SNARC effects with numerical and non-numerical symbolic comparative judgments: Instructional and cultural dependencies.

Abstract

With English-language readers in an experiment requiring pairwise comparative judgments of the sizes of animals, the nature of the association between the magnitudes of the animal pairs and the left or right sides of response (i.e., the SNARC effect) was reversed depending on whether the participants had to choose either the smaller or the larger member of the pair. In contrast, such a dependence of the direction of the SNARC effect on the form of the comparative instructions was not evident for pairwise comparisons of numerical magnitude made by a similar group of participants. Furthermore, exactly the same configuration of findings was obtained for a single group of Israeli-Palestinian right-to-left reading and writing participants, except that the spatial direction of the SNARC effects for both the animal-size and number comparisons were completely reversed. In a final experiment with English readers, SNARC effects paralleling those for the animal-size comparisons were obtained for pairwise comparative judgments involving the just-learned height relations between 6 imaginary individuals. As will be discussed, such results serve to extend the generality of the SNARC effect far beyond the current modal view that it simply reflects culturally influenced, long-term learned associations between numerical magnitudes and the locations on a fixed mental number line. The implications that these results have for both the Proctor and Cho (2006) polarity correspondence view and the Gevers, Verguts, Reynvoet, Caessens, and Fias (2006) computational model of the SNARC effect will also discussed.

SNARC for numerosities is modulated by comparative instruction (and resembles some non-numerical effects)

“…The task and stimuli were designed following the procedure of Patro and Haman (2012) for comparison of non-symbolic numerosities, which closely resembled the procedure of Shaki et al (2012) for comparison of Arabic numbers. The experiment was run using the E-Prime software.…”

“…An example of such dissociation has been reported between spatial coding of Arabic numbers and animals' size (Shaki et al 2012). In this study, English (left-to-right reading)-or Hebrew-and Arabic (right-to-left reading)-speaking participants had to choose which one of the two simultaneously displayed Arabic numbers or animals is larger or smaller.…”

“…Children were presented with two sets of rectangles (plates of sweets), laterally displayed on a touch screen, and were asked to choose the set which contained either fewer sweets or more sweets. So, the general design resembled the one by Shaki et al (2012), but with different stimuli used. Nevertheless, the children's performance in this task was consistent neither with the rigid and stable SNARC pattern, such as that for comparison of Arabic numbers, nor with instruction-dependent SNARC, like the one for nonnumerical magnitudes.…”

“…The two kinds of stimuli were, however, dissociated from each other: While number-space associations appeared to be rigid and instructionally independent, the associations between nonnumerical stimuli (at least animal sizes and just-learned heights) depended on the form of the comparative instruction (i.e., to choose the smaller animal or to choose the larger animal). According to Shaki et al (2012), these results indicate that ''the directional nature of such associations seems to be an integral part of the long-term representation of numerical magnitude information but not of either the long-term or the more shorter-term representations of the two types of non-numerical magnitude information examined here (where in the latter two cases, it seems that the directional nature of such spatial information arises simply as a consequence of the directional manner in which the pair magnitude is being processed at the time),'' p. 525.…”

The discovery and comparison of symbolic magnitudes

“…More recently, SNARC-like effects have also been observed in comparison judgment tasks, but the empirical picture is quite complex. Shaki, Petrusic, and Leth-Steensen (2012) reported that (1) a typical SNARC effect is found for digit comparisons with both ''larger'' and ''smaller'' instructions, (2) a typical SNARC effect is found for animal size comparisons with a ''choose smaller'' instruction, but a reverse SNARC effect is found for a ''choose larger'' instruction; (3) a short, newly-learned height ordering behaves much like size comparisons; (4) the above pattern for English speakers (1-3) is reversed for Israeli-Palestinians who habitually read right-to-left. A rough characterization of Shaki et al's (2012) findings is that although by default small numerical magnitudes are associated with the left, for non-numerical continua this bias is overridden by a preference to place the reference point on the left (or more generally, on the side from which orderings usually begin-hence the reversal due to cultural experience).…”