Adults and Numbers: Stuck on Stupid

Over the weekend, I highlighted this video, showing a baby having trouble with object permanence. You probably think you’ve left all such child-like cognitive problems in the distant past.

Well, if you’ve been reading this blog, maybe you’ve started to suspect that’s not always the case.

Researchers recently tested adults on another simple, cognitive task: conservation of number. The British Psychological Society blog explains:

Present a child younger than seven with two rows of items (buttons, for example) and ask them to say whether the two rows contain an equal number of items or not. You’ll probably find that they base their answer on the length of the rows, regardless of the actual number of items in each row. The error reveals the child’s use of an inappropriate “length=number” strategy.

Well, it turns out kids aren’t the only ones to make this mistake. When the researchers put nine men in fMRI machines and gave them the task, they took longer to respond when the longer row held fewer items. What’s more, the brain-scan revealed increased activity in a large swathe of brain areas compared to the simpler task (when the length of the row and the number of items matched up). The regions included frontal regions such as the middle frontal gyrus and anterior cingulate cortex, which are known to be involved in inhibitory control.

In other words, while the men got the answers right for the most part, they had to work extra-hard to inhibit the child-like “length=number” strategy.

So, even when we get a perceptual task right, we’re often working against biases that want to make us idiots.