Cognitive style influences number-space associations

Evidence for number-space associations comes from the spatial-numerical association of response-codes (SNARC) effect, consisting in faster reaction times to small/large digits with the left/right hand respectively. The cognitive processes underlying the SNARC effect are suggested to be task-dependent, such that number-space interactions result from verbal-spatial and visual-spatial number coding in parity and magnitude judgment tasks respectively (van Dijck et al., 2009). Moreover, the SNARC effect is characterized by high inter-individual variability (Hoffmann et al., 2014). Here we aimed to determine whether differences between the cognitive styles of individuals could influence the SNARC effect in a parity and magnitude judgment task.

To distinguish between verbal and visual cognitive styles and between object- and spatial-visualizers, participants (n=74, 36 females, mean age=23.45 years) completed a modified version of Kirby et al.’s (1988) Verbalizer-Visualizer Questionnaire (VVQ, as in Mendelson & Thorson, 2004) and the Object-Spatial Imagery Questionnaire (OSIQ, Blajenkova et al., 2006, purchased from MM Virtual Design, LLC) respectively. Each item was placed on a five-point rating scale between strongly agree and strongly disagree, allowing us to compute verbal, visual, object and spatial scores for each participant. Participants that featured visual/verbal and spatial/object score ratios that were either both below or above the respective median ratio (visual/verbal ratio: M=1.09; spatial/object ratio: M=0.87) were classified as verbalizers (n=25, 16 females) and spatial-visualizers (n=25, 10 females) respectively. Participants subsequently performed the classical parity and magnitude judgment tasks.

In verbalizers, the SNARC effect was significantly negative in the parity (slope=-11.2, p=0.001), but not the magnitude judgment task (slope=-1.2, p=0.53). Their verbal cognitive style might thus have induced a strong number-space association in tasks that supposedly draw on these cognitive processes, while it prevented spatial-numerical interactions in tasks that activate visuo-spatial number coding. Conversely, spatial-visualizers featured a significantly negative magnitude SNARC effect (slope=-4.8, p=0.04), indicating that a visuo-spatial style is not only necessary but sufficient to generate a number-space association in tasks that favour visuo-spatial number coding. Interestingly, they also manifested a significantly negative parity SNARC effect (slope=-9.9, p<0.001). It is likely that the spatial-visualizers switched strategy for the parity judgment task and - despite their visuo-spatial preferences - adopted the better-suited verbal strategy. Indeed, in contrast to verbalizers, their parity and magnitude SNARC effects did not correlate (spatial-visualizers: r=0.14, p=0.5; verbalizers: r=0.4, p=0.05). All in all, differences in cognitive styles might provide an additional explanation for the high inter-individual variability of the SNARC effect. Moreover, we provided further evidence for the verbal-spatial and visuo-spatial nature of the parity and magnitude SNARC effects respectively.