I spoke with behavioral ecologist Manuel Leal, an assistant professor in the Biology Department at Duke University, about his recent discovery that lizards have the ability to learn and relearn. Leal's experimentation with the cognitive abilities of lizards was inspired by his long-time love for lizard diversity. This drove him to study their evolution and behavior.
How did you conduct your experiment?
We used very similar methodology to what has been used to study the cognitive ability of birds and mammals. This was a food reward worm-based test using a block with two wells. One well was empty the other had a worm but both were covered with different colored disks. They had to remove the disk in order to get the worm. Once they learned to associate the color or brightness of the chip with their reward, I placed the worm under the other cap to see if they could reverse the association. At first, all the lizards bumped or bit the disk that previously had the worm (blue), but after a few mistakes, the lizards figured it out.
Why are the results significant?
The results suggest that lizards can learn radically quickly. Birds usually get to try six times a day, but lizards eat less, so they only got one try per day. The lizards had to remember if they made a mistake and how to correct it until the next day. They had to store the info because we did one trial a day. It disproves prior thoughts that birds and mammals are more cognitively able than lizards.
What prior research led to the misconceptions about lizards’ cognitive abilities?
It’s unclear to me. People usually overlook lizards because they haven’t been studied much compared to birds and mammals. Lizards have always been considered more robotic. Comparatively, the brains of lizards are less complex than those of birds or mammals, so that may have something to do with the preconceived notions.
What do your findings reflect about the evolution of cognition?
This definitely showed the cognitive flexibility of lizards. Such flexibility may mean lizards are able to explore more habitats since they so easily learn and relearn. That should help them adjust to a new environment.
How is the cognitive process of unlearning different from the process of learning?
Actually, broadly speaking, it’s the same thing. It’s not so much unlearning as it is relearning and processing new information. The process is in storing information and when that stored information is no longer true, breaking association. It’s remarkable how quickly the lizards were able to modify and break associations. This ability to learn new things adds to lizards’ cognitive flexibility.
Leal would like to further his research by studying the cognitive abilities of other lizard species, to have a better idea how they compare to Anolis lizards. He also wants to set up other tasks for lizards since while this experiment proved their cognitive ability when it comes to non-spatial memory and associations, it did not test their spatial cognition.