Hear it playing low and slow: How pitch level differentially influences time perception

Variations in both pitch and time are important in conveying meaning through speech and music, however, research is scant on perceptual interactions between these two domains. Using an ordinal comparison procedure, we explored how different pitch levels of flanker tones influenced the perceived duration of empty interstimulus intervals (ISIs). Participants heard monotonic, isochronous tone sequences (ISIs of 300, 600, or 1200 ms) composed of either one or five standard ISIs flanked by 500 Hz tones, followed by a final interval (FI) flanked by tones of either the same (500 Hz), higher (625 Hz), or lower (400 Hz) pitch. The FI varied in duration around the standard ISI duration. Participants were asked to determine if the FI was longer or shorter in duration than the preceding intervals. We found that an increase in FI flanker tone pitch level led to the underestimation of FI durations while a decrease in FI flanker tone pitch led to the overestimation of FI durations. The magnitude of these pitch-level effects decreased as the duration of the standard interval was increased, suggesting that the effect was driven by differences in mode-switch latencies to start/stop timing. Temporal context (One vs. Five Standard ISIs) did not have a consistent effect on performance. We propose that the interaction between pitch and time may have important consequences in understanding the ways in which meaning and emotion are communicated.     

Effects of accenting and regularity on the detection of temporal deviations: does regularity facilitate performance?

In an experiment on the effect of intensity accents on the perception of time intervals between tones, H. G. Tekman (2001) found that the regular placement of deviant time intervals in short sequences of tones reduced detection, especially if intensity accents marked the deviant time intervals. That was the opposite of what one would have expected on the basis of the dynamic attending theory of M. R. Jones (1976). The effect might have occurred because temporally deviant tones create cumulative onset shifts that affect all the subsequent tones. If the deviations were randomly placed, then they could follow each other in close succession and change the local tempo. In the present study, the changes of local tempo, which might have acted as a cue for the detection of temporal deviations in the random sequences, were eliminated by compensating for deviant time intervals with equal deviations in the opposite direction in the interval that followed. That change in the stimuli eliminated the negative main effect of regularity, and the accenting interacted with regularity in favor of detection in the regular sequences. However, a simple advantage of regular over random sequences was not observed. The author discusses possible reasons for the lack of a facilitatory effect of regularity.     

Influenceability of Sex Differences under Conditions of Risk Taking

In an experiment on the effect of intensity accents on the perception of time intervals between tones. H. G. Tekman (2001) found that the regular placement of deviant time intervals in short sequences of tones reduced detection, especially if intensity accents marked the deviant time intervals. That was the opposite of what one wòuld have expected on the basis of the dynamic attending theory of M. R. Jones (1976). The effect might have occurred because temporally deviant tones create cumulative onset shifts that affect all the subsequent tones. If the deviations were randomly placed, then they could follow each other in close succession and change the local tempo. In the present study, the changes of local tempo, which might have acted as a cue for the detection of temporal deviations in the random sequences, were eliminated by compensating for deviant time intervals with equal deviations in the opposite direction in the interval that followed. That change in the stimuli eliminated the negative main effect of regularity, and the accenting interacted with regularity in favor of detection in the regular sequences. However, a simple advantage of regular over random sequences was not observed. The author discusses possible reasons for the lack of a facilitatory effect of regularity.     

Studies in auditory timing: 1. Simple patterns

Listeners' accuracy in discriminating one temporal pattern from another was measured in three psychophysical experiments. When the standard pattern consisted of equally timed (isochronic) brief tones, whose interonset intervals (IOIs) were 50, 100, or 200 msec, the accuracy in detecting an asynchrony or deviation of one tone in the sequence was about as would be predicted from older research on the discrimination of single time intervals (6%-8% at an IOI of 200 msec, 11%-12% at an IOI of 100 msec, and almost 20% at an IOI of 50 msec). In a series of 6 or 10 tones, this accuracy was independent of position of delay for IOIs of 100 and 200 msec. At 50 msec, however, accuracy depended on position, being worst in initial positions and best in final positions. When one tone in a series of six has a frequency different from the others, there is some evidence (at IOI = 200 msec) that interval discrimination is relatively poorer for the tone with the different frequency. Similarly, even if all tones have the same frequency but one interval in the series is made twice as long as the others, temporal discrimination is poorer for the tones bordering the longer interval, although this result is dependent on tempo or IOI. Results with these temporally more complex patterns may be interpreted in part by applying the relative Weber ratio to the intervals before and after the delayed tone. Alternatively, these experiments may show the influence of accent on the temporal discrimination of individual tones.     

