Differences in American English, Spanish, and monkey perception of thesay-stay trading relation

An interesting phenomenon in human speech perception is the trading relation, in which two different acoustic cues both signal the same phonetic percept. The present study compared American English, Spanish, and monkey listeners in their perception of the trading relation between gap duration andFl transition onset frequency in a syntheticsay-stay continuum. For all the subjects, increased gap duration caused perception to change fromsay tostay; however, subjects differed in the extent to which theFl cue traded with gap duration. For American English listeners, a change from a low to a highF1 onset caused a phoneme boundary shift of 26 msec toward shorter gap durations, indicating a strong trading relation. For Spanish listeners, the shift was significantly smaller at 13.7 msec, indicating a weaker trading relation. For monkeys, there was no shift at all, indicating no trading relation. These results provide evidence that thesay-stay trading relation is dependent on perceptual learning from linguistic exposure.     

Trading relations in the perception of speech by 5-year-old children

Five-year-old children were tested for perceptual trading relations between a temporal cue (silence duration) and a spectral cue (F₁ onset frequency) for the “say-stay” distinction. Identification functions were obtained for two synthetic “say-stay” continua, each containing systematic variations in the amount of silence following the /s/ noise. In one continuum, the vocalic portion had a lower F₁ onset than in the other continuum. Children showed a smaller trading relation than has been found with adults. They did not differ from adults, however, in their perception of an “ay-day” continuum formed by varying F₁ onset frequency only. The results of a discrimination task in which the two acoustic cues were made to “cooperate” or “conflict” phonetically supported the notion of perceptual equivalence of the temporal and spectral cues along a single phonetic dimension. The results indicate that young children, like adults, perceptually integrate multiple cues to a speech contrast in a phonetically relevant manner, but that they may not give the same perceptual weights to the various cues as do adults.     

Ability in perceiving nonnative contrasts: performance on natural and synthetic speech stimuli.

The perception of the distinction between /r/ and /l/ by native speakers of American English and of Japanese was studied using natural and synthetic speech. The American subjects were all nearly perfect at recognizing the natural speech sounds, whereas there was substantial variation among the Japanese subjects in their accuracy of recognizing /r/ and /l/ except in syllable-final position. A logit model, which additively combined the acoustic information conveyed by F1-transition duration and by F3-onset frequency, provided a good fit to the perception of synthetic /r/ and /l/ by the American subjects. There was substantial variation among the Japanese subjects in whether the F1 and F3 cues had a significant effect on their classifications of the synthetic speech. This variation was related to variation in accuracy of recognizing natural /r/ and /l/, such that greater use of both the F1 cue and the F3 cue in classifying the synthetic speech sounds was positively related to accuracy in recognizing the natural sounds. However, multiple regression showed that use of the F1 cue did not account for significant variance in natural speech performance beyond that accounted for by the F3 cue, indicating that the F3 cue is more important than the F1 cue for Japanese speakers learning English. The relation between performance on natural and synthetic speech also provides external validation of the logit model by showing that it predicts performance outside of the domain of data to which it was fit.     

The perception of stop consonant voicing by Spanish-English bilinguals

The performance of Spanish-English bilinguals in two perception tasks, using a synthetic speech continuum varying in voice onset time, was compared with the performance of Spanish and English monolinguals. Voice onset time in speech production was also compared between these groups. Results in perception of bilinguals differed from that of both monolingual groups. Results of bilingual production in their two languages conformed with results obtained from each monolingual group. The perceptual results are interpreted in terms of differences in the use of available acoustic cues by bilingual and monolingual listeners of English and Spanish.     

