The brain is (mostly) not a computer

I recently had my attention drawn to this essay from May 2016 – The Empty Brain – written by psychologist Robert Epstein (thanks Andrew). In it, Epstein argues that the dominant information processing (IP) model of the brain is wrong. He states that human brains do not use symbolic representations of the world and do not process information like a computer. Instead, the IP model is one chained to our current level of technological sophistication. It is just a metaphor, with no biological validity.

Epstein points out that no-one now believes that the human brain works like a hydraulic system. However, this was the dominant model of intelligence from 300 BCE to the 1300s. It was based on the technology of the times. Similarly, no-one now argues that the brain works like a telegraph. This model was popularised by physicist Hermann von Helmholtz in the mid 1800s. The IP model of the brain can be traced back to the mid 20th century. Epstein cites John von Neumann (mathematician) and George Miller (psychologist) as being particularly influential in its development. His conclusion is that it is as misguided as the hydraulic and telegraphy models of earlier times.

If Epstein is correct, his argument has significant implications for the world of artificial intelligence. If humans are not information processors, with algorithms, data, models, memories and so on, then how could computing technology be programmed to become artificially intelligent? Is it even possible with current computing architectures? (*) There has been no successful ‘human brain project’ so far using such a model. I’m convinced (as both a computer scientist and psychologist) that there never will be.

However, I disagree with what I interpret as Epstein’s (applied) behaviourist view of human intelligence. The argument that we act solely on combinations of stimuli reinforced by the rewards or punishment that follow has been thoroughly debunked (+). There is a difference between explaining something and explaining away┬ásomething. The behaviourist obsession with explaining away rather than attempting explanations of mental events is a serious blind spot to progress. As serious as the obsession with the IP model, to the exclusion of other possibilities, exhibited by many cognitive scientists.

Living together in perfect harmony on my bookshelf - some of the many psychological traditions.
Living together in perfect harmony on my bookshelf – some of the many psychological traditions.

Just because we can’t currently say how the brain changes in response to learning something, or how we later re-use this knowledge, doesn’t mean that the task will always be impossible. It certainly doesn’t mean that our brains don’t have biological analogues of memories or rules. Declarative and procedural knowledge exists, even if there isn’t a specific collection of neurons assigned to each fact or process we know.

Furthermore, the limits of our current understanding of brain architecture doesn’t invalidate the IP paradigm per-se – at least for partly explaining human intelligence. We shouldn’t be surprised at this. After all, blood circulates around the body – and brain – using hydraulics. This earlier model of how the brain functions therefore isn’t completely invalid – at least, at a low-level. It may therefore turn out that the IP model of intelligence is at least partly correct too.

Epstein finishes his essay by saying asserting “We are organisms, not computers. Get over it.” He’s right – up to a point. But the explanations (or explaining away) he offers are partial at best. Psychologists from all traditions have something to add to the debate about human intelligence. Discarding one approach solely on the grounds that it can’t explain everything that makes up human intelligence is just silly. And that’s something which Epstein definitely needs to get over.

 

(*) I asked the same question at the end of Brainchildren – Exploding robots and AI. I’m still not ready to answer it!

(+) For example, see Dennett’s essay Skinner Skinned in Brainstorms.