Do Not Ask Whether They Have a Cognitive Map, but How They Find Their Way About

The publication of "The hippocampus as a cognitive map" (O'Keefe & Nadel, 1978) has had a remarkable impact, stimulating a huge amount of both behavioural and neurobiological research on spatial learning and memory, involving both laboratory and field studies, and employing a variety of novel techniques. The reviews of this general area of research provided by the previous contributors to this special issue attest to the progress that has been made since 1978. No one would now doubt that the hippocampus is implicated in the use of configurations of landmarks to locate a goal-in both mammals and birds, although the precise nature of that implication remains a matter of much speculation and debate. On balance, however, the behavioural evidence does not seem to have supported O'Keefe and Nadel's original hypothesis that true spatial or locale learning is quite distinct from simple associative learning and depends on the establishment of a cognitive map of the environment. "It's just the study of rats in mazes" was a popular description of experimental psychology in the middle of the 20 th century, and the image of rats trundling their way through a maze, learning by blind trial and error, became a symbol of everything that was wrong with old-fashioned behaviourism. The publication of O'Keefe and Nadel's book, The Hippocampus as a Cognitive Map (1978), changed all that. The study of spatial learning and memory has flourished as never before. Over the past 25 years, psychologists, ethologists and neurobiologists have all mounted major research programs to study spatial behaviour; the ability to find their way round their world is seen as of critical adaptive significance to the animals who do so; above all, the mechanisms underlying such behaviour can now be seen to be a great deal more complex (and cognitive) than the traditional denunciation of such experiments implied. New experimental procedures and paradigms for the study of spatial learning, memory and navigation have been devised, and new theories developed. As this issue of the journal shows, much has been discovered in the past 25 years-but no doubt much remains to be learned. What is this spatial learning and memory that we are talking about? In their natural environment, some animals navigate over long distances-from summer to winter quarters, to and from their breeding grounds, to their home