TY  - JOUR
A1  - Shaki, Samuel
A1  - Fischer, Martin H.
T1  - Competing Biases in Mental Arithmetic
BT  - When Division Is More and Multiplication Is Less
JF  - Frontiers in human neuroscience
N2  - Mental arithmetic exhibits various biases. Among those is a tendency to overestimate addition and to underestimate subtraction outcomes. Does such “operational momentum” (OM) also affect multiplication and division? Twenty-six adults produced lines whose lengths corresponded to the correct outcomes of multiplication and division problems shown in symbolic format. We found a reliable tendency to over-estimate division outcomes, i.e., reverse OM. We suggest that anchoring on the first operand (a tendency to use this number as a reference for further quantitative reasoning) contributes to cognitive biases in mental arithmetic.
KW  - heuristics and biases
KW  - numerical cognition
KW  - mental arithmetic
KW  - mental number line
KW  - operational momentum
Y1  - 2017
U6  - https://doi.org/10.3389/fnhum.2017.00037
SN  - 1662-5161
VL  - 11
PB  - Frontiers Research Foundation
CY  - Lausanne
ER  - 
TY  - GEN
A1  - Shaki, Samuel
A1  - Fischer, Martin H.
T1  - Competing Biases in Mental Arithmetic
BT  - When Division Is More and Multiplication Is Less
N2  - Mental arithmetic exhibits various biases. Among those is a tendency to overestimate addition and to underestimate subtraction outcomes. Does such “operational momentum” (OM) also affect multiplication and division? Twenty-six adults produced lines whose lengths corresponded to the correct outcomes of multiplication and division problems shown in symbolic format. We found a reliable tendency to over-estimate division outcomes, i.e., reverse OM. We suggest that anchoring on the first operand (a tendency to use this number as a reference for further quantitative reasoning) contributes to cognitive biases in mental arithmetic.
T3  - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 312 
KW  - heuristics and biases
KW  - mental arithmetic
KW  - mental number line
KW  - numerical cognition
KW  - operational momentum
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-103492
ER  - 
TY  - JOUR
A1  - Shaki, Samuel
A1  - Pinhas, Michal
A1  - Fischer, Martin H.
T1  - Heuristics and biases in mental arithmetic
BT  - revisiting and reversing operational momentum
JF  - Thinking & Reasoning
N2  - Mental arithmetic is characterised by a tendency to overestimate addition and to underestimate subtraction results: the operational momentum (OM) effect. Here, motivated by contentious explanations of this effect, we developed and tested an arithmetic heuristics and biases model that predicts reverse OM due to cognitive anchoring effects. Participants produced bi-directional lines with lengths corresponding to the results of arithmetic problems. In two experiments, we found regular OM with zero problems (e.g., 3+0, 3-0) but reverse OM with non-zero problems (e.g., 2+1, 4-1). In a third experiment, we tested the prediction of our model. Our results suggest the presence of at least three competing biases in mental arithmetic: a more-or-less heuristic, a sign-space association and an anchoring bias. We conclude that mental arithmetic exhibits shortcuts for decision-making similar to traditional domains of reasoning and problem-solving.
KW  - Heuristics
KW  - mental arithmetic
KW  - mental number line
KW  - operational momentum
KW  - problem-solving
Y1  - 2017
U6  - https://doi.org/10.1080/13546783.2017.1348987
SN  - 1354-6783
SN  - 1464-0708
VL  - 24
IS  - 2
SP  - 138
EP  - 156
PB  - Routledge, Taylor & Francis Group
CY  - Abingdon
ER  -