Duration Discrimination Task Research Articles

Task difficulty modulates voluntary attention allocation, but not distraction in an auditory distraction paradigm

Keeping task-relevant sensory events in the focus of attention while ignoring irrelevant ones is crucial for optimizing task behavior. This attention-distraction balance might change with the perceptual demands of the ongoing task: while easy tasks might be performed with low attentional effort, difficult ones require enhanced attention. The goal of the present study was to investigate how task difficulty affected allocation of attention and distractibility in an auditory distraction paradigm. Participants performed a tone duration discrimination task in which tones were rarely, occasionally presented at a rare pitch (distracters), and task difficulty was manipulated by the duration difference between short and long tones. Short tones were consistently 200 ms long, while long tone duration was 400 ms in the easy, and 260 ms in the difficult condition. Behavioral results and deviant-minus-standard event-related potential (ERP) waveforms suggested similar magnitudes of distraction in both conditions. ERPs without such a subtraction showed that tone onsets were preceded by a negative-going trend, suggesting that participants prepared for tone onsets. In the difficult condition, N1 amplitudes to tone onsets were enhanced, indicating that participants invested more attentional resources. Increased difficulty also slowed down tone offset processing as reflected by significantly delayed offset-related P1 and N1/N2 waveforms. These results suggest that although task difficulty compels participants to attend the tones more strongly, this does not have significant impact on distraction-related processing.

Perceptual Doping: An Audiovisual Facilitation Effect on Auditory Speech Processing, From Phonetic Feature Extraction to Sentence Identification in Noise.

We have previously shown that the gain provided by prior audiovisual (AV) speech exposure for subsequent auditory (A) sentence identification in noise is relatively larger than that provided by prior A speech exposure. We have called this effect "perceptual doping." Specifically, prior AV speech processing dopes (recalibrates) the phonological and lexical maps in the mental lexicon, which facilitates subsequent phonological and lexical access in the A modality, separately from other learning and priming effects. In this article, we use data from the n200 study and aim to replicate and extend the perceptual doping effect using two different A and two different AV speech tasks and a larger sample than in our previous studies. The participants were 200 hearing aid users with bilateral, symmetrical, mild-to-severe sensorineural hearing loss. There were four speech tasks in the n200 study that were presented in both A and AV modalities (gated consonants, gated vowels, vowel duration discrimination, and sentence identification in noise tasks). The modality order of speech presentation was counterbalanced across participants: half of the participants completed the A modality first and the AV modality second (A1-AV2), and the other half completed the AV modality and then the A modality (AV1-A2). Based on the perceptual doping hypothesis, which assumes that the gain of prior AV exposure will be relatively larger relative to that of prior A exposure for subsequent processing of speech stimuli, we predicted that the mean A scores in the AV1-A2 modality order would be better than the mean A scores in the A1-AV2 modality order. We therefore expected a significant difference in terms of the identification of A speech stimuli between the two modality orders (A1 versus A2). As prior A exposure provides a smaller gain than AV exposure, we also predicted that the difference in AV speech scores between the two modality orders (AV1 versus AV2) may not be statistically significantly different. In the gated consonant and vowel tasks and the vowel duration discrimination task, there were significant differences in A performance of speech stimuli between the two modality orders. The participants' mean A performance was better in the AV1-A2 than in the A1-AV2 modality order (i.e., after AV processing). In terms of mean AV performance, no significant difference was observed between the two orders. In the sentence identification in noise task, a significant difference in the A identification of speech stimuli between the two orders was observed (A1 versus A2). In addition, a significant difference in the AV identification of speech stimuli between the two orders was also observed (AV1 versus AV2). This finding was most likely because of a procedural learning effect due to the greater complexity of the sentence materials or a combination of procedural learning and perceptual learning due to the presentation of sentential materials in noisy conditions. The findings of the present study support the perceptual doping hypothesis, as prior AV relative to A speech exposure resulted in a larger gain for the subsequent processing of speech stimuli. For complex speech stimuli that were presented in degraded listening conditions, a procedural learning effect (or a combination of procedural learning and perceptual learning effects) also facilitated the identification of speech stimuli, irrespective of whether the prior modality was A or AV.

