Behaviorists view personality as primarily shaped by environmental reinforcements and consequences. According to this perspective, behavior is influenced by external stimuli, and individuals adjust their actions based on rewards and punishments. Over time, learning histories — accumulated patterns of reinforcement — play a significant role in shaping personality. Behaviors that lead to positive outcomes are reinforced, while those resulting in negative outcomes are diminished. Radical behaviorists, such as B.F. Skinner, emphasize that differences in personality largely result from variations in learning experiences rather than innate traits or early childhood experiences.

Radical behaviorists reject the notion that early childhood is uniquely critical in shaping personality. While childhood experiences are important, they believe personality continues to evolve throughout life as individuals encounter new environmental contingencies. From this perspective, personality is not a fixed internal structure but a collection of habits shaped by classical and operant conditioning. Radical behaviorists argue that personality does not cause behavior; rather, personality is behavior — encompassing both observable actions and internal processes, like thoughts and feelings.

In terms of causality, radical behaviorists align with determinism, much like psychoanalysts. They assert that all actions are products of preexisting influences, making free will an illusion. Behavior, in this view, is driven by genetic factors and environmental contingencies, not by conscious choice. While people may believe they are freely choosing their actions, this perception often overlooks the subtle situational factors that guide behavior.

Radical behaviorists also highlight unconscious processing. People may be unaware of the external triggers that drive their behavior, such as unnoticed background music prompting someone to hum a tune. This suggests that much of what influences behavior operates outside of conscious awareness.