Attention 2 Flashcards
Describe a specific study which focuses on inattentional blindness
An outline image is shown with a word wrote over it every 500ms in a stream. In task one participants were instructed to focus on and remember the words and to ignore the pictures, Afterwards the attended words were remembered with 70% accuracy.
In task two participants were instructucted to focus on and remember the pictures and to ignore the words. Afterwards, the unattended words (surprise recognition task) are not remembered: unattended words are just as well ‘remembered’ as words that were not shown at all (foils).
Why did they use words for this study on inattentional blindness?
In the visual cortex and frontal cortex, there are regions that specifically respond to words and not non words (nonsense strings of letters)
What is the name given to these word areas in the visual and frontal areas?
Visual- visual word area
Frontal- frontal word form area
What is the significance of these word brain regions to the study revolving around inattentional blindness?
When the participants are not attending to these words and non words, there is no difference in activation. This suggests that there is (medium) early selection
What is the third experimental paradigm mentioned in the lecture? Mention the two others
Attentional Blink
Inattentional blindness, change blindness
What is meant by attentional blink?
the inability to memorize and report a stimulus (T2) that is presented briefly after (up to ~500 ms) a stimulus (T1) that has to be reported or memorized
What study demonstrates the inattentional blink?
Participants are instructed to push a button when they see a face. They are then shown houses at varying temporal distances from the first stimuli. The detection of the first target generally impedes the detection of the second as mediated by the length of the interval.
What is the significance of pushing the button?
The task is important for the attentional blink to occur
What were the fMRI results of the attentional blink task
Missed (unseen) T2 houses nevertheless evoke selective attention of the PPA. This activation is only amplified when the target is seen > late selection
Name a factor which may account for why some of the reason why some studies find evidence for early selection and others find evidence for late selection
The type of attention that is employed
Describe the structure of a study which examined how different types of attention evoke different latencies in attention
Images are shown of a face in the square at the centre and a house in the background. In the first task, participants have to detect repetition of a face (1-back task).In a second task, the quality of these images are lowered (noise mask), increasing the perceptual demand. In other tasks, participants had to detect whether the face was the same as the one 2 faces or three faces back, requiring a higher working memory load. Meanwhile in the background scenes are shown , either with repetitions or always new ones.
Describe the results of the study which examined how different types of attention evoke different latencies in attention (4)
Due to repetition priming the PPA will respond stronger to new scenes than to repeated scenes, but only if the PPA is selectively processing and ‘recognising’ these scenes.
So yes, there is repetition effect in PPA when attention is on faces (repeated is weaker than unrepeated), indicating selective processing of house scenes in the PPA > late selection
Also when the working memory load increases (2-back task), there is still selective PPA processing > late selection
However, when the perceptual load increases (faces are more noisy hence difficult to see), the selective PPA processing (repetition effect) of the background houses disappears > early selection
What conclusions were drawn from this, and other studies, about certain types of attention occurring at different latencies?
‘Cognitive’ attention (memory, etc) has little effect on visual processing of unattended stimuli. ‘Perceptual’ attention (trying to see better) has.
(attention is a broad name denoting a multitude of concepts)
Name three brain structures which are involved in overt attention
Colliculus superior: saccadic eye movements, orientating
Pulvinar: attention shifts
Frontal eye fields
Name five brain areas involved in covert attention
Pulvinar, FEF Ventral Frontal Cortex Dorso-lateral PreFrontal cortex Superior Parietal Lobe (SPL) Temporo-Parietal Junction (TPJ)
How do we know that the superior colliculus is only involved in overt and not covert attention?
Visual or visuomotor cels were recorded from in the superior colliculus
a. Visual stimulus in RF evokes response
b. This response is enhanced when it is used for an eye movement (presumably via reciprocal interactions between visual and motor layers of the SC)
c. But not when the eye movement is not related to that of the stimulus
d. Also not when the stimulus is covertly attended
What form of attention are parietal neurons involved in?
Parietal neurons are involved in both saccade generation and in covert attention
How was it shown that parietal neurons are involved in both saccade generation and in covert attention?
Neurons in the parietal lobe were measured as a monkey looked at a passive fixation point. There would either be a saccade to a stimulus on the right (overt) or the monkey would signal that he attend to the stimuli by reaching towards to, but maintaining fixation on the fixation point (covert).
Activity was shown in the parietal neurons in both regions.
How is the Pulvinar structure in the brain involved in attention?
Switching attention
How can this role of the pulvinar in attention be demonstrated?
Inactivation of the Pv results in less efficient attention switching following a spatial cue; In the Posner cueing task, invalid cueing is less quickly followed by disengagement of attention and shifting toward other location.
Stimulation of the Pv results in somewhat more rapid disengagement and redirection of attention.
