Effects of amount of reward on strength of approach in an approach-avoidance conflict.

In a recent, discussion of approach-avoidance conflict theory, Miller (1959) assumed that the strength or excitatory potential of the approach response should vary with factors which have been found to affect performance in nonconflict situations, namely: (1) the number of reinforced trials, (2) the strength of drive motivating the approach response, (3) the delay of reward, and (4) the amount of reward. He has also emphasized the importance of using several different test situations and measures to confirm assumptions about intervening variables, such as excitatory potential for the approach response. With an increase in the excitatory potential for the approach response, stronger punishments (electric shocks) should be required to prevent .Ss from reaching the goal. This deduction has been confirmed for Variables 1 through 3 listed above (Miller, 1944, 1959). The purpose of the present experiments was to test the effect on approach-avoidance conflict of Variable 4, the amount of reward. It is known that increases in amount of reward increase excitatory potential as measured either by the speed of running down a straight alley to reward (Crespi, 1942; Beier, 1958) or by the choice of that response receiving the larger of two rewards (Davenport, 1959). It is predicted that increasing the amount of reward will produce corresponding increases in the strength of electric shock required to deter 5 from the goal. Confirmation of this deduction with the new measure, resistance to conflict motivated by punishment, would increase not only the generality of the law but also the usefulness of the concept of excitatory potential for the approach response. In a small pilot study conducted to test