Larger, smaller, odd or even? Task-specific effects of optokinetic stimulation on the mental number space

Mariagrazia Ranzini, Matteo Lisi, Elvio Blini, Marco Pitteri, Barbara Treccani, Konstantinos Priftis, Marco Zorzi

Research output: Contribution to journalArticlepeer-review


Previous studies have shown that number processing can induce spatial biases in perception and action and can trigger the orienting of visuospatial attention. Few studies, however, have investigated how spatial processing and visuospatial attention influences number processing. In the present study, we used the optokinetic stimulation (OKS) technique to trigger eye movements and thus overt orienting of visuospatial attention. Participants were asked to stare at OKS, while performing parity judgements (Experiment 1) or number comparison (Experiment 2), two numerical tasks that differ in terms of demands on magnitude processing. Numerical stimuli were acoustically presented, and participants responded orally. We examined the effects of OKS direction (leftward or rightward) on number processing. The results showed that rightward OKS abolished the classic number size effect (i.e., faster reaction times for small than large numbers) in the comparison task, whereas the parity task was unaffected by OKS direction. The effect of OKS highlights a link between visuospatial orienting and processing of number magnitude that is complementary to the more established link between numerical and visuospatial processing. We suggest that the bidirectional link between numbers and space is embodied in the mechanisms subserving sensorimotor transformations for the control of eye movements and spatial attention.

Original languageEnglish
Pages (from-to)459-470
Number of pages12
JournalJournal of Cognitive Psychology
Issue number4
Publication statusPublished - May 19 2015


  • Embodied cognition
  • Magnitude processing
  • Number processing
  • Number-space associations

ASJC Scopus subject areas

  • Arts and Humanities (miscellaneous)
  • Experimental and Cognitive Psychology


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