Sunday, October 31, 2010

Why do Humans Reason?

More education via Jonathan Haidt - one of the best papers I have read this year Why do Humans Reason? Arguments for an argumentative theory by Hugo Mercier and Dan Sperber

Abstract:
Reasoning is generally seen as a means to improve knowledge and make better decisions. However, much evidence shows that reasoning often leads to epistemic distortions and poor decisions. This suggests that the function of reasoning should be rethought. Our hypothesis is that the function of reasoning is argumentative. It is to devise and evaluate arguments intended to persuade. Reasoning so conceived is adaptive given the exceptional dependence of humans on communication and their vulnerability to misinformation. A wide range of evidence in the psychology of reasoning and decision making can be reinterpreted and better explained in the light of this hypothesis. Poor performance in standard reasoning tasks is explained by the lack of argumentative context. When the same problems are placed in a proper argumentative setting, people turn out to be skilled arguers. Skilled arguers, however, are not after the truth but after arguments supporting their views. This explains the notorious confirmation bias. This bias is apparent not only when people are actually arguing but also when they are reasoning proactively from the perspective of having to defend their opinions. Reasoning so motivated can distort evaluations and attitudes and allow erroneous beliefs to persist. Proactively used reasoning also favours decisions that are easy to justify but not necessarily better. In all these instances traditionally described as failures or flaws, reasoning does exactly what can be expected of an argumentative device: look for arguments that support a given conclusion, and favour conclusions for which arguments can be found.

Inference (as the term is most commonly understood in psychology) is the production of new mental representations on the basis of previously held representations. Examples of inferences are the production of new beliefs on the basis of previous beliefs, the production of expectations on the basis of perception, or the production of plans on the basis of preferences and beliefs. So understood, inference need not be deliberate or conscious. It is at work not only in conceptual thinking but also in perception and in motor control (Kersten, Mamassian, & Yuille, 2004; Wolpert & Kawato, 1998). It is a basic ingredient of any cognitive system. ‘Reasoning’, as commonly understood, refers to a very special form of inference at the conceptual level, where not only is a new mental representation (or 'conclusion') consciously produced, but the previously held representations (or ‘premises’) that warrant it are also consciously entertained. The premises are seen as providing reasons to accept the conclusion. Most work in the psychology of reasoning is about reasoning so understood. Such reasoning is typically human. There is no evidence that it occurs in non-human animals or in pre-verbal children.

How do humans reason? Why do they reason? These two questions are mutually relevant, since the mechanisms for reasoning should be adjusted to its function. While the how-question has been systematically investigated (e.g., Evans, Newstead, & Byrne, 1993; Johnson-Laird, 2006; Oaksford & Chater, 2007; Rips, 1994) there is very little discussion of the why-question. How come? It may be that the function of reasoning is considered too obvious to deserve much attention. According to a long philosophical tradition, reasoning is what allows the human mind to go beyond mere perception, habit, and instinct. In the first, theoretical section of this article we sketch a tentative answer to the how question and then focus on the why-question: We outline an approach to reasoning based on the idea that the primary function for which it evolved is the production and evaluation of arguments in communication. In sections 2 to 5, we consider some of the main themes and findings in the experimental literature on reasoning and show how our approach helps make better sense of much of the experimental evidence, and hence gains empirical support from it.

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