Choice, as opposed to latency, measures in avoidance suggest that vasopressin and oxytocin do not affect memory in rats.

Latency measures from passive avoidance studies are frequently used as an index of memory. Thus, vasopressin (VP) is thought to enhance memory, since it has been shown to increase re-entry latencies. Conversely, several substances, such as oxytocin (OT), are supposed to have amnestic effects since they may decrease latencies. We describe a novel avoidance design, which allows latency to be assessed, but also permits the animal to re-enter into a distinctive compartment where shock had not been experienced (choice measure). Latency scores indicated that VP may improve memory, but the choice index suggested that this was not the case.