Nonlinear spelling in graphemic buffer deficit

ABSTRACT

In this paper, we describe a case of nonlinear spelling and its implications for theories of the graphemic buffer. C.T.J., an individual with an acquired deficit of the graphemic buffer, often wrote the letters of his responses in a nonlinear temporal order when writing to dictation. The spatial ordering of the letters was maintained: Letters in the later positions of the words were written towards the right side of the response, even when written before letters in earlier positions. This unusual phenomenon has been briefly reported in three prior cases but this study provides the most detailed analysis of the phenomenon to date. We specifically contend that the decoupling of the temporal and spatial aspects of spelling is difficult to reconcile with competitive queuing accounts of the graphemic buffer.

KEYWORDS:

• Spelling
• graphemic buffer
• written spelling
• acquired dysgraphia
• competitive queuing

Acknowledgements

We are grateful to Gabriele Miceli for alerting us to other cases of nonlinear spelling. We thank two anonymous reviewers and the editor, Brenda Rapp, for helpful comments on the first draft of this paper.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Teresa Schubert http://orcid.org/0000-0002-1627-3893

Lyndsey Nickels http://orcid.org/0000-0002-0311-3524

Notes

1 On one theory, an impairment that affects nonword repetition and spelling would be localized to the phonological buffer (Caramazza, Miceli, & Villa, 1986) and would affect all tasks with auditory input (e.g., minimal pair discrimination, word repetition, word spelling to dictation; nonword tasks perhaps more severely affected). On the second theory, the deficit would be localized to acoustic to phonological conversion (Kay, Lesser, & Coltheart, 1996), which would only affect nonword auditory input. C.T.J.’s performance across a number of input tasks is mixed (e.g., Nickels & Howard, 1999) and does not clearly differentiate between the theories. As C.T.J.’s repetition of the current spelling to dictation word list is quite good, we focus on this performance and avoid drawing a precise conclusion about an additional nonword repetition/spelling deficit.

2 C.T.J. often wrote the initial letter of an item in upper case and then continued in lower case (e.g., Meck for “meek”). If we treat these items as same case on the grounds that these are an acceptable standard response format (e.g., De Bastiani & Barry, 1989; Hanley & Peters, 1996), the distribution across response modes remains equivalent.

3 The V-metric is defined as the depth of the serial position curve minus the asymmetry of the curve, divided by a constant, and depends on the accuracies at the normalized positions A, C, & E. A score of 1 indicates a perfect V-shape, and a score of 0 indicates a flat curve. See Goldberg and Rapp (2008) for more details.

4 Another limitation of current competitive queuing models is that they cannot simulate letter perseveration errors, which are present in many individuals with graphemic buffer deficit and suggest that a letter’s activation persists after its production (Fischer-Baum, McCloskey, & Rapp, 2010).

Additional information

Funding

The first author was supported by the Australian Research Council Centre of Excellence for Cognition and its Disorders (www.ccd.edu.au) [grant number CE110001021]. The second author was supported by an Australian Research Council Future Fellowship [grant number FT120100102].