Temporal course of perceived auditory duration

A series of experiments explored the temporal course of the perceived duration of an auditory stimulus. A backward recognition masking paradigm was utilized, in which the subject was to determine which of two target durations was presented on a given trial. The target tone was followed, after a variable silent intertone interval, by a masking tone which could assume one of three possible durations. Identification of the long target was found to improve consistently with increases in the intertone interval. In contrast, identification of the short target was as accurate at the short as at the long intertone intervals. Blocking the intertone interval across experimental sessions eliminated these differences between the two target tones. Performance on both the long and the short target tones improved monotonically with increases in the intertone interval. When masking tone duration was randomized within an experimental session, identification of the long (short) target was most accurate with the longer (shorter) masking tone. Blocking the duration of the masking tone across experimental sessions eliminated the effect of the duration of the mask, but did not alter any of the other results. A model, proposed to account for the results, assumes that the percept of target duration grows over time, and can be terminated by the onset of the masking tone. The masking tone also acts to lengthen the perceived duration of the target tone, and this lengthening is a direct function of the duration of the masking tone.     

Examining auditory kappa effects through manipulating intensity differences between sequential tones

The auditory kappa effect is a tendency to base the perceived duration of an inter-onset interval (IOI) separating two sequentially presented sounds on the degree of relative pitch distance separating them. Previous research has found that the degree of frequency discrepancy between tones extends the subjective duration of the IOI. In Experiment 1, auditory kappa effects for sound intensity were tested using a three-tone, AXB paradigm (where the intensity of tone X was shifted to be closer to either Tone A or B). Tones closer in intensity level were perceived as occurring closer in time, evidence of an auditory-intensity kappa effect. In Experiments 2 and 3, the auditory motion hypothesis was tested by preceding AXB patterns with null intensity and coherent intensity context sequences, respectively. The auditory motion hypothesis predicts that coherent sequences should enhance the perception of motion and increase the strength of kappa effects. In this study, the presence of context sequences reduced kappa effect strength regardless of the properties of the context tones.     

Accenting and detection of timing variations in tone sequences: Different kinds of accents have different effects

The effect of intensity and pitch accents on the perception of timing was examined in two experiments using a signal detection procedure. Analyses of sensitivity and response bias revealed opposite effects of intensity and pitch accents under similar conditions. Time intervals preceding intensity accents were perceived as longer, but time intervals preceding pitch accents were perceived as shorter. These results showed that listeners found it easier to detect timing variations that were contrary to expectations, as compared with variations that were consistent with expectations. In the present case, listeners should have expected shorter time intervals before intensity accents and longer intervals before pitch accents. The fact that the effects were observed with stimuli that had minimal musical structure demonstrated the contribution of psychoacoustic factors to such phenomena.     

Accenting and detection of timing variations in tone sequences: different kinds of accents have different effects.

The effect of intensity and pitch accents on the perception of timing was examined in two experiments using a signal detection procedure. Analyses of sensitivity and response bias revealed opposite effects of intensity and pitch accents under similar conditions. Time intervals preceding intensity accents were perceived as longer, but time intervals preceding pitch accents were perceived as shorter. These results showed that listeners found it easier to detect timing variations that were contrary to expectations, as compared with variations that were consistent with expectations. In the present case, listeners should have expected shorter time intervals before intensity accents and longer intervals before pitch accents. The fact that the effects were observed with stimuli that had minimal musical structure demonstrated the contribution of psychoacoustic factors to such phenomena.     

