Interval Discrimination Research Articles

Discrimination of visually perceived intervals of time.

The discrimination of short intervals of time, demarcated by a foveally presented spatially distinct double pulse of light, was studied under several conditions of pulse intensity, angular diameter, and duration. We defined temporal acuity as a measure of discrimination capacity in terms of d′ values. It is shown that the acuity mechanism uses largely integrated information—in the spatial and temporal domain, up to at least 56′ and 32 msec, respectively. Acuity increases slightly with increasing integrated pulse energy, but seems quite independent of the presence of an adapting field of appreciable brightness. Studies on the effect of the foveal site aimed at by the pulses of light have shown that temporal projections lead to significantly poorer acuity values than nasal projections. Monoptic and dichoptic stimulation, however, are fully equivalent.

Discrimination of spatial and temporal intervals defined by three light flashes: Effects of spacing on temporal judgments and of timing on spatial judgments

Observers were presented stimulus patterns consisting of a sequence of three laterally displaced light flashes, which defined two spatial intervals and two temporal intervals. The position and time of the second flash were varied factorially, and observers were asked to make relative judgments of either the two spatial intervals or the two temporal intervals. “Induction” effects of stimulus timing on spatial judgments and of stimulus spacing on temporal judgments were both found; however, the directionality of these effects differed between subjects. The results are inconsistent with the hypothesis, derived from previous findings, that such effects are determined primarily by a tendency toward perceiving constant velocity of apparent motion; it is proposed that the directionality of the induction effects is determined largely by the strategy adopted by the observer for combining spatial and temporal stimulus information.

Discrimination of time intervals marked by brief acoustic pulses of various intensities and spectra

Experienced observers were asked to identify, in a four-level 2AFC situation, the longer of two unfilled time intervals, each of which was marked by a pair of 20-msec acoustic pulses. When all the markers were identical, high-level (186-dB SPL) bursts of coherently gated sinusoids or bursts of band-limited Gaussian noise, a change in the spectrum of the markers generally did not affect performance. On the other hand, for 1-kHz tone-burst markers, intensity decreases below 25 dB SL were accompanied by sizable deterioration of the discrimination performance, especially at short (25-msec) base intervals. Similarly large changes in performance were observed also when the two tonal markers of each interval were made very dissimilar from each other, either in frequency (frequency difference larger than 1 octave) or in intensity (level of the first marker at least 45 dB below the level of the second marker). Time-difference thresholds in these two latter cases were found to be nonmonotonically related to the base interval, the minima occurring between 40- and 80-msec onset separations.

Balancing the scales for music and speech

The results of our experiments on the identification and discrimination of musical intervals, along with the results of experiments by other investigators, are interpreted with regard to the possible “natural” basis of musical scales. We have concluded, primarily from basic differences in the perception of intervals by musicians and nonmusicians, that there is little evidence for the existence of “natural” interval categories, either in the sense of being innately determined by characteristics of the auditory processing system, or in the sense of early learning of the relations between partials in natural sounds. In light of the fact that many of the characteristics associated with the perception of speech, e.g., robust categorical perception, adaptation, and dichotic ear advantage, are also evident in the perception of musical intervals, the general question of the relationship between music perception and speech perception is also discussed.

The effect of marker variability on the discrimination of temporal intervals

This research investigates the human observer’s ability to discriminate between the durations of two silent intervals, each interval preceded and followed by noise bursts called markers. The markers are separated by T or T + ΔT′ msec and T ranges from 0.3 to 1,000 msec. ΔT is defined as that value of ΔT′ for which the probability of discriminating T from T + ΔT′ is 0.75. We compared the value of AT for conditions in which the markers were fixed in amplitude and duration with conditions in which the marker amplitudes and durations were randomly chosen. ΔT increased by as much as a factor of 4 when the amplitude and duration of the markers were randomized. The performance decrement was primarily due to randomizing the first marker duration.

Discrimination of short temporal intervals: A comparison of two models

Duration-discrimination data from an experiment using empty auditory intervals in a two-alternative forced-choice paradigm are presented. The observed functional relationship between standard deviation of the psychometric density function and stimulus duration is shown to be fit significantly better by a Weber’s law model of duration discrimination than by Creelman’s counter model. Both models fail to predict the rapid rise in the Weber fraction observed for durations longer than about 2 sec. However, the Weber’s law model, based on a generalization of Weber’s law, accurately predicts the initial drop in the Weber fraction for very short durations and the observed constancy of the Weber fraction for durations up to 2 sec.

