First, two identical stuffed bunnies, one in a green shirt and the other in orange, appeared on stage with plates of graham crackers. “Mmmm, yum!” they said. The curtain fell. This was the equivalent of the opening sonnet in a Shakespeare play, a sort of framing device for what followed.
The curtain rose again. A lamb puppet appeared onstage, struggling to open a plastic box with a toy inside. The orange bunny flounced over and slammed the lid shut. My child flinched at this, though it was hard to say if it was the sound of the slamming or the rabbit’s nastiness that spooked her. Her brow furrowed. Then she got bored. A bell dinged after she looked away from the scene for two seconds, and the curtain fell.
It soon rose again: Cue the green bunny. Instead of foiling the lamb’s plans, he helped lift the lid of the toy box. The baby stared, drummed plump fingers on the table for a moment, then looked away. The curtain fell.
This scenario was repeated six times, so the baby would grasp what she was seeing, but the green bunny was always nice and the orange bunny was always mean. At the curtain call, the lab manager emerged with the two puppets. Each offered the baby a graham cracker. I was about to tell the experimenters that my daughter had never even seen a graham cracker and was an extremely picky eater when she grabbed the treat from the nice bunny, as most of the previous babies had done. I felt an unwarranted surge of parental pride. I was not alone in my delight.
“She chose the good guy!” Tasimi said. “After all that, she chose the good guy.”
When babies at the Yale lab turn 2, their parents are tactfully invited to return to the university after the child’s third birthday. Researchers tend to avoid that event horizon of toddlerhood, the terrible twos. Renowned for their tantrums, 2-year-olds are tough to test. They speak, but not well, and while active they’re not particularly coordinated.
But not all researchers shun 2-year-olds. The next lab I visited was at Harvard University in Cambridge, Massachusetts, and it has made this age group something of a specialty, through work on toddler altruism (a phrase that, admittedly, rings rather hollow in parental ears).
One advantage of testing slightly older babies and children is that they are able to perform relatively complicated tasks. In the Laboratory for Developmental Studies, the toddlers don’t watch puppets help: They themselves are asked to help.
The chief scientist is Felix Warneken, another young researcher, though not one whose appearance initially telegraphs baby scientist. He stands 6-foot-6. He usually greets children from the floor, playing with them before standing up at the last possible moment. “Only then do they realize they’ve been dealing with a giant,” Warneken says. He usually wore the same red sweater in all his experiments, because he thinks kids like it. In addition to designing groundbreaking studies, he has also dreamed up several toys to reward or distract subjects, including an ingenious device he calls a jingle box: An angled xylophone concealed in a cardboard container, it makes a thrilling sound when wooden blocks are dropped inside.