Implicit and Explicit Number-Space Associations Differentially Relate to Interference Control in Young Adults With ADHD

Abstract

Behavioral evidence for the link between numerical and spatial representations comes from the spatial-numerical association of response codes (SNARC) effect, consisting in faster reaction times to small/large numbers with the left/right hand respectively. The SNARC effect is, however, characterized by considerable intra- and inter-individual variability. It depends not only on the explicit or implicit nature of the numerical task, but also relates to interference control. To determine whether the prevalence of the latter relation in the elderly could be ascribed to younger individuals’ ceiling performances on executive control tasks, we determined whether the SNARC effect related to Stroop and/or Flanker effects in 26 young adults with ADHD. We observed a divergent pattern of correlation depending on the type of numerical task used to assess the SNARC effect and the type of interference control measure involved in number-space associations. Namely, stronger number-space associations during parity judgments involving implicit magnitude processing related to weaker interference control in the Stroop but not Flanker task. Conversely, stronger number-space associations during explicit magnitude classifications tended to be associated with better interference control in the Flanker but not Stroop paradigm. The association of stronger parity and magnitude SNARC effects with weaker and better interference control respectively indicates that different mechanisms underlie these relations. Activation of the magnitude-associated spatial code is irrelevant and potentially interferes with parity judgments, but in contrast assists explicit magnitude classifications. Altogether, the present study confirms the contribution of interference control to number-space associations also in young adults. It suggests that magnitude-associated spatial codes in implicit and explicit tasks are monitored by different interference control mechanisms, thereby explaining task-related intra-individual differences in number-space associations.

The influence of semantic processing and response latency on the SNARC effect

“…The relationship between the slope distributions of the different tasks were further investigated with Pearson's correlation coefficient (Table 3 and Figure 3). In line with previous studies (ρ = 0.08 in Georges, Hoffmann, & Schiltz, 2017 and ρ = 0.2 in Georges, Hoffmann, & Schiltz, 2018), the magnitude classification and the parity judgement tasks did not correlate. The only significant positive correlation emerged between the magnitude classification and phoneme detection tasks.…”

The SNARC and MARC effects measured online: Large-scale assessment methods in flexible cognitive effects

“…Here we decided to use a fixed block order, because we mainly aimed to investigate individual differences in the SNARC and the effects in small yet theoretically important subgroups (e.g., left-handers or individuals with dyscalculia). Keeping the block order fixed across participants had also been adopted in other studies investigating individual differences in the SNARC (e.g., Georges, Hoffmann, & Schiltz, 2018).…”

The role of cognitive control in the SNARC effect: A review

“…As shown in Figure 2, in the conflict stage, there is implicit conflict when S–R mapping is incongruent (Georges et al, 2018; Gevers, Ratinckx, et al, 2006; Schroeder et al, 2016; Toomarian et al, 2019; Zhao et al, 2015), and the resolution of this implicit conflict requires the involvement of cognitive control. In other words, the appearance of the SNARC effect is related to the level of cognitive control involved in resolving S–R mapping conflict.…”

“…Different types of interference inhibition appear to have different effects on the size of the SNARC effect. For example, Georges et al (2018) asked participants to perform a parity judgment task, magnitude comparison task, a flanker task in which participants were asked to respond to the central target while inhibiting the distraction of flankers (Eriksen, 1995; Sanders & Lamers, 2002; Xie et al, 2017), and a Stroop task in which participants judged the print color (e.g., red) of a color word (e.g., green; MacLeod, 1991; Stroop, 1935). The SNARC effect in the parity judgment task was found to be negatively correlated to performance in Stroop interference control but not in flanker interference control.…”

“…In contrast, the SNARC effect in the magnitude comparison task was positively correlated with performance in flanker interference control but not Stroop interference control. Georges et al (2018) suggested that the spatial coding of the SNARC effect in the parity judgment task is affected by the semantic or verbal‐related inhibition control process rather than by spatial‐related interference control in the flanker task. In the magnitude comparison task, the positive correlation between the SNARC effect and flanker interference control might be due to the close connection between numerical‐spatial processing (i.e., in the magnitude comparison task) and spatial visualization (i.e., in the flanker task) under the shared function of the right parietal cortex (Lamm et al, 1999).…”