Sensation Attention And Perception Flashcards
Cognitive neuroscience
The field of study focussing on neural substrates of mental processing
Sensation
Is the process of transforming physical stimuli to electrical signals
Perception
Process of interpreting these signals for conscious awareness
Sensation
Difined as initial stimulation of our sensory system
Each sensory input sends electrical signals to our brain
Each sense has it own area in the brain
Vision
Light enters the eye through the cornea
Passes through the pupil and lens focuses it on the retina
Retina converts light into signals for the brain using rods and cones
Cones detect colour rods black and white
Bipolar cellls detect changes in rods and cones triggering action potentials in retina, gangalion cells
Primary visual pathways
Information goes from the ye via optic nerve across optic chasm to the dorsal part of the lateral ge icukate nucleus along optic radiation’s to the primary visual cortex in occipital lobe
Information then travels along two large cortical pathways a ventral stream and a dorsal stream
Auditions
Cells respond to auditory information and travel along 2 streams
Corti converts movement of inner hair cells into electrical brain activity to send to brain
Ventral
What
Dorsal
Where
Deficits in visual and auditory perception
Key term- double dissociation
Demonstration of independence between 2 cognitive processes
Suggests functions are localised in different part of brain
Eg lesions in brain structure A impairs function x but not y whilst lesion to brain structure b impairs function y spares function x
Allows interference about brain function and function localisation
Damage to ventral stream
Unable to recognise shape size and orientation of objects but very accurate reaching grasping
Damage dorsal stream
Difficulty in positioning of hand when reaching for an object but object recognition
Deficits in locating sound but intact sound differentiation
Ventral and dorsal stream case study
Goodall and Milner
Bilateral damage to her lateral occipital cortex
Profound defecit in visual object perception
Df retains ability to use information about for, of objects to control grasping
Ventral stream impaired
Dorsal stream unaffected
Perception
How we perceive the world not neserilt how it actually is
Top down processing
Higher level cognitive processing determine of perception eg prior knowledge experiences
Bottom up processing
Lower level information about stimulus eg shapes and shading determine perception
Bottom up approaches
Gibson - theory of direct perception
No influence of cognitive processes
Perception directly determined by moving through environment
Light entering retina sends signals to brain - visual perception
Perception of movement movement of objects around us compared to static aspects of visual scene eg driv8ng down a road behaviour in response to things we perceive based on avoidances we need not know as chair is for sitting on as shape affords the action of sitting
Top down approaches
Constructivist accounts
A by product of sensations and thoughts about the world need to interpret information from senses
Influences by individual differences and past exoeinces
Sensation vs perception
Sensation - bottom up process by whic our senses receive and relay external stimuli
Perception is the top down mechanism that our brains use to organise and interpret data which we put into context
In bottom up processing sensation and perception are the same we perceive items via sensation
In top down processing processing perception and sensation are separate first we use context and expectations to create holistic perception off the world and then we start to focus on smaller details usin sensation
What is prosopagnosia
Face blindness is a neurological disorder whey cannot recognise familiar faces
Can observe facial characteristics such eye couloir and facial features
Perception - Gasault psychology
The whole is more than just sum of its parts
Attention
Selective attentions we focus on what most significant
Directs filters and controls how we process Mim formation
Can be implicit or explicit
Visual attention
1) voluntary endogenous goal directed top-down
Involved in selection of sensory information and responses
Influenced by expectation knowledge and current goals
2) involuntary exogenous stimulus driven ( bottom -up)
Involved in detection of salient or conspicuous unattended visual stimuli
Unexpected and potentially salient stimulus redirects attention from current focus
Auditory attention
Cocktail party effect focussing attention on a particular stimulus whilst filtering out all other information in envronmemt
Failures of attention
Change blindness and intentional blindness failure. To perceive significant events in visual field by focussing attention elswhere
Visual neglect
A sense of awareness on one side of visual space from a stroke
Most usually occurs in left visual field after damage to right parietal part of brain
Fail to shave left side of face
Vision is intact just attentional deficits
