Distinct temporal mechanisms modulate numerosity perception

Abstract

Our ability to process numerical and temporal information is an evolutionary skill thought to originate from a common magnitude system. In line with a common magnitude system, we have previously shown that adaptation to duration alters numerosity perception. Here, we investigate two hypotheses on how duration influences numerosity perception. A channelbased hypothesis predicts that numerosity perception is influenced by adaptation of onset/offset duration channels which also encode numerosity or wire together with numerosity channels (duration/numerosity channels). Hence, the onset/offset duration of the adapter is driving the effect regardless of the total duration of adaptation. A strength-of-adaptation hypothesis predicts that the effect of duration on numerosity perception is driven by the adaptation of numerosity channels only, with the total duration of adaptation driving the effect regardless of the onset/ offset duration of the adapter. We performed two experiments where we manipulated the onset/offset duration of the adapter, the adapter's total presentation time, and the total duration of the adaptation trial. The first experiment tested the effect of adaptation to duration on numerosity discrimination, whereas the second experiment tested the effect of adaptation to numerosity and duration on numerosity discrimination. We found that the effect of adaptation to duration on numerosity perception is primarily driven by adapting duration/numerosity channels, supporting the channel-based hypothesis. In contrast, the effect of adaptation to numerosity on numerosity perception appears to be driven by the total duration of the adaptation trial, supporting the strength-of-adaptation hypothesis. Thus, we show that adaptation of at least two temporal mechanisms influences numerosity perception.

Serial dependence in time and numerosity perception is dimension-specific

“…If, on the other hand, serial dependence involves dimension-specific mechanisms, or it is specific for the task at hand, then we should expect only an effect of inducer duration on reference duration and of inducer numerosity on reference numerosity. Note that we predict a direct effect of the magnitude dimensions of the inducer on the magnitude perception of the reference – similar for instance to what has been observed in the case of adaptation ( Tsouli, Dumoulin, te Pas, & van der Smagt, 2019 ; Tsouli, van der Smagt, Dumoulin, & te Pas, 2019 )—and not an effect on the perception of the reference that is mediated by a biased perception of the inducer itself.…”

“…Previous results also support this idea. Indeed, it has been shown than duration adaptation biases the perceived numerosity of a subsequent stimulus in a repulsive fashion ( Tsouli, Dumoulin, et al, 2019 ; Tsouli, van der Smagt, et al, 2019 ). Additionally, repulsive adaptation effects across numerosity and duration also appear to be asymmetric, with an opposite pattern compared to magnitude integration, that is, duration adaptation affects perceived numerosity, but numerosity adaptation does not affect perceived time ( Tsouli, Dumoulin, et al, 2019 ).…”

“…Cross-dimensional effects in a trial history context have been observed before. For instance, perceptual adaptation (see Kohn, 2007 for a review) has been shown to generalize across time and numerosity, although this effect is asymmetric (i.e., duration adaptation affects perceived numerosity, but in the opposite direction the effect is weaker or absent; Tsouli, Dumoulin, te Pas, & Van der Smagt, 2019 ; Tsouli et al, 2019 ). If serial dependence occurs at a similar abstract level of representation, it may then similarly generalize across different dimensions.…”

The role of neural tuning in quantity perception

“…These theories are supported by neuroimaging findings showing overlapping brain activations during different quantity tasks [5,7,141] and perceptual interactions between quantity dimensions. However, overlapping brain activations do not necessarily imply a common neural code for different quantities, and recent behavioral studies examining the interaction of different quantities paint a more complex picture [78,142,143]. Furthermore, evidence from animal electrophysiology and human fMRI are not entirely consistent with the idea of a common neural mechanism Selective responses to each quantity are organized into topographic maps, that is, regions where the preferred quantity changes gradually across the cortical surface.…”

Can Implicit or Explicit Time Processing Impact Numerical Representation? Evidence From a Dual Task Paradigm

“…In contrast, there is insufficient evidence to support/reject the effect of numerosity adaptation on duration judgment. Successively, Tsouli et al (2019b), investigated how duration influences numerosity perception, and they showed that at least two temporal mechanisms are involved. Tsouli et al (2019b) found that: (i) the effect of "adaptation to duration" on numerosity perception is independent from adaptation duration (channel based hypothesis); (ii) the effect of "adaptation to numerosity" on numerosity perception is driven by the total duration of the adaptation trials (strength-of-adaptation hypothesis).…”