III. Whither the Cookie Task?
WARNING: What you are about to read may contain graphic statistical content. Side effects may include: contagious yawning, inappropriate arousal, and / or spontaneous combustion, depending on how you like your math cooked... darling.
Psychologists often think about the cookie task as a test of cognitive control, and in keeping with this, tend to assume that it is a measure both of prefrontal maturity, and of executive brain function, more generally. The idea, then, is that non-delayers are unable to delay gratification – in the same way that three-year olds are unable to switch – because their frontal lobes simply aren’t as serviceable. Indeed, in the 2006 Psych Science paper that brought this idea to the big screen, the authors suggested that “performance in the delay-of-gratiﬁcation task may serve as an early marker of individual differences in the functional integrity of [fronto-striatal] circuitry.”
If this is right, a case could be made that self-control is largely biologically determined. Indeed, such evidence would suggest that children who exhibit poor “self control” in the delay task have relatively weak executive functioning, which subsequently manifests in long-term attentional and self-regulatory issues. This is certainly an intriguing, if contentious possibility. The curious thing about it, however, is that there’s almost no evidence for it.
Take the surprising findings of the Psych Science paper I mentioned: when kids in one of the original delay of gratification tasks were brought back into the lab fourteen years later and their cognitive control was measured (via a go / no-go task), researchers found *no* correlation between the kids’ original delay time and their later control abilities. This is particularly striking given that the whole reason that delay of gratification is interesting, is because delay time does correlate so well with many measures of later attainment.
Even odder, the only correlation that the researchers did find was the *opposite* of what you’d expect if delay of gratification were simply the same thing as adult cognitive control. When the researchers kept delay time constant, they found that how much time the kid had spent oggling the cookie during the task was actually negatively correlated with later cognitive function.
What’s that mean? Well – what the researchers did, was split the kids into two groups: they wanted to compare the kids in the task who spent proportionally more time looking at the reward – and therefore had more temptation to overcome – with the kids who spent less time looking at the reward – and thus had less temptation to overcome. Just to be thoroughly offensive, let’s call these the “Catholics” (more temptation) and the “Protestants” (less).
The researchers then controlled for delay times, meaning they looked at Catholics and Protestants who ended up waiting the same amount of time. You might expect that the Catholics – who spent way more time tempting themselves, but the same amount of time patiently waiting – would have higher marks for cognitive control. After all, they spent all that time staring at the thing, but didn’t bite! But actually, the researchers found just the opposite: in fact, the “see-no-evil” Protestants were better on adolescent measures of cognitive control than the woefully-tempted Catholics. (It might be tempting to see this a case of tortoise-vs.-hare syndrome – with the Protestants catching up in the end – but in truth, I'm not sure anyone knows quite what to make of this.)
So, the findings in the Psych Science paper are actually quite astonishing: The results suggest that later neural functioning isn’t predicted either by actual performance in the cookie task, or by how well children overcome temptation. Which – going back to the question I posed earlier – indicates that the workings of our prefrontal cortex may not be the most important determinate of how we control our behavior.
Given that many papers treat “delay of gratification” tasks as tests of cognitive control, this could have important implications for how behavior in the task is characterized and understood. However, I don’t think that the Psych Science provides us with a conclusive basis on which to decide yea or nay what the “cookie task” is testing. Even if the authors had found a correlation between delay times and later executive function, this would not have thereby established that the task was a test of executive function, only that it was predictive of later function. And similarly, the failure to find such a connection does not thereby rule out whether the cookie task measures cognitive control.
That said, directly testing whether it does should be simple enough. There are an array of classic cognitive control tasks, such as the DCCS, that are demonstrably related to cortical development. Why not simply run kids through a battery of such tasks, and then see how their performance on those measures links up with their delay times?
This year, two scientists in my lab, Michael Ramscar and Christine Tran, decided to do just that. They hypothesized that if the cookie task were indeed a test of cognitive control, then delay times should be tightly coupled with scores on the DCCS, and similar tasks. But, if the task were better seen as a test of how good children are at strategically distracting themselves, then delay times should be more strongly linked with, say, vocabulary development – which is a good proxy for strategic competence and practice.
To tease apart these factors, they ran 3 – 4 ½ year olds through a battery of tests, which assessed cognitive function, measured delay of gratification, and calculated vocabulary size. What they found is that vocab is a much, much better predictor of delay-success than cognitive function: in particular, while delay-times strongly correlated with verbal inventory scores, they only weakly correlated with measures of cognitive control; a finding that is in keeping with the Psych Science results.
Taken together, these findings indicate that delay of gratification isn’t merely down to cognitive functioning. Rather, how long a child delays seems to have more to do with how good they are at strategizing and distracting themselves, an ability which may largely reflect their learning environment. This is not to say that this rules out the contribution of “cognitive control,” or neural functioning, more generally. It simply shifts the focus.
Encouragingly, I don’t think this is a conclusion Mischel would disagree with. Indeed, much of his research in this domain has focused on how strategies for delay of gratification may be learned and taught, and how these strategies may play out effectively in the long run. As he notes, children who learn early on how to use effective strategies to help regulate their behavior – and thus how to exercise self control – will begin life with a distinct advantage, which may bear more and more fruit over time.
The Daily Fact Check
Eigsti, I., Zayas, V., Mischel, W., Shoda, Y., Ayduk, O., Dadlani, M., Davidson, M., Aber, J., & Casey, B. (2006). Predicting Cognitive Control From Preschool to Late Adolescence and Young Adulthood Psychological Science, 17 (6), 478-484 DOI: 10.1111/j.1467-9280.2006.01732.x
Peake PK, Mischel W, & Hebl M (2002). Strategic attention deployment for delay of gratification in working and waiting situations. Developmental Psychology, 38 (2), 313-26 PMID: 11881765
Mischel, W., Shoda, Y., & Rodriguez, M. (1989). Delay of gratification in children Science, 244 (4907), 933-938 DOI: 10.1126/science.2658056