BCS 111 Unit 5.2

Divided attention

Recognition performance in 3 conditions

Executive control of resource allocation is crucial in controlling attention

When multitasking: If Task A is shadowing, and Task B is changing oil

Automatic processing

Can you notice the black dot right away while reading the tongue twister below at the same time? Will finding it (within a time limit) affect how fast you can read the tongue twister?

What is exactly “automatic processing”

Posner and Snyder (1975)

• Three criteria

1. Processing occurs without intention 

2. Unaware of the process of noticing the target

3. Not interfering with other mental activity

Requires very little mental effort to process

Controlled processing

Can you find the lightest blue dot right away while reading the tongue twister below at the same time? Will finding it (within a time limit) affect how fast you can read the tongue twister?

Automatic processing

notice something with little mental effort

Controlled processing

actively shift your attention from one thing to another à requiring a lot more mental efforts than automatic

How do we test automatic vs. controlled processing experimentally? - Visual search task

Automatic processing takes place when the target is quite distinct from the rest of the items

How to test “automatic processing”?

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Consistent mapping condition:

• Target and distractors are different types of stimuli

• Target in the current display won’t appear anywhere in the next display

  • Automatic processing (finding the one that stands out)

Varied mapping condition

• Target and distractors are the same type of items (i.e. letters).

• Target in the current display CAN still appear as a distractor in the next display

• Controlled processing (shift your attention from “G” to “B” in Trial 2 in this example)

Four independent variables

1. Varied vs. consistent mapping

2. Frame size: quantity of letters/numbers in each display

3. Frame time (duration):20–800ms

   1. Memory set size: Number of possible targets

Schneider & Shiffrin (1977)

Summary of Schneider and Shiffrin (1977)

• Consistent mapping (easy): only frame time matters

  • Automatic processing

• Varied mapping (hard): frame time, frame size, memory set size (number of targets)

  • Controlled processes

  • Need to allocate limited resources

More about controlled processing

Attention shift task

• Switch between two features of a stimulus

  • Control what you need to attend to at the moment

• Measure “cost of switch/shift”

Neural underpinnings of attention

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Controlled process

From the external stimuli to internal state

The role of primary somatosensory cortex in attentional control: evidence from fMRI

Zimmermann et al (2012)

• Finger sequences

• Training: Either think about the action of moving your fingers (internal focus “IN”) OR focus on the physical button presses (external focus “EX”)

• Testing/scanning: same task but:

  • IN-trained group asked to focus EX

  • EX-trained group asked to focus IN

• S1 activated in both types of attention switch; PMC also activated when switched to EX condition

  • IN-trained → EX

  • Left premotor cortex (PMC)

• EX-trained → IN

• Left primary somatosensory (S1)

What happens if there’s damage to the right parietal lobe?

• Hemineglact: unaware of the objects in the visual field contralateral to the lesion site

• “Reduced awareness of stimuli on one side of space, even though there may be no sensory loss”