Objective The present study was designed to evaluate human performance and workload associated with an auditory vigilance task that required spatial discrimination of auditory stimuli. Background Spatial auditory displays have been increasingly developed and implemented into settings that require vigilance toward auditory spatial discrimination and localization (e.g., collision avoidance warnings). Research has yet to determine whether a vigilance decrement could impede performance in such applications. Method Participants completed a 40-minute auditory vigilance task in either a spatial discrimination condition or a temporal discrimination condition. In the spatial discrimination condition, participants differentiated sounds based on differences in spatial location. In the temporal discrimination condition, participants differentiated sounds based on differences in stimulus duration. Results Correct detections and false alarms declined during the vigilance task, and each did so at a similar rate in both conditions. The overall level of correct detections did not differ significantly between conditions, but false alarms occurred more frequently within the spatial discrimination condition than in the temporal discrimination condition. NASA-TLX ratings and pupil diameter measurements indicated no differences in workload. Conclusion Results indicated that tasks requiring auditory spatial discrimination can induce a vigilance decrement; and they may result in inferior vigilance performance, compared to tasks requiring discrimination of auditory duration. Application Vigilance decrements may impede performance and safety in settings that depend on sustained attention to spatial auditory displays. Display designers should also be aware that auditory displays that require users to discriminate differences in spatial location may result in poorer discrimination performance than non-spatial displays.

Simpson et al. [JASA 129(4), 2489, (2011)] found that localization of a target presented in a simultaneous masker improved when, on a trial-by-trial basis, a preview of the masking stimulus was presented at the location of the upcoming masker. Subsequent research revealed that this improvement resulted solely from cueing the location of the masker (i.e., cueing spectro-temporal properties of the masker provided no additional benefit). In the present study, we examined the degree to which the benefit of cueing masker location depended on the modality in which this cue was provided. In separate blocks of trials, the location of the masker was cued auditorily, visually (LED activated at the masker location) and audio-visually, and compared to performance in a no-cue baseline. The results revealed a substantial (∼10 dB) benefit of cueing the masker auditorily over the no-cue condition, consistent with previous results. Importantly, there was also a substantial (albeit smaller) benefit of a visual cue (∼6 dB). Performance with a bimodal cue was no different than performance with an auditory cue. Thus, although hearing a sound from the upcoming masker location was most effective, the ability to effectively cue space crossmodally suggests that the spatial information itself is most critical.

Non-native, accented speech spoken by unfamiliar talkers can be challenging to recognize, but rapid improvements in perception are often observed after a short period of exposure. However, it is not clear whether these improvements are retained over multiple sessions. Stimulus variability facilitates learning for non-native speech, so it is possible it may also induce increased retention of learning for speech produced with an unfamiliar accent. In this paper, we conduct a retrospective analysis of a dataset well suited to examine learning of non-native English speech on both a within-session and across-session basis. During data collection, participants completed a protocol involving recognition of matrix sentences recorded by native and non-native talkers with different first languages. Listeners completed the protocol in a self-paced approach, including 15 blocks of 50 trials over 4-7 days, separated by an average of 1-2 days. Learning was strongest within the first day, and improvements were retained at subsequent test sessions. The pace of learning was faster for stimuli produced by native speakers of English as compared to non-native English speakers.

Performance on auditory change detection tasks can be improved by training. We examined the stimulus specificity of these training effects in behavior and ERPs. A flicker change detection task was employed in which spatialized auditory scenes were alternated until a "change" or "same" response was made. For half of the trials, scenes were identical. The other half contained changes in the spatial locations of objects from scene to scene. On Day 1, participants were either trained on this auditory change detection task (trained group), or trained on a non-auditory change detection task (control group). On Day 2, all participants were tested on the flicker task while EEG was recorded. The trained group showed greater change detection accuracy than the control group. They were less biased to respond "same" and showed full generalization of learning from trained to novel auditory objects. ERPs for "change" compared to "same" trials showed more negative going P1, N1, and P2 amplitudes, as well as a larger P3b amplitude. The P3b amplitude also differed between the trained and control group, with larger amplitudes for the trained group. Analysis of ERPs to scenes viewed prior to a decision revealed build-up of a difference between "change" and "same" trials in N1 and P2. Results demonstrate that training has an impact early in the "same" versus "change" decision-making process, and that the flicker paradigm combined with the ERP method can be used to study the build-up of change detection in auditory scenes.

