SNARC (spatial–numerical association of response codes) meets SPARC (spatial–pitch association of response codes): Automaticity and interdependency in compatibility effects

Abstract

Concepts, including the mental number line, or addressing pitch as high and low, suggest that the spatial–numerical and spatial–pitch association of response codes (SNARC and SPARC) effects are domain-specific and thus independent. Alternatively, there may be dependencies between these effects, because they share common automatic or controlled decision mechanisms. In two experiments, participants were presented with spoken numbers in different pitches; their numerical value, pitch, and response compatibility were varied systematically. This allowed us to study SNARC and SPARC effects in a factorial design (see also Fischer, Riello, Giordano, & Rusconi, 2013). Participants judged the stimuli on numerical magnitude, pitch, or parity (odd–even). In all tasks, the SNARC and SPARC effects had superadditive interactions. These were interpreted as both effects sharing a common mechanism. The task variation probes the mechanism: In the magnitude judgement task, numerical magnitude was explicit, whereas pitch was implicit; in the pitch judgement task, it was vice versa. In the parity judgement task, both dimensions were implicit. Regardless of whether they were implicit or explicit, both SNARC and SPARC effects occurred in all tasks. We concluded that by not requiring focal attention the common mechanism operates automatically.

Keywords:

• Stimulus–response compatibility
• Numerical magnitude
• Pitch height
• Spatial representation
• Parity judgement

Notes

¹In this respect, a potentially important omission has been a fourth divergence from the design of Fischer et al. (2013). Our studies leave out the reference stimulus in both the magnitude judgement and pitch judgement tasks. In Cho et al. (2012), presence of the reference tone was responsible for the appearance of the effect in task-irrelevant conditions. Our experiments, however, predate this result. Moreover, we believe that the other factors listed here are at least as important for generating implicit effects.