You know how it feels after you’ve gorged on a large packet of pretzels or crisps – you have a mouth like a salt mine, an unquenchable thirst, and the thought occurs to you that wouldn’t mind if you never saw another pretzel again in your life. Except you know that’s not really true. That’s why you leave the other packets snug in the kitchen cupboard, fully aware that tomorrow evening you’ll be delighted to get munching again.

In other words, you have “episodic foresight”. You are able to look beyond your current physical state (extreme thirst) to anticipate being in a different state in the future, and thus plan accordingly (let’s ignore for now the fact you’re not thinking about the long-term health effects of eating all those pretzels!). Psychologists are interested in when and how this sophisticated anticipatory ability develops. A new study published in Infant and Child Development finds that young children, up to the age of seven, mostly can’t discount their current states when anticipating their future wants.

Caitlin Mahy invited 90 children (aged three to seven) to her lab and offered them a drink of apple juice. This was to make sure they weren’t thirsty at the start of the study. Next she she showed them a photo of some pretzels and a glass of water and asked them which they’d prefer to have now. Nearly 80 per cent said they’d prefer pretzels. Regardless of how they answered, all the children were offered pretzels to eat as they listened to a children’s story that took about six minutes.

Next the pretzels were taken away and Mahy asked the children to imagine that they were coming back to the lab tomorrow, and to say whether they’d prefer water or pretzels during the story. Now nearly 70 per cent said they’d prefer water tomorrow, presumably because their current state was that they were feeling thirsty. Finally, the children were offered a drink of water and the question about tomorrow was repeated. Having quenched their thirst, most of them now said once again that they’d prefer pretzels tomorrow, contradicting the answer they’d given moments earlier. There was no evidence that the older children were any better at thinking about their future preferences than the younger children.

What was going on in the children’s heads? To try to find out, Mahy asked them to justify their choices. The children’s answers suggest they had little insight into how their current state was influencing their thoughts about the future. For example, after eating the pretzels and saying they’d prefer water tomorrow, one child said “… because focusing makes my mouth get dry”; another said “because it’s healthy for you.” After having a drink of water and switching back to a future preference for pretzels, one child said “since I wouldn’t want to unscrew the bottle cap.” It seems the ability to mentally time travel and think in sophisticated ways about our future needs does not emerge until some time after age 7. However, the ability to make creative excuses like a seasoned politician seems to come quite naturally much earlier!

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Mahy, C. (2015). Young Children Have Difficulty Predicting Future Preferences in the Presence of a Conflicting Physiological State Infant and Child Development DOI: 10.1002/icd.1930

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

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