Gender Difference in Gender Bias: Transcranial Direct Current Stimulation Reduces Male's Gender Stereotypes.
ABSTRACT: Stereotypes exist in the interactions between different social groups, and gender stereotypes are particularly prevalent. Previous studies have suggested that the medial prefrontal cortex (mPFC) is involved in the social cognition that plays an important role in gender stereotypes, but the specific causal effect of the mPFC remains controversial. In this study, we aimed to use transcranial direct current stimulation (tDCS) to identify a direct link between the mPFC and gender bias. Implicit stereotypes were measured by the gender implicit association test (IAT), and explicit prejudice was measured by the Ambivalent Sexism Inventory (ASI). We found that male and female participants had different behavioral and neural correlates of gender stereotypes. Anodal tDCS significantly reduced male participants' gender D-IAT scores compared with cathodal and sham stimulation, while the stimulation had an insignificant effect in female participants. The reduction in male participants' gender bias mainly resulted from a decrease in the difference in reaction time (RT) between congruent and incongruent blocks. Regarding the explicit bias measurement, male and female participants had distinct attitudes, but tDCS had no effect on ASI. Our results revealed that the mPFC played a causal role in controlling implicit gender stereotypes, which is consistent with previous observations and complements past lesion, neuroimaging, and transcranial magnetic stimulation (TMS) studies and suggests that males and females have different neural bases for gender stereotypes.
Project description:In a cross-sectional study of youth ages 8-15, we examined implicit and explicit gender stereotypes regarding math and language abilities. We investigated how implicit and explicit stereotypes differ across age and gender groups and whether they are consistent with cultural stereotypes. Participants (N = 270) completed the Affect Misattribution Procedure (AMP) and a survey of explicit beliefs. Across all ages, boys showed neither math nor language implicit gender biases, whereas girls implicitly favored girls in both domains. These findings are counter to cultural stereotypes, which favor boys in math. On the explicit measure, both boys' and girls' primary tendency was to favor girls in math and language ability, with the exception of elementary school boys, who rated genders equally. We conclude that objective gender differences in academic success guide differences in children's explicit reports and implicit biases.
Project description:OBJECTIVES:Implicit regulation of emotions involves medial-prefrontal cortex (mPFC) regions exerting regulatory control over limbic structures. Diminished regulation relates to aberrant mPFC functionality and psychopathology. Establishing means of modulating mPFC functionality could benefit research on emotion and its dysregulation. Here, we tested the capacity of transcranial direct current stimulation (tDCS) targeting mPFC to modulate subjective emotional states by facilitating implicit emotion regulation. MATERIALS AND METHODS:Stimulation was applied concurrently with functional magnetic resonance imaging to validate its neurobehavioral effect. Sixteen participants were each scanned twice, counterbalancing active and sham tDCS application, while undergoing negative mood induction (clips featuring negative vs. neutral contents). Effects of stimulation on emotional experience were assessed using subjective and neural measures. RESULTS:Subjectively, active stimulation led to significant reduction in reported intensity of experienced emotions to negatively valenced (p?=?0.005) clips but not to neutral clips (p?>?0.99). Active stimulation further mitigated a rise in stress levels from pre- to post-induction (sham: p?=?0.004; active: p?=?0.15). Neurally, stimulation increased activation in mPFC regions associated with implicit emotion regulation (ventromedial-prefrontal cortex; subgenual anterior-cingulate cortex, sgACC), and in ventral striatum, a core limbic structure (all ps?<?0.05). Stimulation also altered functional connectivity (assessed using whole-brain psycho-physiological interaction) between these regions, and with additional limbic regions. Stimulation-induced sgACC activation correlated with reported emotion intensity and depressive symptoms (rs?>?0.64, ps?<?0.018), suggesting individual differences in stimulation responsivity. CONCLUSIONS:Results of this study indicate the potential capacity of tDCS to facilitate brain activation in mPFC regions underlying implicit regulation of emotion and accordingly modulate subjective emotional experiences.
Project description:Women's representation in science has changed substantially, but unevenly, over the past 40 years. In health and biological sciences, for example, women's representation among U.S. scientists is now on par with or greater than men's, while in physical sciences and engineering they remain a clear minority. We investigated whether variation in proportions of women in scientific disciplines is related to differing levels of male-favoring explicit or implicit stereotypes held by students and scientists in each discipline. We hypothesized that science-is-male stereotypes would be weaker in disciplines where women are better represented. This prediction was tested with a sample of 176,935 college-educated participants (70% female), including thousands of engineers, physicians, and scientists. The prediction was supported for the explicit stereotype, but not for the implicit stereotype. Implicit stereotype strength did not correspond with disciplines' gender ratios, but, rather, correlated with two indicators of disciplines' scientific intensity, positively for men and negatively for women. From age 18 on, women who majored or worked in disciplines perceived as more scientific had substantially weaker science-is-male stereotypes than did men in the same disciplines, with gender differences larger than 0.8 standard deviations in the most scientifically-perceived disciplines. Further, particularly for women, differences in the strength of implicit stereotypes across scientific disciplines corresponded with the strength of scientific values held by women in the disciplines. These results are discussed in the context of dual process theory of mental operation and balanced identity theory. The findings point to the need for longitudinal study of the factors' affecting development of adults' and, especially, children's implicit gender stereotypes and scientific identity.
