The Distributed Nature of Self Questions to keep in mind: - What causes a sense of self? - Does the left hemisphere ‘interpreter’ bring together a unified

The Distributed Nature of Self

Questions to keep in mind:

- What causes a sense of self?

- Does the left hemisphere ‘interpreter’ bring together a unified sense of self?

What is Self?

•Consciousness of your own identity (one’s own self)

•The total, essential, or particular being of each person

•Narratives that address our past, present, and future

"Knowledge of the self, the disposition to focus one's ten senses of sight, hearing, taste, touch, smell, feeling, thought, consciousness, memory and experience upon the self, is a part of the process which brings about the cessation of the self."

Do you really know yourself??

Is self knowledge its own entity?

fMRI study on brain activation under three conditions where participants made judgments on presented trait adjectives

1. self-descriptive adjectives2. adjectives describing US President George W. Bush3. words presented in uppercase font

Is self knowledge its own entity?

Results: * Increased Left Inferior Frontal Cortex Activation for judgments about the self or familiar individuals (George Bush)

Self as a Percept

Ability to recognize one’s own face Is this seen in the right cerebral hemisphere or left pre-frontal cortex?

Seen in both, so does this contradict the split brain, left interpreter dominance theory?

The Self as an Associative Network

Cowell and Pleydell-Pearce(2000)

idea of self memory systemKnowledge base

Autobiographical knowledgeAbstractconceptual

processes of access to the knowledgeStudies show left for retrieval in autobiographical memories

The Self as an Associative Network

However, Markowitsch, 1998

During retrieval, right hemisphere more activated

So…“One hemisphere sets retrieval goals while the other reconstructs the resultant episode.”

The Left Hemisphere Interpreter


Metcalfe et al., 1995

When given :

Left and right respond differently….



When given :

RIGHT



When given :

Left










* Experiment done by Turk on split-brain patient to assess person-recognition.

* Experiment tested hemispheric differences in person-recognition as information

The Interpreter and Self-Recognition Test(Assessing person-recognition)

•Experiment consisted of a split brain patient (JW) viewing morphed facial photographs

* The morphed photos range from 0% to 100% with self images in increments of 10%.

* Experiment was done in random order

* Images of JW or a familiar doctor were presented 4 times to each cerebral hemisphere for 250ms each



•Results

* Double dissociation in J.W.’s face-recognition performance

* Right hemisphere biased towards recognizing familiar faces not as self

* Left hemisphere biased in self recognition


Ensuring dissociation

* Other targets used

* Same double dissociation, and demonstrated again left hemisphere bias for self recognition and right hemisphere for other faces.

Both hemispheres by themselves can recognize faces. BUT cortical networks in the left hemisphere play a more significant role in self recognition.

This shows evidence that self recognition is dissociable from general face processing.

This is important to take into account for building a model of social cognition!

What does this mean?

•If the left hemisphere can recognize self, it might play an important role in the self-memory system (SMS)

•Even in a disconnected brain, the self appears to be a unified construct and interpreter.

•When disconnected, the left hemisphere interpreter makes confabulated interpretation.

•FMRI Studies also show that left parietal areas may be involved in forming egocentric representations.

The Left Hemisphere ….Further Thoughts

The article shows that self referential trait processing is unique from other forms of semantic and episodic representation.

There also it showed evidence for a left hemisphere interpreter that generates unified sense of self. This was done in the person recognition process of JW - the split brain patient.

This shows the importance of the left hemisphere interpreter in self recognition even in a disconnected brain. This interpreter may give rise to consciousness and a unified sense of self.

But it is important to understand that while the split brain appears to be dual brains, it is one self!

CONCLUSION

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The Distributed Nature of Self Questions to keep in mind: - What causes a sense of self? - Does the left hemisphere ‘interpreter’ bring together a unified