Roger Sperry & Michael Gazzaniga 1967

Aim

To test lateralization by finding functions that are unique to each hemisphere

Method

Quantitative quasi-experiment repeated measure design ; non invasive and correlation

Procedure

Variables:

IV: The severed corpus callosum

DV: the lateralization of functions from each hemisphere

4/10 participants

Initial observation: no change in personality nor intelligence

Set up: Board put was put in front of the face of the participant with items below it.

Shown a picture of a spoon

Shown the word pencil

Shown a word split in half "heart"

Asked to spell words with the left hand

Replicate a drawing with each hand

Shown an image of a nude woman

Results

Left hand picked up a spoon but could not articulate the item they saw

The person could not articulate the word, but was able to pick up the correct item

The "he" was presented to the right hemisphere, and the "art" to the left

Spelled simple words, but could not articulate them

Drawing was more accurate with the left hand

Both elicited an emotional response

Conclusion

The dominance of right hemisphere in visual construction, with the ability of simple language production

The dominance of the left hemisphere in language production

Concludes the lack strict lateralization because of shared ability of language and emotion, but there is dominance.

Strengths

→ consent from the participants

→ High population validity

→ sampling had shared traits and the elimination of participant variability

Weaknesses

→ Low ecological validity

→ possible extraneous variables: demand characteristics and experimenter bias