Toddlers tend to choose the last item in a set… (file under “parenting” or maybe “preschool politics”)

Science News has a discovery that should at least change the way research methods and court examinations are carried out. Very young kids have an inherent bias toward selecting the last item in any list of choices:

That bias, described in PLOS ONE on June 12, suggests that young children’s answers to these sorts of questions don’t actually reflect their desires. Instead, kids may simply be echoing the last thing they heard.

This verbal quirk can be used by parents to great effect, as the researchers point out in the title of their paper: “Cake or broccoli?” More fundamentally, the results raise questions about what sort of information a verbal answer actually pulls out of a young child’s mind. This murkiness is especially troublesome when it comes to questions whose answers call for adult action, such as: “Did you hit your sister on purpose or on accident?”

…researchers led by Emily Sumner at the University of California, Irvine, asked 24 1- and 2-year-olds a bunch of two-choice questions, some of which involved a polar bear named Rori or a grizzly bear named Quinn. One question, for example, was, “Does Rori live in an igloo or a tepee?” Later, the researchers switched the bear and the order of the options, asking, for example, “Does Quinn live in a tepee or an igloo?”

The toddlers could answer either verbally or, for reluctant speakers, by pointing at one of two stickers that showed the choices. When the children answered the questions by pointing, they chose the second option about half the time, right around chance. But when the toddlers spoke their answers, they chose the second option 85 percent of the time, regardless of the bear.

Adults actually have the opposite tendency: We’re more inclined to choose the first option we’re given (the primacy bias). To see when this shift from last to first occurs, the researchers studied transcripts of conversations held between adults and children ages 1.5 to 4. In these natural conversations, 2-year-olds were more likely to choose the second option. But 3- and 4-year-olds didn’t show this bias, suggesting that the window closes around then.