Attention & Consciousness Flashcards
(35 cards)
Define Attention
A cognitive mechanism that allows certain information to be more thoroughly processed in the cortex than non-selected information
Define Consciousness
Contents of awareness
What is bottom-up processing, and how is it generally tested?
It’s stimulus driven (exogenous); attention is drawn by external cues rather than by voluntary control; It’s tested by having irrelevant stimuli suddenly appear, and seeing the effects they have on responses to task-relevant stimuli
What was found when auditory topics, such as “imagine playing tennis” was played to a patient in a vegetative state?
The imagery was processed the same as controls; shows he was awake but no with signs of awareness
What are two ways in which we can measure consciousness?
Detection and Signal Detection Theory
Describe Signal Detection Theory
It’s a mathematical theory of the detection of stimuli, which involves discriminating a signal from noise in which it’s embedded and which takes sensitivity into account (willingness to report detecting stimuli)
Another way of measuring consciousness is through Alternative Forced-Choice, whereby participants choose between one of two stimuli. What three components does this paradigm take into account?
Unconscious influence of subset of trials; Inattentional amnesia (failure of memory rather than unconscious); Access vs. Phenomenal consciousness (briefly conscious to it, then not)
List the common methods used to render the invisible, visible (consciousness paradigms)
Visual crowding; masking; binocular rivalry; motion induced blindness; inattentional blindness; change blindness; attentional blink
One approach with visual masking is to mask a stimulus with a colour and ask Ps to report if the stimulus is a word or non-word. What results been found using this paradigm?
When the mask colour is compatible with the word (e.g. pink) RT is much faster; seems to be processed unconsciously
In a target detection study using visual masking, RTs were faster for hits when the masks were compatible. What was found for misses?
RT for incompatible masks was faster, suggesting different processing involved
What influence does a temporal gap between stimuli in visual masking tasks have on detection accuracy?
We’re much better at detection than when stimuli are close together
In a visual masking task, in what regions was more activity found in controls than in the masking condition, and what does it suggest?
Occipital areas; Suggests that the occipital lobe is involved in consciousness, and that masking occurs at stages of early processing
In Anderson et al.’s (2012) visual crowding study, what behavioural responses were found in the change-same condition?
Participants were worse at detecting the change when the target pattern was facing the same orientation as the flankers, than when they were oriented differently (change-different), or no change
What did fMRI scans in Anderson et al.’s study show?
There were much higher BOLD signal responses in V1 the change-different condition, compared to no-change or same-change, suggesting V1 is sensitive to the contrast
What are some limitations with the previous Masking and Crowding studies?
Different stimuli were used for conscious vs. unconscious conditions, so this could have caused the effect; masking is brief, but fMRI is slow to measure the changes; crowding effects may not be unconscious, just low resolution in the periphery; detection and identification could be confounded
What is measured in Binocular Rivalry?
An image is presented to each eye separately and both go in an out of consciousness, then they look at what parts of the brain are sensitive to these fluctuations
What stage of processing is influenced by binocular rivalry?
Early processing
What’s involved in Motion Induced Blindness (MIB)?
Ps focus on a spinning circle at the centre of a screen, with a yellow dot in the periphery; the rate of the dot being visible and invisible in the visual cortex is measured (comes in and out of awareness)
What are the advantages of Binocular Rivalry and Motion Induced Blindness studies?
There’s no difference in stimuli between conscious and unconscious trials; trials have a relatively long duration (allowing time to capture effects through fMRI)
What are the disadvantages of Binocular Rivalry and Motion Induced Blindness studies?
Unpredictable fluctuations in perception (influenced by subjective biases - might show preferences for particular stimuli); mixed perception (can see both at the same time)
What’s involved with Continuous Flash Suppression?
A stationary image is presented to one eye, and random flashed patterns in the other eye; the static stimulus becomes consciously suppressed by the dynamic stimuli presented in the other eye
In Mack and Rock’s Inattentional Blindness task, Ps were asked which limb of a cross is longer (vertical or horizontal). What were the three trial types, and the results?
Inattention trials, divided attention trials, and full attention trials; Inattentional blindness on 25% of cases
When looking at a scene in a natural environment, local transients normally draw attention to the location of any change, which is readily detected. What happens when these changes occur when presented with successive glimpses of a scene?
Change Blindness; the mask provides a visual transient signal across the whole of the scene, which overrides local transients associated with the change
Which region of neural correlates are associated with Inattentional Blindness (IB) and Change Blindness (CB)?
Lateral prefrontal cortex
