The cue-dependent nature of state-dependent retrieval

An enduring problem in the study of human state-dependent retrieval concerns the apparent unpredictability of the phenomenon. Although many investigators have observed that utilization of information in episodic memory critically depends for its success on restoration, at the time of attempted retrieval, of the pharmacological state in which the information was originally acquired, many others have been unable to find evidence of such state-dependent effects. Indeed, negative results are so common that human state dependence has come to be popularly regarded as an untrustworthy phenomenon of little practical or theoretical significance. The message of this article is that the unpredictability of state-dependent effects in man is more apparent than real. Evidence is presented to the effect that, with very few exceptions, failures to demonstrate state dependence are restricted to situations in which utilization of stored information is tested in the presence of discretely identifiable retrieval cues, and successes, to situations in which retrieval occurs in the absence of any observable reminders. It is also shown that when the conditions of retrieval, with respect to the presence or absence of explicit cues, remain constant, the probability of demonstrating state dependence also remains constant across a relatively broad spectrum of experimental conditions. Speculations about the nature of the cognitive mechanisms underlying the so-called “cuing effect” in human state dependence are offered, and promising new directions for research are outlined.