Dichotic Perception of Mandarin Tones by Chinese and American Listeners

The dichotic perception of Mandarin tones by native and nonnative listeners was examined in order to investigate the lateralization of lexical tone. Twenty American listeners with no tone language background and 20 Chinese listeners were asked to identify dichotically presented tone pairs by identifying which tone they heard in each ear. For the Chinese listeners, 57% of the total errors occurred via the left ear, indicating a significant right ear advantage. However, the American listeners revealed no significant ear preference, with 48% of the errors attributable to the left ear. These results indicated that Mandarin tones are predominantly processed in the left hemisphere by native Mandarin speakers, whereas they are bilaterally processed by American English speakers with no prior tone experience. The results also suggest that the left hemisphere superiority for native Mandarin tone processing is similar to native processing of other tone languages.     

Categorical perception: effects of the extent and rate of spectral change

ABSTRACT

Two experiments evaluated a potential explanation of categorical perception (CP) for place of articulation – namely, that listeners derive limited information from rapid spectral changes. Experiment 1 examined vowel context effects for /b/–/d/ continua that included consonant–vowel tokens with F2 onset frequencies that varied systematically from the F2 frequencies of their corresponding steady-states. Phoneme categorisation sharply shifted with F2 direction at locations along the continuum where discrimination performance peaked, indicating CP. Experiment 2 compared findings for a replicated condition against conditions with vowels reduced to match consonant duration or consonants extended to match vowels. CP was similarly obtained for replicated and vowel-reduced conditions. However, listeners frequently perceived diphthongs centrally on the consonant-extended continuum. Some listeners demonstrated CP, although aggregate performance appeared more continuous. These experiments indicate a model based upon the perceived direction of frequency transitions.     

Auditory apparent motion in the free field: the effects of stimulus duration and separation.

The effects of stimulus duration and spatial separation on the illusion of apparent motion in the auditory modality were examined. Two narrow-band noise sources (40 dB, A-weighted) were presented through speakers separated in space by 2.5 degrees, 5 degrees, or 10 degrees, centered about the subject's midline. The duration of each stimulus was 5, 10, or 50 msec. On each trial, the sound pair was temporally separated by 1 of 10 interstimulus onset intervals (ISOIs): 0, 2, 4, 6, 8, 10, 15, 20, 50, or 70 msec. Five subjects were tested in nine trial block; each block represented a particular spatial-separation-duration combination. Within a trial block, each ISOI was presented 30 times each, in random order. Subjects were instructed to listen to the stimulus sequence and classify their perception of the sound into one of five categories: single sound, simultaneous sounds, continuous motion, broken motion, or successive sounds. Each subject was also required to identify the location of the first-occurring stimulus (left or right). The percentage of continuous-motion responses was significantly affected by the ISOI [F(9,36) = 5.67, p less than .001], the duration x ISOI interaction [F(18,72) = 3.54, p less than .0001], and the separation x duration x ISOI interaction [F(36,144) = 1.51, p less than .05]. The results indicate that a minimum duration is required for the perception of auditory apparent motion. Little or no motion was reported at durations of 10 msec or less. At a duration of 50 msec, motion was reported most often for ISOIs of 20-50 msec.(ABSTRACT TRUNCATED AT 250 WORDS)     

Facilitative and inhibitory effects of cuing sound duration, intensity, and timbre

Two experiments are reported in which the possibility that auditory attention may be controlled in a stimulus-driven manner by duration, intensity, and timbre cues was examined. In both experiments, listeners were presented with a cue followed, after a variable time period of a 150-, 450-, or 750-msec stimulus onset asynchrony (SOA), by a target. In three different conditions for each experiment, the duration, intensity, or timbre relation between the cue and the target was varied so that, on 50% of the trials, the two sounds were identical and, on 50% of the trials, the two sounds were different in the manipulated feature. The two experiments differed only in the judgment required, with listeners in Experiment 1 identifying the duration, intensity, or timbre of the target and listeners in Experiment 2 indicating whether the target incorporated a brief silent gap. In both experiments, performance was observed to depend on both the similarity of and the time between the cue and the target. Specifically, whereas at the 150-msec SOA performance was best when the target was identical to the preceding cue, at the 750-msec SOA performance was best when the cue and the target differed. This pattern establishes the existence of duration-, intensity-, and timbre-based auditory inhibition of return. The theoretical implications of these results are considered.     

