Mechanisms of perceptual timing: Beat-based or interval-based judgements?

Summary What is the nature of the human timing mechanism for perceptual judgements about short temporal intervals? One possibility is that initial periodic events, such as tones, establish internal beats which continue after the external events and serve as reference points for the perception of subsequent events. A second possibility is that the timer records the intervals produced by events. Later, the stored intervals can be reproduced or compared to other intervals. A study by Schulze (1978) provided evidence favoring beat-based timing. In contrast, our two experiments support an interval theory. The judgements of intervals between tones is not improved when the events are synchronized with internal beats established by the initial intervals. The conflict between the two sets of results may be resolved by the fact that an interval timer can recycle from one interval to the next, thus operating in a beat-like mode. However, a timer of this sort is just as accurate when comparing intervals that are off the beat.     

A proximal change experiment testing two communication exercises with intimate partner violent men

This study tests the immediate impact of two interventions for intimate partner violent (IPV) men in affecting behavioral and emotional change during arguments with their partners. Couples with an abusive male partner (N = 100) discussed an area of conflict twice, interrupted by a brief intervention. Men were randomly assigned to receive (a) an editing-out-the-negative skills training, (b) an accepting influence skills training, or (c) a time-out. IPV men in both skills-training conditions showed greater decreases in aggressive feelings than IPV men in the time-out condition based on their self-report and observed affective behavior. Women also reported feeling less aggressive when their husbands were assigned to one of the skills-training conditions as compared to the control (time-out) condition. Results suggest that IPV men can learn to adopt new communication skills and that they do appear to have a positive impact on the emotional tone of their arguments. Clinically, communication skills training may be a useful addition to battering intervention programs, although these skills may need to be taught to both men and women involved in violent relationships.     

Conditioned acceleration and conditioned suppression in pigeons

Two experiments were performed to investigate the effects on pigeons' keypecking behavior of stimuli that signal different kinds of aversive events: time-out from positive reinforcement, electric shock, loud noise, and loud tone. Behavior maintained by a variable-interval schedule of reinforcement was suppressed by a stimulus before shock, was accelerated by a stimulus before time-out from positive reinforcement, and was unchanged by a stimulus before loud noise or a stimulus before loud tone. Conditioned acceleration with time-out from positive reinforcement and conditioned suppression with shock were obtained regardless of whether a response contingent or response-independent procedure was employed.     

Stimulus control of EMG burst duration in human locomotion

To better understand constraints on EMG activity, burst duration was restricted for the rectus femoris (RF) muscle as subjects walked on a motor-driven treadmill. Once in each step cycle (touchdown to touchdown of the left foot) a computer-activated light discriminated a short burst (if green) and silence (if red). All four subjects rapidly met the criterion of 90% success in 50 cycles for a burst 100–300 msec long within a performance duration, PDUR, of 700 msec. In contrast, two of the four failed to reduce the burst to conform to a 100–200 msec requirement. Several variables were ruled out as bearing on these between-subject performance differences: (1) complete failure to produce a short burst within the PDUR, since many were successful; (2) a differential effect upon subjects of two “reinforcer” types (a high tone after success and a low tone after failure, or else audible EMG biofeedback before the high or low tone); (3) appreciable differences in cycle duration or swing/stance ratios; (4) the presence or absence of concomitant activity in other leg muscles whose EMG was recorded. The frequent failure to accurately terminate the burst was suggested to be due to a greater susceptibility, whether reflexive or conditioned, to simulation arising in the contracting RF muscle itself.     

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.     

Shortening of subjective tone intervals followed by repetitive tone stimuli

Accumulated evidence shows that a subjective time interval is lengthened by preceding or concurrent presentation of flickers or repetitive tone stimuli that have been hypothesized to increase the frequency of pulse generation by a brain pacemaker. In the present study, we presented a series of repetitive tone stimuli after an interval that started and ended with tone markers. We found that subjective perception of the preceding interval was not lengthened but shortened by the tone stimuli that followed the interval. The perceived duration decreased as the frequency of the repetitive tone stimuli increased. The effect disappeared when the repetitive tone stimuli were delivered with a delay of 500 msec after the test interval or when continuous sound was delivered instead of delivering a rapid series of tones. On the basis of the results, we propose that the pulse count accumulated during a test interval was normalized by the clock frequency just after the test interval in a postdictive manner.     

