Why good memory may be bad for you: The counterintuitive finding that too good a memory makes foragers inefficient reveals a glimpse of the forces that govern the evolution of intelligence.

From the article:

It's easy to imagine that a good memory would confer significant benefits to a foraging animal.

But it's not quite so straightforward, say Denis Boyer at Universite Paul Sabatier in France and Peter Walsh at the Universidad Nacional Autonoma de Mexico in Mexico.

These guys have created one of the first computer models to take into account a creature's ability to remember the locations of past foraging successes and revisit them.

Their model shows that in a changing environment, revisiting old haunts on a regular basis is not the best strategy for a forager.

It turns out instead that a better approach strategy is to inject an element of randomness into a regular foraging pattern. This improves foraging efficiency by a factor of up to 7, say Boyer and Walsh.

Clearly, creatures of habit are not as successful as their opportunistic cousins.