Selective Auditory Attention and Spatial Disorientation Cues Effect on Flight Performance.

INTRODUCTION: The auditory system is not as heavily involved in the pilot's spatial orientation as the visual and vestibular systems; however, it plays a significant role in the cockpit for communication and warning information. The aim of this research was to investigate the combined effect of selective auditory attention and simulator-induced spatial disorientation (SD) cues on pilots' flight performance. We hypothesized that the flight performance in both disoriented and oriented flight profiles would be impaired by selective auditory attention.METHODS: Using an SD simulator, 40 male military pilots (M = 31.9; SD = 7.41) were exposed to 12 flight sequences, where 6 contained a SD-conflict, 3 with motion illusions and 3 with visual illusions. The pilots performed a duration discrimination task (DDT) involving sound stimuli while completing these profiles under SD-conflict and nonconflict conditions.RESULTS: In five flight profiles tested, the DDT and SD cues increased the pilots' cognitive workload, adversely affecting their flight performance. In the approach and landing profiles involving visual illusions, significant differences between the control and DDT groups were found for both nonconflict and SD-conflict flight sequences, whereas differences were only significant between nonconflict and SD-conflict flights for the two vestibular SD profiles.DISCUSSION: The results obtained partially support our hypothesis that performing the DDT, even in the absence of SD-conflict, significantly affects pilots' flight performance. In some cases, despite the large increase in cognitive workload, pilots did not activate the "posture first" principle. Pilots should be trained not to respond to auditory stimuli until they have recovered their spatial orientation.Lewkowicz R, Stróżak P, Bałaj B, Francuz P, Augustynowicz P. Selective auditory attention and spatial disorientation cues effect on flight performance. Aerosp Med Hum Perform. 2018; 89(11):976-984.

Temporal Processing of Joyful and Disgusting Food Pictures by Women With an Eating Disorder.

The present study used the presentation of food pictures and judgements about their duration to assess the emotions elicited by food in women suffering from an eating disorder (ED). Twenty-three women diagnosed with an ED, namely anorexia (AN) or bulimia nervosa (BN), and 23 healthy controls (HC) completed a temporal bisection task and a duration discrimination task. Intervals were marked with emotionally pre-rated pictures of joyful and disgusting food, and pictures of neutral objects. The results showed that, in the bisection task, AN women overestimated the duration of food pictures in comparison to neutral ones. Also, compared to participants with BN, they perceived the duration of joyful food pictures as longer, and tended to overestimate the duration of the disgusting ones. These effects on perceived duration suggest that AN women experienced an intense reaction of fear when they were confronted to food pictures. More precisely, by having elevated the arousal level and activated the defensive system, food pictures seemed to have speeded up the rhythm of the AN participants’ internal clock, which led to an overestimation of images’ duration. In addition, the results revealed that, in both tasks, ED women presented a lower temporal sensitivity than HC, which was related to their ED symptomatology (i.e., BMI, restraint and concern) and, particularly, to their weaker cognitive abilities in terms of attention, processing speed and working memory. Considered all together, the findings of the present experiment highlight the role of fear and anxiety in the manifestations of AN and point out the importance of considering non-temporal factors in the interpretation of time perception performance.

The Validity of Functional Near-Infrared Spectroscopy Recordings of Visuospatial Working Memory Processes in Humans.

