Fig. 2.

Internal conflict in Miller & Brown’s rat. A “hunger agent” attempts to approach food when food is identified and idles otherwise, and a “fear agent” attempts to avoid danger when danger is identified and idles otherwise. The agents usually move freely within each pair of states. However, when food and danger are in the same location, the simultaneous initiation of approach and avoidance is “illegal.” The definition of conflict is satisfied in that if any one agent idled, the other agent could have obtained its goal. Elements in this example resemble ones in the formal proof of conflict (Supporting Appendix). Whereas here only four states are shown, the formal proof allows for many behavioral states, a technical requirement for proving description parsimony.