Contextual effects on the perception of duration

Abstract In the experiments reported here, listeners categorized and discriminated speech and non-speech analogue stimuli in which the durations of a vowel and a following consonant or their analogues were varied orthogonally. The listeners' native languages differed in how these durations covary in speakers' productions of such sequences. Because auditorist and autonomous models of speech perception hypothesize that the auditory qualities evoked by both kinds of stimuli determine their initial perceptual evaluation, they both predict that listeners from all the languages will respond similarly to non-speech analogues as they do to speech in both tasks. Because neither direct realist nor interactive models hypothesize such a processing stage, they predict instead that in the way in which vowel and consonant duration covary in the listeners' native languages will determine how they categorize and discriminate the speech stimuli, and that all listeners will categorize and discriminate the non-speech differently from the speech stimuli. Listeners' categorization of the speech stimuli did differ as a function of how these durations covary in their native languages, but all listeners discriminated the speech stimuli in the same way, and they all categorized and discriminated the non-speech stimuli in the same way, too. These similarities could arise from listeners adding the durations of the vowel and consonant intervals (or their analogues) in these tasks with these stimuli; they do so when linguistic experience does not influence them to perceive these durations otherwise. These results support an autonomous rather than interactive model in which listeners either add or apply their linguistic experience at a post-perceptual stage of processing. They do not however support an auditorist over a direct realist model because they provide no evidence that the signal's acoustic properties are transformed during the hypothesized prior perceptual stage.

How visual cues to speech rate influence speech perception

Spoken words are highly variable and therefore listeners interpret speech sounds relative to the surrounding acoustic context, such as the speech rate of a preceding sentence. For instance, a vowel midway between short /ɑ/ and long /a:/ in Dutch is perceived as short /ɑ/ in the context of preceding slow speech, but as long /a:/ if preceded by a fast context. Despite the well-established influence of visual articulatory cues on speech comprehension, it remains unclear whether visual cues to speech rate also influence subsequent spoken word recognition. In two ‘Go Fish’-like experiments, participants were presented with audio-only (auditory speech + fixation cross), visual-only (mute videos of talking head), and audiovisual (speech + videos) context sentences, followed by ambiguous target words containing vowels midway between short /ɑ/ and long /a:/. In Experiment 1, target words were always presented auditorily, without visual articulatory cues. Although the audio-only and audiovisual contexts induced a rate effect (i.e., more long /a:/ responses after fast contexts), the visual-only condition did not. When, in Experiment 2, target words were presented audiovisually, rate effects were observed in all three conditions, including visual-only. This suggests that visual cues to speech rate in a context sentence influence the perception of following visual target cues (e.g., duration of lip aperture), which at an audiovisual integration stage bias participants’ target categorization responses. These findings contribute to a better understanding of how what we see influences what we hear

Testing the limits of contextual constraint: interactions with word frequency and parafoveal preview during fluent reading

Contextual constraint is a key factor affecting a word's fixation duration and its likelihood of being fixated during reading. Previous research has generally demonstrated additive effects of predictability and frequency in fixation times. Studies examining the role of parafoveal preview have shown that greater preview benefit is obtained from more predictable and higher frequency words versus less predictable and lower frequency words. In two experiments, we investigated effects of target word predictability, frequency, and parafoveal preview. A 3 (Predictability: low, medium, high) × 2 (Frequency: low, high) design was used with Preview (valid, invalid) manipulated between experiments. With valid previews, we found main effects of Predictability and Frequency in both fixation time and probability measures, including an interaction in early fixation measures. With invalid preview, we again found main effects of Predictability and Frequency in fixation times, but no evidence of an interaction. Fixation probability showed a weak Predictability effect and Predictability-Frequency interaction. Predictability interacted with Preview in early fixation time and probability measures. Our findings suggest that high levels of contextual constraint exert an early influence during lexical processing in reading. Results are discussed in terms of models of language processing and eye movement control

Word skipping: implications for theories of eye movement control in reading

This chapter provides a meta-analysis of the factors that govern word skipping in reading. It is concluded that the primary predictor is the length of the word to be skipped. A much smaller effect is due to the processing ease of the word (e.g., the frequency of the word and its predictability in the sentence)

