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Dive into the research topics where Wanja Wolff is active.

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Featured researches published by Wanja Wolff.


Substance Abuse Treatment Prevention and Policy | 2014

Using response-time latencies to measure athletes’ doping attitudes: the brief implicit attitude test identifies substance abuse in bodybuilders

Ralf Brand; Wanja Wolff; Detlef Thieme

BackgroundKnowing and, if necessary, altering competitive athletes’ real attitudes towards the use of banned performance-enhancing substances is an important goal of worldwide doping prevention efforts. However athletes will not always be willing to reporting their real opinions. Reaction time-based attitude tests help conceal the ultimate goal of measurement from the participant and impede strategic answering. This study investigated how well a reaction time-based attitude test discriminated between athletes who were doping and those who were not. We investigated whether athletes whose urine samples were positive for at least one banned substance (dopers) evaluated doping more favorably than clean athletes (non-dopers).MethodsWe approached a group of 61 male competitive bodybuilders and collected urine samples for biochemical testing. The pictorial doping Brief Implicit Association Test (BIAT) was used for attitude measurement. This test quantifies the difference in response latencies (in milliseconds) to stimuli representing related concepts (i.e. doping–dislike/like–[health food]).ResultsProhibited substances were found in 43% of all tested urine samples. Dopers had more lenient attitudes to doping than non-dopers (Hedges’s g = -0.76). D-scores greater than -0.57 (CI95 = -0.72 to -0.46) might be indicative of a rather lenient attitude to doping. In urine samples evidence of administration of combinations of substances, complementary administration of substances to treat side effects and use of stimulants to promote loss of body fat was common.ConclusionThis study demonstrates that athletes’ attitudes to doping can be assessed indirectly with a reaction time-based test, and that their attitudes are related to their behavior. Although bodybuilders may be more willing to reveal their attitude to doping than other athletes, these results still provide evidence that the pictorial doping BIAT may be useful in athletes from other sports, perhaps as a complementary measure in evaluations of the effectiveness of doping prevention interventions.


PLOS ONE | 2015

The Effect of Implicitly Incentivized Faking on Explicit and Implicit Measures of Doping Attitude: When Athletes Want to Pretend an Even More Negative Attitude to Doping

Wanja Wolff; Sebastian Schindler; Ralf Brand

The Implicit Association Test (IAT) aims to measure participants’ automatic evaluation of an attitude object and is useful especially for the measurement of attitudes related to socially sensitive subjects, e.g. doping in sports. Several studies indicate that IAT scores can be faked on instruction. But fully or semi-instructed research scenarios might not properly reflect what happens in more realistic situations, when participants secretly decide to try faking the test. The present study is the first to investigate IAT faking when there is only an implicit incentive to do so. Sixty-five athletes (22.83 years ± 2.45; 25 women) were randomly assigned to an incentive-to-fake condition or a control condition. Participants in the incentive-to-fake condition were manipulated to believe that athletes with lenient doping attitudes would be referred to a tedious 45-minute anti-doping program. Attitudes were measured with the pictorial doping brief IAT (BIAT) and with the Performance Enhancement Attitude Scale (PEAS). A one-way MANOVA revealed significant differences between conditions after the manipulation in PEAS scores, but not in the doping BIAT. In the light of our hypothesis this suggests that participants successfully faked an exceedingly negative attitude to doping when completing the PEAS, but were unsuccessful in doing so on the reaction time-based test. This study assessed BIAT faking in a setting that aimed to resemble a situation in which participants want to hide their attempts to cheat. The two measures of attitude were differentially affected by the implicit incentive. Our findings provide evidence that the pictorial doping BIAT is relatively robust against spontaneous and naïve faking attempts. (B)IATs might be less prone to faking than implied by previous studies.


Frontiers in Behavioral Neuroscience | 2015

Cerebral correlates of faking: evidence from a brief implicit association test on doping attitudes