Facilitative and inhibitory effects of cuing sound duration, intensity, and timbre.

Two experiments are reported in which the possibility that auditory attention may be controlled in a stimulus-driven manner by duration, intensity, and timbre cues was examined. In both experiments, listeners were presented with a cue followed, after a variable time period of a 150-, 450-, or 750-msec stimulus onset asynchrony (SOA), by a target. In three different conditions for each experiment, the duration, intensity, or timbre relation between the cue and the target was varied so that, on 50% of the trials, the two sounds were identical and, on 50% of the trials, the two sounds were different in the manipulated feature. The two experiments differed only in the judgment required, with listeners in Experiment 1 identifying the duration, intensity, or timbre of the target and listeners in Experiment 2 indicating whether the target incorporated a brief silent gap. In both experiments, performance was observed to depend on both the similarity of and the time between the cue and the target. Specifically, whereas at the 150-msec SOA performance was best when the target was identical to the preceding cue, at the 750-msec SOA performance was best when the cue and the target differed. This pattern establishes the existence of duration-, intensity-, and timbre-based auditory inhibition of return. The theoretical implications of these results are considered.     

Perception Abilities of L1 Cypriot Greek Listeners - Types of Errors Involving Plosive Consonants in L2 English

This paper investigates the difficulties adult second language (L2) users of English encounter with plosive consonants in the L2. It presents the results of a task examining the acquisition of plosive voicing contrasts by college students with Cypriot Greek (CG) linguistic background. The task focused on the types of errors involving plosive consonants indicating that performance was significantly better in the voiceless plosive category. Participants were able to perceive voiced plosives but they treated such instances as a /nasal + voiced plosive/ sequence. Therefore, the question raised concerns different phonological contrasts realised through similar phonetic cues. The patterns observed suggested that this gap between phonetic cues and phonological contrast might explain why CG users have difficulties perceiving voiced English plosives. In this context, voice onset time (VOT) differences between the L1 and L2 are of crucial importance. In English, voiced plosives are characterised by short lag VOT while their voiceless counterparts fall within the long lag VOT continuum. The same phonetic contrast is used in CG to differentiate between single and geminate voiceless plosives. The results are discussed in relation to the frameworks of second language phonology and speech perception suggesting that the difficulties faced by the L2 listeners support the operation of a phonetic-phonological challenge.     

Temporal discrimination as a function of marker duration

In a series of three experiments, the effect of marker duration on temporal discrimination was evaluated with empty auditory intervals bounded by markers ranging from 3 to 300 msec or presented as a gap within a continuous tone. As a measure of performance, difference thresholds in relation to a base duration of 50 msec were computed. Performance on temporal discrimination was significantly better with markers ranging from 3 to 150 msec than with markers ranging from 225 to 300 msec or under the gap condition. However, within each range of marker duration (3–150 msec; 225–300 msec or gap) performance did not differ significantly. A fourth experiment provided evidence that the effect of marker duration cannot be explained in terms of marker-induced masking. A good approximation of the relationship between marker duration and temporal discrimination performance in the present experiments is a smooth step function, which can account for 99.3% of the variance of mean discrimination performance. Thus, the findings of the present study point to the conclusion that two different mechanisms are used in the processing of temporal information, depending on the duration of the auditory markers. The tradeoff point for the hypothetical shift from one timing mechanism to the other may be found at a marker duration of approximately 200 msec.     

