The measures used in animal studies have parallels with performance tasks described in human research, but are more narrowly defined and are almost exclusively focused on response inhibition and delay aversion. Tasks that measure the inability to withhold responses are characterized by periods during which responding is reinforced, coupled with periods in which either (1) the absence of responding is explicitly reinforced or (2) the occurrence of responding is neither reinforced nor punished. In some procedures, the different periods are signaled by unique cues (e.g. a go/no-go procedure in which a light indicates responding will be reinforced and a tone signals responses will be accompanied by foot shock). In other procedures, only the period in which responding is reinforced is signaled (e.g. responding in a location signaled by a light in the five choice serial reaction time task; Robbins 2002). In yet other procedures, only internal signals indicate when responses will be reinforced (e.g. internal signals that indicate the passage of time in a differential reinforcement of low-rate responding procedure; DRL). Tasks that measure delay aversion (delay discounting) are characterized
