Vision 3
- Created by: becky_99
- Created on: 26-12-19 22:38
Terms
Perception - processing stimuli from the self or environment.
Cognition - the mental process by which external or internal input is transformed, reduced, elaborated, stored, recovered, and used.
- Involves a variety of functions such as attention, memory processing, decision-making, reasoning, problem-solving, imaging, planning and executing actions
Motor behaviour - the planning and execution of actions.
Response activation theory
"Response activation" theory predicts that non-target objects activate actions.
Condition 1: participants were able to inhibit the visual processing of the non-target object in the slow response time condition. This resulted in net response inhibition, causing the trajectory of the movement to veer away from the non-target.
Condition 2: in the quick response time condition, however, participants did not have enough time to inhibit the target object. This resulted in a net activation of the action that veered towards the non-target object.
(Welsh & Elliot, 2004).
Navarro, Van der Kamp, Ranwaud & Savelsbergh (2013
Task - participants required to aim penalty kick to one of two target locations.
60 trials:
- 20 trials 'no goalkeeper'
- 20 trials 'goalkeeper'
- 20 trials 'knowledgeable goalkeeper'
Measures:
- Performance: hits, misses, failures
- Accuracy: absolute variability from target centre and goal centre
- Variability: variable error from target centre and goal centre
- Ball speed: distance to goal (m) / foot contact to goal contact time (s)
Navarro, Van der Kamp, Ranwaud & Savelsbergh (2013
Questions to think about:
Results: was performance influenced by the presence of the goalkeeper?
Discussion: do the authors relate their results to any theories?
- Response activation theory (Welsh & Elliot, 2004)
- Ironic effects theory (Wegner, 1994)
Do the authors make any applied recommendations?
- Practice in the presence of a goalkeeper
- Optimise gaze control during practice
- Longer waiting time before executing the penalty (Jordet et al., 2009)
Visual areas of the brain
V1:
- Simple object orientations and shapes
- Global organisations of scenes
- Main connection from the LGN of the thalamus
V2:
- Receives connections from V1
- Neurons in this region respond to slightly more complex properties such as contours and figure-ground segregation
- Also has connections to dorsal and ventral pathways
V3:
- Responsible for processing complex combinations of visual stimuli
- Contains stronger connections to dorsal and ventral pathways and weaker connections from V1
Visual areas of the brain
V4:
- Encodes stimulus saliency and colour
- Also has shown to be more responsive to selective attention than other areas (Moran & Desimone, 1985)
V5:
- Located along the ventral pathway in the temporal lobe
- Contains neurons that are responsive to the direction of motion
- Also contains strong connections to other cortical areas
Object perception
Step 1: object segregation - i.e. figuring out what, in a complex scene, are the individual objects.
Step 2: object recognition - mapping the object to something that is already known.
Gestalt principles of perceptual organisation
Laws of:
- Figure-ground segregation
- Similarity
- Proximity
- Closure
- Continuation
- Common fate
Object segregation
Object segregation:
- Contours and grouping cues
- Occurs largely automatically
Once you have performed object segregation and can see the objects as distinct from the background and other subjects, does that mean you have recognised it?
Binocular disparity
- The two eyes have a slightly different image of the world on the retina (retinal disparity)
- The close of an object is to you, the greater the difference in the two images
- The brain can use this retinal disparity information to calculate how close the object is to you
- This information becomes less effective as objects get further away; it is primarily useful for objects within arm's distance
- The ability to use binocular disparity develops in children by about 2 years of age and if your eyes do not work together properly during that time period, then binocular disparity will not develop
Monocular depth cues
- Occlusion
- Shading
- Shadows
- Aerial perspective
- Linear perspective
- Height in plane
- Familiar size
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