11.17 Notes

Question 1

What percentage of the world is left-handed?

Answer 1

1%

Question 2

What percentage of the world are inconsistently handed?

Answer 2

9%

Question 3

Non-right-handers

Answer 3

Larger corpus callosum: possibly more myelination and more inter-hemisphere connections; greater symmetry between the two hemispheres: bilateral representation of cortical functions; have better episodic memories; Overrepresented in populations who are mentally retarded, schizophrenic, alcoholics, criminals, the mathematically gifted, and the artistic

Question 4

What percentage of individuals who have an immediate family member who is left-handed?

Answer 4

35%

Question 5

Geschwind and Galaburda Theory

Answer 5

Argued that testosterone was responsible for handedness; either there was an increased sensitivity to testosterone or too much testosterone in the womb; Would speed up the development of the right hemisphere; testosterone impacts the development of the thyroid, immune response, increased autoimmune disorders in the non-right-handers

Question 6

Stanley Coren

Answer 6

Argued that prenatal trauma is responsible for handedness; brain damage to the left hemisphere is more common in non-right-handers

Question 7

Gender differences in neurology

Answer 7

Males: have bigger brains and right hemispheres, and are better at spatial tasks; Females: language centers in the left hemisphere are bigger, greater connectivity between hemispheres, bilateral representation of some cortical functions, Similar to non-right-handers in brains, larger vocabulary

Question 8

What percentage of the world is right-handed?

Answer 8

90%