I teach psychophysiology and method.

Eklund, R., Gerdfeldter, B., & Wiens, S. (2019). Effects of a manual response requirement on early and late correlates of auditory awareness. Frontiers in Psychology, 10(2083). https://doi.org/10.3389/fpsyg.2019.02083

Eklund, R., & Wiens, S. (2019). Auditory awareness negativity is an electrophysiological correlate of awareness in an auditory threshold task. Consciousness and Cognition, 71, 70-78. https://doi.org/10.1016/j.concog.2019.03.008

Wiens, S., Szychowska, M., Eklund, R., & van Berlekom, E. (2018). Cascade and no-repetition rules are comparable controls for the auditory frequency mismatch negativity in oddball tasks. Psychophysiology, https://doi.org/10.1111/psyp.13280

Eklund, R., & Wiens, S. (2018). Visual Awareness Negativity is an early neural correlate of awareness: A preregistered study with two Gabor sizes. Cognitive, Affective & Behavioral Neuroscience, 18(1), 176-188. https://doi.org/10.3758/s13415-018-0562-z

Olofsson, J. K., Syrjänen, E., Ekström, I., Larsson, M., & Wiens, S. (2018). “Fast” versus “slow” word integration of visual and olfactory objects: EEG biomarkers of decision speed variability. Behavioral Neuroscience, in press. doi: http://dx.doi.org/10.1037/bne0000266

Syrjänen, E., Wiens, S., Fischer, H., Zakrzewska, M., Wartel, A., Larsson, M., & Olofsson, J. K. (2018). Background Odors Modulate N170 ERP Component and Perception of Emotional Facial Stimuli. Frontiers in Psychology, 9. doi: 10.3389/fpsyg.2018.01000

Ströberg, K., Andersen, L. M., & Wiens, S. (2017). Electrocortical N400 effects of semantic satiation. Frontiers in Psychology, 8, 2117. doi: 10.3389/fpsyg.2017.02117

Tutorial on Aladins Bayes Factor in R

Wiens, S. (2017): Aladins Bayes Factor in R. figshare.
10.17045/sthlmuni.4981154

Wiens, S., Szychowska, M., Eklund, R., & Nilsson, M.E. (2017). Data on the auditory duration mismatch negativity for different sound pressure levels and visual perceptual loads. Data in Brief, 11, 159-164. doi: 10.1016/j.dib.2017.02.007 Refers to Szychowska et al, 2017.

A selection from Stockholm University publication database

• Dissociation Between Speech and Emotion Effects in Short-Term Memory

  2021. Stefan Wiens. Meta-Psychology 5

  Article

  Performance in visual serial recall tasks is often impaired by irrelevant auditory distracters. The duplex-mechanism account of auditory distraction states that if the distracters provide order cues, these interfere with the processing of the order cues in the serial recall task (interference by process). In contrast, the unitary account states that distracters capture only attention on a general level (attentional distraction) without interfering specifically withorder processing. Marsh et al. (2018, Journal of Experimental Psychology-Learning Memory and Cognition, 44, 882-897) reported finding a dissociation between the effects of serial recall tasks and those of a missing-item task on the disruptive effects of speech and of emotional words, as predicted by the duplex-mechanism account. Critically, the reported analyses did not test specifically for the claimed dissociation. Therefore, I reanalyzed the Marsh et al. data and conducted the appropriate analyses. I also tested the dissociation more directly and added a Bayesian hypothesis test to measure the strength of the evidence for a dissociation. Results provided strong evidence for a dissociation (i.e., crossover interaction) between effects of speech and of emotion. Because the duplex-mechanism account predicts this dissociation between speech effects (interference by process) and emotion effects (attentionaldiversion) whereas the unitary account does not, Marsh et al.’s data support the duplex-mechanism account. However, to show that this dissociation is robust, researchers are advised to replicate this dissociation in an adversarial registered report.

