Profiles

Stefan Wiens, porträtt. Foto: Niklas Björling.

Stefan Wiens

Professor

Visa sidan på svenska
Works at Department of Psychology
Telephone 08-16 39 33
Email sws@psychology.su.se
Visiting address Frescati hagväg 9A
Room 215
Postal address Psykologiska institutionen 106 91 Stockholm

About me

I am a professor of Psychology (Psychophysiology).

Research

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. doi: 10.3758/s13415-018-0562-z, http://rdcu.be/EXSX

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.

Publications

A selection from Stockholm University publication database
  • 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.

  • 2016. Stefan Wiens, Malina Szychowska, Mats E. Nilsson. PLoS ONE 11 (1)

    Because the auditory system is particularly useful in monitoring the environment, previous research has examined whether task-irrelevant, auditory distracters are processed even if subjects focus their attention on visual stimuli. This research suggests that attentionally demanding visual tasks decrease the auditory mismatch negativity (MMN) to simultaneously presented auditory distractors. Because a recent behavioral study found that high visual perceptual load decreased detection sensitivity of simultaneous tones, we used a similar task (n= 28) to determine if high visual perceptual load would reduce the auditory MMN. Results suggested that perceptual load did not decrease the MMN. At face value, these nonsignificant findings may suggest that effects of perceptual load on the MMN are smaller than those of other demanding visual tasks. If so, effect sizes should differ systematically between the present and previous studies. We conducted a selective meta-analysis of published studies in which the MMN was derived from the EEG, the visual task demands were continuous and varied between high and low within the same task, and the task-irrelevant tones were presented in a typical oddball paradigm simultaneously with the visual stimuli. Because the meta-analysis suggested that the present (null) findings did not differ systematically from previous findings, the available evidence was combined. Results of this meta-analysis confirmed that demanding visual tasks reduce the MMN to auditory distracters. However, because the meta-analysis was based on small studies and because of the risk for publication biases, future studies should be preregistered with large samples (n > 150) to provide confirmatory evidence for the results of the present meta-analysis. These future studies should also use control conditions that reduce confounding effects of neural adaptation, and use load manipulations that are defined independently from their effects on the MMN.

  • 2015. Danielle Cosme, Stefan Wiens. PLoS ONE 10 (3)

    As a form of attention, mindfulness is qualitatively receptive and non-reactive, and is thought to facilitate adaptive emotional responding. One suggested mechanism is that mindfulness facilitates disengagement from an affective stimulus and thereby decreases affective reactivity. However, mindfulness has been conceptualized as a state, intervention, and trait. Because evidence is mixed as to whether self-reported trait mindfulness decreases affective reactivity, we used a multi-method approach to study the relationship between individual differences in self-reported trait mindfulness and electrocortical, electrodermal, electromyographic, and self-reported responses to emotional pictures. Specifically, while participants (N = 51) passively viewed pleasant, neutral, and unpleasant IAPS pictures, we recorded high-density (128 channels) electrocortical, electrodermal, and electromyographic data to the pictures as well as to acoustic startle probes presented during the pictures. Afterwards, participants rated their subjective valence and arousal while viewing the pictures again. If trait mindfulness spontaneously reduces general emotional reactivity, then for individuals reporting high rather than low-mindfulness, response differences between emotional and neutral pictures would show relatively decreased early posterior negativity (EPN) and late positive potential (LPP) amplitudes, decreased skin conductance responses, and decreased subjective ratings for valence and arousal. High mindfulness would also be associated with decreased emotional modulation of startle eyeblink and P3 amplitudes. Although results showed clear effects of emotion on the dependent measures, in general, mindfulness did not moderate these effects. For most measures, effect sizes were small with rather narrow confidence intervals. These data do not support the hypothesis that individual differences in self-reported trait mindfulness are related to spontaneous emotional responses during picture viewing.

Show all publications by Stefan Wiens at Stockholm University

Last updated: October 11, 2018

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