Auditory-visual conflicts in the perceived duration of lights, tones and gaps

The perceived duration of a short tone (1,000 or 1,500 msec) was longer than that of a separately presented light of equal length. Thus, when light and tone were presented simultaneously, there was a conflict in perceived duration. In that case, the perceived duration of an interval filled with both light and tone was close to that of an interval filled with tone alone. A silent gap in otherwise continuous tone was perceived as longer than a gap in otherwise continuous light, and the perceived duration of a gap occurring simultaneously in both light and tone was close to that of a gap in tone alone. Thus, auditory dominance occurred under the preceding conditions-that is, auditory-visual conflicts in perceived duration, whether occurring between filled intervals or gaps, were resolved in favor of the auditory modality. Visual dominance occurred only under one condition, in which the intensity of tone was reduced, and in which the perceived duration of a 500-msec light was longer than that of a 500-msec tone. The finding of auditory dominance in the perception of time runs counter to the results of studies of sensory conflicts in spatial perception, where vision typically dominates audition and touch.     

Cooperative tapping: time control under different feedback conditions.

The same isochronous tone sequence was presented simultaneously to two mutually isolated subjects. In half the trials, accentuation in this sequence was accomplished by doubling the duration of the first and then of every fourth tone; in the other half, by doubling the frequency of those tones. The subjects' task was to follow the rhythm of the resulting four-tone patterns by finger tapping to tone onsets. There were four auditory feedback (FB) conditions: (1) no FB; (2) FB from the subject's own motor responses; (3) "alien" FB from the motor responses of the other pair member who, in turn, was listening to FB from his/her own tapping; (4) mutually "crossed" FB, where each pair member listened to FB from the tapping of the other. Tap onsets regularly preceded stimulus onsets. The observed order of the amount of this anticipation (from least to greatest) was: (1) own FB, (2) no FB, (3) alien FB, and (4) crossed FB. No mutual dynamic influence between simultaneously performing subjects was detected. Anticipation was more pronounced for sequences that were accentuated by frequency rather than by duration changes. The type of accent also influenced timing of intertap intervals in the rhythmic patterns. For the frequency accent, regular timing was produced, whereas for the durational accent, shortening of the second and lengthening of the fourth (the last) intertap interval were observed. The presence and source of feedback as well as the character of accentuation are therefore relevant factors in the timing of auditorally controlled rhythmic motor behavior.     

Cooperative tapping: Time control under different feedback conditions

The same isochronous tone sequence was presented simultaneously to two mutually isolated subjects. In half the trials, accentuation in this sequence was accomplished by doubling the duration of the first and then of every fourth tone; in the other half, by doubling the frequency of those tones. The subjects’ task was to follow the rhythm of the resulting four-tone patterns by finger tapping to tone onsets. There were four auditory feedback (FB) conditions: (1) no FB; (2) FB from the subject’s own motor responses; (3) “alien” FB from the motor responses of the other pair member who, in turn, was listening to FB from his/her own tapping; (4) mutually “crossed” FB, where each pair member listened to FB from the tapping of the other. Tap onsets regularly preceded stimulus onsets. The observed order of the amount of this anticipation (from least to greatest) was: (1) own FB, (2) no FB, (3) alien FB, and (4) crossed FB. No mutual dynamic influence between simultaneously performing subjects was-detected. Anticipation was more pronounced for sequences that were accentuated by frequency rather than by duration changes. The type of accent also influenced timing of intertap intervals in the rhythmic patterns. For the frequency accent, regular timing was produced, whereas for the durational accent, shortening of the second and lengthening of the fourth (the last) intertap interval were observed. The presence and source of feedback as well as the character of accentuation are therefore relevant factors in the timing of auditorally controlled rhythmic motor behavior.     

