What type of group contingency is implied when every student who meets a goal can participate in a pizza party?

The correct understanding of this scenario is that it describes an independent group contingency. In this type of contingency, reinforcement is provided to individuals based on their own performance, rather than the performance of the group as a whole. Here, each student has the opportunity to participate in the pizza party if they personally meet the established goal; their individual success is what determines their eligibility for the reward.

This contrasts with dependent group contingencies, where one student’s performance determines the reinforcement for the entire group. In interdependent group contingencies, the performance of the entire group impacts whether they all receive a reward. Lastly, sequential contingencies involve members completing tasks in a specific order, which is not the case here. The focus on individual achievement leading to a collective reward through the achievement of personal goals clearly identifies this as an independent group contingency.