If you ask a toddler, “would you like cake or broccoli?” the answer—8 times out of 10—will be broccoli, report researchers.
This has less to do with parents successfully instilling healthy food preferences than the order of the choices. The new study in PLOS ONE finds that toddlers are highly subject to recency bias when faced with “or” questions: They tend to pick the last option, even if it’s not what they actually want.
“Adults are able to distinguish between choices and are oftentimes more likely to select the first one. This is called primacy bias,” says the study’s lead author, Emily Sumner, a doctoral candidate in cognitive sciences at the University of California, Irvine. “But kids, particularly toddlers under three, who may not know language as well, demonstrate a recency bias when responding to questions verbally, meaning the last choice presented is more often selected. This area hasn’t been studied in children before, so this is fascinating to pinpoint.”
Recency bias in action
Researchers asked 24 toddlers between 21 and 27 months old 20 questions in which they had to choose between option 1 and option 2. They then posed the same questions again, with the options in reverse order. After speaking each answer, the children received a sticker depicting their selection. If they didn’t say which option they wanted, both stickers were shown when the question was asked, and they pointed to their choice.
When toddlers responded verbally, they picked the last option presented 85.2 percent of the time. When pointing rather than speaking, they chose the last option only 51.6 percent of the time. According to Sumner, this difference is related to the development of children’s working memory, which is concerned with immediate conscious perception and linguistic processing, along with something called the phonological loop.
“When a child is pointing, they can see the options and choose their actual preference,” she explains. “When they have no visual references and only hear ‘or,’ they’re able to hold onto the most recently mentioned option by depending on the phonological loop. The children understand how speech sounds but not necessarily what the words mean. So when speaking, they’re just parroting back the most recently mentioned choice.”
The researchers also reviewed the Child Language Data Exchange System, a computerized database of transcribed conversations between parents and their children to determine if the same bias applies in real-world interactions. They analyzed 534 “or” questions and discovered that the likelihood of responding with the second option decreased as children got older. Two-year-olds selected it 64 percent of the time, while 3- and 4-year-olds chose the second option 50 percent of the time. This suggests that recency bias is present until about the age of 3.
The researchers conducted additional experiments with 24 preschoolers to determine if working memory constraints, such as age and word length, drive recency bias. The children were asked to name toy cartoon characters by choosing between two nonsense words varying in syllable count—Stog or Meeb, for example, or Hootamawhirl or Haykidosi.
Researchers found that most preschoolers were apt to exhibit a recency bias throughout the entire process. Further results showed that with most of the children, the more syllables the words had, the stronger the recency bias. This suggests that when working memory is constrained, even older kids are more likely to revert back to recency bias.
“Our study demonstrates the importance of swapping the order of options when asking young children about their preferences, because they don’t always know what they’re saying,” Sumner says. “For experimental psychologists, research methods that require verbal responses should be carefully counterbalanced. Parents, however, may wish to use such a biased design when asking toddlers if they’d like cake or broccoli.”
Coauthors are from the University of Minnesota; the University of Rochester; Stanford University; and the University of California, Berkeley. Funding came from the Jacobs Foundation and the University of Rochester Bilski-Mayer fellowship program.
Source: UC Irvine