Memory for sequences of tone bursts in the rat: Reliance on temporal cues and evidence for an instructional ambiguity explanation of the choose-few effect

Two groups of rats were trained in a symbolic delayed matching-to-sample task with a 0-s delay to discriminate sample stimuli that consisted of sequences of tone bursts. For one group, sequences varied in number with total sequence duration controlled. For the other group, total sequence duration, sum of the tone durations, and sum of the gap durations were all controlled. The former group of rats acquired the discrimination, but the latter group of rats were not able to learn the discrimination with the additional temporal cues controlled. Retention functions for the group that acquired the discrimination exhibited a choose-many bias at the 1-s delay and a choose-few bias at the 8-s delay regardless of the similarity in the intertrial interval and delay interval illumination condition. The asymmetrical retention functions appeared to be due to instructional ambiguity which resulted from the similarity of the delay interval to temporal features of the tone burst sequence, such as the gap between tone bursts and the total duration of tone. In Experiment 2, diagnostic tests provided evidence that rats discriminated the sequences of tone bursts by timing and summing the duration of individual tone bursts rather than using an event switch to count tones. Like pigeons, rats use multiple temporal features rather than number to discriminate sequences of successive events.     

“Octave illusion” or “Deutsch’s illusion”?

The “Deutsch’s illusion” occurs in most people when a dichotic pair of tones spaced an octave apart is presented repeatedly in alternation, so that when the right ear receives the high tone, the left ear receives the low tone, and vice versa. The illusory percept consists typically in a single low tone heard at one ear alternating with a single high tone heard at the other ear. Here, we investigate whether the frequency interval between the tones and their duration play a role in the perception of the illusion. By testing 74 subjects we demonstrate that the illusion is not confined to tones spaced an octave apart but it is perceivable also with tones separated by a major seventh, a minor ninth, a major ninth, and a minor tenth. Regarding duration, the present results show that the illusion is stronger with tones lasting 500 than 200 ms. The present results suggest that the perceptual mechanisms at the basis of the illusion are not strictly linked to the frequency relationships between the dichotic tones.     

Tempo sensitivity in isochronous tone sequences: the multiple-look model revisited

Factors affecting tempo sensitivity in isochronous tone sequences were investigated in two experiments. Participants listened to tones in sequence conditions in which the number of time intervals in isochronous standard and comparison sequences was varied, and they were asked to judge the tempo of the comparison relative to the standard. When the duration of the standard interval was held constant, tempo sensitivity was affected by the number of comparison intervals, but not by the number of standard intervals. In contrast, when the duration of the standard interval was varied randomly from trial to trial, tempo sensitivity was affected by the number of intervals in both sequences. The present findings are discussed in the context of a generalized multiple-look model that posits independent contributions of both sequences to tempo sensitivity. Quantitative model fits suggest that the relative contribution of the number of the standard intervals to tempo thresholds depends on (1) the availability of a stable long-term referent for the standard tempo and (2) a priori knowledge about the number of standard intervals.     

Age-related changes in auditory temporal processing

Two tone bursts separated by a silent interval and imbedded in a background white noise were presented to elderly subjects (M age = 71.3 years) and young subjects (M age = 22.2 years). Subjects were required to judge when the two tone bursts fused perceptually by adjusting the duration of tone-one. The bursts were separated by six discrete interstimulus intervals of 4, 8, 16, 24, 32, or 40 ms. The tone-two burst was held constant at 100 ms. Fusion point was defined as that critical tone-one duration at which the two tones fused (were perceived as one). Elderly subjects reached fusion point at longer critical tone-one durations than young subjects at each interval tested. The function relating tone-one duration and interval conformed to an exponential curve and is discussed with respect to an exponential decay model of the inhibitory interactions of neural systems responding to onsets and offsets of sensory events.     

