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Research Article

Parts, Wholes, and Context in Reading: A Triple Dissociation

  • Denis G. Pelli mail,

    To whom correspondence should be addressed. E-mail: denis.pelli@nyu.edu

    Affiliation: Psychology and Neural Science, New York University, New York, New York, United States of America

    X
  • Katharine A. Tillman

    Affiliation: Psychology and Neural Science, New York University, New York, New York, United States of America

    X
  • Published: August 01, 2007
  • DOI: 10.1371/journal.pone.0000680

Reader Comments (10)

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Mapping word identity and word shape on a single continuum

Posted by Potsdam_EM_Group on 28 Sep 2007 at 22:07 GMT

The authors offered a wonderfully clear operational definition of word shape. Letter substitutes were determined by ensuring that substitutes were indistinguishable from the original letters when viewed at 10° eccentricity in the visual periphery. During the experiment, however, these words were presented in the fovea, where word shape equals word identity. Would it be interesting to map out a single continuum between word shape and word identity (by using different eccentricities), to estimate the contribution of word shape in the fovea? In addition, in the L-knockout condition, there may be interference of irrelevant information on word identification processes. We wonder whether it would be interesting to knockout L by removing high spatial-frequency content of words (e.g., by blurring them) instead of substituting single letters? It would also be interesting to know whether participants were tempted to use the strategy of defocussing or reading in the periphery (contrary to the instruction) in the L-knockout condition.


RE: Mapping word identity and word shape on a single continuum

DenisPelli replied to Potsdam_EM_Group on 26 Oct 2007 at 17:14 GMT

Thank you.

“Would it be interesting to map out a single continuum between word shape and word identity (by using different eccentricities), to estimate the contribution of word shape in the fovea?”
Good question. We’ve been very interested the effects of crowding and eccentricity on reading. Our paper on this (Pelli et al., 2007) will be appearing any day now in the Journal of Vision special issue on “Crowding”. [References below.]

“In addition, in the L-knockout condition, there may be interference of irrelevant information on word identification processes….”
Yes, it is true that by substituting letters, we not only took away information, but gave wrong information. This issue is hard to solve. We think you are suggesting that low-pass filtering would knock out L and spare W. Given the strong evidence that letters are identified and words are read by means of a single spatial frequency channel (Majaj et al., 2002; Majaj et al., 2003), your suggestion of blurring would be equivalent to simply reducing contrast, and thus unlikely to distinguish the L and W processes. A better control might be to use substitutes that are similar to English letters but are unfamiliar to English-reading participants.

“It would also be interesting to know whether participants were tempted to use the strategy of defocussing or reading in the periphery (contrary to the instruction) in the L-knockout condition.”
None of our observers have reported using such a strategy.

Denis Pelli & Katharine Tillman
http://psych.nyu.edu/pell...

References

Majaj, N. J., Pelli, D. G., Kurshan, P., & Palomares, M. (2002) The role of spatial frequency channels in letter identification. Vision Research, 42, 1165-1184.

Majaj, N. J., Liang, A., Martelli, M., Berger, T. D., & Pelli, D. G. (2003) The channel for reading. Vision Sciences Society, Sarasota, Florida, May 2003. http://psych.nyu.edu/pell...

Pelli, D. G., Tillman, K. A., Freeman, J., Su, M., Berger, T. D., & Majaj, N. J. (2007) Crowding and eccentricity determine reading rate. Journal of Vision. In press.
http://journalofvision.co...