Most speech perception studies assume that the talkers are speaking to the subject, but little is known regarding subject ability to monitor exchanges between interlocutors (i.e., “eavesdrop”). The current study measured subject ability to monitor two concurrent, artificially generated “conversations” using phrases from the Coordinate Response Measure corpus. Individual conversations consisted of a “prompt” phrase of the form: “Ready [call sign] go to [color]-[number] now” and a “response” phrase of the form: “[same call sign] going to [color]-[number]”. A color and/or number prompt-response mismatch occurred within a conversation on 50% of trials. The listener was asked to identify whether a mismatch took place and, if so, identify in which of the two conversations the mismatch occurred. The (virtual) conversations were either co-located or spatially separated (±15°, ±90°). All talkers were of the same gender, or competing prompters and competing responders were of different genders. Group-mean performance ranged from about 65–80% correct in mismatch detection, and about 70%–85% correct in call sign identification (for mistake-ID correct trials). Performance improved when competing talkers were separated to ±15 deg in space, and/or in gender. This suggests that, on average, listeners can follow simultaneous conversations over time, particularly when competing talkers differ in pitch or space.

Hearing-protection devices (HPD) are critical to hearing health in hazardous noise environments, but can be detrimental to job effectiveness and safety when degrading a wearer’s sound localization accuracy. Understanding specifically how localization is disrupted by HPDs is critical for mitigating the deleterious effects of HPDs on situation awareness. This study attempts to better quantify the effects of the degradations by predicting horizontal sound localization. A 360 deg horizontal array with 10 deg between-speaker spacing is used to collect head-related transfer functions (HRTFs) and to measure localization [ANSI/ASA S3.71] for the different conditions (open-ear, passive plugs, and both passive and active muffs). Our model attempts to select the response location that was most likely to have elicited the observed stimulus for the trial, by comparing narrow-band statistics between prior knowledge (“templates”) and trial observations. Bone conduction related noise is added, and the degree to which the priors are “device-related” (i.e., based on HRTFs captured for the device) or “open ear” related is varied. Results are discussed in terms of two potential mechanisms: (1) the wrong location is chosen due to a prior/template mismatch in percent device-related and (2) multiple response locations are viable because cue variability is reduced between locations compared to within.

