At the recent Australian College of Educators conference in Melbourne, John Sweller summarised his talk as follows: “Biologically primary, generic-cognitive skills do not need explicit instruction. Biologically secondary, domain-specific skills do need explicit instruction.”
Biologically primary and biologically secondary cognitive skills
This distinction was proposed by David Geary, a cognitive developmental and evolutionary psychologist at the University of Missouri. In a recent blogpost, Greg Ashman refers to a chapter by Geary that sets out his theory in detail.
If I’ve understood it correctly, here’s the idea at the heart of Geary’s model:
The cognitive processes we use by default have evolved over millennia to deal with information (e.g. about predators, food sources) that has remained stable for much of that time. Geary calls these biologically primary knowledge and abilities. The processes involved are fast, frugal, simple and implicit.
But we also have to deal with novel information, including knowledge we’ve learned from previous generations, so we’ve evolved flexible mechanisms for processing what Geary terms biologically secondary knowledge and abilities. The flexible mechanisms are slow, effortful, complex and explicit/conscious.
Biologically secondary processes are influenced by an underlying factor we call general intelligence, or g, related to the accuracy and speed of processing novel information. We use biologically primary processes by default, so they tend to hinder the acquisition of the biologically secondary knowledge taught in schools. Geary concludes the best way for students to acquire the latter is through direct, explicit instruction.
On the face of it, Geary’s model is a convincing one. The errors and biases associated with the cognitive processes we use by default do make it difficult for us to think logically and rationally. Children are not going to automatically absorb the body of human knowledge accumulated over the centuries, and will need to be taught it actively. Geary’s model is also coherent; its components make sense when put together. And the evidence he marshals in support is formidable; there are 21 pages of references.
However, on closer inspection the distinction between biologically primary and secondary knowledge and abilities begins to look a little blurred. It rests on some assumptions that are the subject of what Geary terms ‘vigorous debate’. Geary does note the debate, but because he plumps for one view, doesn’t evaluate the supporting evidence, and doesn’t go into detail about competing theories, teachers unfamiliar with the domains in question could easily remain unaware of possible flaws in his model. In addition, Geary adopts a particular cultural frame of reference; essentially that of a developed, industrialised society that places high value on intellectual and academic skills. There are good reasons for adopting that perspective; and equally good reasons for not doing so. In a series of three posts, I plan to examine two concepts that have prompted vigorous debate – modularity and intelligence – and to look at Geary’s cultural frame of reference.
The concept of modularity – that particular parts of the brain are dedicated to particular functions – is fundamental to Geary’s model. Physicians have known for centuries that some parts of the brain specialise in processing specific information. Some stroke patients for example, have been reported as being able to write but no longer able to read (alexia without agraphia), to be able to read symbols but not words (pure alexia), or to be unable to recall some types of words (anomia). Language isn’t the only ability involving specialised modules; different areas of the brain are dedicated to processing the visual features of, for example, faces, places and tools.
One question that has long perplexed researchers is how modular the brain actually is. Some functions clearly occur in particular locations and in those locations only; others appear to be more distributed. In the early 1980s, Jerry Fodor tackled this conundrum head-on in his book The modularity of mind. What he concluded is that at the perceptual and linguistic level functions are largely modular, i.e. specialised and stable, but at the higher levels of association and ‘thought’ they are distributed and unstable. This makes sense; you’d want stability in what you perceive, but flexibility in what you do with those perceptions.
Geary refers to the ‘vigorous debate’ (p.12) between those who lean towards specialised brain functions being evolved and modular, and those who see specialised brain functions as emerging from interactions between lower-level stable mechanisms. Although he acknowledges the importance of interaction and emergence during development (pp. 14,18) you wouldn’t know that from Fig 1.2, showing his ‘evolved cognitive modules’.
At first glance, Geary’s distinction between stable biologically primary functions and flexible biologically secondary functions appears to be the same as Fodor’s stable/unstable distinction. But it isn’t. Fodor’s modules are low-level perceptual ones; some of Geary’s modules in Fig. 1.2 (e.g. theory of mind, language, non-verbal behaviour) engage frontal brain areas used for the flexible processing of higher-level information.
