Dissecting the symbolic distance effect: Comparison and priming effects in numerical and nonnumerical orders

Abstract

When participants are asked to compare two stimuli, responses are slower for stimuli close to each other on the relevant dimension than for stimuli further apart. Previously, it has been proposed that this comparison distance effect originates from overlap in the representation of the stimuli. This idea is generally accepted in numerical cognition, where it is assumed that representational overlap of numbers on a mental number line accounts for the effect (e.g., Cohen Kadosh et al., 2005). In contrast, others have emphasized the role of response-related processes to explain the comparison distance effect (e.g., Banks, 1977). In the present study, numbers and letters are used to show that the comparison distance effect can be dissociated from a more direct behavioral signature of representational overlap, the priming distance effect. The implication is that a comparison distance effect does not imply representational overlap. An interpretation is given in terms of a recently proposed model of quantity comparison (Verguts, Fias, & Stevens, 2005).

A critical reexamination of doing arithmetic nonconsciously

“…For symbolic primes and targets (e.g., Arabic numbers), it is commonly found that as numerical prime-target distance increases, priming effects decrease in a V-shaped manner (Reynvoet, Brysbaert, & Fias, 2002;Roggeman, Verguts, & Fias, 2007). This wellestablished feature of numerosity priming is generally explained by representational overlap between the prime and the target (Van Opstal, Gevers, De Moor, & Verguts, 2008). Thus, if the data reported in Sklar et al (2012) involve genuine number processing, one should observe a V-shaped priming function for prime-target distances.…”

Number Compasison and Number Line Estimation Rely on Different Mechanisms

“…This finding might be explained by either an even more compressed number line, or alternatively, the SE might be originated by alternative mechanisms. For instance, on the basis of connectionist modelling, Verguts and colleagues (Verguts et al, 2005;Van Opstal, Gevers, De Moor, & Verguts, 2008) demonstrated that the SE can be explained by decisional processes in comparison. They showed that representational overlap is not a necessary condition for this effect to emerge.…”

Beyond magnitude: Judging ordinality of symbolic number is unrelated to magnitude comparison and independently relates to individual differences in arithmetic

“…Additionally, distance effects have also been observed with the use of nonnumerical ordered symbols, such as letters (Jou & Aldridge, 1999;Van Opstal, Gevers, De Moor, & Verguts, 2008). For example, Van Opstal and colleagues (2008) showed that the NDE could be obtained with letters, which have no magnitude associations.…”

“…Therefore the NDE, which can be obtained with non-numerical symbol stimuli, is not necessarily indicative of overlapping representations of numerical magnitude. Thus, it has been suggested that some distance effects arise from processes related to the decision process and the resolution of response alternatives, rather than arising from overlapping representations of cardinal numbers (Van Opstal et al, 2008). This is also important to bear in mind when interpreting the correlations with math performance.…”