Letter string processing and visual short-term memory

Abstract

The present study investigated whether expertise with letter string processing influences visual short-term memory capacity. Specifically, we examined whether performance in a change-detection task would vary as a function of stimulus type (letters vs. symbols) and type of display (horizontal, vertical, and circular). Participants were asked to detect a one-character change in a briefly presented character array following a delay of 900 ms. Concurrent articulation was used to limit effects of rehearsal. Type of display significantly affected performance with letters, but not with symbols, with a selective increase in change-detection accuracy for horizontally presented letter arrays compared with vertical and circular arrays. These findings confirm the standard limits of storage in visual short-term memory, but critically reveal a selective advantage for letter arrays over symbol arrays when presented horizontally. Such an advantage is probably due to the utilization of a specialized encoding mechanism built up over years of reading experience.

Keywords:

• Letter string processing
• Visual short-term memory
• Expertise

Acknowledgments

This research was supported by European Research Council (ERC) Grant 230313. The authors thank the Quarterly Journal of Experimental Psychology (QJEP) associate editor M. Traxler, C. Whitney, and an anonymous reviewer for their valuable comments on an earlier version of this work.