Stefan Wiens Foto: Datorenheten/HB

Stefan Wiens


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Arbetar vid Psykologiska institutionen
Telefon 08-16 39 33
Besöksadress Frescati hagväg 9A
Rum 215
Postadress Psykologiska institutionen 106 91 Stockholm

Om mig

Jag är professor i psykologi (psykofysiologi). 

Jag är intresserad i medvetande och i samspelet mellan att rikta uppmärksamhet på en uppgift och att hantera eventuella andra sinnesintryck som kan distrahera. På vägen hit har jag också forskat om andra ämnen, delvis pga studenter som hade särskilda intressen (exempelvis semantic satiation och mindfulness).

I min forskning använder jag fysiologiska mått (mestadels elektroencefalografi, EEG och event-relaterade potentialer, ERP).

Jag är också intresserad i statistik och metod (Bayes factor, Meta analys).



Jag undervisar i psykofysiologi och metodik.

Malina Szychowska studerar effekter av riktad uppmärksamhet på bearbetning av ljud.

Kim Ströberg studerar semantiska processes med hjälp av EEG.

Billy Gerdfeldter studerar medvetande med hjälp av EEG.

Före detta forskarstudenter

Rasmus Eklund studerar neuronala korrelater av medvetande. Han disputerade i Oktober 2019


Eklund, R., Gerdfeldter, B., & Wiens, S. (2020). Is auditory awareness negativity confounded by performance? Consciousness & Cognition, in press.

Wiens, S., van Berlekom, E., Szychowska, M., & Eklund, R. (2019). Visual Perceptual Load Does Not Affect the Frequency Mismatch Negativity. Frontiers in Psychology, 10(1970).

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).

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.

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,

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.

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:

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.

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.


I urval från Stockholms universitets publikationsdatabas
  • 2019. Stefan Wiens (et al.). Psychophysiology 56 (1)

    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.

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

    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.

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

    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.

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

    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.

  • 2017. Stefan Wiens (et al.).

    The data presented in this article are related to our research article entitled “Effects of sound pressure level and visual perceptual load on the auditory mismatch negativity” (M. Szychowska, R. Eklund, M.E. Nilsson, S. Wiens, 2016) [1]. The duration MMN was recorded at three sound pressure levels (SPLs) during two levels of visual perceptual load. In an oddball paradigm (standard=75 ms, deviant=30 ms, within-subjects design), participants were presented with tones at 56, 66, or 76 dB SPL (between-subjects design). At the same time, participants focused on a letter-detection task (find X in a circle of six letters). In separate blocks, perceptual load was either low (the six letters were the same) or high (the six letters differed). In the first data collection, tones had only 76 dB SPL [2]. In a follow-up data collection with exactly the same procedure, tones had 56 and 66 dB SPL [1]. Here, we report the procedure, the recording of electroencephalography (EEG) and its preprocessing in terms of event-related potentials (ERPs), the preprocessing of behavioral data, as well as the grand mean ERPs in figures. For each participant, the reported ERP data include mean amplitudes for standards, deviants, and the difference wave (MMN) at Fz (with tip of nose as a reference), separately for the combinations of SPL and load. Reported behavioral data include the signal-detection measure d’ as an index of detection performance.

  • 2017. Kim Ströberg, Lau M. Andersen, Stefan Wiens. Frontiers in Psychology 8

    Semantic satiation is characterised by the subjective and temporary loss of meaning after high repetition of a prime word. To study the nature of this effect, previous electroencephalography (EEG) research recorded the N400, an ERP component that is sensitive to violations of semantic context. The N400 is characterised by a relative negativity to words that are unrelated vs. related to the semantic context. The semantic satiation hypothesis predicts that the N400 should decrease with high repetition. However, previous findings have been inconsistent. Because of these inconsistent findings and the shortcomings of previous research, we used a modified design that minimises confounding effects from non-semantic processes. We recorded 64-channel EEG and analysed the N400 in a semantic priming task in which the primes were repeated 3 or 30 times. Critically, we separated low and high repetition trials and excluded response trials. Further, we varied the physical features (letter case and format) of consecutive primes to minimise confounding effects from perceptual habituation. For centrofrontal electrodes, the N400 was reduced after 30 repetitions (vs. 3 repetitions). Explorative source reconstructions suggested that activity decreased after 30 repetitions in bilateral inferior temporal gyrus, the right posterior section of the superior and middle temporal gyrus, right supramarginal gyrus, bilateral lateral occipital cortex, and bilateral lateral orbitofrontal cortex. These areas overlap broadly with those typically involved in the N400, namely middle temporal gyrus and inferior frontal gyrus. The results support the semantic rather than the perceptual nature of the satiation effect.

