BCS 111 Unit 5.1

How do we choose what information to attend to?

Selective attention

• Focus on a very limited events/objects/tasks

• For efficient processing

• But do we ever process anything from the information that we didn’t pay attention to?

Driving in an unfamiliar place

if the driver doesn't notice the hot air balloon flying by and only focuses on the traffic

4 theories to explain this scenario:

• Filter

• Attenuation

• Spotlight

• Schema

Filter theory

Irrelevant information is filtered out

Filter theory of attention

• Limited capacity to process information

• Overflow info is filtered through the ‘bottleneck’

• All unattended messages filtered out

How do we test selective attention

• Participants repeat what they heard (from either ear) - “shadowing”

• Most people can repeat the attended message from one ear with very few errors

Dichotic listening task (DLT)

If the unattended message sounds weird (e.g., backward speech), some people can notice the difference

Evidence against the filter theory of attention

• Cocktail party effect

• When you hear a fire alarm (or something important) in a loud concert while talking to your friends, you can still notice it!

How to test this using DLT?

Play subject’s name to the unattended ear and see if they notice it

Cocktail party effect

• Pashler (1998)

  • Only 33% heard their name if not informed about the possibility of hearing their name before the experiment

• …Other different ways to test the processing of info in the unattended ear? → Switch ears

Evidence against the filter theory of attention

Switch ears: message played to one (attended) ear switched to another (unattended) ear

Treisman (1960)

• People repeated a few words from the unattended ear right after switch

• People not aware of the switch and their own repetition of the words from the unattended ear

  • Attention can also be influenced by the nature of the message itself – the meaning of the message

  • Another evidence for top-down process

  • Evidence against the filter theory

DLT tasks: Filter vs Attenuation

-

Filter theory

• Only process and hear the attended messages

• Not a valid account given the findings from DLT task

Attenuation theory

• Unattended message tuned down

  • Higher attention level for familiar/important content

Spotlight approach

• Perceive everything but actively cast a ”spotlight” on the target; things on the edge of the spotlight can still be processed
  

• Is selective attention like “spotlight”?

  • Size of the spotlight varies with the size of the objects to focus on

    • Depending on the processing demands of each object/event

  • Control where to direct our attention

Schema

only take what you need; everything else untouched (not even entering the processing pipelines)

Interim summary of selective attention

pt 2

Neurophysiological evidence for selective attention

Banich (1997)

• Two types of tones: long vs. short. Both can be heard in either left or right ear

  • Target: long tone presented

EEG evidence for selective attention

• N1: early event-related potential reflecting attention process

• When target is heard and attended in the left ear, N1 more negative in the left than right.

• When target is heard and attended in the right ear, N1 more negative in right than left

Selective attention can also be influenced by arousal level

• Kahneman (1973)

  • Attention: allocation of resources

  • Attention modulated by arousal level

    • Task difficulty

    • Level of interest