Week 3 - Attention

what is the difference between selective attention and divided attention?

• selective attention:

  • tasks that require attending to one stimulus and ignore another

  • informs us about the process of selection and what happens to the unattended stimuli

• divided attention:

  • tasks that require attending to all stimuli or performing multiple tasks

  • informs us about processing limits and attentional capacity

what is inattentional blindness?

• the failure to see a prominent stimulus, even if one is staring right at it

• attention is focused elsewhere

what is change blindness?

• the inability to detect changes in a scene, despite looking at it directly

• changes may be disrupted visually or gradually

what is unilateral neglect? how is it caused?

• refers to patients with damage to the right hemisphere (parietal lobe) after a stroke, neglecting the left side

• fundamentally an attention disorder, not a sensory deficit

what is selective attention?

• when one focuses on one input or one task while ignoring the other stimuli

what is a dichotic listening task? how does shadowing relate to this task?

• people were presented with different audio inputs in each ear via headphones

  • they were instructed to only pay attention to one side’s input (attended channel) and ignore the other input (unattended channel)

  • shadowing: repeat out loud the info from the attended channel to assure that participants were paying attention

what is the cocktail party effect?

• the ability to focus on one conversation and tune out other conversations in the background

how does the early selection model explain our failure to perceive things because of a lack of attention? what is the evidence for this? what is the limitation of the evidence?

• early selection model: selection based on physical characteristics

  • it states that the information is filtered on the basis of our inability to perceive

• evidence

  • electrical activity in the brain show that unattended stimuli receive less processing than attended stimuli

• limitation

  • does not explain why subjects are sometimes aware of the semantic content in the unattended channel

how is the late selection model different from the early selection? what evidence do we have for late selection model? what are the limitations of the evidence?

• late selection model: selection based on semantic content

  • it states that the information is filtered on the basis of our inability to remember the information

• evidence

  • subjects asked to assess which line is longer

  • judgement was affected by supposedly irrelevant and unattended dots

how is the attenuation model different from early and late selection model of information filtering?

• attenuation model: attended is enhanced, unattended is reduced, but both are processed

  • not ALL OR NOTHING, think of volume slider

what are the different types of priming discussed in lecture?

• expectation-based priming: what we use to selectively attend, effortful

  • top-down activation of detectors you are expecting to use

• stimulus-driven priming: requires no effort / cognitive resources

  • bottom-up activation of detectors based on features in the stimulus

what does the phrase “attention as a spotlight” mean?

• the movement of the beam refers to the movement of attention, not movement of eyes

  • attentional shifts can occur before or independently of eye movements

what are the different types of attention discussed in lecture?

• endogenous attention

  • consciously choose what we attend to

  • sometimes referred to as voluntary / top-down attention

• exogenous attention

  • an external stimulus seizes your attention

  • sometimes referred to as involuntary / bottom-up attention

what evidence do we have that context affects voluntary eye movements?

• in a study where people were asked to analyze a picture with eye tracking

  • where their eyes were directed was completely dependent on the prompt (analyze clothes, give ages, estimate material wealth)

what is the difference between feature search and conjunction search?

• feature search: automatic & parallel

  • looking for one feature

  • “pop-out” lead to constant time regardless of set size

• conjunction search: effortful & serial (one-by-one)

  • scanning for two features

what are the three factors that determine if we can divide our attention?

• cognitive budget

  • divided attention will fail if the combination of tasks exceeds our limited mental resources

• generality of resources

  • a single pool of resources that you can divide up among multiple concurrent tasks

• domain-specificity of resources

  • different modalities have different pools of resources, similar task compete for the same resources

what are the different task-general resources?

• response selector

  • required for selecting and initiating responses

• executive control

  • required to set goals and priorities, avoid conflict among competing habits or responses

  • can only handle one task at a time

what factors affect performance of multi-tasking?

• task similarity

  • relatively easy to do dissimilar tasks (ex. use different modality-specific resources) than similar tasks

• task difficulty

  • the more difficult the task, the more it will draw on your resources

• practice

  • the more you practice a task, the less resources it requires