The vigilance decrement is a temporal decline in performance that tends to occur within tasks that require vigilance, or sustained attention for the detection of rare, unpredictable events (Warm, Parasuraman, & Matthews, 2008). A leading explanation for the vigilance decrement is resource theory, which suggests that vigilance tasks deplete an observer’s information-processing resources more quickly than they can be replenished (Davies & Parasuraman, 1982). Resource theory is supported by research showing that vigilance performance is hindered, and the vigilance decrement is made worse, when task demands are increased (Warm et al., 2008). The link between task demands and vigilance performance may be leveraged to mitigate the vigilance decrement by designing vigilance tasks that have reduced attentional demands. One method of reducing attentional demands in vigilance is to integrate ecological signals into vigilance displays (Hancock, 2013). Ecological signals are representative of stimuli from the “natural world” that are relevant to human survival. Such stimuli may be processed more rapidly and easily than relatively artificial stimuli. Examples include biological motion cues (Parasuraman et al., 2009) and stereoscopic depth cues (Greenlee et al., 2015); both have been used to attenuate the vigilance decrement. One limitation of previous research on the utility of ecological signals in vigilance tasks is that all studies have focused on the visual domain. This is problematic, because some operational settings require operators to monitor auditory vigilance displays (Seagull et al., 2001). Given that, like vision, hearing plays a critical role in human survival, it is likely that relatively easy-to-process, ecological stimuli may be found in the auditory modality. One possibility is spatial auditory cues, or the information that allows human listeners to discriminate the locations of sounds in space, a skill that is useful for day-to-day function and survival (Simpson et al., 2005). Given that previous research suggests that vigilance is driven by supramodal resources (Shaw et al., 2009), auditory ecological stimuli may attenuate the auditory vigilance decrement by reducing cognitive load. The purpose of this study was to explore this possibility by examining the effects that a suspected ecological auditory stimulus parameter, spatial (3-D) auditory cues, had upon performance and workload within an auditory vigilance task. If 3-D auditory cues are relatively easy-to-process, ecological stimuli, they should reduce cognitive workload, improve performance, and mitigate the vigilance decrement – in contrast to more traditional 2-D auditory stimuli. Thirty-four participants (8 Men, 26 Women) were assigned at random to one of two conditions: A 3-D condition or a 2-D condition. In the 3-D condition, participants discriminated between spatially lateralized critical signals and centrally located neutral stimuli. In the 2-D condition, participants discriminated between critical and neutral stimuli based upon stimulus duration. In both conditions, the vigilance task lasted 40 minutes (5% signal probability, 30 events per minute). Correct detection rate was recorded in tandem with eye tracking measures of workload (pupillometry, blink rate). Results revealed no differences between conditions on any measure. Instead, all measures indicated that 2-D and 3-D versions of this vigilance task were highly demanding. Vigilance performance declined over time, while eye tracking measures of workload increased over time. The magnitudes of these effects were indistinguishable between conditions. These results suggest that the spatial auditory cues used in the current study provided no advantage for vigilance. This is likely a consequence of the chosen parameter (auditory cues about spatial lateralization) and should not be taken as general evidence that ecological stimuli would not benefit auditory vigilance. More work needs to be done to identify ecologically relevant auditory cues that do facilitate superior vigilance performance by alleviating processing demands.

The effects of training on an auditory flicker task were examined in this study, where auditory scenes alternated until a participant responded “change” or “same.” Change scenes differed in the location (on the horizontal plane) of two or more sounds. Half of participants were trained with auditory scenes on Day 1, and half were trained on a visual task. On Day 2, all participants were tested on auditory scenes containing either trained sounds or novel sounds within scenes; EEG was collected during testing. Participants trained with auditory scenes performed better overall than control participants. Both groups had lower reaction times to correct response change trials than same trials. Trained participants performed no better on trained sounds than novel sounds, but did perform better on trained sounds than control participants. Electrophysiologically, there were differences in ERP components based on the type of trial (change versus same auditory scene). For same trials, N1 and P2 amplitudes were significantly higher, and P3b amplitudes were significantly lower than change trials. Additionally, P2 showed a general decrease in amplitude as scene presentations neared the response. These data show that training reduces change deafness, and improvements are not limited to the sounds experienced during training.

Speech comprehension is enhanced when a talker's face is visible, and amplitude modulations in speech support intelligibility. Listeners may benefit from visual speech by extracting amplitude modulation cues, which are represented by the mouth aperture of the talker. This multimodal enhancement of speech is often desirable, but the visual presentation of a talker's face is not always feasible. The present study investigated the degree to which a “low-fidelity” amplitude-modulation cue – an LED that changed in luminance with the amplitude of the speech envelope – contributes to speech perception for a target signal (a phrase from the Coordinate Response Measure, CRM) presented with two competing CRM speech phrases. Each trial consisted of 3 simultaneous speech streams of 5 sequential CRM phrases each. One stream included a target phrase (defined by a preset call sign) and originated from a location directly in front of the listener; competing sequences were placed at + /- 10 deg relative to that location. Listeners responded with the color and number associated with the target call sign. The presence of amplitude modulation cues and target timing cues enhanced performance. Further effects of cue type by signal-to-noise ratio will be discussed, as well as applications and future work.

