Neuroscience and Rhetoric

* Hugo Mercier, ‘The Argumentative Theory: Predictions and Empirical Evidence’, Trends in Cognitive Sciences, 20 (2016), 689-700.
* Hugo Mercier and Dan Sperber, ‘Why do Humans Reason? Arguments for an Argumentative Theory’, Behavioural and Brain Sciences, 34 (2011), 57–111. [Includes lots of interesting commentary.]

This is another article of a kind I have enjoyed before (and said so): where they say ‘you’d think we’d have evolved to be better at X, but we haven’t, because evolution has preferred to make us good at Y’. The Y here, and before, is social life. Mercier argues in the Trends article that there is increasing evidence to support the proposal made in the earlier piece cited above, written with Dan Sperber. The point of reasoning, he says, is first and foremost ‘to exchange arguments with others’. We’re biased when we make cases, putting them competitively out there without effective reflection. But when we hear others’ cases, we’re more ‘objective and demanding’. This is a ‘fundamental asymmetry between production and evaluation’, they say, and I am going along with the idea so far.
      Not least because there are very interesting consequences, I think. From a social point of view, it might be efficient. Easy answers move quickly, but difficult ones don’t: ‘the more debate and conflict between opinions there is, the more argument evaluation prevails over argument production, resulting in better outcomes’. I am not sure that my experience on committees validates this word ‘better’, but I do recognise this idea that a slow-starting discussion, in which nobody is all that engaged, begins to take off once there is some opinion in the room to deal with. Does this always lead to ‘the spread of the best ideas present in the group’? Maybe. It can lead to worthwhile proposals being stalled because they aren’t watertight, but I suppose it means that truly slack things are very unlikely to get through if we’re functioning at all.


One of the things Mercier hopes to inaugurate is a ‘a change in the norms used to evaluate good reasoning performance’. Rather than classical logic, for example, he wonders about something more Bayesian. (I said I’d be using that term a few times back here, and that’s why I defined it there.) In proposing the beginnings of ‘a neuroscience of argumentation’, he notes an interesting possibility in relation to experiments on reasoning.
      Sometimes it comes across as if participants evaluate statements put to them poorly; his argument is that it might just be that they are doing perfectly well at being objective in that phase of thinking, but that ‘it is the subsequent production of unaddressed counterarguments that leads to these apparently irrational reactions’. That is, what the experiments are finding is not that subjects are bad at evaluation but that they are typically lazy in thinking for themselves.
      In modern societies, he says, there may be a problem with some of these mechanisms, in that ‘we often encounter arguments without being able to have a discussion with their source; for instance, when we read the newspaper, watch TV, or participate in a psychology experiment on argument evaluation’. I would say that this is something that goes back rather a long way beyond conventional descriptions of the ‘modern’, to a time when societies evolved beyond their simplest forms – perhaps the development of writing as a means of carrying argument was a significant shift. Nevertheless it does seem possible that nowadays things are a bit out of kilter. Some might say that 2016 was a year of bad arguments, poorly evaluated. Let’s hope 2017 is better.


It’s interesting to me that in the cultures I know a bit about the formal art of rhetoric is very important, and it is as old as literate culture itself, more or less. Classical and Renaissance thinkers might well have recognised the idea that reasoning and social persuasion are entwined; later ages criticised them for it. When I say rhetoric in this context I think of it as a science of argumentative culture. It sets itself up as means of persuading others but it may also be thought of as, perhaps, an analysis of reasoning that (as Mercier would have it) understands it as something which is fundamentally linked to social life.
      There were a happy few day a while ago when I wandered around muttering ‘rhetoric is a cognitive science!’ as if I had found the key to all mythologies. A more processed version of that thought made its way into my book Shakespeare, Rhetoric and Cognition (2011). My point was that the tropes of rhetoric seemed to map out a lot of cognitive operations, linking parts to wholes, representing efficient organisations, and could usefully be thought of as a map of the mind, not just of ornate speech. Here we are again, a little bit: in what way might a new ‘neuroscience of argumentation’ interact with the traditional ‘science of argumentation’? My guess would be that the ways in which we respond to arguments do involve some rhetorical habits of thought — ways of thinking (working on certain words; making certain kinds of connection; turning the order of things around) that are described in the rhetorical manuals. The main thing is that a neuroscience of argumentation is (i) a lovely idea, and (ii) not always breaking new ground.

E-mail me at rtrl100[at]

Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.