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• Visual load effects on the auditory steady state responses to 20-, 40-, and 80-Hz amplitude-modulated tones

  2021. Malina Szychowska, Stefan Wiens. Physiology & Behavior 228

  Article

  Ignoring background sounds while focusing on a visual task is a necessary ability in everyday life. If attentional resources are shared between modalities, processing of task-irrelevant auditory information should become attenuated when attentional capacity is exhausted by visual demands. According to earlyfilter theory, top-down attenuation of auditory responses is possible at various stages of the auditory pathway through multiple recurrent loops. Furthermore, the adaptive filtering model of selective attention suggests that filtering occurs early when concurrent visual tasks are demanding (e.g., high load) and late when tasks are easy (e.g., low load). This study examined effects of visual load on auditory steady state responses (ASSRs) to determine where in the auditory pathway the filtering occurs. Subjects performed a visual task with three levels of load (no, low, and high) while ignoring task-irrelevant sounds. The auditory stimuli were 500-Hz tones amplitude-modulated at 20 Hz, 40 Hz, or 80 Hz to target different processing stages of the auditory pathway. Results from bayesian analyses suggest that ASSRs are unaffected by visual load. These findings also suggest that attentional resources are modality specific and that the attentional filter of auditory processing does not vary with visual task demands.

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• Visual load does not decrease the auditory steady‐state response to 40‐Hz amplitude‐modulated tones

  2020. Malina Szychowska, Stefan Wiens. Psychophysiology 57 (12)

  Article

  The auditory pathway consists of multiple recurrent loops of afferent and efferent connections that extend from the cochlea up to the prefrontal cortex. The early-filter theory proposes that these loops allow topdown filtering of early and middle latency auditory responses. Furthermore, the adaptive filtering model suggests that filtering of irrelevant auditory stimuli should start lower in the pathway during more demanding tasks. If so, the 40-Hz auditory steady state responses (ASSRs) to irrelevant sounds should be affected by top-down crossmodal attention to a visual task, and effects should vary with the load of the visual task. Because few studies have examined this possibility, we conducted two preregistered studies that manipulated visual load (Study 1: N = 43, Study 2: N = 45). Study 1 used two levels (low and high), and Study 2 used four levels (no, low, high, and very high). Subjects were asked to ignore a 500-Hz taskirrelevant tone that was amplitude-modulated to evoke 40-Hz ASSRs. Results from Bayesian analyses provided moderate to extreme support for no effect of load (or of task) on ASSRs. Results also supported no interaction with time (i.e., over blocks, over minutes, or with changes in ASSRs that were synchronized with the onset of the visual stimuli). Further, results provided moderate support for no correlation between effects of load and working memory capacity. Because the present findings support the robustness of ASSRs against manipulations of crossmodal attention, they are not consistent with the adaptive filtering model.

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• The early but not the late neural correlate of auditory awareness reflects lateralized experiences

  2021. Rasmus Eklund, Billy Gerdfeldter, Stefan Wiens. Neuropsychologia 158

  Article

  Theories disagree as to whether it is the early or the late neural correlate of awareness that plays a critical role in phenomenal awareness. According to recurrent processing theory, early activity in primary sensory areas corresponds closely to phenomenal awareness. In support, research with electroencephalography found that in the visual and somatosensory modality, an early neural correlate of awareness is contralateral to the perceived side of stimulation. Thus, early activity is sensitive to the perceived side of visual and somatosensory stimulation. Critically, it is unresolved whether this is true also for hearing. In the present study (N = 26 students), Bayesian analyses showed that the early neural correlate of awareness (auditory awareness negativity, AAN) was stronger for contralateral than ipsilateral electrodes whereas the late correlate of auditory awareness (late positivity, LP) was not lateralized. These findings demonstrate that the early but not the late neural correlate of auditory awareness reflects lateralized experiences. Thus, these findings imply that AAN is a more suitable NCC than LP because it correlates more closely with lateralized experiences.

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• Is auditory awareness negativity confounded by performance?

  2020. Rasmus Eklund, Billy Gerdfeldter, Stefan Wiens. Consciousness and Cognition 83

  Article

  Research suggests that the electrophysiological correlates of consciousness are similar in hearing as in vision: the auditory awareness negativity (AAN) and the late positivity (LP). However, from a recently proposed signal-detection perspective, these correlates may be confounded by performance, as the strength of the internal responses differs between aware and unaware trials. Here, we tried to apply this signal-detection approach to correct for performance in an auditory discrimination and detection task (N = 28). A large proportion of subjects had to be excluded because even a small response bias distorted the correction. For the remaining subjects, the correction mainly increased noise in the measurement. Furthermore, the signal-detection approach is theoretically problematic because it may isolate post-perceptual processes and eliminate awareness-related activity. Therefore, we conclude that AAN and LP are not confounded by performance and that the contrastive analysis identifies both as correlates of awareness.