Virtual localization experiments have demonstrated that Head Related Transfer Functions measured a few millimeters inside a blocked ear canal can produce localization performance approaching what is measured in the free field. This suggests that an earplug inserted entirely inside the ear canal should be able to preserve normal localization performance so long as the stimulus is loud enough to overcome any insertion loss in the device at all frequencies. In this study, localization performance of normal-hearing listeners was measured with the Lyric extended wear hearing aid, both in active mode (where it acted like an electronic pass-through earplug) and in passive mode (where it acted like a passive hearing protector). In an active mode, localization accuracy approached the open-ear condition. However, under the passive condition, localization was much worse than with the open ear even at high stimulus levels where the full spectrum should have been audible. This result suggests there may be fundamental limitations on localization accuracy with passive hearing protection that are unrelated to the directionality of the HRTF. [The views expressed in this abstract are those of the authors and do not reflect the official policy of the Department of the Army/Air Force, Department of Defense, or U.S. Government.]

Sabin et al. (2005) measured localization accuracy for 250-ms broadband noises that varied in location along a spherical surface, and varied in stimulus level, from 0 to 60 dB above the detection threshold. They found that, for lower stimulus levels, responses tended to be biased towards lower elevations and to the front, and were more accurate at higher stimulus levels. Whereas Sabin et al. (2005) randomized level and location between trials, the current study fixed location and increased level until a correct response was given (or the 80 dB SPL limit was reached). Our initial level was 12.5 dB SPL, and our step size 2.5 dB SPL. Responses tended to be biased towards lower vertical elevations and to the front at low stimulus levels, and be more accurate at higher levels, consistent with Sabin et al. The percentage of front/back errors was generally greater for locations in the rear hemifield relative to those in the frontal hemifield, and for locations at higher elevations relative to locations at lower elevations. Audibility analysis, performed using a KEMAR manikin, showed that localization errors tended to decrease the most when audible bandwidth increased at the acoustically better ear.

Recent studies show that pre-stimulus band-specific power and phase in the electroencephalogram (EEG) can predict accuracy on tasks involving the detection of near-threshold stimuli. However, results in the auditory modality have been mixed, and few works have examined pre-stimulus features when more complex decisions are made (e.g. identifying supra-threshold sounds). Further, most auditory studies have used background sounds known to induce oscillatory EEG states, leaving it unclear whether phase predicts accuracy without such background sounds. To address this gap in knowledge, the present study examined pre-stimulus EEG as it relates to accuracy in a tone pattern identification task. On each trial, participants heard a triad of 40-ms sinusoidal tones (separated by 40-ms intervals), one of which was at a different frequency than the other two. Participants' task was to indicate the tone pattern (low-low-high, low-high-low, etc.). No background sounds were employed. Using a phase opposition measure based on inter-trial phase consistencies, pre-stimulus 7-10 Hz phase was found to differ between correct and incorrect trials similar to 200 to 100 ms prior to tone-pattern onset. After sorting trials into bins based on phase, accuracy was found to be lowest at around (+)(-)pi relative to individuals' most accurate phase bin. No significant effects were found for pre-stimulus power. In the context of the literature, findings suggest an important relationship between the complexity of task demands and pre-stimulus activity within the auditory domain. Results also raise interesting questions about the role of induced oscillatory states or rhythmic processing modes in obtaining pre-stimulus effects of phase in auditory tasks.

