button as soon as they see a target in one of 2 boxes to the sides. Valid cues pointing to the correct box facilitates response time, invalid cues inhibit response times which demonstrates covert orienting of attention without eye movements.
How do we know attention is an automatic process?
It is effected by practice, for example reading leads to difficulties in The stroop effect and driving a familiar route can cause individuals to forget how they got there because practice makes it automatic - once activated it runs to completion.
What 3 factors affect divided attention (completing simultaneous tasks)?
How similar the tasks are(overlap in storage, processing or output)
How practiced the operator is
Difficulty of task
What is trait anxiety?
The extent to which an individual is generally anxious.
What is state anxiety?
Refers to the extent of anxiousness that an individual feels at a given moment.
