Final answer:
Psychologists who accept a biological explanation of behavior understand that complex behavior cannot be fully explained by simple or reductionist explanations.
Step-by-step explanation:
Psychologists who accept a biological explanation of behavior make certain assumptions about the nature of behavior. One of these assumptions is that complex behavior is best understood if it is broken down into smaller, physical units of analysis.
However, the question asks for an assumption that would NOT be made by psychologists who accept a biological explanation of behavior. So, the correct answer in this case would be that simple behavior can explain complex behavior.
Pychologists who accept a biological explanation of behavior understand that complex behavior cannot be fully explained by simple or reductionist explanations. They recognize that it is important to consider the interactions between biological, environmental, and experiential factors in order to fully understand human behavior.