Ability in perceiving nonnative contrasts: Performance on natural and synthetic speech stimuli

The perception of the distinction between /r/ and /l/ by native speakers of American English and of Japanese was studied using natural and synthetic speech. The American subjects were all nearly perfect at recognizing the natural speech sounds, whereas there was substantial variation among the Japanese subjects in their accuracy of recognizing /r/ and /l/ except in syllable-final position. A logit model, which additively combined the acoustic information conveyed byF1-transition duration and byF3-onset frequency, provided a good fit to the perception of synthetic /r/ and /l/ by the American subjects. There was substantial variation among the Japanese subjects in whether theF1 andF3 cues had a significant effect on their classifications of the synthetic speech. This variation was related to variation in accuracy of recognizing natural /r/ and /l/, such that greater use of both theF1 cue and theF3 cue in classifying the synthetic speech sounds was positively related to accuracy in recognizing the natural sounds. However, multiple regression showed that use of theF1 cue did not account for significant variance in natural speech performance beyond that accounted for by theF3 cue, indicating that theF3 cue is more important than theF1 cue for Japanese speakers learning English. The relation between performance on natural and synthetic speech also provides external validation of the logit model by showing that it predicts performance outside of the domain of data to which it was fit.     

Speeded detection of vowels: A cross-linguistic study

In four experiments, listeners’ response times to detect vowel targets in spoken input were measured. The first three experiments were conducted in English. In two, one using real words and the other, nonwords, detection accuracy was low, targets in initial syllables were detected more slowly than targets in final syllables, and both response time and missed-response rate were inversely correlated with vowel duration. In a third experiment, the speech context for some subjects included all English vowels, while for others, only five relatively distinct vowels occurred. This manipulation had essentially no effect, and the same response pattern was again observed. A fourth experiment, conducted in Spanish, replicated the results in the first three experiments, except that miss rate was here unrelated to vowel duration. We propose that listeners’ responses to vowel targets in naturally spoken input are effectively cautious, reflecting realistic appreciation of vowel variability in natural context.     

非言语声音影响汉语听者言语声音的知觉

采用启动范式, 以汉语听者为被试, 考察了非言语声音是否影响言语声音的知觉。实验1考察了纯音对辅音范畴连续体知觉的影响, 结果发现纯音影响到辅音范畴连续体的知觉, 表现出频谱对比效应。实验2考察了纯音和复合音对元音知觉的影响, 结果发现与元音共振峰频率一致的纯音或复合音加快了元音的识别, 表现出启动效应。两个实验一致发现非言语声音能够影响言语声音的知觉, 表明言语声音知觉也需要一个前言语的频谱特征分析阶段, 这与言语知觉听觉理论的观点一致。     

The effects of experimental variables on the perception of American English /r/ and /l/ by Japanese listeners.

The effects of variations in response categories, subjects' perception of natural speech, and stimulus range on the identification of American English /r/ and /l/ by native speakers of Japanese were investigated. Three experiments using a synthesized /rait/-/lait/ series showed that all these variables affected identification and discrimination performance by Japanese subjects. Furthermore, some of the perceptual characteristics of /r/ and /l/ for Japanese listeners were clarified: (1) Japanese listeners identified some of the stimuli of the series as /w/. (2) A positive correlation between the perception of synthesized stimuli and naturally spoken stimuli was found. Japanese listeners who were able to easily identify naturally spoken stimuli perceived the synthetic series categorically but still perceived a /w/ category on the series. (3) The stimulus range showed a striking effect on identification consistency; identification of /r/ and /l/ was strongly affected by the stimulus range, the /w/ identification less so. This indicates that Japanese listeners tend to make relative judgments between /r/ and /l/.     