Failure to detect change in an auditory scene (i.e., change deafness) has been found to occur with alterations to object identities and the location of objects. Event-related potential (ERP) correlates of change deafness for object identity have been identified, but to our knowledge, ERP comparisons between spatial and identity change deafness are non-existent. We examined whether ERP differences exist between spatial and identity (ID) changes, and among levels of change detection accuracy (correct change identified vs. wrong change identified vs. change deaf). Within a trial, listeners were presented with two consecutive auditory scenes, each composed of four environmental sounds played simultaneously at separate azimuths on the horizontal plane. Scene 2 was either identical to the first ("no change"), had one sound replaced ("ID change"), or contained the same sounds at different locations ("space change"). Accuracy was similar for ID and space change trials (~60% correct), but error patterns differed. On space change trials, listeners made few ID change responses. However, on ID change trials listeners were nearly equal in their tendencies to make a no change and space change response. N1-P2 complexes locked to scene onsets were largest on trials where a change was indicated, but the wrong change type was chosen. P3b amplitudes locked to Scene 2 onset were monotonically related to accuracy (larger for correct and wrong change trials than change deaf trials). Effects were similar for space and ID changes, but scalp topography of P3b differed for change types (larger amplitudes for ID change trials at left temporal electrodes). Data indicate that P3b amplitude is a reliable indicator of successful change detection across different types of scene changes, showing different topography reflecting different "what" and "where" processing streams. N1-P2 complex effects suggest better encoding of scenes in relation to change detection, but unknown change type.

Seemingly, there should be a close relationship between spatial release from masking and sound localization, but this is not always the case. For example, in binaural detection, randomizing the spatial parameters of the target or masker from trial to trial has little impact on threshold. In contrast, Simpson (Ph.D. dissertation, 2011) found that left/right localization judgments for a 60-ms target masked by a simultaneous 60-ms noise were considerably less accurate (equivalent to 10-dB reduction in SNR) when the location of the masker varied randomly from trial to trial than when the masker location was fixed. However, when a forward masker fringe was added, so that the noise was turned on 500 ms before the target, the impact of location variability was very small (about 1 dB, comparable to the detection literature). To determine if the presence of masker fringe could have limited the impact of spatial variability in previous detection experiments, the current study examines the effect of masker fringe and both target and masker spatial variability on detectability in conditions comparable to those of Simpson. The results will be compared to previous findings and models reported in the binaural detection and sound localization literature.

The auditory sense plays a critical role in human performance on the battlefield. Effective verbal communication is key to the success of all military operations, the ability to detect and localize sounds in the immediate environment is critical for supporting situation awareness, and the ability to identify sound sources is required for labeling items and events as hostile or friendly. However, operational environments tend to be extremely noisy, and most warfighters are regularly exposed to hazardous noise levels, necessitating the use of hearing protection to reduce the chance of experiencing temporary or permanent hearing loss. Unfortunately, the use of hearing protection can have a deleterious effect on communication, sound source identification, and overall situation awareness. For this reason, operators often choose to perform all, or part, of their mission without the appropriate hearing protection in place. In order to protect warfighters’ hearing, appropriate hearing protection needs to be selected that will provide enough protection from the expected hazardous sounds, while also enabling the hearing-critical tasks that are required for the mission. This presents a great challenge for those who make the decisions on what hearing protection to prescribe.

Aviation mishaps resulting from degraded visual environments (DVEs) represent a significant loss in military personnel and aircraft every year. DVEs can be caused by any type of environmental condition (e.g., sand, snow, fog) that obstructs the pilot’s vision, and can cause spatial disorientation. The current study was a tri-service effort exploring the implementation of spatial audio cueing to aid pilot navigation in DVEs. Directional cueing (i.e., indicating the location of target waypoints) was achieved by spatializing an auditory stimulus. Pilots performed multiple flight maneuvers in a full-motion UH-60 Black Hawk flight simulator at the U.S. Army Aeromedical Research Laboratory. Performance was assessed by measures of error, completion time, and failure rate. Findings from this study provide information on sensory cueing display design for helicopter flight in DVEs.

