A theoretical approach to animal´s impulsive preference: Impulsive choice behavior is interpreteded as a result of reward-maximization failure

Humans and other animals often prefer small, short-delayed rewards to large, long-delayed rewards. A standard interpretation is that such impulsive preference might originate in the subjective reward value that is temporally discounted. Although this interpretation is consistent with animal´s impulsive choice behavior observed in many studies, the biological significance remains unclear. Another interpretation is that impulsive preference might originate in reward-maximization failure while animals might attempt to maximize the physical amount of reward. We introduced a synaptic learning rule for reward-maximization to simulate in a standard inter-temporal choice task for non-human animals. As a result, on the assumption that animals do not discriminate the states after one choice from that after another, a synaptic learning rule with long-tailed eligibility traces reproduced animals´ impulsive preference.