The results suggest that babies may have a natural aversion to plants, which protects them from the potential dangers of plants, Wertz said. And it's not that babies are afraid of the plants — instead, they instinctively employ this protective behavioral strategy when they identify an object as a plant. Of course, this raises the question: Why would the infants have touched the plants at all?
"With the experimental setup, we very much stacked the deck against ourselves," Wertz explained. Specifically: The babies were in a bland room with a single object placed in front of them. Part of the reason they ended up touching the plants may be because the plants were the only thing around to touch, but Wertz is interested in seeing what happens under normal experiences.
Interestingly, there is some anecdotal evidence backing up the results. "What tends to happen when I present this study, is that I have people who have kids come up to me and say, 'Oh yeah, that's right: My kids go for everything, but leave the plants alone,'" Wertz said. "Or they'll say, 'My kids put everything in their mouths, but not the plants.'"
Wertz and Wynn are now testing how infants rapidly acquire information about which plants are edible. They also want to look at possible cross-cultural differences in infants' plant aversions, as well as how nonhuman primates interact with plants. Another interesting research avenue is to determine how infants identify objects as plants.
"There's lot that needs to be done and a lot of gaps I want to fill in," Wertz said.
Read the study in the journal Cognition.