Time errors and differential sensation weighting

Sixteen pairs of successive tones, with different amplitude combinations, were presented with 16 combinations of tone duration and interstimulus interval. A separate group of 12 subjects was assigned to each presentation condition and made comparative loudness judgments for each of the pairs. Perceived within-pair loudness differences were scaled by a Thurstonian method using the subjective width of the "equal" category as the unit. The scale differences were well described by weighted linear combinations of the sensation magnitudes of the tones in the pairs. The time error can be regarded as an effect of this differential weighting. For the longer interstimulus intervals, the weight of the second tone was the greater, causing the usual inverse relation between time error and stimulus intensity level. For the shorter interstimulus intervals, these effects were reversed. An analysis of the pattern of weights led to the development of two models, one of which is a generalization of Michels and Helson's time error model. The weights could be interpreted as reflecting the differential efficiency of the loudness information from the two compared stimuli.     

Cross-octave masking of single tones and musical sequences: The effects of structure on auditory recognition

A series of experiments explored the role of structural information in the auditory recognition process, within the context of a backward recognition masking paradigm. A masking tone presented after a test tone has been found to interfere with the perceptual processing of the test tone, the degree of interference decreasing with increased durations of the silent intertone interval between the test and masking tones. In the current studies, the task was modified to utilize three-tone sequences as the test stimuli. Six test sequences were employed (LMH, LHM, MLH, MHL, HLM, HML), where L, M, and H represent the lowest, middle, and highest frequencies in the melody. The observers identified these six possible sequences when the three tones of the test sequence were interleaved with three presentations of a single masking tone. All three tones of the test sequence were drawn from the same octave, while the masking tones could be drawn from any of three octaves, symmetrical around the octave containing the test tones. Under these conditions, interference occurred primarily from masking tones drawn from the same octave as the test tones. Masking tones drawn from other octaves were found to produce little, if any, interference with perception of the test tones. This effect was found to occur only for the identification of tonal sequences. Substantial masking of single-tone targets occurred with masking tones drawn from octaves other than that containing the targets. The results make apparent the use of structural information during auditory recognition. A theoretical interpretation was advanced which suggests that, while single tones are perceived on the basis of absolute pitch, the presence of auditory structure may allow relational information, such as exact pitch intervals or melodic contour, to facilitate perception of the tonal sequence.     

Infants’ and adults’ use of duration and intensity cues in the segmentation of tone patterns

Adults and 8-month-olds were presented with sequences in which every third complex tone was either longer or more intense. Segmentation was measured by comparing the detection of silent gaps inserted into three possible locations in each pattern: Silent gaps inserted at perceived segmentation boundaries are harder to detect than gaps within perceived phrases or groups. A go/no-go conditioned head-turn (hand-raising for adults) procedure was used. In Experiment 1, detection was worse for the gaps following the longer complex tones than for the gaps at the other locations, suggesting that the longer tones marked the ends of perceived groups for both infants and adults. Experiment 2 showed that an increase in intensity did not result in any systematic grouping at either age.     

Infants' and adults' use of duration and intensity cues in the segmentation of tone patterns

Adults and 8-month-olds were presented with sequences in which every third complex tone was either longer or more intense. Segmentation was measured by comparing the detection of silent gaps inserted into three possible locations in each pattern: Silent gaps inserted at perceived segmentation boundaries are harder to detect than gaps within perceived phrases or groups. A go/no-go conditioned head-turn (hand-raising for adults) procedure was used. In Experiment 1, detection was worse for the gaps following the longer complex tones than for the gaps at the other locations, suggesting that the longer tones marked the ends of perceived groups for both infants and adults. Experiment 2 showed that an increase in intensity did not result in any systematic grouping at either age.     

Time perception and the filled-duration illusion

A reproduction design is used to show that temporal intervals containing brief tones appear longer than empty intervals of the same duration, the effect being independent of duration. These and previous data are discussed within a theoretical framework which allows for the interrelation of data from different time perception tasks; and a reversible encoding model is stated which accounts for much of the data obtained with empty intervals. A “chunking” model, in which tones occurring in an interval serve to segment the interval during encoding, can account for the filled-duration illusion if certain conditions are met. Finally, mechanisms that are consistent with these conditions are stated.