Perception and production of brief durations: beat-based versus interval-based timing

Two experiments examined whether timing of short intervals is beat- or interval-based. In Experiment 1, subjects heard a sequence of standard tones followed by 2 test tones; they compared the interval between test tones to the interval between the standards. If optimal precision required beat-based timing, performance should be best in blocks in which the interval between standard and test reliably matched the standard interval. No such effect was observed. In Experiment 2, subjects heard 2 test tones and reproduced the intertone interval by producing 2 keypress responses. Entrainment to the beat was apparent: First-response latency clustered around the standard interval and was positively correlated with the produced interval. However, responses occurring on or near the beat showed no better temporal fidelity than off-beat responses. One plausible interpretation of these findings is that the brain always times brief intervals with an interval timer; however, this timer can be used in a cyclic fashion to trigger rhythmic responses.     

Experimental RunTime System: Software for developing and running reaction time experiments on IBM-compatible PCs

The Experimental RunTime System (ERTS) is a recent addition to the small collection of commercial software packages available for writing and running reaction time experiments on IBM-compatible PCs. Experiments are written using any text editor and a relatively small set of ERTS commands. Millisecond timing is provided by a software timer with no additional hardware requirements. All displays are in high-resolution VGA graphics. The Creative Labs Soundblaster card is supported in 16-bit mode, but is not required for simple tone generation. Voice-key support is available via the Soundblaster card. Keyboard, mouse, and external keys may be used as reaction keys, and the mouse or a joystick may be used as a tracking device. The stimulus-centered design and powerful display control commands of ERTS make it appropriate for developing a wide range of trial-based experiments.     

A bidimensional model of pitch in the recognition of melodies

Pitch can be conceptualized as a bidimensional quantity, reflecting both the overall pitch level of a tone (tone height) and its position in the octave (tone chroma). Though such a conceptualization has been well supported for perception of a single tone, it has been argued that the dimension of tone chroma is irrelevant in melodic perception. In the current study, melodies were subjected to structural transformations designed to evaluate the effects of interval magnitude, contour, tone height, and tone chroma. In two transformations, the component tones of a melody were displaced by octave intervals, either preserving or violating the pattern of changes in pitch direction (melodic contour). Replicating previous work, when contour was violated perception of the melody was severely disrupted. In contrast, when contour was preserved the melodies were identified as accurately as the untransformed melodies. In other transformations, a variety of forms of contour information were preserved, while eliminating information for absolute pitch and interval magnitude. The level of performance on all such transformations fell between the levels observed in the other two conditions. These results suggest that the bidimensional model of pitch is applicable to recognition of melodies as well as single tones. Moreover, the results argue that contour, as well as interval magnitude, is providing essential information for melodic perception.     

Behavioral engineering: the use of response priming to improve prescribed self-medication

A major problem in outpatient treatment has been the extreme irregularity with which patients use medication prescribed for them. As a new approach to resolving this problem, a portable operant apparatus was developed based on response priming and escape reinforcement. The apparatus sounded a tone at the time that a pill was to be taken. When the user turned a knob to terminate the tone, the apparatus delivered the pill into the user's hand. The apparatus was evaluated with six normal adults using a medically inert pill. A greater proportion of the pills were taken by each subject when using the special apparatus as compared with the use of a portable alarm timer or the usual wristwatch. These results demonstrate a new approach for increasing the regularity of self-administration of medicines.     

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.     

Timing and trajectory in rhythm production

The Wing-Kristofferson movement timing model (A. M. Wing & A. B. Kristofferson, 1973a, 1973b) distinguishes central timer and motor implementation processes. Previous studies have shown that increases in interresponse interval (IRI) variability with mean IRI are due to central timer processes, not motor implementation. The authors examine whether this is true with IRI duration changes in binary rhythm production. Ten participants provided IRI and movement data in bimanual synchronous tapping under equal (isochronous) and alternating (rhythm) interval conditions. Movement trajectory changes were observed with IRI duration (300, 500, or 833 ms) and for 500-ms IRIs produced in rhythm contexts (300/500 ms, 500/833 ms). However, application of the Wing-Kristofferson model showed that duration and context effects on IRI variability were attributable largely to timer processes with relatively little effect on motor processes.     

