@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} } @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} } @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} } @article{FelisattiLaubrockShakietal.2020, author = {Felisatti, Arianna and Laubrock, Jochen and Shaki, Samuel and Fischer, Martin H.}, title = {A biological foundation for spatial-numerical associations}, series = {Annals of the New York Academy of Sciences}, volume = {1477}, journal = {Annals of the New York Academy of Sciences}, number = {1}, publisher = {Wiley}, address = {Hoboken}, issn = {0077-8923}, doi = {10.1111/nyas.14418}, pages = {44 -- 53}, year = {2020}, abstract = {"Left" and "right" coordinates control our spatial behavior and even influence abstract thoughts. For number concepts, horizontal spatial-numerical associations (SNAs) have been widely documented: we associate few with left and many with right. Importantly, increments are universally coded on the right side even in preverbal humans and nonhuman animals, thus questioning the fundamental role of directional cultural habits, such as reading or finger counting. Here, we propose a biological, nonnumerical mechanism for the origin of SNAs on the basis of asymmetric tuning of animal brains for different spatial frequencies (SFs). The resulting selective visual processing predicts both universal SNAs and their context-dependence. We support our proposal by analyzing the stimuli used to document SNAs in newborns for their SF content. As predicted, the SFs contained in visual patterns with few versus many elements preferentially engage right versus left brain hemispheres, respectively, thus predicting left-versus rightward behavioral biases. Our "brain's asymmetric frequency tuning" hypothesis explains the perceptual origin of horizontal SNAs for nonsymbolic visual numerosities and might be extensible to the auditory domain.}, language = {en} }