Fish Capable of Judgment Calls
In a report in the journal Behavioral Ecology, fish learned from watching other fish find food and comparing their success rates. Cynthia Graber reports.

[The following is an exact transcript of this podcast.]

There’s plenty of evidence that animals learn from one another. But until now, it was thought that only humans make judgment calls, such as “that woman seems to be finding more food than that other guy, and she’s eating more than I am, so I’ll follow her.” This ability to selectively follow such cues shows sophisticated social learning.

Now, scientists say they’ve found the first animal example of this behavior in a common fish, the nine-spined stickleback. Two-hundred-seventy fish were study subjects. The researchers gave some of the fish access to one feeder stocked with lots of worms and one that didn’t. So the fish learned which feeder was best.

Then the fish watched other fish eat, but the feeders were switched. From their own experience the sticklebacks had learned that feeder A gave more worms, but by watching, they could see that feeder B was now more plentiful.
And when going back for seconds, they relied on social cues, not their own experiences, and headed over to B. The study is in the journal Behavioral Ecology. Another study demonstrating that the idea of the absolute uniqueness of human intelligence may be a bit…fishy.

—Cynthia Graber