Twelfth Annual Meeting

Time:              Saturday, March 16, 2002, 8:30 a.m. - 4:30 p.m.

Place:              Lecture Room, Sterling Memorial Library, Yale University

                        120 High Street (entrance on Wall Street), New Haven, CT

Organizer:       Bruno H. Repp, Haskins Laboratories

                        E-mail: repp@haskins.yale.edu

Assistant:         Peter Keller, Haskins Laboratories

PROGRAM

8:30 - 9:00       Welcome (Continental breakfast served)

9:00 - 9:30

MODELING RHYTHMIC EXPECTATIONS IN SHORT INTERVAL TIMING:

A COMPARISON OF ENTRAINMENT AND INTERVAL-BASED APPROACHES TO TIME PERCEPTION

Devin McAuley

Bowling Green State University

e-mail: <mcauley@bgnet.bgsu.edu>

An emerging issue in current research on short-interval timing is the role of rhythmic context in people’s judgments about relative duration.  In one such study, Barnes and Jones [Cognitive Psychology, 41, 254–311 (2000)] presented listeners with rhythmic context sequences followed by standard-comparison pairs of time intervals; listeners judged the duration of the comparison interval relative to the standard, while trying to ignore the context sequence. The critical manipulation involved the timing of the tone marking the end of the standard time interval; the onset of this tone was either early, on time, or late in relation to the rhythm of the context sequence. Time estimates were shown to be more accurate, measured by proportion of correct time judgments, when a standard ended on time than when it ended early or late.  Barnes and Jones termed this pattern of findings an expectancy profile.  In this talk, I will report recent data collected in our laboratory on the nature of expectancy profiles in time judgment behavior. Then, I will discuss these finding in terms of oscillator- and interval-based perspectives on timing.  To structure this discussion, I will propose a generalized modeling framework for interpreting effects of rhythmic context on time judgments and then consider the implications of the best-fitting model within this framework for existing theories.

9:30 – 10:00

EFFECTS OF TEMPORAL STRUCTURE ON THE SPEEDED DETECTION OF TONES IN SEQUENCES

Amandine Penel and Mari Riess Jones

Ohio State University

e-mail: <penel.1@osu.edu>

Music and speech are temporally structured. Temporal regularities enable listeners to predict when an event will occur, and perhaps to focus attention on expected points in time. Previous work has shown that, following a regular induction sequence of tones, accuracy of time and pitch judgments is higher for on-time than for early or late tones (relative to the sequence). We undertook a series of experiments examining the effects of temporal structure on speeded detection of tones differing in pitch. Is a tone which occurs on-time detected faster or slower than one which occurs early or late? Alternatively, the temporal structure of the induction sequence may have no effect. Following sequences of between N = 4 and 8 identical short high-pitched tones, target tones (three semi-tones lower) were presented at various randomized temporal positions (e.g., for a sequence with a 500 ms IOI, targets were presented between 300 and 900 ms after the last induction tone). Participants were asked to press a button as soon as they detected the target. Preliminary results suggest slower reaction times for on-time targets, when (1) N is randomized and the temporal irregularity preceding the target is relevant to the task, (2) N is blocked and the range of presented temporal positions includes more late than early targets, and to some extent when (3) N is randomized and the temporal irregularity is irrelevant to the task. It appears that the temporal structure of a sequence influences listeners' responses to subsequent events, in a way that depends on their relative temporal position.

10:00 – 10:30

TAPPING TO THE BEAT OF AUDITORY AND VISUAL RHYTHMIC SEQUENCES

Aniruddh D. Patel^a, Bruno H. Repp^b, John R. Iversen^a, and Yanqing Chen^a

^aThe Neurosciences Institute, San Diego       ^bHaskins Laboratories, New Haven

e-mail: <apatel@nsi.edu>

Rhythmic patterns can be presented in both the auditory and visual modalities.  The cognitive experience of these patterns, however, is quite different. Beat perception is a cognitive process which is well known from audition but little explored in vision. We sought to compare beat perception in audition and vision by examining the relationship between metrical structure and beat tapping in identical sequences presented as either auditory (tone) or visual (flash) patterns.  Participants were presented with temporal sequences which varied in their degree of metrical structure, ranging from isochronous sequences to temporally complex patterns with weakly or strongly metrical properties.  The beat (always 800 ms) was indicated briefly at the beginning of each sequence, and the participants’ task was to maintain this beat throughout the sequence by tapping. The dependent measure was the variability of inter-tap-intervals and of tap-to-tone or tap-to-flash asynchronies. For auditory patterns, tapping was less variable to strongly metrical than to weakly metrical sequences. In addition, tapping was least variable to isochronous sequences with a single subdivision between beats. For visual sequences, synchronization was unreliable, except for the simple 800 ms isochronous sequences. For those individuals who could synchronize to more complex sequences, there was no benefit of metricality or subdivision. The results suggest that the extraction of a beat from complex temporal sequences is a special property of the auditory system, and that purely temporal visual sequences offer poor support for metrical structure.