Discrimination of the temporal separation between pairs of sinusoidal bursts

In 1948, Henry [J. Exp. Psychol. 38, 734–743 (1948)] found that duration of pure tones is most discriminable in the 0.5–2-kHz frequency range. The present study represents an attempt to examine whether frequency effects can be observed also in the discrimination of time intervals marked by two bursts of pure tones, identical in frequency. The frequency of the markers covered a range from 0.5 to 4 and their level was 86 dB SPL. Each tone burst marker had a 20-msec total duration and its envelope was smoothened so that the major part of the sound energy be kept within the 50-Hz range surrounding the tonal frequency. Data of three trained listeners, obtained for interburst intervals (t) ranging from 20 to 140 msec, indicate that the logarithm of the interburst interval difference discriminable at threshold (Δtd′=1.0) is a nearly linear function of log t. The slope of this function is close to 0.5 for the 0.5- and the 4-kHz markers, whereas it is approximately 0.8 for the 1- and 2-kHz markers. Pitch difference cues in the pairs of markers may only partly account for the observed frequency effect. [Supported by NINDS Grant No. 03586.]

Temporal discrimination of short intervals of dreamless sleep.

6 Ss were wakened prior to dream on 3 successive nights and gave estimates of sleep duration. Clock intervals were 60, 30, and 90 min. respectively. While daytime estimation was considerably more accurate, Ss showed systematic differences in sleep time estimation. This suggests that temporal discrimination is still possible even in the absence of stored mentation.

The control of interresponse time probabilities by the magnitude of reinforcing brain stimulation

To assess the relation between the probability of individual interresponse times (IRTs) and the magnitude of contingent reinforcing brain stimulation, a schedule was used which restricts reinforcer presentation to responses spaced by a minimum temporal interval. The probability of IRTs falling in the region of the criterion interval increased monotonically with current amplitude across a wide range of scheduled intervals. These results contrast with IRT performance under continuous and variable-interval schedules, where a wide variety of idiosyncratic functional relations has been found. Use of the IRT schedule thus helps to clarify the function of brain stimulation magnitude in free-operant responding, providing an alternative datum to potentially confounded average response rate measures. The scheduled spacing of responses also allows an analysis in terms of the discrimination of temporal intervals. As brain stimulation magnitude increased, IRT distributions showed more discrete peaking near the criterion interval, and thus finer temporal discrimination. IRTs following a reinforced response were paced more accurately than IRTs following a nonreinforced response, pointing to the discriminative function of reinforcer presentation (proportional to brain stimulation magnitude) in temporal discrimination procedures. A signal detection analysis indicated that an animal's bias toward emission of subcriterion IRTs increases along with temporal discrimination accuracy in proportion to brain stimulation magnitude.

Melodic interval discrimination and the influence of training

Abstract The influence of training on melodic interval discrimination was examined using 48 Ss. Experimental and control groups were matched on the basis of age, general intelligence and musical intelligence. A test of melodic interval discrimination was administered to all Ss followed by a period of training for the experimental Ss. A second test of melodic interval discrimination was then administered to all Ss. It was found that training improved performance on the second test irrespective of prior formal music experience and that the greatest gains in performance were obtained by Ss with low musical intelligence. Melodic interval discrimination was found to be related to both pitch discrimination and musical intelligence.

Responses of auditory cortical neurons to paired clicks

In cats immobilized with tubocurarine, a paired-click method was used to determine the duration of the refractory period of 75 auditory cortical neurons responding to clicks with a latent period of up to 30 msec. Sixty-eight of the neurons exhibited no spontaneous activity, while in the other seven spontaneous activity was infrequent and irregular. It was found that a click makes responding neurons refractory to a second click for a long time. The duration of this refractory period is 3 to 700 msec; it is constant for each neuron, but varies from one neuron to another. A direct relationship was found between the number of neurons responding to the second click and the interval between the first and second clicks: the shorter the interval the fewer neurons respond to the second click. It is postulated that this dependence lies at the basis of the neurophysiological mechanism of perception and discrimination of short time intervals.

The effects of maternal nicotine absorption or hypoxic episodes upon appetitive behavior of rat offspring.

AbstractOffspring of rats which had received either daily nicotine injections or hypoxic episodes throughout gestation were tested at adulthood on various appetitive schedules in a double‐bar Foringer chamber. The hypoxic offspring and the offspring whose mothers had received nicotine throughout gestation and the nursing period performed more poorly on fixed‐ratio, variable interval discrimination, and discrimination reversal schedules. Possible explanatory hypotheses are discussed.