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• Auditory awareness negativity is an electrophysiological correlate of awareness in an auditory threshold task

  2019. Rasmus Eklund, Stefan Wiens. Consciousness and Cognition 71, 70-78

  Article

  One theory of visual awareness proposes that electrophysiological activity related to awareness occurs in primary visual areas approximately 200 ms after stimulus onset (visual awareness negativity: VAN) and in fronto-parietal areas about 300 ms after stimulus onset (late positivity: LP). Although similar processes might be involved in auditory awareness, only sparse evidence exists for this idea. In the present study, we recorded electrophysiological activity while subjects listened to tones that were presented at their own awareness threshold. The difference in electrophysiological activity elicited by tones that subjects reported being aware of versus unaware of showed an early negativity about 200 ms and a late positivity about 300 ms after stimulus onset. These results closely match those found in vision and provide convincing evidence for an early negativity (auditory awareness negativity: AAN), as well as an LP. These findings suggest that theories of visual awareness are also applicable to auditory awareness.

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• Effects of a Manual Response Requirement on Early and Late Correlates of Auditory Awareness

  2019. Rasmus Eklund, Billy Gerdfeldter, Stefan Wiens. Frontiers in Psychology 10

  Article

  In hearing, two neural correlates of awareness are the auditory awareness negativity (AAN) and the late positivity (LP). These correlates of auditory awareness are typically observed with tasks in which subjects are required to report their awareness with manual responses. Thus, the correlates may be confounded by this manual response requirement. We manipulated the response requirement in a tone detection task (N = 52). Tones were presented at each subject’s individual awareness threshold while high-density electroencephalography (EEG) activity was recorded. In one response condition, subjects pushed a button if they were aware of the tone and withheld responding if they were unaware of the tone. In the other condition, subjects pushed a button if they were unaware of the tone and withheld responding if they were aware of the tone. To capture AAN and LP, difference waves were computed between aware and unaware trials, separately for trials in which responses were required and trials in which responses were not required. Results suggest that AAN and LP are unaffected by the response requirement. These findings imply that in hearing, early and late correlates of awareness are not confounded by a manual response requirement. Furthermore, the results suggest that AAN originates from bilateral auditory cortices, supporting the view that AAN is a neural correlate of localized recurrent processing in early sensory areas.

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• Visual Perceptual Load Does Not Affect the Frequency Mismatch Negativity

  2019. Stefan Wiens (et al.). Frontiers in Psychology 10

  Article

  The mismatch negativity (MMN) has been of particular interest in auditory perception because of its sensitivity to auditory change. It is typically measured in an oddball task and is computed as the difference of deviant minus standard tones. Previous studies suggest that the oddball MMN can be reduced by crossmodal attention to a concurrent, difficult visual task. However, more recent studies did not replicate this effect. Because previous findings seem to be biased, we preregistered the present study and used Bayesian hypothesis testing to measure the strength of evidence for or against an effect of visual task difficulty. We manipulated visual perceptual load (high and low load). In the task, the visual stimuli were identical for both loads to avoid confounding effects from physical differences of the visual stimuli. We also measured the corrected MMN because the oddball MMN may be confounded by physical differences between deviant and standard tones. The corrected MMN is obtained with a separate control condition in which the same tone as the deviant (critical tone) is equiprobable with other tones. The corrected MMN is computed as deviant minus critical tones. Furthermore, we assessed working memory capacity to examine its moderating role. In our large sample (N = 49), the evidential strength in support of no effect of visual load was moderate for the oddball MMN (9.09 > BF01 > 3.57) and anecdotal to moderate for the corrected MMN (4.55 > BF01 > 2.17). Also, working memory capacity did not correlate with the visual load effect on the oddball MMN and the corrected MMN. The present findings support the robustness of the auditory frequency MMN to manipulations of crossmodal, visual attention and suggest that this relationship is not moderated by working memory capacity.

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• Cascade and no-repetition rules are comparable controls for the auditory frequency mismatch negativity in oddball tasks

  2019. Stefan Wiens (et al.). Psychophysiology 56 (1)

  Article

  The mismatch negativity (MMN) has been widely studied with oddball tasks to index processing of unexpected auditory change. The MMN is computed as the difference of deviant minus standard and is used to capture the pattern violation by the deviant. However, this oddball MMN is confounded because the deviant differs physically from the standard and is presented less often. To improve measurement, the same tone as the deviant is presented in a separate condition. This control tone is equiprobable with other tones and is used to compute a corrected MMN (deviant minus control). Typically, the tones are in random order except that consecutive tones are not identical (no-repetition rule). In contrast, a recent study on frequency MMN presented tones in a regular up-and-down sequence (cascade rule). If the cascade rule is detected more easily than the no-repetition rule, there should be a lower risk of a confounding MMN within the cascade condition. However, in previous research, the cascade and no-repetition conditions differed not only in the regularity of the tone sequence but also in number of tones, frequency range, and proportion of tones. We controlled for these differences to isolate effects of regularity in the tone sequence. Results of our preregistered analyses provided moderate evidence (BF01>6) that the corrected MMN did not differ between cascade and no-repetition conditions. These findings imply that no-repetition and cascade rules are processed similarly and that the no-repetition condition provides an adequate control in frequency MMN.