10:30 – 10:50

Coffee break

10:50 – 11:20

TAPPING IN ANTI-PHASE WITH AUDITORY SEQUENCES CONTAINING REGULAR AND IRREGULAR ACCENTS

Peter E. Keller and Bruno H. Repp

Haskins Laboratories, New Haven

e-mail: <keller@haskins.yale.edu>

When people attempt to tap between tones comprising a rapid isochronous sequence, there is a tendency to drift from the intended anti-phase relationship to an in-phase relationship between taps and tones. Imposing a regular, higher-order structure that groups the tones in equal numbers may stabilize anti-phase tapping by facilitating periodic corrections to the timing mechanism that guides performance. This hypothesis was investigated in two experiments requiring anti-phase tapping with isochronous tone sequences that either did or did not contain regular accents (produced by sounding two tones simultaneously). In Experiment 1, performance with ‘metric’ sequences containing regular accents (either every two, three, or four tones) was compared with performance with sequences where tones were either all accented (‘strong beat’) or all unaccented (‘weak beat’). Performance stability was assessed by measuring the variability of asynchronies and phase drift for series of 60 taps. Variability and drift were greatest with strong beat sequences. Contrary to expectations, performance with metric and weak beat sequences was similar in terms of overall variability, but, as expected, drift was more prevalent with the weak beat sequences. Interestingly, autocorrelational analyses revealed higher-order periodicities in the asynchrony series for metric sequences. To test whether these regular fluctuations in asynchrony reflect a periodic correction or anticipation process, or are merely reflexive responses to accented tones, Experiment 2 included sequences with ‘irregular’ accents. Even though the ratio of accented to unaccented tones was matched across metric and irregular sequences, variability and drift increased markedly in the latter. Furthermore, taps that occurred immediately after accents had different timing characteristics in metric and irregular sequences. These findings may provide evidence for a phase adjustment mechanism based on higher-order periodicities.

11:20 – 11:50

TIMING CONTROL DIFFERENCES FOR TIMING CIRCLES AND TAPS IS NOT DUE JUST TO TRAJECTORY CONTROL PROCESSES

H.N. Zelaznik^a, R.M.C. Spencer^a, K.H. Haslett^a, and R.I. Ivry^b   

^aPurdue University        ^bUniversity of California at Berkeley

e-mail: <hnzelaz@purdue.edu>

In past work we (Zelaznik, Spencer, & Ivry, JEP:HP&P, in press) have shown that individual differences in timing variability for continuous drawing and tapping were not correlated. That result, coupled with the finding that an intermittent drawing task, which required that the drawing cycle be divided into a movement and pause phase, was correlated with tapping, but not with continuous drawing, led us to propose that motor tasks that were not continuous and smooth required that the participant use an explicit temporal representation in order to time necessary intervals. On the other hand, the timing of continuous drawing tasks does not utilize this explicit process. Instead, the temporal characteristics of these movements emerge as a result of the control of dynamical aspects of these movements. We report two new experiments. The first experiment has individuals produce a single tap or circle on a given trial. The variability of the timing of movement initiation is the same across the two tasks. We argue that this result is consistent with the notion that the timing of movement initiation utilizes an explicit process. In the second experiment, participants tapped or drew circles with an alternating rhythm. Now, we show that individual differences in timing variability are correlated across tasks. Why? Participants in the alternating circle drawing task need to utilize an explicit representation of the changing intervals to successfully complete the timing requirements. Overall, we take these results to infer that the use of explicit and implicit timing processes are not just the result of whether movements are continuous or discrete.

A NOVEL TYPE OF Motor SEQUENCE LEARNING RevealS EARLY WORKING MEMORY DEFICITS IN PRE-SYMPTOMATIC HUNTINGTON'S DISEASE (p-HD)                                          [presented by Maria Felice Ghilardi]