Study Interval, Manipulated Frequency, and Verbal Discrimination Learning

Two hypotheses suggested by a frequency theory of verbal discrimination learning were investigated: (a) than an increase in study time would facilitate acquisition of a verbal discrimination list; and (b) that increasing familiarization with stimulus materials prior to training would retard acquisition rate of a verbal discrimination list. Study intervals of 2 and 4 seconds were factorially combined with verbal discrimination pairs of high and low frequency. Free recall learning was employed to produce frequency differentials among discrimination pairs. No evidence was found to support the hypothesis regarding a possible relationship between study time and verbal discrimination acquisition. A significant effect in speed of acquisition due to differential frequency was obtained, indicating faster learning of low frequency pairs.

The Influence of Selected Factors on Interval Identification

1HE MUSICAL INTERVAL may be considered the basic unit of musical construction.1 With its two tones presented sequentially, the interval is the basic melodic unit; with the tones presented simultaneously, the unit is harmonic. A highly developed awareness and understanding of musical intervals is considered basic to good musicianship. Interval discrimination has been used as an indicator of musical aptitude in tests developed by Drake2 and Lundin.3 Ottman4 indicates that a close relationship exists between skill in sightsinging and interval identification. Training designed to develop ability in interval identification is included in the ear training portions of most beginning college theory classes. Considering the apparent importance of this ability, it is surprising to discover the small amount of research that has been done in an attempt to understand what is involved in identifying intervals. Texts designed for the development of basic musicianship, such as those by Wedge,5 Bauman and Walton,6 and Ottman,7 offer some procedural suggestions for learning to identify intervals, but are not concerned with presenting experimental evidence or hypothetical speculation in support of these suggestions. An examination of texts and articles in the psychology of music provides some information concerning interval identification, but much of

An investigation into the development of melodic interval discrimination

Trotter's “melometer” was used to investigate some proposals concerning melody discrimination. An analysis of covariance which controlled for scores on the “Wing Test of Musical Intelligence” showed that discrimination differed in artists, professional musicians and students. The significant difference between the groups indicated three levels of discrimination, one of which was attributed to musical training and the other to some underlying ability common to the Fine Arts. This finding was contrasted with some of Trotter's proposals, the method was evaluated and some possible limitations of the experiment given.

Second interval discrimination conditioning of the GSR as a function of UCS intensity and trace and delay conditioning paradigms.

Second interval discrimination conditioning of the GSR as a function of UCS intensity and trace and delay conditioning paradigms.

Effect upon auditory interval discrimination by perturbations in the nanosecond region

A temporal uncertainty, or jitter, of less than 200 nsec in the intervals of an auditory pulse train significantly raises the interval (pitch) discrimination threshold. The results suggest a preneural, i.e., cochlear, analysis for high frequency auditory pulse trains.

Discrimination of mean temporal interval within jittered auditory pulse trains.

Thresholds for the auditory discrimination of mean interpulse interval were determined as a function of the number of intervals and of temporal variability, or “jitter.” Interval discrimination at low pulse frequencies is relatively independent of the number of pulses and of jitter. By contrast, interval discrimination at high pulse frequencies is extremely dependent upon the number of pulses and the level of jitter. The precision of interval discrimination achieved suggests that pulse interval discrimination for high pulse frequencies is carried out by a spectral analysis, rather than by a temporal analysis, of auditory information.

Cooperative Research in Programed Learning: Taped Interval Discrimination Drills

IJDUCATORS HAVE ample reason to wonder if a book, method, instructional innovation, or research project which is developed in one situation would be effective in some distant locale under somewhat different conditions. Each public school, college, and university has its own staff in addition to its own special problems. Many instructional progTams and practices evolve which are effective in a particular institution and, perhaps, with a particular teacher. This study was made to determine if a set of programed taped interval drills, which were developed for use at a large midwestern university, could be used effectively in a smaller southern state college in which the educational situation was quite different.

Transfer of a Discrimination and a Discrimination Reversal between Two Manipulandum-Defined Responses

An experiment was performed to determine the extent to which the effects of continuous reinforcement, variable interval reinforcement, discrimination training, and discrimination reversal training would transfer between a vertical and a horizontal bar-pressing response in the free operant situation. No transfer of continuous or variable interval reinforcement was found. However, both discrimination training and discrimination reversal training showed very appreciable amounts of inter-response transfer. These results are discussed in terms of a mediational process involving classically conditioned mediators which exert discriminative control over overt responding.