A psychologist shows participants films designed to make them either happy or sad. She measures the participants' brain activity levels with an electroencephalograph (EEG) during the films. This psychologist is probably conducting research on

A) cerebral asymmetry.
B) brain damage.
C) temperament.
D) classical conditioning.

The psychologist is measuring brain activity levels with an EEG while participants watch films designed to elicit different emotions. This suggests that she may be investigating differences in brain activity between positive (happy) and negative (sad) emotional states, which is commonly studied through the concept of cerebral asymmetry. Brain damage, temperament, and classical conditioning do not necessarily relate to this specific experimental design.