TY - JOUR
T1 - The Relation between Probability and Evidence Judgment
T2 - An Extension of Support Theory
AU - Chen Idson, Lorraine
AU - Krantz, David H.
AU - Osherson, Daniel
AU - Bonini, Nicolao
N1 - Funding Information:
*Research in this paper was partly supported by NSF grants SBR-9818849 to D. H. Krantz and IIS-9978135 to D. Osherson.
PY - 2001
Y1 - 2001
N2 - We propose a theory that relates perceived evidence to numerical probability judgment. The most successful prior account of this relation is Support Theory, advanced in Tversky and Koehler (1994). Support Theory, however, implies additive probability estimates for binary partitions. In contrast, superadditivity has been documented in Macchi, Osherson, and Krantz (1999), and both sub- and superadditivity appear in the experiments reported here. Nonadditivity suggests asymmetry in the processing of focal and nonfocal hypotheses, even within binary partitions. We extend Support Theory by revising its basic equation to allow such asymmetry, and compare the two equations' ability to predict numerical assessments of probability from scaled estimates of evidence for and against a given proposition. Both between- and within-subject experimental designs are employed for this purpose. We find that the revised equation is more accurate than the original Support Theory equation. The implications of asymmetric processing on qualitative assessments of chance are also briefly discussed.
AB - We propose a theory that relates perceived evidence to numerical probability judgment. The most successful prior account of this relation is Support Theory, advanced in Tversky and Koehler (1994). Support Theory, however, implies additive probability estimates for binary partitions. In contrast, superadditivity has been documented in Macchi, Osherson, and Krantz (1999), and both sub- and superadditivity appear in the experiments reported here. Nonadditivity suggests asymmetry in the processing of focal and nonfocal hypotheses, even within binary partitions. We extend Support Theory by revising its basic equation to allow such asymmetry, and compare the two equations' ability to predict numerical assessments of probability from scaled estimates of evidence for and against a given proposition. Both between- and within-subject experimental designs are employed for this purpose. We find that the revised equation is more accurate than the original Support Theory equation. The implications of asymmetric processing on qualitative assessments of chance are also briefly discussed.
KW - Evidence judgment
KW - Probability judgment
KW - Subaddivity
UR - http://www.scopus.com/inward/record.url?scp=0041783474&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0041783474&partnerID=8YFLogxK
U2 - 10.1023/A:1011131017766
DO - 10.1023/A:1011131017766
M3 - Article
AN - SCOPUS:0041783474
SN - 0895-5646
VL - 22
SP - 227
EP - 249
JO - Journal of Risk and Uncertainty
JF - Journal of Risk and Uncertainty
IS - 3
ER -