My youngest daughter is a fan of the film Inside Out, which is set inside the head of a little girl called Riley Andersen. The film focuses on five characters who each represent one of Riley’s emotions and who observe the outside world on a screen in a control room. As such, it represents a common idea. When faced with the mystery of human consciousness, how many of us as children have imagined a little person or homunculus inside our head, pulling levers and turning dials? The trouble is that it doesn’t solve the problem it addresses, it just shifts it. What is in the tiny person’s head? Is it ever tinier persons all the way down?
As educated adults, we probably don’t imagine our minds in this way, but that doesn’t stop us from perhaps making a similar error.
In 1974, building on previous work on short- and long-term memory, Baddeley and Hitch proposed replacing the concept of a short-term memory store with ‘working memory’. The original model of working memory contained three components, a ‘central executive’ and two ‘slave’ systems known as the ‘phonological loop’ and the ‘visuo-spatial sketchpad’. The need for these two separate systems stemmed from the fact that experiments seemed to show that people could process verbal and visual information at the same time, with little loss of efficiency. In 2000, Baddeley added a third slave system, the ‘episodic buffer’.
The notion of working memory, alongside the experimental finding that it appears to be extremely limited in its capacity, is a key concept in Cognitive Load Theory. But what of Baddeley and Hitch’s central executive? How does it know which levers to pull and dials to turn? What is directing the central executive? Is it another central executive?
In their 2011 book, Sweller, Ayres and Kalyuga presented a solution – ditch the central executive. It doesn’t sound like much of a solution at first because we must have some kind of system for directing our attention. We live in stimulus-rich environments and yet, due to working memory limitations, we can only process a few items of information at a time. So how do we know what to attend to?
Sweller et al. claim that our actions are directed by knowledge held in long-term memory. They argue that this is the only system that can logically serve the role of a central executive:
“If knowledge held in long-term memory does not have the attributes normally attributed to a central executive, we are immediately faced with the question of how a knowledge-independent central executive determines its actions. We require another central executive governing the first central executive that in turn requires a third central executive, etc.”
If true, who you are and why you do what you do is a result of what you know. In some ways, this is perhaps a profound idea. In others ways, it is perhaps blindingly obvious.
Yet there seems to exist a kind of homunculus bias. Although we would be embarrassed to suggest that there are little people in our heads, we often find ourselves proposing the existence of similar entities. In education, one example might be the suggestion that there are trainable general-purpose skills such as critical thinking, problem solving and creativity. To the extent that such skills exist, they must consist of knowledge held in long-term memory. When faced with a problem, we can either retrieve some information relevant to solving it or we are forced to use guess-and-check. Even mildly useful heuristics such as ‘draw a diagram’ consist of things we know. How could they not?
Nevertheless, people constantly suggest that variants on problem-based learning or inquiry learning provide a gym workout for the little critical thinking, problem solving and creativity people in our heads.
Someone should make a movie.