Tutorial 3

Question 1

Change-Blindness Research: Rensink, O’Regan, & Clarke (1997)

Answer 1

Change-blindness demos introduce a brief blank frame between two frames

This produces transients all over the visual field, so attention is no longer automatically attracted to the region of change

Now we can only detect a change by comparing the present display with memory for objects in the previous frame

We don’t notice gross changes in the field unless we happen to have attended recently to the region of the change
–> very limited memory for the objects in the previous frame (just the very few items last attended to)

Question 2

How is change-blindness interpreted?

Answer 2

Representation of objects in the visual field after display offset is very short-lived and unstable - this is “sensory memory”
–> Unless ‘fixed by focal attention, which creates a record in “visual short term memory”
–> VSTM apparently encodes the location and appearance only very few recently attended objects
–> The world acts as an ‘external memory’

Question 3

What is cued recall?

Answer 3

One can improve retrieval by creating the way that the information was encoded and having strong retrieval cues

Question 4

What is illustrated by the stroop effect?

Answer 4

Response conflict
Limits to selective attention
Incomplete control of task-set
Increase in automaticity of a task with practice

Question 5

What is the primacy and recency effect?

Answer 5

Primacy Effect - the beginning of the list is remembered (retrieval from LTM)

Recency Effect - “ end of the list (working memory)

Question 6

What is the classic ‘Amnesic Syndrome’

Answer 6

DIfficulty in remembering episodes before the brain injury

Subtypes to Know:
- Anterograde Amnesia: Difficulty forming new memories after a certain event, often due to brain injury or trauma.

• Retrograde Amnesia: Loss of memories before a specific event, such as a head injury or traumatic experience.
• Transient Global Amnesia: Temporary loss of ability to form new memories and recall past events, typically lasting several hours

Question 7

In what conditions has response inhibition found to be impaired? (stop-signal paradigm)

Answer 7

ADHD and Tourettes and OCD

Question 8

Describe one type of evidence that demonstrates that short-term and long-term storage in memory rely on distinct mechanisms?

Answer 8

Double Dissociation

Patient HM and KF (learn !!)

–> HM: after hippocampus removal HM suffered with impairments to long-term memory, but short-term memory was unaffected
–> KF: after brain damage, KF’ short term memory was impaired but not his long-term

Short and long-term memory are separate and rely on distinct mechanisms

Question 9

How does context at encoding affect later retrieval from LTM? (With experimental evidence)

Answer 9

If a person is in a similar situation/environment when they are trying to recall long-term memory they should be MORE ACCURATE than if they were in a contrasting environment
–> Grant et al. –> highest scores in recognition and recall tests where silent-silent or noisy-noisy: when there was a mismatch in testing and learning, performance decreased

Question 10

Briefly outline Treisman’s “filter attenuation theory” of attention

Answer 10

Treisman’s Attenuation Theory suggests that rather than a strict filter, attention operates more like a volume knob, where certain stimuli are attenuated (lowered in intensity) rather than completely filtered out. In this model, all stimuli are processed to some extent, but the processing of irrelevant stimuli is reduced.

*  It is not all-or-none: it attenuates (turns down) input from unattended sources (hence, with the support of top-down activation, unattended words, if salient or contextually relevant, can still activate meanings)
*  Early filtering is an optional strategy (not a fixed structural bottleneck):

Question 11

Describe an example of neuroscience evidence of the effect of early visual attention

Answer 11

Early Selection in Primary Visual Cortex and even LGN (FMRI STUDY)

* While fixation maintained on central point,
	○ series of digits appears at fixation, and
	○ high or low contrast checkerboards appear in left and right periphery

* P either counts digits at fixation, or detects random luminance changes in left (or right) checkerboard

* fMRI BOLD signal in LGN/V1 voxels that react to checkerboard luminance change is greater with attention directed to that side (red lines) than with attention to fixation (black lines) [Continuous/dotted = high/low contrast conditions] 

So: at least some selection (for regions in the visual field) occurs very early in processing

Question 12

What is the ‘cocktail party problem’

Answer 12

The cocktail party problem refers to the challenge faced by individuals in focusing their attention on one conversation or sound source while filtering out background noise and other distractions in a crowded social setting, like a cocktail party.
–> It highlights the selective nature of attention and the brain’s ability to prioritize certain stimuli (eg. name) over others despite competing sensory inputs.

Question 13

What is the ‘availability heuristic’ and describe one consequence of using it

Answer 13

The availability heuristic is a mental shortcut where people base JUDGEMENTS and decisions on information that is READILY AVAILABLE to them, often relying on recent or vivid examples.

One consequence of using this heuristic is the OVERESTIMATION of the likelihood or frequency of events that are more easily recalled, leading to biased perceptions or decisions.
–> For example, if someone hears about a plane crash in the news, they might become more fearful of flying, even though flying is statistically safer than driving.