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• Background Odors Modulate N170 ERP Component and Perception of Emotional Facial Stimuli

  2018. Elmeri Syrjänen (et al.). Frontiers in Psychology 9

  Article

  Successful social interaction relies on the accurate decoding of other peoples' emotional signals, and their contextual integration. However, little is known about how contextual odors may lead to modulation of cortical processing in response to facial expressions. We investigated how unpleasant and pleasant contextual background odors affected emotion perception and cortical event-related potential (ERP) responses to pictures of faces expressing happy, neutral and disgusted facial expressions. Faces were, regardless of expression, rated more positively in the pleasant odor condition and more negatively in the unpleasant odor condition. Faces were overall rated as more emotionally arousing in the presence of an odor, irrespective of its valence. Contextual odors also interacted with facial expressions, such that happy faces were rated as especially non-arousing in the unpleasant odor condition. The early, face-sensitive N170 ERP component also displayed an interaction effect. Here, disgusted faces were affected by the odor context such that the N170 revealed a relatively larger negativity in the context of a pleasant odor compared with an unpleasant odor. There were no odor effects on the responses to faces in other measured ERP components (P1, VPP, P2, and LPP). These results suggest that odors bias socioemotional perception early stages of the visual processing stream. However, effects may vary across emotional expressions and measurements.

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• Fast Versus Slow Word Integration of Visual and Olfactory Objects

  2018. Jonas K. Olofsson (et al.). Behavioral Neuroscience 132 (6), 587-594

  Article

  In psychological experiments, behavioral speed varies across trials, and this variation is often associated with corresponding fluctuations in cortical activity. Little is known about such cortical variations in semantic priming tasks where target words are matched with preceding sensory object cues. Here, two visually presented target words (pear and lilac) were repeatedly cued by corresponding odors or pictures, and the participants were to indicate matching or nonmatching combinations. Data were split in behaviorally fast versus slow trials. We hypothesized that slow trials would be associated with higher prestimulus alpha activity and reduced ERP amplitudes, and that response-time differences between odor-cued and picture-cued trials would be especially large in slow behavioral trials. Results confirmed that slow trials showed increased alpha-band activity prior to word target onset, as well as amplitude decreases in the sensory P1 and semantic N400 components. However, no interactions between cue-modality and processing speed were observed. Instead, odor-cue integration responses were uniquely delayed on incongruent trials, a novel behavioral effect that was not observed in EEG measures. The results show that semantic integration speed is reflected in cortical activity before and during stimulus processing. Behavioral interactions with cue modality did not correspond to observed cortical activity changes, perhaps because olfactory circuits are not readily observed in scalp-recorded EEG. We conclude that combining behavioral speed variability and cortical EEG measures is useful in understanding the fluctuating nature of cognitive processing sequences.

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• Visual awareness negativity is an early neural correlate of awareness

  2018. Rasmus Eklund, Stefan Wiens. Cognitive, Affective, & Behavioral Neuroscience 18 (1), 176-188

  Article

  Electrophysiological recordings are commonly used to study the neural correlates of consciousness in humans. Previous research is inconsistent as to whether awareness can be indexed with visual awareness negativity (VAN) at about 200 ms or if it occurs later. The present study was preregistered with two main aims: First, to provide independent evidence for or against the presence of VAN, and second, to study whether stimulus size may account for the inconsistent findings. Subjects were shown low-contrast Gaussian filtered gratings (Gabor patches) in the four visual quadrants. Gabor size (large and small) was varied in different sessions and calibrated to each subject’s threshold of visual awareness. Event-related potentials were derived from trials in which subjects localized the Gabors correctly to capture the difference between trials in which they reported awareness versus no awareness. Bayesian analyses revealed very strong evidence for the presence of VAN for both Gabor sizes. However, there was no evidence for or against an effect of stimulus size. The present findings provide evidence for VAN as an early neural correlate of awareness.

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