Memory Foraging: When the Brain Behaves Like a Bee

From Scientific American:

In search of nectar, a honeybee flies into a well-manicured suburban garden and lands on one of several camellia bushes planted in a row. After rummaging through the ruffled pink petals of several flowers, the bee leaves the first bush for another. Finding hardly any nectar in the flowers of the second bush, the bee flies to a third. And so on. Our brains may have evolved to forage for some kinds of memories in the same way, shifting our attention from one cluster of stored information to another depending on what each patch has to offer. Recently, Thomas Hills of the University of Warwick in England and his colleagues found experimental evidence for this potential parallel. “Memory foraging” is only one way of thinking about memory—and it does not apply universally to all types of information retained in the brain—but, so far, the analogy seems to work well for particular cases of active remembering.

Hills and his colleagues asked 141 Indiana University Bloomington students to type the names of as many animals as they could think of in three minutes. For decades, psychologists have used such “verbal fluency tasks” to study memory and diseases in which memory breaks down, such as Alzheimer's and dementia. Again and again, researchers have found that people name animals—or vegetables or movies—in clusters of related items. They might start out saying “cat, dog, goldfish, hamster”—animals kept as pets—and then, having exhausted that subcategory, move onto ocean animals: “dolphin, whale, shark, octopus.” On average, the students in Hills's experiment named 37 animals in three minutes and, like so many of their predecessors, the lists they typed were organized into groups of animals unified by a single theme—pets, the savanna, etcetera. What Hills and his colleagues really wanted to know was whether the students shifted from one themed cluster to another the same way some animals hop from patch to patch of food. To make the most of its time and get the most food possible, a bird feeding on berries, for example, should only stay on any one particular bush if the plant will yield more berries than nearby bushes. At some point, the bird has eaten so many berries on the first bush that it makes more sense to switch to one with more to offer.

More here.