Functional near infrared spectroscopy (fNIRS) is increasingly used for investigating cognitive processes. To provide converging evidence for the validity of fNIRS recordings in cognitive neuroscience, we investigated functional activation in the frontal cortex in 43 participants during the processing of a visuospatial working memory (WM) task and a sensory duration discrimination (DD) task functionally unrelated to WM. To distinguish WM-related processes from a general effect of increased task demand, we applied an adaptive approach, which ensured that subjective task demand was virtually identical for all individuals and across both tasks. Our specified region of interest covered Brodmann Area 8 of the left hemisphere, known for its important role in the execution of WM processes. Functional activation, as indicated by an increase of oxygenated and a decrease of deoxygenated hemoglobin, was shown for the WM task, but not in the DD task. The overall pattern of results indicated that hemodynamic responses recorded by fNIRS are sensitive to specific visuospatial WM capacity-related processes and do not reflect a general effect of increased task demand. In addition, the finding that no such functional activation could be shown for participants with far above-average mental ability suggested different cognitive processes adopted by this latter group.

Selective Attention and Working Memory Under Spatial Disorientation in a Flight Simulator

ABSTRACTObjective: The aim of this study was to test the effects of visual and vestibular spatial disorientation on the cognitive performance of military aviators while they were piloting a flight simulator.Background: Spatial disorientation (SD), the inability to correctly determine the position and orientation of the aircraft in relation to the ground, poses a serious threat in aviation and can impair the cognitive performance of pilots while flying. More evidence is needed on the effects of visual and vestibular SD on cognition in flight simulators.Method: Pilots performed an auditory selective attention (duration discrimination) task (Experiment 1, N = 16) or an auditory working memory (N-back) task (Experiment 2, N = 16) while completing 6 different flight profiles in the disorientation and control conditions in the GYRO-IPT flight simulator. The flight scenarios included 3 visual illusions (false horizon, shape constancy, size constancy) and 3 vestibular illusions (somatogyral illusion, Coriolis effect, the leans).Results: In both experiments the cognitive performance (task accuracy) decreased for flight profiles with the leans illusion. Also, the flight performance (measured as the number of control reversal errors) was worse for the false horizon illusion and for the somatogyral illusion in both experiments.Conclusion: The results suggest that SD, particularly the vestibular illusion of the leans, can impair selective attention and working memory processes.

Adaptation reveals unbalanced interaction between numerosity and time

Processing quantities such as the number of objects in a set, size, spatial arrangement and time is an essential means of structuring the external world and preparing for action. The theory of magnitude suggests that number and time, among other continuous magnitudes, are linked by a common cortical metric, and their specialization develops from a single magnitude system. In order to investigate potentially shared neural mechanisms underlying numerosity and time processing, we used visual adaptation, a method which can reveal the existence of a dedicated processing system. We reasoned that cross-adaptation between numerosity and duration would concur with the existence of a common processing mechanism, whereas the absence of cross-adaptation would provide evidence against it. We conducted four experiments using a rapid adaptation protocol where participants adapted to either visual numerosity or visual duration and subsequently performed a numerosity or duration discrimination task. We found that adapting to a low numerosity altered the estimation of the reference numerosity by an average of 5 dots, compared to adapting to a high numerosity. Similarly, adapting to a short duration altered the estimation of the reference duration by an average of 43 msec, compared to adapting to a long duration. In the cross-dimensional adaptation conditions, duration adaptation altered numerosity estimation by an average of 1 dot, whereas there was not sufficient evidence to either support or reject the effect of numerosity adaptation on duration judgments. These results highlight that there are partially overlapping neural mechanisms which are dedicated for processing both numerosity and time.

Auditory temporal perceptual learning and transfer in Chinese-speaking children with developmental dyslexia

