@article{MioniFischerShaki2021,
  author    = {Mioni, Giovanna and Fischer, Martin H. and Shaki, Samuel},
  title     = {Heuristics and biases in the mental manipulation of magnitudes},
  series = {Quarterly journal of experimental psychology / published in association with Experimental Psychology Society},
  volume    = {74},
  journal   = {Quarterly journal of experimental psychology / published in association with Experimental Psychology Society},
  number    = {3},
  publisher = {SAGE Publishing},
  address   = {Thousand Oaks, CA},
  issn      = {1747-0218},
  doi       = {10.1177/1747021820967663},
  pages     = {536 -- 547},
  year      = {2021},
  abstract  = {There is a debate about whether and why we overestimate addition and underestimate subtraction results (Operational Momentum or OM effect). Spatial-attentional accounts of OM compete with a model which postulates that OM reflects a weighted combination of multiple arithmetic heuristics and biases (AHAB). This study addressed this debate with the theoretically diagnostic distinction between zero problems (e.g., 3 + 0, 3 - 0) and non-zero problems (e.g., 2 + 1, 4 - 1) because AHAB, in contrast to all other accounts, uniquely predicts reverse OM for the latter problem type. In two tests (line-length production and time production), participants indeed produced shorter lines and under-estimated time intervals in non-zero additions compared with subtractions. This predicted interaction between operation and problem type extends OM to non-spatial magnitudes and highlights the strength of AHAB regarding different problem types and modalities during the mental manipulation of magnitudes. They also suggest that OM reflects methodological details, whereas reverse OM is the more representative behavioural signature of mental arithmetic.},
  language  = {en}
}
@article{ShakiPinhasFischer2017,
  author    = {Shaki, Samuel and Pinhas, Michal and Fischer, Martin H.},
  title     = {Heuristics and biases in mental arithmetic},
  series = {Thinking \& Reasoning},
  volume    = {24},
  journal   = {Thinking \& Reasoning},
  number    = {2},
  publisher = {Routledge, Taylor \& Francis Group},
  address   = {Abingdon},
  issn      = {1354-6783},
  doi       = {10.1080/13546783.2017.1348987},
  pages     = {138 -- 156},
  year      = {2017},
  abstract  = {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.},
  language  = {en}
}
@misc{FischerShaki2018,
  author    = {Fischer, Martin H. and Shaki, Samuel},
  title     = {Number concepts: abstract and embodied},
  series = {Philosophical transactions of the Royal Society of London : B, Biological sciences},
  volume    = {373},
  journal   = {Philosophical transactions of the Royal Society of London : B, Biological sciences},
  number    = {1752},
  publisher = {Royal Society},
  address   = {London},
  issn      = {0962-8436},
  doi       = {10.1098/rstb.2017.0125},
  pages     = {8},
  year      = {2018},
  abstract  = {Numerical knowledge, including number concepts and arithmetic procedures, seems to be a clear-cut case for abstract symbol manipulation. Yet, evidence from perceptual and motor behaviour reveals that natural number knowledge and simple arithmetic also remain closely associated with modal experiences. Following a review of behavioural, animal and neuroscience studies of number processing, we propose a revised understanding of psychological number concepts as grounded in physical constraints, embodied in experience and situated through task-specific intentions. The idea that number concepts occupy a range of positions on the continuum between abstract and modal conceptual knowledge also accounts for systematic heuristics and biases in mental arithmetic, thus inviting psycho-logical approaches to the study of the mathematical mind.},
  language  = {en}
}
@article{FischerShaki2018,
  author    = {Fischer, Martin H. and Shaki, Samuel},
  title     = {Repeating Numbers Reduces Results: Violations of the Identity Axiom in Mental Arithmetic},
  series = {Frontiers in psychology},
  volume    = {9},
  journal   = {Frontiers in psychology},
  publisher = {Frontiers Research Foundation},
  address   = {Lausanne},
  issn      = {1664-1078},
  doi       = {10.3389/fpsyg.2018.02453},
  pages     = {9},
  year      = {2018},
  abstract  = {Even simple mental arithmetic is fraught with cognitive biases. For example, adding repeated numbers (so-called tie problems, e.g., 2 + 2) not only has a speed and accuracy advantage over adding different numbers (e.g., 1 + 3) but may also lead to under-representation of the result relative to a standard value (Charras et al., 2012, 2014). Does the tie advantage merely reflect easier encoding or retrieval compared to non-ties, or also a distorted result representation? To answer this question, 47 healthy adults performed two tasks, both of which indicated under-representation of tie results: In a result-to-position pointing task (Experiment 1) we measured the spatial mapping of numbers and found a left-bias for tie compared to non-tie problems. In a result-to-line-length production task (Experiment 2) we measured the underlying magnitude representation directly and obtained shorter lines for tie-compared to non-tie problems. These observations suggest that the processing benefit of tie problems comes at the cost of representational reduction of result meaning. This conclusion is discussed in the context of a recent model of arithmetic heuristics and biases.},