Previous work has shown that change deafness can occur with changes in the spatial location of objects within auditory scenes. Whether performance can be improved with training has yet to be directly tested. In the present study, the impact of training was examined in a “flicker”-like paradigm, where an initial scene comprising environmental sounds presented on the horizontal plane alternated with the presentation of a comparison scene, which was either the same or contained a change in the location of one or more sounds. Trained participants were trained on a set of sounds on day 1, while control subjects completed an unrelated visual task. On day 2, participants were tested using the same paradigm, with trained subjects hearing either the sounds they were trained on or new sounds, and controls being exposed to the paradigm for the first time. Overall, trained participants performed better (93% accuracy) than untrained participants (79%). Both groups had lower reaction times on correct-response change trials than on correct-response no-change trials. Trained subjects performed no better on trained sounds than new sounds. These data indicate that training can improve task performance, but improvements may be not be limited to sounds experienced during training.

Localization accuracy for a target presented in a simultaneous masker, whose location varies randomly from trial to trial, improves when a preview of the masker location is provided (by playing a sound from that location) prior to the target + masker interval (i.e., a pre-trial cue) [B. Simpson, Ph.D. dissertation (Wright State University, 2011)]. One explanation is that knowing the masker location allows a listener to establish a “spatial attention filter” at the masker location. The present study compares the effect of such a pre-trial cue to the case in which the cue comes after the target + masker interval (post-trial cueing). That is, the cue is presented either 500 ms prior to the onset of a 60-ms, 100-Hz click-train target embedded in a 60-ms broadband masker, or 500 ms subsequent to the offset of the target + masker stimulus. The data indicate that both cue types lead to similar improvements in performance over the no-cue condition, with the greatest improvement from cueing (~6 dB) seen for localization in the left/right dimension. While these data are roughly consistent with previous results, they cannot be explained by a simple spatial filter hypothesis.