Novices and experts; novelty and automation
Later in his chapter, Geary refers to research involving these frontal brain areas. Two findings are particularly relevant to his modular theory. The first is that frontal areas of the brain are initially engaged whilst people are learning a complex task, but as the task becomes increasingly automated, frontal area involvement decreases (p.59). Second, research comparing experts’ and novices’ perceptions of physical phenomena (p.69) showed that if there is a conflict between what people see and their current schemas, frontal areas of their brains are engaged to resolve the conflict. So, when physics novices are shown a scientifically accurate explanation, or when physics experts are shown a ‘folk’ explanation, both groups experience conflict.
In other words, what’s processed quickly, automatically and pre-consciously is familiar, overlearned information. If that familiar and overlearned information consists of incomplete and partially understood bits and pieces that people have picked up as they’ve gone along, errors in their ‘folk’ psychology, biology and physics concepts (p.13) are unsurprising. But it doesn’t follow that there must be dedicated modules in the brain that have evolved to produce those concepts.
If the familiar overlearned information is, in contrast, extensive and scientifically accurate, the ‘folk’ concepts get overridden and the scientific concepts become the ones that are accessed quickly, automatically and pre-consciously. In other words, the line between biologically primary and secondary knowledge and abilities might not be as clear as Geary’s model implies. Here’s an example; the ability to draw what you see.
The eye of the beholder
Most of us are able to recognise, immediately and without error, the face of an old friend, the front of our own house, or the family car. However, if asked to draw an accurate representation of those items, even if they were in front of us at the time, most of us would struggle. That’s because the processes involved in visual recognition are fast, frugal, simple and implicit; they appear to be evolved, modular systems. But there are people can draw accurately what they see in front of them; some can do so ‘naturally’, others train themselves to do so, and still others are taught to do so via direct instruction. It looks as if the ability to draw accurately straddles Geary’s biologically primary and secondary divide. The extent to which modules are actually modular is further called into question by recent research involving the fusiform face area (FFA).
Fusiform face area
The FFA is one of the visual processing areas of the brain. It specialises in processing information about faces. What wasn’t initially clear to researchers was whether it processed information about faces only, or whether faces were simply a special case of the type of information it processes. There was considerable debate about this until a series of experiments found that various experts used their FFA for differentiating subtle visual differences within classes of items as diverse as birds, cars, chess configurations, x-ray images, Pokémon, and objects named ‘greebles’ invented by researchers.
What these experiments tell us is that an area of the brain apparently dedicated to processing information about faces, is also used to process information about modern artifacts with features that require fine-grained differentiation in order to tell them apart. They also tell us that modules in the brain don’t seem to draw a clear line between biologically primary information such as faces (no explicit instruction required), and biologically secondary information such as x-ray images or fictitious creatures (where initial explicit instruction is required).
What the experiments don’t tell us is whether the FFA evolved to process information about faces and is being co-opted to process other visually similar information, or whether it evolved to process fine-grained visual distinctions, of which faces happen to be the most frequent example most people encounter.
We know that brain mechanisms have evolved and that has resulted in some modular processing. What isn’t yet clear is exactly how modular the modules are, or whether there is actually a clear divide between biologically primary and biologically secondary abilities. Another component of Geary’s model about which there has been considerable debate is intelligence – the subject of the next post.
Incidentally, it would be interesting to know how Sweller developed his summary because it doesn’t quite map on to a concept of modularity in which the cognitive skills are anything but generic.
Fodor, J (1983). The modularity of mind. MIT Press.
Geary, D (2007). Educating the evolved mind: Conceptual foundations for an evolutionary educational psychology, in Educating the evolved mind: Conceptual foundations for an evolutionary educational psychology, JS Carlson & JR Levin (Eds). Information Age Publishing.
I thought the image was from @greg_ashman’s Twitter timeline but can’t now find it. Happy to acknowledge correctly if notified.