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  - 
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  - JOUR
A1  - Fischer, Martin H.
A1  - Shaki, Samuel
T1  - Implicit Spatial-Numerical Associations: Negative Numbers and the Role of Counting Direction
JF  - Journal of experimental psychology : Human perception and performance
N2  - It has been debated whether negative number concepts are cognitively represented on the same mental number line as positive number concepts. The present study reviews this debate and identifies limitations of previous studies. A method with nonspatial stimuli and responses is applied to overcome these limitations and to document a systematic implicit association of negative numbers with left space, thus indicating a leftward extension of the mental number line. Importantly, this result only held for left-to-right counting adults. Implications for the experiential basis of abstract conceptual knowledge are discussed.
KW  - negative numbers
KW  - counting direction
KW  - embodied cognition
KW  - IAT
KW  - SNARC effect
Y1  - 2017
U6  - https://doi.org/10.1037/xhp0000369
SN  - 0096-1523
SN  - 1939-1277
VL  - 43
SP  - 639
EP  - 643
PB  - American Psychological Association
CY  - Washington
ER  -