The role of tone duration in dichotic temporal order judgment

A common timing mechanism across different millisecond domains: evidence from perceptual and motor tasks

Temporal information processing (TIP) constitutes a complex construct that underlies many cognitive functions and operates in a few hierarchically ordered time domains. This study aimed to verify the relationship between the tens of milliseconds and hundreds of milliseconds domains, referring to perceptual and motor timing, respectively. Sixty four young healthy individuals participated in this study. They underwent two auditory temporal order judgement tasks to assess their performance in the tens of milliseconds domain; on this basis, groups of high-level performers (HLP) and low-level performers (LLP) were identified. Then, a maximum tapping task was used to evaluate performance in the hundreds of milliseconds domain. The most remarkable result was that HLP achieved a faster tapping rate and synchronised quicker with their "internal clock" during the tapping task than did LLP. This result shows that there is a relationship between accuracy in judging temporally asynchronous stimuli and ability to achieve and maintain the pace of a movement adequate to one's internal pacemaker. This could indicate the strong contribution of a common timing mechanism, responsible for temporal organisation and coordination of behaviours across different millisecond domains.

Holistic temporal order judgment of tones requires top-down disentanglement

How temporal sequence gets organized is a central topic in cognitive processing. In a high-frequency time window of tens of milliseconds, the temporal order is reconstructed rather than mirroring the sequence of events objectively in physical time. Two separate phases or strategies, a holistic coding phase that groups successively presented events as a gestalt and a disentanglement phase that decodes the temporal order of discrete events from the gestalt representation, may presumably be involved in the perception of temporal order across different modalities. With a temporal order adaptation protocol of pure tones using glide adaptors, the present study demonstrated a dissociation between constant discriminability and shifted subjective simultaneity across different adaptor directions. While discriminability of temporal order was not adapted by glides, revealing a constant coding sensitivity of different asynchronies, the shift of subjective simultaneity indicated the recalibration of a top-down disentanglement of the holistic processing under the influence of glide adaptors. The results suggest a dual-phase holistic processing in temporal order perception, supporting two separate cognitive strategies for event timing on the sub-second level.

Perceptual simultaneity range for two dichotically presented pure tones with frequency separation below 0.5 Bark

The perceptual simultaneity range for two diotically presented tones increases with decreasing frequency separation of the two tones from approximately 0.5 Bark. As the present study of two frequency regions shows, this effect is not observed when the two tones are not presented to the same ear, i.e., presented dichotically. Since the increase in simultaneity is only observed when the tones are presented to the same ear, it is possible that it reflects the time-frequency uncertainty within a cochlear filter.

The Effects of Psychophysical Methods on Spectral and Spatial TOJ Thresholds

(1) Background: A large number of studies have used different psychophysical methods for measuring temporal order judgment (TOJ) thresholds, which makes it difficult to compare the results of different studies. In this study, we aimed to compare the thresholds measured by the two main procedures used in many studies, the adaptive procedure, and the method of constant stimuli; (2) Methods: Study 1 tested spatial TOJ and included 109 participants, 50 using the adaptive procedure and 59 using the constant stimuli procedure. Study 2 tested spectral TOJ and included 223 participants, 119 using the adaptive procedure and 104 using constant stimuli; (3) Results: Both the spatial and spectral TOJ results showed no difference between the psychophysical methods, either in (1) the form of the distribution; (2) the mean; or (3) the standard deviation. However, Bayesian analysis showed a large Bayes factor only for spatial TOJ; (4) Conclusions: There is no difference between spatial TOJ thresholds measured by an adaptive procedure and the method of constant stimuli, and their results can be compared across studies. A similar conclusion can be drawn also for spectral TOJ, but should be considered more cautiously.

The role of tone duration in dichotic temporal order judgment II: Extending the boundaries of duration and age

Temporal order judgment (TOJ) measures the ability to correctly perceive the order of consecutive stimuli presented rapidly. Our previous research suggested that the major predictor of auditory dichotic TOJ threshold, a paradigm that requires the identification of the order of two tones, each of which is presented to a different ear, is the time separating the onset of the first tone from the onset of the second tone (stimulus-onset-asynchrony, SOA). Data supporting this finding, however, was based on a young adult population and a tone duration range of 10–40 msec. The current study aimed to evaluate the generalizability of the earlier finding by manipulating the experimental model in two different ways: a) extending the tone duration range to include shorter stimulus durations (3–8 msec; Experiment 1) and b) repeating the identical testing procedure on a different population with temporal processing deficits, i.e., older adults (Experiment 2). We hypothesized that the SOA would predict the TOJ threshold regardless of tone duration and participant age. Experiment 1 included 226 young adults divided into eight groups (each group receiving a different tone duration) with duration ranging from 3–40 msec. Experiment 2 included 98 participants aged 60–75 years, divided into five groups by tone duration (10–40 msec). The results of both experiments confirmed the hypothesis, that the SOA required for performing dichotic TOJ was constant regardless of stimulus duration, for both age groups: about 66.5 msec for the young adults and 33 msec longer (100 msec) for the older adults. This finding suggests that dichotic TOJ threshold is controlled by a general mechanism that changes quantitatively with age. Clinically, this has significance because quantitative changes can be more easily remedied than qualitative changes. Theoretically, our findings show that, with dichotic TOJ, tone duration affects threshold by providing more time between the onsets of the consecutive stimuli to the two ears. The findings also imply that a temporal processing deficit, at least among older adults, does not elicit the use of a different mechanism in order to judge temporal order.