Perceptual learning refers to the improvement of perceptual performance as a function of training. Recent studies found that auditory perceptual learning may improve phonological skills in individuals with developmental dyslexia in alphabetic writing system. However, whether auditory perceptual learning could also benefit the reading skills of those learning the Chinese logographic writing system is, as yet, unknown. The current study aimed to investigate the remediation effect of auditory temporal perceptual learning on Mandarin-speaking school children with developmental dyslexia. Thirty children with dyslexia were screened from a large pool of students in 3th-5th grades. They completed a series of pretests and then were assigned to either a non-training control group or a training group. The training group worked on a pure tone duration discrimination task for 7 sessions over 2 weeks with thirty minutes per session. Post-tests immediately after training and a follow-up test 2 months later were conducted. Analyses revealed a significant training effect in the training group relative to non-training group, as well as near transfer to the temporal interval discrimination task and far transfer to phonological awareness, character recognition and reading fluency. Importantly, the training effect and all the transfer effects were stable at the 2-month follow-up session. Further analyses found that a significant correlation between character recognition performance and learning rate mainly existed in the slow learning phase, the consolidation stage of perceptual learning, and this effect was modulated by an individuals' executive function. These findings indicate that adaptive auditory temporal perceptual learning can lead to learning and transfer effects on reading performance, and shed further light on the potential role of basic perceptual learning in the remediation and prevention of developmental dyslexia.

Color and time perception: Evidence for temporal overestimation of blue stimuli

The perceived duration of a visual stimulus depends on various features, such as its size, shape, and movement. Potential effects of stimulus color have not been investigated in sufficient detail yet, but the well-known effects of arousal on time perception suggest that arousing hues, such as red, might induce an overestimation of duration. By means of a two-interval duration discrimination task in the sub-second range, we investigated whether participants overestimate the duration of red stimuli in comparison to blue stimuli, while controlling for differences in brightness (individual adjustments by means of flicker photometry) and saturation (colorimetric adjustment in terms of the CIELAB color space). Surprisingly, our results show an overestimation of the duration of blue compared to red stimuli (indicated by a shift of the point of subjective equality), even though the red stimuli were rated as being more arousing. The precision (variability) of duration judgments, i.e., the duration difference limen, did not differ between red and blue stimuli, questioning an explanation in terms of attentional processes.

Synchronized stimuli are perceived to be shorter

PURPOSE: Processing and telling time, or time perception, is vital for the survival of any organism. A variety of spatial cues have been found to be effective in modulating observers’ time perception. Here, we investigated the effect of synchronization, a form of temporal cue, on the perceived duration of visual stimuli in which spatial cues were largely controlled. METHODS AND RESULTS: Stimuli were 100 non-overlapping Gabor patches moving in one of two directions that orthogonal to their orientations. Synchronization of Gabor patches were defined by entropy and correlation; entropy refers to the probability of moving direction change and correlation refers to the likelihood that all Gabor elements reverse their motion directions simultaneously. In Experiment 1, nineteen observers performed a duration discrimination task that included four pairs of stimuli that differed in entropy and correlation and found that stimuli with high synchronization were perceived significantly shorter (by ~50ms) than random but otherwise identical stimuli of the same duration. This contraction effect couldn’t be explained by change in perceived speed (Experiment 2). Varying the display duration from 350 to 1050ms didn’t significantly affect the magnitude of perceived contraction (Experiment 3). Furthermore, we found no significant difference in both appearance and disappearance detection times to stimuli (Experiment 4), ruling out the possibility of different detection time with stimuli of different synchronization factors. CONCLUSIONS: Taken together, our findings suggest that synchronization can also effectively modulate time perception, possibly acting via slowing down the pacemaker, an essential part of the internal clock.

Duration compression induced by visual and phonological repetition of Chinese characters.

Our prior experience heavily influences our subjective time. One of such phenomena is repetition compression, that is, repeated stimuli are perceived shorter than novel stimuli. However, most of the studies on repetition compression used identical stimuli, leaving the question whether similar repetition effects could take place in phonological and semantic level repetition. We used Chinese characters to manipulate different levels of repetition in a duration discrimination task. We replicated earlier findings that repetition of visual identical characters shortened the apparent duration and found the repetition compression was spatially independent. Phonological repetition also caused the duration compression though the effect was weaker than the visual repetition. However, we observed no duration compression during the semantic repetition. The results suggest that repetition compression is mediated by visual and phonological representation of a stimulus in an early stage in processing hierarchy. We explained our findings according to the framework of predictive coding.

