A Picture Is Worth… Both Spelling and Sound

Testing for canonical form orientation in speech tempo perception

We report on two experiments that aimed to test the hypothesis that English listeners orient to full pronunciation forms-"canonical forms"-in judging the tempo of speech that features deletions. If listeners orient to canonical forms, this should mean that the perceived tempo of speech containing deletions is highly relative to the speech's articulation rate calculated on the basis of surface phone strings. We used controlled stimuli to test this hypothesis. We created sentences with one ambiguous word form (for example, support~sport), to give half of the listeners an orthographic form that includes support and the other half an otherwise identical orthographic form with sport. In both experiments, listeners judged the tempo of the sentences, which allowed us to assess whether the difference in imposed interpretation had an impact on perceived tempo. Experiment 1 used a tempo rating task in which listeners evaluated the tempo of experimental stimuli relative to comparison stimuli, on a continuous scale. Experiment 2 used a tempo comparison task in which listeners judged whether second members of stimulus pairs were slower or faster than first members. Both experiments revealed the predicted effect of the imposed word interpretation: sentences with an imposed "schwa" interpretation for the ambiguous word form were judged faster than (the same) sentences with an imposed "no schwa" interpretation. However, in both experiments the effect was small and variables related to the experimental design had significant effects on responses. We discuss the results' implications for our understanding of speech tempo perception.

Measuring the influence of phonological neighborhood on visual word recognition with the N400: Evidence for semantic scaffolding

Research in visual word recognition has shown that phonological neighborhood density facilitates visual word recognition. The current research was designed to determine the electrophysiological effect of phonological neighborhood density (PND). In two experiments, participants made lexical decisions to words varying on phonological neighborhood while Event-related Potentials (ERPs) were recorded. Behaviorally, the results replicate previous research by showing that words with many phonological neighbors were responded to more rapidly than were words with few phonological neighbors. However, the main contribution of the current research is that it shows an effect of PND on the N400 and Late Positive Component Event-Related Potentials. In contrast to previous reports in the literature, the nature of the effect was such that the N400 was larger to words with few phonological neighbors than to words with many. Experiment 2 replicated these findings and provided estimates of the independent components' time course and source localization. The increased N400 for small neighborhood words is thought to reflect additional semantic processing required for these words due their weaker phonological representations.