Which psychologist used the operant chamber for efficiently testing operant methodology?

The most prevalent form of dementia is

a. psychogenic dementia. b. dementia praecox. c. Alzheimer's disease. d. Parkinson's disease. e. cerebral infarction.

The idea that heredity affects IQ is BEST supported by the very high correlation between IQ scores of ______

a. identical twins reared together c. fraternal twins reared together b. identical twins reared separately d. fraternal twins reared separately