They crafted the second artifact out of green pipe cleaners to test if babies don't like to touch green objects. The object also mimicked plants' swaying movement when disturbed.
After testing 47 infants, who were between 8 and 18 months old, the researchers found that the babies took, on average, 5 seconds longer to touch the plants and artificial plants than the novel artifacts. Importantly, the infants didn't have any social information about the plants, as they didn't see anyone touching those specific plants.
As part of the experiment, Wertz and Wynn also gave the parents a questionnaire about their babies' experiences with plants. On a five-point scale (1 being "never" and 5 being "nearly every day"), the survey probed how often the infants see their parents handling plants, how often the babies touch plants and how often the parents stop their infants from touching plants.
The infants' own experiences with plants didn't affect how long it took them to touch the plants in the experiment. Oddly, however, babies who saw their parents caring for plants more often actually took longer to touch plants, though the researchers don't know why.
Given the visual differences between the fabricated objects and the plants (both real and artificial), Wertz and Wynn decided to test if the infants were just more interested in touching novel things. They also tested if the babies were more prone to touch objects that are manmade — it could be the case that the infants think anything manmade is made to be handled, and anything that's not a manmade object should be treated with some care, Wertz said.
They repeated the first experiment with 44 babies, this time using the same fabricated objects, seashells (natural objects) and spoons and lamps (familiar manmade objects that the infants were allowed to touch and not allowed to touch at home, respectively). The babies weren't reluctant to touch any of the objects in this experiment, but they did take a little longer to touch the novel fabricated objects than the seashells, spoons and lamps.