How the differences between what babies are incredibly bad at, and what they’re incredibly good at, might all lie on one dimension.

I’m sitting watching an eye gaze trace of an infant, doing a short-term memory experiment in the next door room. It’s a simple task. There are two windows on the screen and no distractions. An elephant appears in one window, then disappears, then a flower appears in the middle between the two windows, and then disappears again. If they look back to the window where the object disappeared, they get a reward.

The baby who’s doing the experiment is 12 months old. Previously, outside in the waiting room, he was showing off his cruising skills, walking around the room, flashing coy smiles at the research assistant. His mother pulled out her phone to take a photo and he recognised what was coming, and struck a pose that he knew would make us all laugh.

On the eye gaze trace that I’m watching I can see that the baby has followed the object, seen it disappear, and looked to the flower for about 500ms (half a second), until it disappears. I can see, then, from his eye movements (and from his expression on the monitor) that he’s thinking ‘where did that elephant go?’ His performance is completely at chance – even after a 500 ms maintenance delay. And I’m thinking, as I have done time and time again, ‘how can he possibly have forgotten that quickly?’ I’ve tried many times to design experiments to measure infants’ ability to remember things for short periods of time, and time and again I’ve come away from a piloting session with the same impression: how can a creature who is so recognisable, so sophisticated in so many ways be so terrible at these kinds of tasks?

They’re equally bad at other tasks that are thought to be closely related. I’ve spent a lot of time, for example, trying to design eyetracker tasks in which there are two objects on screen - object A is more salient (i.e. more immediately attention-getting), but object B gives, in this particular task, a much bigger reward than object A when looked at. Can baby learn to inhibit the urge to look at A, to get the bigger reward for looking at B? Again I’ve tried this multiple times, using different paradigms. And again, babies are terrible at it.

None of these observations are, of course, at all original. Back to the earliest days of EEG recordings in infants, in the 40s and 50s, it was assumed that the frontal cortex was functionally silent. And recent research supports that idea that myelination on anterior-posterior white matter tracks is pretty much non-existent, at least in a <6-month-old.

But I’ve been trying to understand babies for a while, now in these terms – ‘what is cognition, or attention, like, without a frontal cortex?’ And somehow it never seems a helpful way to think of things. So instead I’m going to try to think of it in a different way – taking an idea, possibly as a metaphor, from the literature into D1 and D2 balances. D1 is a “high energy barrier [that] favours robust online maintenance of information” and D2 is a “low energy barrier [that] is beneficial for flexible and fast switching among representational states”. What babies are bad at, hypothetically, is high energy-type behaviours.

What I like about this is that you get a yin to your yang. Whereas it’s hard to think of attention behaviours that might be better without a frontal cortex, it’s definitely possible to consider whether, whereas infants are bad at ‘high energy barrier’-type tasks, they might also be good, or at least relatively unimpaired at ‘low energy barrier’-type tasks’.

Because, as any infant psychologist knows well, there are other types of learning at which infants perform pretty well. The famous Saffran artificial language learning tasks are a good example of this – it poses a task that requires you to spot patterns of statistical associations in a large dataset of which you have no prior knowledge. Or this cross-situational word-referent mapping task is another example. I was running this recently, and I got the opposite impression to the one I described above – that I was the dunce, and the babies weren’t doing too badly.

So I wonder, could this distinction between high energy barrier tasks and low energy barrier tasks be used to formalise the distinction between the types of task that infants are terrible at, and those that they’re not too bad at? In my next post I describe a number of tasks that infants might actually be quite good at.