Hand-to-Face Remapping But No Differences in Temporal Discrimination Observed on the Intact Hand Following Unilateral Upper Limb Amputation

Unilateral major limb amputation causes changes in sensory perception. Changes may occur within not only the residual limb but also the intact limb as well as the brain. We tested the hypothesis that limb amputation may result in the detection of hand sensation during stimulation of a non-limb-related body region. We further investigated the responses of unilateral upper limb amputees and individuals with all limbs intact to temporally based sensory tactile testing of the fingertips to test the hypothesis that changes in sensory perception also have an effect on the intact limb. Upper extremity amputees were assessed for the presence of referred sensations (RSs)—experiencing feelings in the missing limb when a different body region is stimulated, to determine changes within the brain that occur due to an amputation. Eight of 19 amputees (42.1%) experienced RS in the phantom limb with manual tactile mapping on various regions of the face. There was no correlation between whether someone had phantom sensations or phantom limb pain and where RS was found. Six of the amputees had either phantom sensation or pain in addition to RS induced by facial stimulation. Results from the tactile testing showed that there were no significant differences in the accuracy of participants in the temporal order judgment tasks (p = 0.702), whereby participants selected the digit that was tapped first by a tracking paradigm that resulted in correct answers leading to shorter interstimulus intervals (ISIs) and incorrect answers increasing the ISI. There were also no significant differences in timing perception, i.e., the threshold accuracy of the duration discrimination task (p = 0.727), in which participants tracked which of the two digits received a longer stimulus. We conclude that many, but not all, unilateral upper limb amputees experience phantom hand sensation and/or pain with stimulation of the face, suggesting that there could be postamputation changes in neuronal circuitry in somatosensory cortex. However, major unilateral limb amputation does not lead to changes in temporal order judgment or timing perception tasks administered via the tactile modality of the intact hand in upper limb amputees.

Exploiting temporal predictability: Event-related potential correlates of task-supportive temporal cue processing in auditory distraction

The human cognitive system has various functions to enhance performance in tasks requiring responses to stimuli. When potentially occurring stimuli are known, we can establish selective attention sets and ignore task-irrelevant events while attending task-relevant ones. When the stimulation is temporally structured, we can rely on constant temporal relationships between stimulus events to prepare for the task-relevant moments. Most distraction paradigms feature task-irrelevant events which are followed by task-relevant ones within a constant interval, and distraction is induced by randomly replacing some of the standard task-irrelevant events. The constant time interval transforms irrelevant events to task-supportive temporal cues, which are integrated into the task-behavior by the participants. The present study investigated whether distracters could be utilized as temporal cues to support task-related processing in a continuous auditory stimulation paradigm. A continuous tone featuring short and long gaps, and pitch glides was presented. Participants performed a gap duration discrimination task, while ignoring glides. Glides could be presented frequently or rarely. In the informative condition, 80% of the glides predicted the presentation time of the forthcoming gap (400ms), while in the uninformative condition, the occurrence of gaps and glides was independent. Rare glides elicited an enhanced N1, mismatch negativity, and P3 event-related potentials in both informative and uninformative conditions. In informative conditions glides were followed by a contingent negative variation; and rare informative glides elicited an N2b, suggesting that despite triggering distraction-related processes, distracters could be integrated into the task-behavior, and could be utilized as task-supportive cues.

Attention-dependent sound offset-related brain potentials.

