Does the brain regularize digits and letters to the same extent?

Abstract

The cognitive system does not just act as a mirror from the sensory input; instead, it tends to normalize this information. Given that letter processing seems to be much more specialized than digit processing in the cortex, we examined whether the regularization process occurs differently from digits to letters than from letters to digits: We employed a masked priming same/different experiment (e.g., probe, VESZED; prime, V35Z3D ; and target, VESZED). When embedded in letter strings, digits that resemble letters (e.g., 3 and 5 in V35Z3D -VESZED) tend to be encoded in a letter-like manner, whereas when embedded in digit strings, letters that resemble digits (e.g., E and S in 9ES7E2–935732) tend not to be encoded in a digit-like manner.

Keywords:

• Word recognition
• Priming
• Letter processing

Acknowledgments

The research reported in this article has been partially supported by Grants CONSOLIDER-INGENIO2010_CSD2008–00048, SEJ2006–09238/PSIC, and PSI2008–04069/PSIC from the Spanish Ministry of Science and Innovation and Grants 1R01HD057153–01 and HD26765 from the National Institute of Health. Jon Andoni Duñabeitia was the recipient of a postgraduate grant from the Basque Government. We thank Simon Liversedge, Richard Shillcock, and an anonymous reviewer for helpful comments on an earlier version of this paper.

Notes

¹ Although the inferior parietal cortex plays a key role in the sense of quantity (see Piazza, Izard, Pinel, LeBihan, & Dehaene, 2004), this may have little to do with the early stages of digit form processing.