TY  - JOUR
PY  - 2011//
TI  - Robust averaging during perceptual judgment
JO  - Proceedings of the National Academy of Sciences of the United States of America
A1  - de Gardelle, Vincent
A1  - Summerfield, Christopher
SP  - 13341
EP  - 13346
VL  - 108
IS  - 32
N2  - An optimal agent will base judgments on the strength and reliability of decision-relevant evidence. However, previous investigations of the computational mechanisms of perceptual judgments have focused on integration of the evidence mean (i.e., strength), and overlooked the contribution of evidence variance (i.e., reliability). Here, using a multielement averaging task, we show that human observers process heterogeneous decision-relevant evidence more slowly and less accurately, even when signal strength, signal-to-noise ratio, category uncertainty, and low-level perceptual variability are controlled for. Moreover, observers tend to exclude or downweight extreme samples of perceptual evidence, as a statistician might exclude an outlying data point. These phenomena are captured by a probabilistic optimal model in which observers integrate the log odds of each choice option. Robust averaging may have evolved to mitigate the influence of untrustworthy evidence in perceptual judgments.<p /> <p>Language: en</p> 
LA  - en
SN  - 0027-8424
UR  - http://dx.doi.org/10.1073/pnas.1104517108
ID  - ref1
ER  -