PubMed HealthSearch

Biomedical subjects

M Radeau

Publications and source records attributed to M Radeau.

9 recordsLinked to original sources

The time course of Braille word recognition.

Skilled blind readers read French nouns with the uniqueness point in different locations, presented in unabbreviated braille, and either pronounced each item (Experiment 1) or classified it as to gender (Experiments 1-3). As in previous studies with spoken words, effects of uniqueness point location on recognition reaction time were taken as demonstrating on-line lexical access. For braille words, significant effects were obtained in Experiment 1 in the two tasks. In Experiment 2, blind Ss demonstrated comparable relative uniqueness point effects for gender classification of braille and of spoken words, showing that on-line lexical access is not specific to speech. Experiment 3 showed that the effect of uniqueness point location is limited to the higher frequency words. Finally, mean finger scanning speed did not differ between the pre- and post-uniqueness point regions of the words.

Adult

The effect of the uniqueness point in spoken-word recognition.

The study examines the possibility of observing on-line recognition of spoken words through manipulations of the location of the uniqueness point (UP) in a gender-classification task. The subjects were presented with spoken French nouns and had to indicate by a key-press response whether each was feminine or masculine. RTs measured from word onset were significantly correlated with UP location, a finding that supports the notion of online processing. The effect of UP location is, however, smaller than that predicted by the original cohort theory (that recognition occurs exactly at the UP). On the other hand, it is stronger when words with respectively early and late UPs are presented in homogeneous blocks rather than in mixed order. It is proposed that the results can be accounted for by the notion of a sub-optimal lexical strategy in which some monitoring of the phonetic data continues past the UP.

Adult

Phonological priming in spoken word recognition: task effects.

In two experiments, we examined the role of phonological relatedness between spoken items using both the lexical decision task and the shadowing task. In Experiment 1, words were used as primes and overlaps of zero (control), one, two, or all four or five (repetition) phonemes were compared. Except for the repetition conditions, in which facilitation was found, phonological overlap resulted in interference on word responses. These effects occurred in both tasks but were larger in lexical decision than in shadowing. The effects that were evident in shadowing can be attributed to an attentional mechanism linked to the subjects' expectancies of repetitions. The extra effects obtained in lexical decision can be interpreted by taking into account both activation of the response corresponding to the prime's lexical status and postlexical processes that check for phonological congruency between prime and target. In Experiment 2, some modifications were introduced to prevent the involvement of strategic factors, and pseudowords were used as primes. No effect at all was observed in shadowing, whereas in lexical decision interference effects occurred, which is consistent with the hypothesis that lexical decision may be negatively affected by finding a phonological discrepancy at the same time as the primed response is reactivated. Neither experiment provided evidence for the occurrence of phonological priming in the perceptual processing of words.

Adult

Signal intensity, task context, and auditory-visual interactions.

A study is reported of the effect of signal intensity on immediate cross-modal bias between vision and audition. Each signal was presented at high or low intensity, giving rise to four conditions. The study also dealt with the effectiveness of instructions and task context in directing attention. Two kinds of task (pointing) contexts were compared: a constant or unimodal context in which the modality of the target signal was the same throughout a session, and a bimodal one in which it changed from trial to trial. In both conditions subjects were instructed that the signals might come from the same or from different positions, depending on the trial. For visual bias of audition the results show that a signal with high intensity was more biasing and less biased than one with low intensity. Auditory bias of vision did not reach significance in any of the four intensity conditions. Type of task context had no effect on the extent of bias, suggesting that a constant-task (unimodal) context was no more effective in directing attention than instructions alone.

Acoustic Stimulation