Reinforcement uncertainty enhances preference for choice in humans.

Under concurrent-chains schedules of reinforcement, participants often prefer situations that allow selection among alternatives (free choice) to situations that do not (forced choice). The present experiment examined the effects of reinforcement probability on choice preferences. Preferences for free versus forced choice were measured under a condition in which participants' choices were always reinforced (reinforcement probability of 1.0) and a condition in which outcomes were uncertain (reinforcement probability of 0.5). Forty-four college students participated and preferences were examined under a concurrent-chains schedule of reinforcement. Participants preferred free choice under uncertain reinforcement, but a bias toward free choice was not observed when reinforcement was certain. These results align with previous findings of preference for free choice under conditions of uncertainty, but suggest that preference may be dependent upon probabilistic reinforcement contingencies in the terminal links of the concurrent-chains arrangement. Thus, reinforcement probability is an important variable to consider when conducting similar studies on the value of choice.