Our own speech rate influences speech perception

During conversation, spoken utterances occur in rich acoustic contexts, including speech produced by our interlocutor(s) and speech we produced ourselves. Prosodic characteristics of the acoustic context have been known to influence speech perception in a contrastive fashion: for instance, a vowel presented in a fast context is perceived to have a longer duration than the same vowel in a slow context. Given the ubiquity of the sound of our own voice, it may be that our own speech rate - a common source of acoustic context - also influences our perception of the speech of others. Two experiments were designed to test this hypothesis. Experiment 1 replicated earlier contextual rate effects by showing that hearing pre-recorded fast or slow context sentences alters the perception of ambiguous Dutch target words. Experiment 2 then extended this finding by showing that talking at a fast or slow rate prior to the presentation of the target words also altered the perception of those words. These results suggest that between-talker variation in speech rate production may induce between-talker variation in speech perception, thus potentially explaining why interlocutors tend to converge on speech rate in dialogue settings

Listeners normalize speech for contextual speech rate even without an explicit recognition task

Speech can be produced at different rates. Listeners take this rate variation into account by normalizing vowel duration for contextual speech rate: An ambiguous Dutch word /m?t/ is perceived as short /mAt/ when embedded in a slow context, but long /ma:t/ in a fast context. Whilst some have argued that this rate normalization involves low-level automatic perceptual processing, there is also evidence that it arises at higher-level cognitive processing stages, such as decision making. Prior research on rate-dependent speech perception has only used explicit recognition tasks to investigate the phenomenon, involving both perceptual processing and decision making. This study tested whether speech rate normalization can be observed without explicit decision making, using a cross-modal repetition priming paradigm. Results show that a fast precursor sentence makes an embedded ambiguous prime (/m?t/) sound (implicitly) more /a:/-like, facilitating lexical access to the long target word "maat" in a (explicit) lexical decision task. This result suggests that rate normalization is automatic, taking place even in the absence of an explicit recognition task. Thus, rate normalization is placed within the realm of everyday spoken conversation, where explicit categorization of ambiguous sounds is rare

Frequency drives lexical access in reading but not in speaking: the frequency-lag hypothesis

To contrast mechanisms of lexical access in production versus comprehension we compared the effects of word frequency (high, low), context (none, low constraint, high constraint), and level of English proficiency (monolingual, Spanish-English bilingual, Dutch-English bilingual) on picture naming, lexical decision, and eye fixation times. Semantic constraint effects were larger in production than in reading. Frequency effects were larger in production than in reading without constraining context but larger in reading than in production with constraining context. Bilingual disadvantages were modulated by frequency in production but not in eye fixation times, were not smaller in low-constraint contexts, and were reduced by high-constraint contexts only in production and only at the lowest level of English proficiency. These results challenge existing accounts of bilingual disadvantages and reveal fundamentally different processes during lexical access across modalities, entailing a primarily semantically driven search in production but a frequency-driven search in comprehension. The apparently more interactive process in production than comprehension could simply reflect a greater number of frequency-sensitive processing stages in production

Distortions of Subjective Time Perception Within and Across Senses

Background: The ability to estimate the passage of time is of fundamental importance for perceptual and cognitive processes. One experience of time is the perception of duration, which is not isomorphic to physical duration and can be distorted by a number of factors. Yet, the critical features generating these perceptual shifts in subjective duration are not understood. Methodology/Findings: We used prospective duration judgments within and across sensory modalities to examine the effect of stimulus predictability and feature change on the perception of duration. First, we found robust distortions of perceived duration in auditory, visual and auditory-visual presentations despite the predictability of the feature changes in the stimuli. For example, a looming disc embedded in a series of steady discs led to time dilation, whereas a steady disc embedded in a series of looming discs led to time compression. Second, we addressed whether visual (auditory) inputs could alter the perception of duration of auditory (visual) inputs. When participants were presented with incongruent audio-visual stimuli, the perceived duration of auditory events could be shortened or lengthened by the presence of conflicting visual information; however, the perceived duration of visual events was seldom distorted by the presence of auditory information and was never perceived shorter than their actual durations. Conclusions/Significance: These results support the existence of multisensory interactions in the perception of duration and, importantly, suggest that vision can modify auditory temporal perception in a pure timing task. Insofar as distortions in subjective duration can neither be accounted for by the unpredictability of an auditory, visual or auditory-visual event, we propose that it is the intrinsic features of the stimulus that critically affect subjective time distortions

The effects of environmental context on laboratory rat social recognition

The effects of environmental context on laboratory rat social recognitio