Final answer:
In the context of B.F. Skinner's theory, Evan's classmates laughing at his behavior is an example of 'contingencies of reinforcement,' which is likely to increase the probability that Evan will repeat the behavior.
Step-by-step explanation:
B.F. Skinner would characterize Evan's classmate's laughter as a form of reinforcement for his behavior. According to Skinner's theory of operant conditioning, the laughter serves as a contingency of reinforcement, which increases the likelihood that Evan will repeat the behavior of throwing paper wads. Laughter following the misbehavior is a satisfying consequence to Evan, encouraging him to engage in the behavior more frequently.
Operant conditioning emphasizes that behaviors followed by pleasant consequences tend to increase. In contrast to the other options provided: 'reciprocal determinism' concerns the interaction between an individual's behavior, personal factors, and the environment; 'self-efficacy' refers to confidence in one's abilities; and 'observational learning' pertains to learning by watching and imitating the actions of others, none of which directly apply to the consequences of a behavior.
Therefore, contingencies of reinforcement best describes the scenario with Evan and his classmates as per Skinner's operant conditioning framework.