G. Silvestria, M. F. Ghilardia,b, A. Feiginc, C. Gheza, and D. Eidelbergc

^aColumbia University       ^bINB-CNR, Milano, Italy

^cNorth Shore–Long Island Jewish Research Institute

e-mail: <gs2005@columbia.edu>

Previous studies have shown that learning may be impaired in individuals with HD. In this study we present novel sequence learning tasks to test ten right-handed p-HD gene carriers and ten normal age-matched controls. Brain activity was simultaneously recorded with O15/PET. All participants moved their right hand on a digitizing tablet from a central point to eight equidistant targets presented on a monitor in synchrony with tones at 1 s intervals in 90 s blocks. Tasks were: 1) learning to reach for and anticipate the appearance of the same repeating sequence of eight targets in two consecutive blocks (SEQ1, SEQ2); 2) learning a different sequence of eight repeating targets by attending to the display without moving for the first block and by reaching in a successive block (VSEQ). In SEQ1, individuals in the control group showed steadily decreased reaction times and, by the end of SEQ1 and in SEQ2, were able to predict five targets on average. In VSEQ, they predicted five to six targets. p-HD participants predicted an average of two to three targets by the end of both SEQ1 and SEQ2, but significantly improved their performance by the end of the VSEQ testing block. During SEQ, PET recordings showed greater activation in p-HD participants than in controls in the left mediodorsal thalamus and dorsolateral prefrontal cortex. The results suggest that sequence learning is impaired in p-HD individuals, with greater impairment when concomitant movements are required. These findings point to an early deterioration of frontal executive functions and abnormalities in striato-frontal processing. Increased activation of mediodorsal thalamic-prefrontal pathways may compensate for early degeneration of the caudate nucleus and its output.

12:20 – 1:10

Lunch break (cold lunch provided)

1:10 – 1:40

PARAMETER STABILITY IN THE TD MODEL FOR COMPLEX CR TOPOGRAPHIES

J. W. Moore, J. S. Marks, V. E. Castagna, and R. J. Polewan

University of Massachusetts

e-mail: <jwmoore@john.sbs.umass.edu>

A long-time goal of quantitative models of classical conditioning has been to describe the topography of the conditioned response (CR), its temporal dynamics following presentation of a conditioned stimulus (CS).  One of the more promising computational approaches to CR topography is Sutton and Barto's Temporal Difference Model with the Complete Serial Compound Implementation, henceforth referred to as the TD (CSC) model. The model assumes a spreading activation mechanism for representing the elapsed time triggered by the onset of a CS. The question of interest concerns the stability of the model's parameters in classical eyeblink conditioning. That is, to what extent do best-fitting parameter values change as a function of amount of training and in relation to CSs of different modalities and susceptibility to blocking because of prior training in one CS?  Parameters of the TD (CSC) model that best fit complex eyeblink CRs do not remain invariant over training and experimental conditions.  Rather, they were found to vary with amount of training and other experimental treatments.  Because of the potential for aligning TD (CSC) model parameters with computational compartments within the cerebellum and its cellular constituents, knowledge of variation in the model's parameters can point the way toward understanding how cellular processes controlling CS salience and higher-order conditioning operate on the scale of the hundreds of milliseconds that constitute a typical trial of eyeblink conditioning.

1:40 – 2:10

SYSTEMATIC DRIFT TOWARD THE EIGENPERIOD IN A RHYTHMIC CONTINUATION TASK

Dagmar Sternad^a, Hong Yu^a, and Daniel M. Russell^b

^aPennsylvania State University          ^bPenn State Berks-Lehigh Valley College

e-mail: <dxs48@psu.edu>

Studies of rhythmic timing have revealed systematic variability and drift in the movement period during metronome pacing and after the metronome has been turned off. Such deviations and fluctuations have often been interpreted as stochastic properties of an internal timekeeper or as peripheral noise. The hypothesis of this study is that period variability and drift arise from biomechanical properties, captured in the difference between the target period and the preferred or natural period of the limb. Participants tracked visual sinusoidal targets of seven different periods, swinging one of three pendulums in their dominant hand (preferred periods approximately 800, 1000, 1200 ms). The target periods were designed such that three target periods were longer (50, 100, 150 ms), three shorter (-50, -100, -150 ms), and one identical to the preferred period. During the synchronization interval (20 s) the visual target motion and on-line continuous feedback of the pendulum position were displayed on a monitor screen. For the continuation interval the monitor was turned off and rhythmic movements were continued for 60 s. In the continuation interval, systematic period drift was observed towards the initially preferred period for a given pendulum. Variability was higher for larger period discrepancies between target and limb movement. Continuous analysis of cycle periods shows an exponential approach towards the initially preferred period. These results are consistent with interpreting variability as the signature of stability in coupled oscillations, and the period drift as indicating an increasingly weaker coupling of the oscillation to a memorized target period.