When performing sensory tasks, knowing the potentially occurring goal-relevant and irrelevant stimulus events allows the establishment of selective attention sets, which result in enhanced sensory processing of goal-relevant events. In the auditory modality, such enhancements are reflected in the increased amplitude of the N1 ERP elicited by the onsets of task-relevant sounds. It has been recently suggested that ERPs to task-relevant sound offsets are similarly enhanced in a tone-focused state in comparison to a distracted one. The goal of the present study was to explore the influence of attention on ERPs elicited by sound offsets. ERPs elicited by tones in a duration-discrimination task were compared to ERPs elicited by the same tones in not-tone-focused attentional setting. Tone offsets elicited a consistent, attention-dependent biphasic (positive-negative--P1-N1) ERP waveform for tone durations ranging from 150 to 450 ms. The evidence, however, did not support the notion that the offset-related ERPs reflected an offset-specific attention set: The offset-related ERPs elicited in a duration-discrimination condition (in which offsets were task relevant) did not significantly differ from those elicited in a pitch-discrimination condition (in which the offsets were task irrelevant). Although an N2 reflecting the processing of offsets in task-related terms contributed to the observed waveform, this contribution was separable from the offset-related P1 and N1. The results demonstrate that when tones are attended, offset-related ERPs may substantially overlap endogenous ERP activity in the postoffset interval irrespective of tone duration, and attention differences may cause ERP differences in such postoffset intervals.

Analysis of Genetic and Non-Genetic Factors Influencing Timing and Time Perception.

Performance on different psychophysical tasks measuring the sense of time indicates a large amount of individual variation in the accuracy and precision of timing in the hundredths of milliseconds-to-minutes range. Quantifying factors with an influence on timing is essential to isolating a biological (genetic) contribution to the perception and estimation of time. In the largest timing study to date, 647 participants completed a duration-discrimination task in the sub-second range and a time-production task in the supra-second range. We confirm the stability of a participant’s time sense across multiple sessions and substantiate a modest sex difference on time production. Moreover, we demonstrate a strong correlation between performance on a standardized cognitive battery and performance in both duration-discrimination and time-production tasks; we further show that performance is uncorrelated with age after controlling for general intelligence. Additionally, we find an effect of ethnicity on time sense, with African Americans and possibly Hispanics in our cohort differing in accuracy and precision from other ethnic groups. Finally, a preliminary genome-wide association and exome chip study was performed on 148 of the participants, ruling out the possibility for a single common variant or groups of low-frequency coding variants within a single gene to explain more than ~18% of the variation in the sense of time.

Heart rate variability and cognitive processing: The autonomic response to task demands

This study investigated variations in heart rate variability (HRV) as a function of cognitive demands. Participants completed an execution condition including the psychomotor vigilance task, a working memory task and a duration discrimination task. The control condition consisted of oddball versions (participants had to detect the rare event) of the tasks from the execution condition, designed to control for the effect of the task parameters (stimulus duration and stimulus rate) on HRV. The NASA-TLX questionnaire was used as a subjective measure of cognitive workload across tasks and conditions. Three major findings emerged from this study. First, HRV varied as a function of task demands (with the lowest values in the working memory task). Second, and crucially, we found similar HRV values when comparing each of the tasks with its oddball control equivalent, and a significant decrement in HRV as a function of time-on-task. Finally, the NASA-TLX results showed larger cognitive workload in the execution condition than in the oddball control condition, and scores variations as a function of task. Taken together, our results suggest that HRV is highly sensitive to overall demands of sustained attention over and above the influence of other cognitive processes suggested by previous literature. In addition, our study highlights a potential dissociation between objective and subjective measures of mental workload, with important implications in applied settings.

Visual-auditory differences in duration discrimination of intervals in the subsecond and second range.

A common finding in time psychophysics is that temporal acuity is much better for auditory than for visual stimuli. The present study aimed to examine modality-specific differences in duration discrimination within the conceptual framework of the Distinct Timing Hypothesis. This theoretical account proposes that durations in the lower milliseconds range are processed automatically while longer durations are processed by a cognitive mechanism. A sample of 46 participants performed two auditory and visual duration discrimination tasks with extremely brief (50-ms standard duration) and longer (1000-ms standard duration) intervals. Better discrimination performance for auditory compared to visual intervals could be established for extremely brief and longer intervals. However, when performance on duration discrimination of longer intervals in the 1-s range was controlled for modality-specific input from the sensory-automatic timing mechanism, the visual-auditory difference disappeared completely as indicated by virtually identical Weber fractions for both sensory modalities. These findings support the idea of a sensory-automatic mechanism underlying the observed visual-auditory differences in duration discrimination of extremely brief intervals in the millisecond range and longer intervals in the 1-s range. Our data are consistent with the notion of a gradual transition from a purely modality-specific, sensory-automatic to a more cognitive, amodal timing mechanism. Within this transition zone, both mechanisms appear to operate simultaneously but the influence of the sensory-automatic timing mechanism is expected to continuously decrease with increasing interval duration.

