In the model of interhemispheric interaction, what 2 aspects of functioning are handled by either hemisphere? Are they capable of being handled independently of the other hemisphere?

- cognitive and emotional functioning

- yes, but that doesn't necessarily mean they do it independently just cuz they can

What is lateralized presentation used for?

What structure is interfered with?

What is lateralized presentation used for?

What structure is interfered with?

- to manipulate the degree to which the hemispheres interact via the corpus callosum to perform a task

What is the difference between within-field and across field in lateralized presentation?

- within-field is when both objects are in one half of the field of vision and thus sent only to the opposite hemisphere

- across-field is where each half of the field of vision has one of the two objects so each hemisphere receives input of the contralateral object

Define metacontrol.

- one hemisphere takes control of cognitive operations even though it is possible for either hemisphere to underlie such operations

How is metacontrol studied?

- by presenting duplicate copies of a stimulus to both visual fields so that either hemisphere can respond.

In the split-brain study of metacontrol, what was done? What happened when patients were given a recognition test?

- duplicate copies of various patterns were presented to each visual field

- RH took control of responding (by pointing)

In the split-brain study of metacontrol, what happened when patients were forced to give a verbal description of the patterns that had been perceived?

Briefly state the important result of this experiment.

In the split-brain study of metacontrol, what happened when patients were forced to give a verbal description of the patterns that had been perceived?

Briefly state the important result of this experiment.

- LH exhibited better memory performance

- the hemisphere that took control of responding was not the hemispehre that was better at performing the task

What was the task in the metacontrol study in intact populations?

-  3 letters presented in a column to either LVF, RVF, or both visual fields. Sx had to pronounce then spell the 'word'

What is one interpretation of the metacontrol study from intact populations? What is Hellige's suggestion?

- metacontrol is sometimes exerted by the hemisphere that is not specialized for performing the task

- that using the processing strategy of the less adept hemisphere may allow both hemispheres to contribute to performance

Interhemispheric Cooperation:  Each hemisphere has some ___ with ___ tasks.

What is the main benefit if interhemispheric cooperation? The main cost?

Interhemispheric Cooperation:  Each hemisphere has some competency with most tasks.

What is the main benefit if interhemispheric cooperation? The main cost?

- using both hemispheres provides greater computational power

- it takes time to transfer information across the corpus callosum

During which type of tasks might interhemispheric cooperation be more helpful? Less helpful?

- more helpful during relatively complex tasks, less helpful during relatively simple tasks

(bcz both hemispheres = more computing power but it takes more time since must transfer info across CC)

In the study that tested the idea that interhemispheric cooperation would be better for more complex tasks but not for simpler ones, explain what within-field vs. across-field presentations were.

- within field meant that the target stimulus, 2 matching letter As, were in the same VF while the non-target stimulus (a letter B) was in the opp. VF.

- across field = one A in one VF, other A plus the B in the opposite VF

In the same study, what was a physical identity match vs. a name identity match?

- physical: must match 'A' with 'A' (same physics characteristics)

- name: must match 'A' with 'a' (same name but different physical traits)

What were the 3 levels of task complexity in the study?

3-item physical, 5-item physical, and 5-item name

What were the results/conclusion of that study?

- for easier tasks, within field matches are faster (3-PI task)

- for harder tasks, across field matches are faster (5-PI and 5-NI tasks)

Describe the PET study that concluded that interhemispheric cooperation can be advantageous.

- Sx were presented with written or spoken words.

- at test, saw each word & decided if it had been written or spoken

- low-performing older adults had unilateral RH activ.

- hi-performing had bilateral activation

What is the basic premise of interhemispheric isolation? What can this do to performance?

- The corpus callosum acts as a barrier that prevents info from being transferred between hemispheres

- this can be advantageous to performance in some situations

What are illusory conjunctions? Which concept do they illustrate?

- illusory conjunctions are when attention doesn't have time to 'bind' the features of an object (such as color and shape).

- example: T H

... ppl see letters for only short time & think they saw red T

- (illustrates interhemispheric isolation)

What experimental result would support the interhemispheric isolation hypothesis?

- if illusory conjunctions occur less often when 'unbound' features are divided between the hemispheres

Briefly summarize the results/conclusion of Sohn's illusory conjunction & interhemispheric isolation study

- Sx sometimes reported seeing target (eg, a red T) even when it wasn't present

- Effect was greater when both target features were present than when only one feature was present for within-field trials but NOT for across-field trials

- supports the interhemispheric isolation hypothesis

What is the selective transfer of information?

- allowing transfer of relevant info across the CC while blocking irrelevent info

- in other words, since IH coop studies suggest cross-CC transfer is beneficial to performance, yet IH isolation studies suggest blocking cross-CC transfer is beneficial... can we have the best of both?