Event Abstract Back to Event The Phase of Spontaneous Pre-stimulus EEG Oscillations Predicts Auditory Pattern Identification Natalie E. Hansen1, 2*, Matthew G. Wisniewski2, Nandini Iyer2, Brian D. Simpson2 and Assaf Harel1 1 Wright State University, United States 2 Air Force Research Laboratory, United States Recent studies have shown that the power and phase of spontaneous pre-stimulus oscillations in the electroencephalogram (EEG) predict behavior on simple perceptual and cognitive tasks. Such findings suggest that pre-stimulus EEG may be used to augment human performance in operational environments. For instance, EEG measures could inform the timing of signal presentation in order to align with an optimal brain state. Work with visual stimuli has consistently demonstrated an influence of pre-stimulus features on performance in simple stimulus detection tasks (e.g. Busch et al., 2009; Dugué et al., 2011). However, results in the auditory modality have been mixed, with a relationship between pre-stimulus EEG and performance seen only with the entrainment of oscillations to rhythmic background stimulation (Ng et al., 2012). Little is known about the predictive capacity of pre-stimulus features when more complex decisions need to be made (e.g. extracting meaning from sounds). This raises the possibility that pre-stimulus cortical oscillatory activity only shows a relationship with performance in supra-threshold tasks requiring more complex processing, given that extensive feature processing in the auditory system occurs sub-cortically. To address this gap in the knowledge, the present study examined pre-stimulus EEG as it relates to accuracy in a rapid auditory processing task. In contrast to previous work in the auditory domain, no background noise was present, and a relatively complex pattern identification task was used. We hypothesized that pre-stimulus power and/or phase in the theta and alpha bands would relate in a predictable way to performance accuracy. On each trial, participants heard three 40-ms sinusoidal tones separated by 40-ms inter-stimulus intervals, one of which was at a different frequency than the other two. Participants’ task was to indicate the order of the tones (low-low-high, low-high-low, etc.). An adaptive one-up, one-down procedure was used to determine the frequency separation associated with each participant’s 50% correct identification threshold. Afterwards, each participant completed 250 trials while the EEG was collected from a 68-channel array of electrodes. Resulting data were sorted into correct and incorrect trials to facilitate single-trial analysis of predictive pre-stimulus EEG features. Using a phase-opposition sum (POS) measure, our results demonstrate that pre-stimulus alpha band phase differs between correct and incorrect trials. Specifically, strong phase opposition occurred between approximately -200 to -100 ms prior to onset of the tones, and fell within the 7 to 11 Hz range (high theta / low alpha band). As a complementary measure of performance-related phase opposition, we sorted individual trials into phase bins, such that each individual’s most accurate bin was aligned at zero; we found a significant difference in mean accuracy between those bins closest to the most accurate bin and those furthest. This was consistent across participants, further supporting the relationship between spontaneous pre-stimulus EEG phase and pattern identification. By performing two further control analyses we were able to rule out the possibility of pre-stimulus contamination by post-stimulus activity. These findings have important ramifications in the neuroergonomics field. For instance, aircraft operators often have many signals to attend to, both visual and auditory. While much work has explored the perceptual and cognitive effects of longer-term brain states such as drowsiness or acute stress, understanding the influences of short-term shifts in brain state may be important for optimizing conditions under which an operator can detect, identify, and understand crucial signals. Being able to present signals in alignment with these short-term states may be one direction towards such optimization; inducing oscillatory entrainment in the operator himself may be another. References Busch, N.A., Dubois, J., & VanRullen, R. (2009). The phase of ongoing EEG oscillations predicts visual perception. Journal of Neuroscience, 29, 7869-7876. Dugué, L., Marque, P., & VanRullen, R. (2011). The phase of ongoing oscillations mediates the causal relation between brain excitation and visual perception. Journal of Neuroscience, 31(33), 11889-11893. Ng, B.S.W., Schroeder, T., & Kayser, C. (2012). A precluding but not ensuring role of entrained low-frequency oscillations for auditory perception. Journal of Neuroscience, 32, 12268-12276. Keywords: pre-stimulus activity, EEG, oscillations, Auditory Perception, phase opposition Conference: 2nd International Neuroergonomics Conference, Philadelphia, PA, United States, 27 Jun - 29 Jun, 2018. Presentation Type: Poster Presentation Topic: Neuroergonomics Citation: Hansen NE, Wisniewski MG, Iyer N, Simpson BD and Harel A (2019). The Phase of Spontaneous Pre-stimulus EEG Oscillations Predicts Auditory Pattern Identification. Conference Abstract: 2nd International Neuroergonomics Conference. doi: 10.3389/conf.fnhum.2018.227.00059 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 02 Apr 2018; Published Online: 27 Sep 2019. * Correspondence: Ms. Natalie E Hansen, Wright State University, Dayton, United States, natalie.hansen@wright.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Natalie E Hansen Matthew G Wisniewski Nandini Iyer Brian D Simpson Assaf Harel Google Natalie E Hansen Matthew G Wisniewski Nandini Iyer Brian D Simpson Assaf Harel Google Scholar Natalie E Hansen Matthew G Wisniewski Nandini Iyer Brian D Simpson Assaf Harel PubMed Natalie E Hansen Matthew G Wisniewski Nandini Iyer Brian D Simpson Assaf Harel Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Recent research has focused on measuring neural correlates of metacognitive judgments in decision and post decision processes during memory retrieval and categorization. However, many tasks (e.g., stimulus detection) may require monitoring of earlier sensory processing. Here, participants indicated which of two intervals contained an 80-ms pure tone embedded in white noise. One frequency (e.g., 1000 Hz) was presented on similar to 80% of all trials (i.e., 'primary' trials). Another frequency (e.g., 2500 Hz) was presented on similar to 20% of trials (i.e., 'probe' trials). The event-related potential (ERP) was used to investigate the processing stages related to confidence. Tone-locked N1, P2, and P3 amplitudes were larger for trials rated with high than low confidence. Interestingly, a P3-like late positivity for the tone-absent interval showed high amplitude for low confidence. No 'primary' vs. 'probe' differences were found. However, confidence rating differences between primary and probe trials were correlated with Ni and tone-present P3 amplitude differences. We suggest that metacognitive judgments can track both sensory- and decision-related processes (indexed by the Ni and P3, respectively). The particular processes on which confidence judgments are based likely depend upon the task an individual is faced with and the information at hand (e.g., presence or absence of a signal).