Final answer:
Behaviourist theories are critiqued for their disregard of internal cognition and for oversimplifying behavior by excluding biological determinants.
Step-by-step explanation:
Two weaknesses of behaviourist theories include the neglect of internal cognition and the oversimplification of complex behavior. Strict behaviorists like Watson and Skinner emphasized the study of observable behavior, treating the mind as a 'black box', which led to underappreciation for the role that thoughts and expectations play in learning. This view was challenged by behaviorists such as Edward C. Tolman, whose experiments suggested that cognitive processes are involved in learning when reinforcement is not immediate, indicating a weakness in earlier behaviorist thought. Secondly, the behaviorist perspective tends to overlook the innate biological factors that contribute to behavior. Skinner, as a radical proponent of behaviorism, argued that environment alone shapes behavior, disregarding inborn personality traits and biological determinants that have since been recognized as significant by fields like behavioral genetics and evolutionary psychology.