Accents in equitone sequences

Equitone sequences are defined as sequences of tones that are identical in all respects: frequency, spectral composition, intensity, and duration. The only parameter varied in these sequences is the time-interval between tones. In such sequences, clear accents are perceived. This paper describes accent perception in equitone sequences containing two alternating intervals; such sequences are perceived as consisting of repeating groups of two tones. An accent is heard on the first tone of a group if the difference between the intervals is about 5% to 10%. If the difference is made bigger, the accent is heard on the last tone of the group; this latter accent is considerably stronger than the accent previously heard on the first tone. In a number of experiments, the conditions under which the two types of accents occur were investigated. From these experiments, it was tentatively concluded that the accent on the last tone is heard because that tone, since it is followed by a longer interval, can be processed more completely. This “intervalproduced” accent indeed occurs only if the between-group interval is considerably longer than the within-group interval and if the latter does not exceed a duration of about 250 msec. The effect is slightly dependent on tone duration. The interval-produced accent can be balanced if the nonaccented tone is increased by about 4 dB in intensity. This shows that the effect is quite robust. The specific type of accentuation reported here might explain some rhythmical phenomena, examples of which are given.     

Parameters of Time-out: Research Update and Comparison to Parenting Programs,Books, and Online Recommendations

In reviews published more than 30 years ago, eight parameters important to the use of time-out were identified and available research was summarized. The purpose of the current paper is to provide an updated summary of existing research for each parameter of time-out. Within each parameter, we conducted a thorough review of the published literature and identified all peer-reviewed articles addressing each parameter. We identified and summarized a total of 46 articles across the eight parameters, including 32 not cited in previous reviews. Sufficient findings were available to draw conclusions regarding time-out warning, schedule of time-out, contingent versus noncontingent release, and duration. Tentative conclusions based on only a few studies could be drawn in regard to instructional versus physical administration and verbalized reason for time-out. No conclusions could be drawn regarding time-out signal and specific time-out location. While we know much more today regarding effective implementation of time-out, there is a clear need for further exploration within these identified parameters. In addition to summarizing the literature, we reviewed recommendations made by behavioral parent training programs, parenting books, and parenting Web sites, and compared how well their recommendations matched current research based on the conclusions drawn from our review. We found that parenting sources made strong and specific recommendations on several of the parameters that were either not consistent with available research or simply lacked a sufficient research base.     

Recognition memory for pitch of fixed and roving stimulus tones

The method of delayed comparison was used to measure pitch memory under two conditions of presentation, either the same standard tone on every trial (fixed S) or one of four equally likely standard tones (roving S), six durations of interference interval ranging from 0.0 to 4.0 sec, and two types of interference interval, either blank or filled with a pure tone. Listeners were instructed not to rehearse the S tone during the interference interval. For both fixed-S and roving-S conditions, accuracy of performance, as measured by area under the ROC curve, declined as interval duration increased and declined more rapidly following an interference-filled than following a blank interval. In general, forgetting proceeded at a slower rate under fixed-S conditions than under roving-S conditions. A second experiment showed that very little forgetting is obtained over 4 sec for roving-S conditions if instructions permit rehearsal of the S tone and suggests that the conclusions from the first experiment be restricted to nonrehearsal instructional conditions.     

MOVEMENT SUPPRESSION TIME-OUT FOR UNDESIRABLE BEHAVIOR IN PSYCHOTIC AND SEVERELY DEVELOP MENTALLY DELAYED CHILDREN

The effects of a movement suppression time-out, which involved punishing any movement or verbalization while a client is in the time-out area, were evaluated in four experiments. The first experiment examined the effects of a DRO procedure and movement suppression plus DRO in suppressing self-injurious behavior in a psychotic child in three different situations. In Experiment 2, the results of the previous experiment were replicated with two dangerous behaviors in a second psychotic child. In a third experiment, movement suppression plus DRO was compared with contingent restraint in reducing inappropriate poking behavior in two settings. The movement suppression procedure eliminated poking whereas contingent restraint had little effect. In the final experiment, movement suppression time-out alone was compared with exclusionary time-out alone and simple corner time-out alone. Self-stimulation occurred at high levels during the exclusionary and simple corner time-out procedures. Self-stimulation was either suppressed or reduced during movement suppression time-out. The movement suppression time-out procedure produced a larger reduction in the target behavior in all three children. The effectiveness of the movement suppression procedure was explained in terms of the suppression of self-stimulation while the time-out procedure was being applied.     