Sebastian Schindler; Wanja Wolff; Johanna Kissler; Ralf Brand

Direct assessment of attitudes toward socially sensitive topics can be affected by deception attempts. Reaction-time based indirect measures, such as the Implicit Association Test (IAT), are less susceptible to such biases. Neuroscientific evidence shows that deception can evoke characteristic ERP differences. However, the cerebral processes involved in faking an IAT are still unknown. We randomly assigned 20 university students (15 females, 24.65 ± 3.50 years of age) to a counterbalanced repeated-measurements design, requesting them to complete a Brief-IAT (BIAT) on attitudes toward doping without deception instruction, and with the instruction to fake positive and negative doping attitudes. Cerebral activity during BIAT completion was assessed using high-density EEG. Event-related potentials during faking revealed enhanced frontal and reduced occipital negativity, starting around 150 ms after stimulus presentation. Further, a decrease in the P300 and LPP components was observed. Source analyses showed enhanced activity in the right inferior frontal gyrus between 150 and 200 ms during faking, thought to reflect the suppression of automatic responses. Further, more activity was found for faking in the bilateral middle occipital gyri and the bilateral temporoparietal junction. Results indicate that faking reaction-time based tests alter brain processes from early stages of processing and reveal the cortical sources of the effects. Analyzing the EEG helps to uncover response patterns in indirect attitude tests and broadens our understanding of the neural processes involved in such faking. This knowledge might be useful for uncovering faking in socially sensitive contexts, where attitudes are likely to be concealed.


International Journal of Drug Policy | 2016

Using the simple sample count to estimate the frequency of prescription drug neuroenhancement in a sample of Jordan employees

Wanja Wolff; Yaser Sandouqa; Ralf Brand

BACKGROUND Epidemiological research indicates that the use of prescription drugs to enhance cognitive functioning is prevalent in Western countries, however, research on this phenomenon in Arab countries is lacking. Our study aimed to investigate the frequency of neuroenhancement (NE) using prescription drugs in a sample of employees in Jordan. METHODS A sample of 1186 employees (37.11±8.37 years old, 495 female), of whom 723 (35.65±7.53 years old, 396 female) served as teachers, completed a paper-pencil questionnaire. The single sample count technique (SSC) was used in order to secure confidential, self-reporting of prescription drug NE. RESULTS The 12-month prevalence of NE, estimated with the SSC was 15.43%. At 26.16%, the prevalence estimate was markedly higher in the subsample of teachers compared to non-teachers, 0.29%. Surprisingly, 336 participants did not use the SSC and directly affirmed or denied prescription drug NE. These direct responses yielded a prevalence of 11.57% for the full sample, 9.73% for the teachers and 15.60% for the non-teachers. CONCLUSION This is the first study of the frequency of NE in an Arab sample. Results indicate that the use of prescription drug NE is not limited to Western countries and that teachers in Jordan might constitute a high-risk population. Further, participants seem to differ in their use of indirect estimation methods for reporting prescription drug NE. For future research, it might be useful to triangulate standard self-reports and indirect estimation methods to assess NE. Possible cultural differences and specific high-risk populations for NE should be investigated further.


Frontiers in Physiology | 2017

That Escalated Quickly : Planning to Ignore RPE Can Backfire

Maik Bieleke; Wanja Wolff

Ratings of perceived exertion (RPE) are routinely assessed in exercise science and RPE is substantially associated with physiological criterion measures. According to the psychobiological model of endurance, RPE is a central limiting factor in performance. While RPE is known to be affected by psychological manipulations, it remains to be examined whether RPE can be self-regulated during static muscular endurance exercises to enhance performance. In this experiment, we investigate the effectiveness of the widely used and recommended self-regulation strategy of if-then planning (i.e., implementation intentions) in down-regulating RPE and improving performance in a static muscular endurance task. 62 female students (age: M = 23.7 years, SD = 4.0) were randomly assigned to an implementation intention or a control condition and performed a static muscular endurance task. They held two intertwined rings as long as possible while avoiding contacts between the rings. In the implementation intention condition, participants had an if-then plan: “If the task becomes too strenuous for me, then I ignore the strain and tell myself: Keep going!” Every 25 ± 10 s participants reported their RPE along with their perceived pain. Endurance performance was measured as time to failure, along with contact errors as a measure of performance quality. No differences emerged between implementation intention and control participants regarding time to failure and performance quality. However, mixed-effects model analyses revealed a significant Time-to-Failure × Condition interaction for RPE. Compared to the control condition, participants in the implementation intention condition reported substantially greater increases in RPE during the second half of the task and reached higher total values of RPE before task termination. A similar but weaker pattern evinced for perceived pain. Our results demonstrate that RPE during an endurance task can be self-regulated with if-then plans. This finding is particularly important given how frequently RPE is used in exercise science as a correlate of physiological processes that ultimately limit performance. Unexpectedly, participants with implementation intentions reported higher RPE than control participants. This suggests that strategies to self-regulate RPE might have ironic effects that hamper performance, maybe by increasing attention to RPE. This implication is important for exercise physiologists, athletes and coaches.


