UBC Theses and Dissertations
The role of low spatial-frequencies in lexical decision and word naming : a masked priming study Boden, Catherine
Does word reading depend more on high or low spatial-frequency information? Although word recognition is often thought by lay people to be a fine detail task, alternative perspectives have been proposed in which the low spatial-frequency information contained in the global word form is processed more quickly than the details. Low spatial-frequencies may merely facilitate word recognition or may be sufficient for a rapid lexical decision (Is that a word?). The premise that low spatial-frequencies are sufficient for facilitating and/or making lexical decisions was examined in the present study. Letter strings were filtered with 3 types of spatial-frequency filter (low pass, high-pass, medium spatial-frequency notch) and unfiltered control. Proficient readers made lexical decisions under unprimed and masked primed conditions. In the unprimed condition, a filtered target was presented for 105 or 400 ms followed, after a 30 ms interstimulus interval (ISI), by a pattern mask. In the masked priming condition, a forward mask was presented for 150 ms, followed 30 ms later by the filtered prime, which was then followed by an unfiltered target after a 30 ms ISI. Naming and lexical decision tasks were completed for the masked priming condition. Sensitivity (d') in the unprimed condition was lowest for the low-pass targets at both ISIs. Both low- and high-pass filtered words (< 3.5 cpd and > 4.6 cpd respectively) produced significant priming effects in the lexical decision task. Low-pass words, however, were not sufficient to facilitate a naming response. In contrast, high-pass words were sufficient to prime a naming response. The data do not support a unique role for low spatial-frequencies in either making a rapid lexical decision or in facilitating lexical decision or naming. The data do suggest that the medium and high spatial-frequencies may be important to lexical decision and naming.
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