Orthographic congruency effects in the suprasegmental domain: evidence from Thai

The influence of orthographic knowledge on lexical tone processing was examined by manipulating the congruency between the tone and the tone marker of Thai monosyllabic words presented in three metalinguistic tasks. In tone monitoring (Experiment 1) and same-different tone judgement (Experiment 2)--that is, tasks that require an explicit analysis of tone information---an orthographic congruency effect was observed: Better performance was found when both tone and tone marker led to the same response than when they led to opposite, competing responses. In rhyme judgement (Experiment 3), a metaphonological task that allows tone to be processed in a more natural way since it does not require explicit analysis of tone, the orthographic effect emerged only when the interstimulus interval was lengthened from 30 to 1,200 ms. In addition to demonstrating the generalization of the orthographic congruency effect to the suprasegmental domain in Thai, the present data also suggest relatively late and task-dependent activation of orthographic representations of tone.     

Auditory sensitivity and equal loudness in the squirrel monkey (Saimiri sciureus).

The effects of the type of reinforcer on auditory sensitivity and equal-loudness data were determined in the squirrel monkey. The monkeys, restrained and provided with earphones, were conditioned to depress and hold a bar down in the presence of a stimulus light and then to terminate the holding response after onset of a tone. In Experiment 1, the specified behavior sequence postponed electric shock; in Experiment 2, a food reinforcer was dependent on bar release during the tone. The shape of the auditory sensitivity function and the acuity level at each frequency were the same for the two procedures. The audible frequency range extended from below 0.125 kHz (lowest frequency used) to 46 kHz. Sensitivity was maximum at 8 kHz. Latency of bar release following tone onset served as the basic data for constructing a family of equal-loudness contours. The type of reinforcer appeared not to be a determinant of either the shape of individual loudness contours or the pattern of family of equal-loudness functions. At the lower sound-pressure levels, the equal-loudness contours closely paralleled the threshold curves. At more-intense levels, the contours tended to flatten and depend less on frequency.     

Orthographic congruency effects in the suprasegmental domain: Evidence from Thai

The influence of orthographic knowledge on lexical tone processing was examined by manipulating the congruency between the tone and the tone marker of Thai monosyllabic words presented in three metalinguistic tasks. In tone monitoring (Experiment 1) and same–different tone judgement (Experiment 2)—that is, tasks that require an explicit analysis of tone information—an orthographic congruency effect was observed: Better performance was found when both tone and tone marker led to the same response than when they led to opposite, competing responses. In rhyme judgement (Experiment 3), a metaphonological task that allows tone to be processed in a more natural way since it does not require explicit analysis of tone, the orthographic effect emerged only when the interstimulus interval was lengthened from 30 to 1,200 ms. In addition to demonstrating the generalization of the orthographic congruency effect to the suprasegmental domain in Thai, the present data also suggest relatively late and task-dependent activation of orthographic representations of tone.     

The influence of perceptual and motor factors on bimanual coordination in a polyrhythmic tapping task

Summary In this study the role of perceptual and motor factors on the motor organization (integrated versus parallel) adopted by musically skilled and unskilled subjects in a polyrhythmic tapping task was investigated. Subjects tapped a 3:2 polyrhythm to match the timing of two isochronous tone trains, one tone train for each hand. Perceptual factors were examined by the manipulation of the frequency difference between the tone trains to produce either an integrated or a streamed percept. Motor factors were examined by comparison of performance on two versions of the 3:2 polyrhythm. In one (simultaneous) version, each cycle of the polyrhythm began with a simultaneous left- and right-hand tap. In the other (shifted) version a 100-ms interval was introduced between the initial left and right taps in each cycle. Examination of the pattern of variances and covariances among intertap intervals suggested that most of the subjects in this study adopted an integrated motor organization that involved interleaving the timing of the two hands. Further analysis revealed that a serial chained model described the pattern of covariances best for the simultaneous pattern, whereas a hierarchical organization described the pattern of covariances for the shifted pattern best. The finding that performance was more accurate with integrated tones than with streamed tones provides some support for a perceptual-motor facilitation hypothesis.