  language  = {en}
}
@misc{FischerMiklashevskyShaki2019,
  author    = {Fischer, Martin H. and Miklashevsky, Alex A. and Shaki, Samuel},
  title     = {Commentary : The Developmental Trajectory of the Operational Momentum Effect},
  series = {Postprints der Universit{\"a}t Potsdam Humanwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam Humanwissenschaftliche Reihe},
  number    = {502},
  issn      = {1866-8364},
  doi       = {10.25932/publishup-42316},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-423169},
  pages     = {3},
  year      = {2019},
  language  = {en}
}
@article{FischerMiklashevskyShaki2018,
  author    = {Fischer, Martin H. and Miklashevsky, Alex A. and Shaki, Samuel},
  title     = {Commentary : The Developmental Trajectory of the Operational Momentum Effect},
  series = {Frontiers in Psychology},
  volume    = {9},
  journal   = {Frontiers in Psychology},
  publisher = {Frontiers Research Foundation},
  address   = {Lausanne},
  issn      = {1664-1078},
  doi       = {10.3389/fpsyg.2018.02259},
  pages     = {3},
  year      = {2018},
  language  = {en}
}
@misc{HartmannMastFischer2015,
  author    = {Hartmann, Matthias and Mast, Fred W. and Fischer, Martin H.},
  title     = {Spatial biases during mental arithmetic},
  series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  number    = {426},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-406504},
  pages     = {8},
  year      = {2015},
  abstract  = {While the influence of spatial-numerical associations in number categorization tasks has been well established, their role in mental arithmetic is less clear. It has been hypothesized that mental addition leads to rightward and upward shifts of spatial attention (along the "mental number line"), whereas subtraction leads to leftward and downward shifts. We addressed this hypothesis by analyzing spontaneous eye movements during mental arithmetic. Participants solved verbally presented arithmetic problems (e.g., 2 + 7, 8-3) aloud while looking at a blank screen. We found that eye movements reflected spatial biases in the ongoing mental operation: Gaze position shifted more upward when participants solved addition compared to subtraction problems, and the horizontal gaze position was partly determined by the magnitude of the operands. Interestingly, the difference between addition and subtraction trials was driven by the operator (plus vs. minus) but was not influenced by the computational process. Thus, our results do not support the idea of a mental movement toward the solution during arithmetic but indicate a semantic association between operation and space.},
  language  = {en}
}
@article{HartmannMastFischer2015,
  author    = {Hartmann, Matthias and Mast, Fred W. and Fischer, Martin H.},
  title     = {Spatial biases during mental arithmetic: evidence from eye movements on a blank screen},
  series = {Frontiers in psychology},
  volume    = {6},
  journal   = {Frontiers in psychology},
  publisher = {Frontiers Research Foundation},
  address   = {Lausanne},
  issn      = {1664-1078},
  doi       = {10.3389/fpsyg.2015.00012},
  pages     = {8},
  year      = {2015},
  abstract  = {While the influence of spatial-numerical associations in number categorization tasks has been well established, their role in mental arithmetic is less clear. It has been hypothesized that mental addition leads to rightward and upward shifts of spatial attention (along the "mental number line"), whereas subtraction leads to leftward and downward shifts. We addressed this hypothesis by analyzing spontaneous eye movements during mental arithmetic. Participants solved verbally presented arithmetic problems (e.g., 2 + 7, 8-3) aloud while looking at a blank screen. We found that eye movements reflected spatial biases in the ongoing mental operation: Gaze position shifted more upward when participants solved addition compared to subtraction problems, and the horizontal gaze position was partly determined by the magnitude of the operands. Interestingly, the difference between addition and subtraction trials was driven by the operator (plus vs. minus) but was not influenced by the computational process. Thus, our results do not support the idea of a mental movement toward the solution during arithmetic but indicate a semantic association between operation and space.},
  language  = {en}
}
@misc{ShakiFischer2017,
  author    = {Shaki, Samuel and Fischer, Martin H.},
  title     = {Competing Biases in Mental Arithmetic},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-103492},
  pages     = {5},
  year      = {2017},
  abstract  = {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.},
  language  = {en}
}
@article{ShakiFischer2017,
  author    = {Shaki, Samuel and Fischer, Martin H.},
  title     = {Competing Biases in Mental Arithmetic},
  series = {Frontiers in human neuroscience},
  volume    = {11},
  journal   = {Frontiers in human neuroscience},
  publisher = {Frontiers Research Foundation},
  address   = {Lausanne},
  issn      = {1662-5161},
  doi       = {10.3389/fnhum.2017.00037},
  year      = {2017},
  abstract  = {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.},
  language  = {en}
}