Spatial and Spectral Auditory Temporal-Order Judgment (TOJ) Tasks in Elderly People Are Performed Using Different Perceptual Strategies

The Temporal-Order Judgment (TOJ) paradigm has been widely investigated in previous studies as an accurate measure of temporal resolution and sequencing abilities in the millisecond time range. Two auditory TOJ tasks are often used: (1) a spatial TOJ task, in which two identical stimuli are presented in rapid succession monaurally and the task is to indicate which ear received the first stimulus and which ear received the second one (left-right or right-left), and (2) a spectral TOJ task, in which two tones of different frequencies are presented asynchronously to both ears binaurally and the task is to report the sequence of these tones (low-high or high-low). The previous literature studies conducted on young volunteers indicated that the measured temporal acuity on these two tasks depended on the procedure used. As considerable data are now available about age-related decline in temporal resolution ability, the aim of the present study was to compare in elderly subjects the pattern of performance on these two tasks. A total of 40 normal healthy volunteers aged from 62 to 78 years performed two TOJ tasks. The measurement was repeated in two consecutive sessions. Temporal resolution was indexed by the Auditory Temporal-Order Threshold (ATOT), i.e., the minimum time gap between successive stimuli necessary for a participant to report a before-after relation with 75% correctness. The main finding of the present study was the indication of differences in the elderly in performance on two tasks. In the spatial task, the distribution of obtained ATOT values did not deviate from the Gaussian distribution. In contrast, the distribution of data in the spectral task deviated significantly from the Gaussian and was spread more to the right. Although lower ATOT values were usually observed in Session 2 than in Session 1, such difference was significant only in the spectral task. We conclude that although temporal acuity and sequencing abilities in the millisecond time range are probably based in neuronal oscillatory activity, the measured ATOTs in the elderly seem to be stimulus-dependent, procedure-related, and influenced by the perceptual strategies used by participants.

Auditory temporal processing, reading, and phonological awareness among aging adults

Auditory temporal processing (ATP) has been related in the literature to both speech perception as well as reading and phonological awareness. In aging adults, it is known to be related to difficulties in speech perception. In the present study, we aimed to test whether an age-related deficit in ATP would also be accompanied by poor reading and phonological awareness. Thirty-eight aging adults were compared to 55 readers with dyslexia and 42 young normal readers on temporal order judgment (TOJ), speech perception, reading, and phonological awareness tests. Aging adults had longer TOJ thresholds than young normal readers, but shorter than readers with dyslexia; however, they had lower speech perception accuracy than both groups. Phonological awareness of the aging adults was better than readers with dyslexia, but poorer than young normal readers, although their reading accuracy was similar to that of the young controls. This is the first report on poor phonological awareness among aging adults. Suprisingly, it was not accompanied by difficulties in reading ability, and might instead be related to aging adults' difficulties in speech perception. This newly discovered relationship between ATP and phonological awareness among aging adults appears to extend the existing understanding of this relationship, and suggests it should be explored in other groups with ATP deficits.

Is conscious perception a series of discrete temporal frames?

This paper reviews proposals that conscious perception consists, in whole or part, of successive discrete temporal frames on the sub-second time scale, each frame containing information registered as simultaneous or static. Although the idea of discrete frames in conscious perception cannot be regarded as falsified, there are many problems. Evidence does not consistently support any proposed duration or range of durations for frames. EEG waveforms provide evidence of periodicity in brain activity, but not necessarily in conscious perception. Temporal properties of perceptual processes are flexible in response to competing processing demands, which is hard to reconcile with the relative inflexibility of regular frames. There are also problems concerning the definition of frames, the need for informational connections between frames, the means by which boundaries between frames are established, and the apparent requirement for a storage buffer for information awaiting entry to the next frame.

