The perception of number from the separability of the stimulus: The Stroop effect revisited

Abstract

The literature on numerical perception is reviewed from the standpoint of research on selective attention, and predictions are made concerning the dimensional interaction between physical and numerical size of numerals. We manipulated stimulus differences to make the classification of numerical value slightly better (Experiment 1), substantially better (Experiment 2), or worse (Experiments 3---4) than classification of physical size. Garner, Stroop, and redundancy effects were used to gauge the degree of interactive processing. For nearly matched discriminability, both number and size appeared separable when the dimensions were varied orthogonally, but showed Stroop interference and redundancy gain when the dimensions were varied in a correlative fashion. When mismatched, asymmetric Garner and Stroop effects emerged in orthogonal contexts along with Stroop and redundancy gains in correlative contexts. These findings define a unique relation: Numerical value and physical size were optionally separable dimensions. We conclude that a magnitude representation is not mandatory for the perception of numerals. Our conclusions offer a new perspective for understanding both numerical perception and the Stroop phenomenon itself.Seldom do we appreciate the paramount importance of numbers in our cognitive milieu. A number stands for our height, another for our IQ, a third indicates the balance in our checking account, a fourth our telephoneand the list is virtually inexhaustible. The ease with which we use numbers masks the fact that complex cognitive processes are required for the mere recognition of numerical stimuli or the execution of the simplest numerical comparisons and calculations. Tapping those processes poses a challenge for students of numerical cognition. In the present study we propose to use selective attention as a tool to uncover the nature of numerical perception. Simultaneously, we will use the results to reflect on models of selective attention itself. The classic measure of selective attention (indeed, its failure), of course, is that based on the seminal work of Stroop (1935), and Strooplike effects have been reported for numerical dimensions. However, recent research has shown Stroop interference to be malleable, its presence depending on several heretofore neglected experimental factors. Therefore, despite a substantial amount of empirical study, we still lack a wide theoretical understanding of the Stroop effect, and we have notoriously little insight into processes of'numerical cognition.This research was supported by Israel Science Foundation Grant 58-93 to D.A. We thank Helena Kadlec, Robert Melara, Michael Masson, and Lawrence Marks for many insightful comments that improved the manuscript. Bob Melara inspired D.A.'s interest in selective attention when they both enjoyed the hospitality and scholarship of Larry Marks in the Pierce Laboratory at Yale University. We appreciate their continuing interest and support. Thanks are also due to Yoav Arieh, Joseph Glickson, and Lilach Shalev for detailed ...

Are numbers special? An overview of chronometric, neuroimaging, developmental and comparative studies of magnitude representation

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Garner interference reveals dependencies between emotional expression and gaze in face perception.

“…The issue of discriminability is critical to the Garner paradigm because differences in baseline discriminability can cause asymmetries in Garner interference between the two tasks (Algom et al, 1996). According to a speed-of-processing account (e.g., Atkinson et al, 2005;Schweinberger et al, 1999), mismatches in discriminability would cause asymmetric interference patterns because the more discriminable dimension (i.e., emotional facial expressions) is computed before the less discriminable dimension (i.e., gaze direction) has been fully processed.…”

“…For example, in Ganel et al (2005) Experiments 1 and 2, an overall reaction time advantage was observed for gaze judgments over emotion judgments, a finding that is indicative of differences in the discriminability of the two dimensions and that suggests that gaze is being processed more quickly than facial emotion (Algom et al, 1996). Baseline discriminability should be matched in the Garner paradigm; otherwise, differences in discriminability can give rise to asymmetries wherein the less discriminable dimension (in this case, emotion) may be affected more by the more discriminable dimension (gaze).…”

“…Overall, reaction times were slower for emotion judgments, suggesting that emotion was less discriminable than gaze (Algom, Dekel, & Pansky, 1996). They found Garner interference in both the gaze and emotion task as manifested by longer reaction times in the orthogonal condition relative to the control condition for both types of judgments.…”

Semantic processing of Arabic, Kanji, and Kana numbers: Evidence from interference in physical and numerical size judgments

“…The disappearance of the semantic process might be attributable to a lower level processing of Kana numbers (see General Discussion). In the indirect task, Kana numbers might be processed as visual objects (Algom, Dekel, & Pansky, 1996;Pansky & Algom, 2002). Otherwise, Kana numbers processing might end at the phonological level (Brysbaert, 2001;Fias, 2001;Fias, Reynvoet, & Brysbaert, 2001).…”