2:10 – 2:40

JOINT TIMING IN REACHING AROUND OBSTACLES

Steven A. Jax^a , Jeremy R. Graham^a, Ruud G. J. Meulenbroek^b ,

David A. Rosenbaum^a, and Jonathan Vaughan^c

^aPennsylvania State University     ^bUniversity of Nijmegen     ^cHamilton College

e-mail: <saj151@psu.edu>

This research tests a computational model of manual obstacle avoidance based on a posture-based theory of motor control [Rosenbaum et al., Psychological Review, 108, 709–734 (2001)]. According to this theory, manual obstacle avoidance is achieved by superimposing a back and forth movement to and from a via posture onto a movement made directly to an end posture. To test this model, we had participants perform reaching movements between targets in the presence of or in the absence of an intervening obstacle. Predictions from several variations of the model, each using different assumptions about movement execution, were compared to the participants’ movements. Similarities between the observed and predicted data lend credence to the main assumptions of the model, whereas differences between the observed and predicted data, which were systematic, offer hints about ways in which the model might be amended or extended.

2:40 – 3:00

Coffee break

3:00 – 3:30

TEMPORAL COORDINATION BETWEEN MENTAL AND MOTOR OPERATIONS: TESTING THE STRATEGIC COORDINATION HYPOTHESIS

Jason S. Augustyn, Sarah E. Benjamin, Kristen N. Gacka, Jeremy R. Graham, and

David A. Rosenbaum

Pennsylvania State University

e-mail: <jsa144@psu.edu>

This study was designed to address the question of how people coordinate mental and motor processes. We asked 20 undergraduates to move the hand from a start position to one of two targets depending on the pitch of a tone (high or low) which came on after a medium-pitched warning tone. The duration of the warning tone was short, medium, or long in different blocks of trials, and the warning tone duration was crossed, in different blocks, with two distances between the starting location and the midpoint between the two targets. An optimal scheduling model predicted that participants would move during the warning interval to minimize the subsequent time to enter the correct target. The behavior of some, but not all, participants approximated the predictions of this model.

3:30 – 4:00

TEMPORAL RELATIONSHIPS BETWEEN ACTIONS AND AUDITORY FEEDBACK IN MUSIC PERFORMANCE

Peter Q. Pfordresher

University of Texas at San Antonio

e-mail: <ppfordresher@utsa.edu>

Three experiments manipulated relative timing relationships between auditory feedback and produced onsets in music performance through delayed auditory feedback (DAF). DAF manipulations in Experiment 1 displaced feedback timing by a percentage of produced inter-onset intervals (IOIs), thereby desychronizing feedback onsets and produced onsets. This manipulation yielded more variable produced timing as DAF percentages increased, with a smaller increase to error rates; overall disruption was reduced when performers subdivided produced IOIs via mental counting. In Experiment 2, feedback pitches were synchronized with produced onsets, but were altered to match the pitches of events produced earlier according to a serial lag. This manipulation primarily increased error rates, with a smaller increase to timing variability. Error rates were reduced when the serial lag of the feedback matched the number of beats separating strong accents in the notated meter for many participants. In Experiment 3, delay types from other experiments were combined: Performers heard pitches that matched earlier produced events and were desynchronized with produced onsets. Disruption did not reflect an additive combination of disruption found in other experiments. These results cannot be fully accounted for by leading theories of DAF disruption; they suggest coupling between the systems underlying perception and production on distinct levels of timing (Experiment 1) and sequencing (Experiment 2), and also interactions between these levels (Experiment 3). Moreover, some results suggest that hierarchical cognitive plans guide this perception/action coupling.

4:00 – 4:30

TIME AND ATTENTION:  INTERFERENCE EFFECTS IN DURATION JUDGMENT AND TEMPORAL ORDER MEMORY TASKS

Scott W. Brown and G. Andrew Smith-Petersen

University of Southern Maine

e-mail: <swbrown@usm.maine.edu>

The purpose of this research is to investigate the attentional resource demands of time perception and temporal order memory.  Participants judged certain temporal attributes of a series of wordlists presented on a computer screen.  The words were displayed for 1.4 s each, and the lists contained 10 words (14 s total), 15 words (21 s total), or 20 words (28 s total).  At the end of each list, participants judged either the list duration, the temporal order of the words, or both duration and temporal order.  In addition, different groups of participants were exposed to control, easy, or difficult mental workload conditions during list presentation.  Participants in the control condition had no additional task requirements other than attending to the lists, participants in the easy (or n-3) condition were required to mentally subtract 3 from a series of random 2-digit numbers read to them by the experimenter, and participants in the difficult (or n-7) condition had to subtract 7 from a series of 2-digit random numbers.  The results showed a clear pattern of bidirectional interference between timing and temporal order:  The temporal order task interfered with time judgments, and the timing task interfered with temporal order judgments.  The mental workload task disrupted both time judgments and temporal order judgments.  The results indicate that duration and temporal order are closely related temporal attributes, and suggest that the processing of these attributes relies on the same set of attentional resources.

5:00 - 6:30

Drinks in a bar

6:30 - 8:30

Dinner at Bentara restaurant (76 Orange Street)

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