The effects of experimental variables on the perception of American English /r/ and /l/ by Japanese listeners

The effects of variations in response categories, subjects’ perception of natural speech, and stimulus range on the identification of American English /r/ and /l/ by native speakers of Japanese were investigated. Three experiments using a synthesized /rait/-/lait/ series showed that all these variables affected identification and discrimination performance by Japanese-subjects. Furthermore, some of the perceptual characteristics of /r/ and /l/ for Japanese listeners were clarified: (1) Japanese listeners identified some of the stimuli of the series-as/w/.(2). Apositive correlation between the perception of synthesized stimuli and naturally-spoken stimuli was found. Japanese listeners who were able to easily identify naturally spoken stimuli perceived the synthetic series categorically but still perceived a /w/ category on the series. (3) The stimulus range showed a striking effect on identification consistency; identification of /r/ and /l/ was strongly affected by the stimulus range, the /w/ identification less so. This indicates that Japanese listeners tend to make relative judgments between /r/ and /l/.     

Threshold recognition of phantom-contour objects requires constant contrast velocity

Recognition of phantom objects--those with contours defined by rapid contrast reversal of adjacent fields of dark and light random dots--was investigated under conditions of abrupt or ramped onset and offset. Discrimination contrast thresholds were determined for a random-dot phantom letter in four possible orientations. For abrupt onset or offset, thresholds were almost independent of the duration of presentation time, over a range that varied tenfold, from 34-340 msec. However, when the onset and offset were shaped by a triangular envelope, thresholds were raised, so that form blindness occurred even when peak d ot contrasts exceeded 60%. Also under ramped onset and offset conditions, threshold contrast varied strictly linearly with stimulus duration in all subjects, suggesting a new construct--contrast velocity, the rate of change of contrast critical for phantom-object recognition.     

The Perceptual Centre of a Stimulus as the Cue for Synchronization to a Metronome: Evidence from Asynchronies

In tasks where subjects are required to tap in synchrony to a sequence of evenly spaced uniform auditory stimuli (a metronome), tap onsets typically tend to anticipate the metronome's stimulus onsets. We investigated this phenomenon, called “negative asynchrony”, as a function of (1) the duration of the stimuli (1 or 2, 50, 100, and 300 msec), (2) the rise time of the stimuli (0%, 40%, and 80% of stimulus duration), and (3) the interstimulus onset interval duration (500, 700, and 900 msec). The results from three experiments with 28 different subjects showed a significant reduction of the negative asynchrony with longer stimulus durations, and the reduction was not significantly affected by the tempo of the stimulus sequence. Also, a prolongation of the rise time of the stimuli caused an analogous reduction of the negative asynchrony. Findings were taken to suggest that subjects use the perceptual centre rather than physical onset of stimulus as the cue with which to synchronize     

The role of variation in the perception of accented speech

Phonetic variation has been considered a barrier that listeners must overcome in speech perception, but has been proved beneficial in category learning. In this paper, I show that listeners use within-speaker variation to accommodate gross categorical variation. Within the perceptual learning paradigm, listeners are exposed to p-initial words in English produced by a native speaker of French. Critically, listeners are trained on these words with either invariant or highly-variable VOTs. While a gross boundary shift is made for participants exposed to the variable VOTs, no such shift is observed after exposure to the invariant stimuli. These data suggest that increasing variation improves the mapping of perceptually mismatched stimuli.     

Phonetic, phonemic, and phonological factors in cross-language discrimination of phonotactic contrasts

Previous research indicates that multiple levels of linguistic information play a role in the perception and discrimination of non-native phonemes. This study examines the interaction of phonetic, phonemic and phonological factors in the discrimination of non-native phonotactic contrasts. Listeners of Catalan, English, and Russian are presented with an initial #CC-#C?C contrast in a discrimination task. For the Catalan group, the phonemes and their phonetic implementation were native, but the #CC phonotactics were not. For Russian listeners, the phonemes and phonetic implementation were not native but Russian allows a large number of #CC sequences. For English listeners, none of the phonetics, phonemes, nor phonotactics are native. Two task variables, stimuli length and order of presentation, were also manipulated. Results showed that the Russian listeners were most accurate overall, suggesting that the presence of the phonotactic structure in the listeners' native language may be more important than either phonemic or phonetic information. The interaction between the task manipulations and the linguistic variables is also addressed.