It has been suggested that the human ability to process number and time both rely on common magnitude mechanisms, yet for time this commonality has mainly been investigated in the sub-second rather than longer time ranges. Here we examined whether number processing is associated with timing in time ranges greater than a second. Specifically, we tested long duration estimation abilities in adults with a developmental impairment in numerical processing (dyscalculia), reasoning that any such timing impairment co-occurring with dyscalculia may be consistent with joint mechanisms for time estimation and number processing. Dyscalculics and age-matched controls were tested on supra-second temporal estimation (12 s), a difficulty-matched non-temporal control task, as well as mathematical abilities. Consistent with our hypothesis, dyscalculics were significantly impaired in supra-second duration estimation but not in the control task. Furthermore, supra-second timing ability positively correlated with mathematical proficiency. All participants reported that they used counting to estimate time, although no specific instructions were given with respect to counting. These results suggest that numerical processing and supra-second temporal estimation share common mechanisms. However, since this conclusion is also based on subjective observations, further work needs to be done to determine whether mathematical impairment co-occurs with supra-second time estimation impairment when counting is not involved in and is objectively controlled for during supra-second timing. We hypothesize that counting, that does not develop normally in dyscalculics, might underlie and adversely affect dyscalculics' supra-second time estimation performance, rather than an impairment of a magnitude mechanism or the internal clock pacemaker.
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© 2014 Copyright 2014 Gilaie-Dotan et al.
- chronometric counting
- time discrimination
- time estimation