Time perception, mindfulness and attentional capacities in transcendental meditators and matched controls

Only a few studies have investigated the sense of time in experienced meditators. In the current case–control study, we investigated whether 20 practitioners in transcendental meditation (TM) showed differences in the perception of time as compared to 20 matched controls. Perception of time was assessed with a battery of psychophysical tasks including duration reproduction and time estimation tasks in the milliseconds-to-minutes range as well as with psychometric instruments related to subjective time and assessments concerning the subjective passage of time. Attentional capacities were measured with the Attention Network Test. Trait-mindfulness was assessed with the Freiburg Mindfulness Inventory. Results indicate that the TM meditators performed more consistently in the duration reproduction tasks in the multiple seconds' range and responded more accurately in the time estimation tasks in the minutes' range as well as in the duration discrimination task than controls. Self-rated mindfulness was more pronounced in meditators, while attentional capacities did not differ. In conclusion, experts in TM performed more accurately in psychophysical time perception tasks and had higher mindfulness than non-meditating controls. Whether these differences are causally related to the practice of meditation should be investigated in future studies.

Contextual factors multiplex to control multisensory processes.

This study analyzed high-density event-related potentials (ERPs) within an electrical neuroimaging framework to provide insights regarding the interaction between multisensory processes and stimulus probabilities. Specifically, we identified the spatiotemporal brain mechanisms by which the proportion of temporally congruent and task-irrelevant auditory information influences stimulus processing during a visual duration discrimination task. The spatial position (top/bottom) of the visual stimulus was indicative of how frequently the visual and auditory stimuli would be congruent in their duration (i.e., context of congruence). Stronger influences of irrelevant sound were observed when contexts associated with a high proportion of auditory-visual congruence repeated and also when contexts associated with a low proportion of congruence switched. Context of congruence and context transition resulted in weaker brain responses at 228 to 257 ms poststimulus to conditions giving rise to larger behavioral cross-modal interactions. Importantly, a control oddball task revealed that both congruent and incongruent audiovisual stimuli triggered equivalent non-linear multisensory interactions when congruence was not a relevant dimension. Collectively, these results are well explained by statistical learning, which links a particular context (here: a spatial location) with a certain level of top-down attentional control that further modulates cross-modal interactions based on whether a particular context repeated or changed. The current findings shed new light on the importance of context-based control over multisensory processing, whose influences multiplex across finer and broader time scales.

Effects of aging on auditory duration discrimination

The effects of aging on auditory processing are well documented. The involved anatomy includes the entire auditory pathway from peripheral to central mechanisms. Existing procedures to identify auditory processing disorders include a wide variety of signals with distortions or reduced redundancy in the temporal or frequency domains or the addition of noise. This project investigated the effects of aging on the ability to discriminate duration of a musical auditory signal. A musical signal was used to add temporally-variant acoustical information that would not be present in a pure tone. A digitized.wav piano note (fo = 422 Hz) with gradually decaying amplitude was edited in Sound Forge to produce two signals equal in spectrum, RMS amplitude, and VU level but differing durations (1000 and 800 ms). One hundred pairs of these musical signals were arranged in random order with half equal and half unequal in duration. The subject’s task was to designate same or different. Subjects ranged in age from 18 to 90 years. A regressions analysis revealed that age is a significant (p = .002) coefficient for predicting performance on a duration discrimination task. The findings suggest that duration discrimination tasks may contribute to identification of auditory processing disorders in adults.