[ExI] persuasion and/or argument

[Damien Broderick]

"Why do humans reason? Arguments for an argumentative theory" in 
BEHAVIORAL AND BRAIN SCIENCES (2011) 34, 57–111 by Hugo Mercie, 
University of Pennsylvania hmercier at sas.upenn.edu 
<http://sites.google.com/site/hugomercier/>
and Dan Sperber, Jean Nicod Institute(EHESS-ENS-CNRS), 75005Paris, 
France; Department  of Philosophy, Central EuropeanUniversity, Budapest, 
Hungary  dan at sperber.fr <http://www.dan.sperber.fr >

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 
favors 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, ceteris 
paribus, favor conclusions for which arguments can be found.
  KeBEHAVIORALANDBRAINSCIENCES(2011)34, 57–111 
doi:10.1017/S0140525X10000968