Dyslexia as a multi-deficit disorder: Working memory and auditory temporal processing

Dyslexia is difficulty in acquiring reading skills despite adequate intelligence and sufficient reading opportunities. Its origin is still under debate. Studies usually focus on a singular cause for dyslexia; however, some researchers argue that dyslexia reflects multiple deficits. Two of the abilities under investigation in dyslexia are working memory (WM) and auditory temporal processing (ATP). In order to better evaluate the relative roles of WM and ATP in dyslexia, in the present study, we tested the contribution of WM and ATP to different types of reading performance and phonological awareness in dyslexia, using a multidimensional approach. Seventy-eight adults with dyslexia and 23 normal-reading adults performed WM and ATP tasks, as well as reading and phonological awareness tests. Readers with dyslexia showed poorer performance on all tests. Both WM and ATP were significant predictors of reading performance and phonological awareness among participants with dyslexia. Dividing participants with dyslexia according to their performance level on WM and ATP tasks revealed group differences in reading and phonological awareness tests. Both WM and ATP contribute to dyslexia, and varying levels of difficulties in both of these abilities are observed among this population. This is strong evidence in favor of the multi-deficit approach in dyslexia, and suggests that researchers should consider this approach in future studies of dyslexia.

EEG correlates of cognitive time scales in the Necker-Zeno model for bistable perception

The Necker-Zeno model of bistable perception provides a formal relation between the average duration of meta-stable percepts (dwell times T) of ambiguous figures and two other basic time scales (t₀, ΔT) underlying cognitive processing. The model predicts that dwell times T covary with t₀, ΔT or both. We tested this prediction by exploiting that observers, in particular experienced meditators, can volitionally control dwell times T. Meditators and non-meditators observed bistable Necker cubes either passively or tried to hold their current percept. The latencies of a centro-parietal event-related potential (CPP) were recorded as a physiological correlate of t₀. Dwell times T and the CPP latencies, correlated with t₀, differed between conditions and observer groups, while ΔT remained constant in the range predicted by the model. The covariation of CPP latencies and dwell times, as well as their quadratic functional dependence extends previous psychophysical confirmation of the Necker-Zeno model to psychophysiological measures.

What Happens in a Moment

There has been evidence for the very brief, temporal quantization of perceptual experience at regular intervals below 100 ms for several decades. We briefly describe how earlier studies led to the concept of "psychological moment" of between 50 and 60 ms duration. According to historical theories, within the psychological moment all events would be processed as co-temporal. More recently, a link with physiological mechanisms has been proposed, according to which the 50-60 ms psychological moment would be defined by the upper limit required by neural mechanisms to synchronize and thereby represent a snapshot of current perceptual event structure. However, our own experimental developments also identify a more fine-scaled, serialized process structure within the psychological moment. Our data suggests that not all events are processed as co-temporal within the psychological moment and instead, some are processed successively. This evidence questions the analog relationship between synchronized process and simultaneous experience and opens debate on the ontology and function of "moments" in psychological experience.

Temporal structure of consciousness and minimal self in schizophrenia

The concept of the minimal self refers to the consciousness of oneself as an immediate subject of experience. According to recent studies, disturbances of the minimal self may be a core feature of schizophrenia. They are emphasized in classical psychiatry literature and in phenomenological work. Impaired minimal self-experience may be defined as a distortion of one’s first-person experiential perspective as, for example, an “altered presence” during which the sense of the experienced self (“mineness”) is subtly affected, or “altered sense of demarcation,” i.e., a difficulty discriminating the self from the non-self. Little is known, however, about the cognitive basis of these disturbances. In fact, recent work indicates that disorders of the self are not correlated with cognitive impairments commonly found in schizophrenia such as working-memory and attention disorders. In addition, a major difficulty with exploring the minimal self experimentally lies in its definition as being non-self-reflexive, and distinct from the verbalized, explicit awareness of an “I.” In this paper, we shall discuss the possibility that disturbances of the minimal self observed in patients with schizophrenia are related to alterations in time processing. We shall review the literature on schizophrenia and time processing that lends support to this possibility. In particular we shall discuss the involvement of temporal integration windows on different time scales (implicit time processing) as well as duration perception disturbances (explicit time processing) in disorders of the minimal self. We argue that a better understanding of the relationship between time and the minimal self as well of issues of embodiment require research that looks more specifically at implicit time processing. Some methodological issues will be discussed.

Different Response Patterns Between Auditory Spectral and Spatial Temporal Order Judgment (TOJ)

Temporal order judgment (TOJ) thresholds have been widely reported as valid estimates of the temporal disparity necessary for correctly identifying the order of two stimuli. Data for two auditory TOJ paradigms are often reported in the literature: (1) spatially-based TOJ in which the order of presentation of the same stimulus to the right and left ear differs; and (2) spectrally-based TOJ in which the order of two stimuli differing in frequency is presented to one ear or to both ears simultaneously. Since the thresholds reported using the two paradigms differ, the aim of the current study was to compare their response patterns. The results from three different experiments showed that: (1) while almost none of the participants were able to perform the spatial TOJ task when ISI = 5 ms, with the spectral task, 50% reached an accuracy level of 75% when ISI = 5 ms; (2) temporal separation was only a partial predictor for performance in the spectral task, while it fully predicted performance in the spatial task; and (3) training improved performance markedly in the spectral TOJ task, but had no effect on spatial TOJ. These results suggest that the two paradigms may reflect different perceptual mechanisms.