  • 2017. Stefan Wiens, Mats E. Nilsson. Educational and Psychological Measurement 77 (4), 690-715

    Because of the continuing debates about statistics, many researchers may feel confused about how to analyze and interpret data. Current guidelines in psychology advocate the use of effect sizes and confidence intervals (CIs). However, researchers may be unsure about how to extract effect sizes from factorial designs. Contrast analysis is helpful because it can be used to test specific questions of central interest in studies with factorial designs. It weighs several means and combines them into one or two sets that can be tested with t tests. The effect size produced by a contrast analysis is simply the difference between means. The CI of the effect size informs directly about direction, hypothesis exclusion, and the relevance of the effects of interest. However, any interpretation in terms of precision or likelihood requires the use of likelihood intervals or credible intervals (Bayesian). These various intervals and even a Bayesian t test can be obtained easily with free software. This tutorial reviews these methods to guide researchers in answering the following questions: When I analyze mean differences in factorial designs, where can I find the effects of central interest, and what can I learn about their effect sizes?

  • 2017. Malina Szychowska (et al.). Neuroscience Letters 640, 37-41

    Auditory change detection has been studied extensively with mismatch negativity (MMN), an event-related potential. Because it is unresolved if the duration MMN depends on sound pressure level (SPL), we studied effects of different SPLs (56, 66, and 76 dB) on the duration MMN. Further, previous research suggests that the MMN is reduced by a concurrent visual task. Because a recent behavioral study found that high visual perceptual load strongly reduced detection sensitivity to irrelevant sounds, we studied if the duration MMN is reduced by load, and if this reduction is stronger at low SPLs. Although a duration MMN was observed for all SPLs, the MMN was apparently not moderated strongly by SPL, perceptual load, or their interaction, because all 95% CIs overlapped zero. In a contrast analysis of the MMN (across loads) between the 56-dB and 76-dB groups, evidence (BF = 0.31) favored the null hypothesis that duration MMN is unaffected by a 20-dB increase in SPL. Similarly, evidence (BF = 0.19) favored the null hypothesis that effects of perceptual load on the duration MMN do not change with a 20-dB increase in SPL. However, evidence (BF = 3.12) favored the alternative hypothesis that the effect of perceptual load in the present study resembled the overall effect in a recent meta-analysis. When the present findings were combined with the meta-analysis, the effect of load (low minus high) was −0.43 μV, 95% CI [−0.64, −0.22] suggesting that the duration MMN decreases with load. These findings provide support for a sensitive monitoring system of the auditory environment.

  • 2017. Maria Larsson, Carlos Tirado, Stefan Wiens. Frontiers in Psychology 8

    Autism Spectrum Disorders (ASD) are often accompanied by atypical visual, auditory, and tactile sensory behavior. Evidence also suggests alterations of the olfactory system, but the pattern of findings appears mixed. To quantify this pattern systematically, we conducted a meta-analysis. Studies were included if they examined olfactory function (i.e., odor threshold, or odor identification) in ASD compared with healthy age-matched control groups. We also coded for the potential moderators gender, age, and IQ. Articles were identified through computerized literature search using Web of Science, PubMed, and Scopus databases. A total of 11 articles compared odor threshold and/or odor identification between cases and controls (for threshold, n = 143 ASD and 148 controls; and for identification, n = 132 ASD and 139 controls). Effects sizes showed a substantial heterogeneity. As a result, the 95% prediction intervals were wide and ranged between a large negative and a large positive effect size for odor threshold, [-1.86, 2.05], and for odor identification, [-1.51, 2.52]. Exploratory analyses suggested that age and IQ may be potential moderators. To conclude, the large heterogeneity is consistent with the notion of both hyposensitivity and hypersensitivity in individuals with ASD. However, future research needs to predict and test the specific direction of the effect to provide convincing evidence for atypical olfactory functions in ASD.

  • 2017. Rebecka N. Addo (et al.). Perception 46 (3-4), 530-537

    Autism spectrum disorders (ASD) are often characterized by atypical sensory behavior (hyperor hyporeactivity) although evidence is scarce regarding olfactory abilities in ASD; 16 adults with high-functioning ASD (mean age: 38.2, SD: 9.7) and 14 healthy control subjects (mean age: 42.0 years, SD: 12.5) were assessed in odor threshold, free and cued odor identification, and perceived pleasantness, intensity, and edibility of everyday odors. Although results showed no differences between groups, the Bayes Factors (close to 1) suggested that the evidence for no group differences on the threshold and identification tests was inconclusive. In contrast, there was some evidence for no group differences on perceived edibility (BF01 = 2.69) and perceived intensity (BF01 = 2.80). These results do not provide conclusive evidence for or against differences between ASD and healthy controls on olfactory abilities. However, they suggest that there are no apparent group differences in subjective ratings of odors.

Visa alla publikationer av Stefan Wiens vid Stockholms universitet

Senast uppdaterad: 1 juni 2020

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