Frontiers in Psychology | 2015

Neuroenhancement and the strength model of self-control

Chris Englert; Wanja Wolff

Neuroenhancement (NE), the use of substances as a means to enhance performance, has garnered considerable scientific attention of late. While ethical and epidemiological publications on the topic accumulate, there is a lack of theory-driven psychological research that aims at understanding psychological drivers of NE. In this perspective article we argue that self-control strength offers a promising theory-based approach to further understand and investigate NE behavior. Using the strength model of self-control, we derive two theory-driven perspectives on NE-self-control research. First, we propose that individual differences in state/trait self-control strength differentially affect NE behavior based on one’s individual experience of NE use. Building upon this, we outline promising research questions that (will) further elucidate our understanding of NE based on the strength model’s propositions. Second, we discuss evidence indicating that popular NE substances (like Methylphenidate) may counteract imminent losses of self-control strength. We outline how further research on NE’s effects on the ego-depletion effect may further broaden our understanding of the strength model of self-control.


Scientific Reports | 2018

Increase in prefrontal cortex oxygenation during static muscular endurance performance is modulated by self-regulation strategies

Wanja Wolff; Maik Bieleke; Anna Hirsch; Christian Wienbruch; Peter M. Gollwitzer; Julia Schüler

Enduring physical strain is an important ability and prototypically required in athletic activities. However, little is known about the psychological determinants of endurance performance and their underlying neural mechanisms. Here, we investigated self-regulation as one such factor. We recruited 60 participants who hold intertwined rings for as long as possible while avoiding contacts between them, either with a goal intention or an implementation intention to perform well. Performance was measured in terms of time-to-failure and contact errors. Additionally, we repeatedly assessed ratings of perceived exertion (RPE) and pain (RPP) and used functional near-infrared spectroscopy (fNIRS) to continuously monitor cerebral oxygenation in dorsal and ventral parts of the lateral prefrontal cortex (LPFC), brain regions associated with effortful attentional control and response inhibition, respectively. Performance, RPE and RPP were similar in the goal and the implementation intention condition. LPFC activity increased over time, but its activation level was generally lower in the implementation intention condition. Both effects were particularly pronounced in the dorsal LPFC. Moreover, the balance between effortful and more automatic regulation seems to differ between self-regulation strategies. Our results indicate that self-regulation plays an important role in endurance performance and that self-regulatory processes during endurance performance might be reflected in LPFC activation.


PLOS ONE | 2018

Self-reports from behind the scenes : Questionable research practices and rates of replication in ego depletion research

Wanja Wolff; Lorena Baumann; Chris Englert

The strength model of self-control is one of the most influential and well-established models of self-regulation in social psychology. However, recent attempts to replicate the ego depletion effect have sometimes failed. The goal of this study is to investigate self-reported replication rates and the frequency of a set of questionable research practices (QRP) in ego depletion research. A literature search resulted in 1721 researchers who had previously published on ego depletion. They were invited to participate in an anonymous online survey. The respondents (n = 277), on average, had published over three papers on ego depletion, and had completed more than two additional, unpublished studies. Respondents indicated that in more than 40% of their studies, results were similar in magnitude to those reported in the existing literature, and more than 60% reported conducting a priori power analyses. 39.2% of respondents were aware of other researchers who engaged in the surveyed QRP’s, while 37.7% affirmed to have employed said QRP’s. These results underline the importance of reducing QRP’s to reliably test the validity of the ego depletion effect.


Frontiers in Psychology | 2016

Editorial: Using Substances to Enhance Performance: A Psychology of Neuroenhancement

Wanja Wolff; Ralf Brand

Within the scientific community and among the general public there exists a lively debate regarding the use of drugs for the enhancement of cognitive performance. The defining feature of this type of functional substance (ab)use behavior is the assumed functionality a user ascribes to a chosen substance for the intended goal (e.g., Wolff and Brand, 2013; Wolff et al., 2014). According to this behavioral approach, such Neuroenhancement (NE) behavior is best understood as a goal-directed behavior that should be investigated with research that is informed by psychological theorizing. Since there is currently a lack of such research, this research topic sets out to address this gap.


Substance Abuse Treatment Prevention and Policy | 2013

Subjective stressors in school and their relation to neuroenhancement: a behavioral perspective on students' everyday life "doping"

Wanja Wolff; Ralf Brand

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Matthias Ziegler

Humboldt University of Berlin

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Detlef Thieme

World Anti-Doping Agency

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Anna Hirsch

University of Konstanz

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