Psychologist Karen Hollis "Goes Fishing" and Nets a Research Breakthrough

When you think about how advances in research occur, you probably don't envision researchers huddled over twenty- gallon fish tanks, counting thousands of tiny swimmers. Yet that's what psychology professor Karen Hollis and her research assistants did to prove a principle psychologists had suspected for decades but that hadn't been confirmed experimentally.

Hollis proved that classical conditioning helps animals survive and reproduce. Classical conditioning in its earliest form involved experiments by Ivan Pavlov, who taught dogs to associate a specific tone with the arrival of food. After training, the dogs salivated at the tone even when no food followed. Ever since Pavlov, psychologists have studied how this mechanism works, and assumed that conditioning helped animals prepare for predictable events. Zoologists studied similar behaviors, such as territoriality, by observing animals in the wild.

<<< The idea for psychology professor Karen Hollis's current work came to her as a graduate student. "We were sitting in a room with no windows talking about the elaborate mechanics of classical conditioning, and I thought, 'I'd love to know how real animals learn, and how conditioning is adaptive behavior in the real world'" After conditioning blue gourami fish, now she knows.

"The point of my research is to see how what psychologists say about learning can be brought to bear on what zoologists study in the field," says Hollis. She designed and conducted experiments to demonstrate that conditioned animals can increase their reproductive success, as measured by the number of offspring they produce.

Using blue gourami fish, each three to five inches long, Hollis set up fish tanks and conditioned male fish to expect the arrival of a female after a specific signal. She then videotaped the fish to see if they mated and produced offspring (called "fry"). As Hollis expected, the fish who could anticipate a female's arrival mated more often and produced more fry than unconditioned fish. But demonstrating this meant that Hollis and student collaborators, including Janet Field FP, had to count each fish. This was difficult, since there were thousands of constantly moving, one-millimeter-long fry in each tank. (One prolific pair alone had 3,500 offspring!)

The National Science Foundation, which sponsored Hollis's project, called it "groundbreaking research," and a key psychological journal agrees. Her research results will be the lead article in the Journal of Comparative Psychology's September issue.

After spending more than a year gathering data for this project, Hollis will take a break from lab work to write during her 1997-98 sabbatical. She'll work on a book about the role of classical conditioning in the everyday life of people. Although she says conditioning governs human sexual behavior too, she has no plans to videotape human couples!