Project description:About 70% of more than half a million Implicit Association Tests completed by citizens of 34 countries revealed expected implicit stereotypes associating science with males more than with females. We discovered that nation-level implicit stereotypes predicted nation-level sex differences in 8th-grade science and mathematics achievement. Self-reported stereotypes did not provide additional predictive validity of the achievement gap. We suggest that implicit stereotypes and sex differences in science participation and performance are mutually reinforcing, contributing to the persistent gender gap in science engagement.
Project description:Mind-wandering, the mind's capacity to stray from external events and generate task-unrelated thought, has been associated with activity in the brain default network. To date, little is understood about the contribution of individual nodes of this network to mind-wandering. Here, we investigated the role of medial prefrontal cortex (mPFC) in mind-wandering, by perturbing this region with transcranial direct current stimulation (tDCS). Young healthy participants performed a choice reaction time task both before and after receiving cathodal tDCS over mPFC, and had their thoughts periodically sampled. We found that tDCS over mPFC - but not occipital or sham tDCS - decreased the propensity to mind-wander. The tDCS-induced reduction in mind-wandering occurred in men, but not in women, and was accompanied by a change in the content of task-unrelated though, which became more related to other people (as opposed to the self) following tDCS. These findings indicate that mPFC is crucial for mind-wandering, possibly by helping construction of self-relevant scenarios capable to divert attention inward, away from perceptual reality. Gender-related differences in tDCS-induced changes suggest that mPFC controls mind-wandering differently in men and women, which may depend on differences in the structural and functional organization of distributed brain networks governing mind-wandering, including mPFC.
Project description:Most research to date on implicit gender stereotyping has been conducted with one age group - young adults. The mechanisms that underlie the on-line processing of stereotypical information in other age groups have received very little attention. This is the first study to investigate real time processing of gender stereotypes at different age levels. We investigated the activation of gender stereotypes in Italian in four groups of participants: third- and fifth-graders, young and older adults. Participants heard a noun that was stereotypically associated with masculine (preside "headmaster") or feminine roles (badante "social care worker"), followed by a male (padre "father") or female kinship term (madre "mother"). The task was to decide if the two words - the role noun and the kinship term - could describe the same person. Across all age groups, participants were significantly faster to respond, and significantly more likely to press 'yes,' when the gender of the target was congruent with the stereotypical gender use of the preceding prime. These findings suggest that information about the stereotypical gender associated with a role noun is incorporated into the mental representation of this word and is activated as soon as the word is heard. In addition, our results show differences between male and female participants of the various age groups, and between male- and female-oriented stereotypes, pointing to important gender asymmetries.
Project description:High rates of sexual partner concurrency have been shown to facilitate the spread of various sexually transmitted infections. Assessments of explicit attitudes to concurrency have however found little difference between populations. Implicit attitudes to concurrency may vary between populations and play a role in generating differences in the prevalence of concurrency. We developed a concurrency implicit associations test (C-IAT) to assess if implicit attitudes towards concurrency may vary between individuals and populations and what the correlates of these variations are. A sample of 869 Belgian students (mean age 23, SD 5.1) completed an online version of the C-IAT together with a questionnaire concerning sexual behavior and explicit attitudes to concurrency. The study participants C-IATs demonstrated a strong preference for monogamy (-0.78, SD = 0.41). 93.2% of participants had a pro-monogamy C-IAT. There was no difference in this implicit preference for monogamy between heterosexual men and women. Men who have sex with men and women who have sex with women were more likely to exhibit implicit but not explicit preferences for concurrency compared to heterosexual men and women. Correlates of the C-IAT varied between men and women.
Project description:Neuroaesthetics has been searching for the neural bases of the subjective experience of beauty. It has been demonstrated that neural activities in the medial prefrontal cortex (mPFC) and the left primary motor cortex (lPMC) correlate with the subjective experience of beauty. Although beauty and ugliness seem to be semantically and conceptually opposite, it is still unknown whether these two evaluations represent extreme opposites in unitary or bivariate dimensions. In this study, we applied transcranial direct current stimulation (tDCS) to examine whether non-invasive brain stimulation modulates two types of esthetic evaluation; evaluating beauty and ugliness. Participants rated the subjective beauty and ugliness of abstract paintings before and after the application of tDCS. Application of cathodal tDCS over the mPFC with anode electrode over the lPMC, which induced temporal inhibition of neural excitability of the mPFC, led to a decrease in beauty ratings but not ugliness ratings. There were no changes in ratings of both beauty and ugliness when applying anodal tDCS or sham stimulation over the mPFC. Results from our experiment indicate that the mPFC and the lPMC have a causal role in generating the subjective experience of beauty, with beauty and ugliness evaluations constituting two distinct dimensions.
Project description:BACKGROUND:This randomised controlled trial (RCT) aims to compare 6-week posttreatment outcomes of an Integrative Adapt Therapy (IAT) to a Cognitive Behavioural Therapy (CBT) on common mental health symptoms and adaptive capacity amongst refugees from Myanmar. IAT is grounded on psychotherapeutic elements specific to the refugee experience. METHODS AND FINDINGS:We conducted a single-blind RCT (October 2017 -May 2019) with Chin (39.3%), Kachin (15.7%), and Rohingya (45%) refugees living in Kuala Lumpur, Malaysia. The trial included 170 participants receiving six 45-minute weekly sessions of IAT (97.6% retention, 4 lost to follow-up) and 161 receiving a multicomponent CBT also involving six 45-minute weekly sessions (96.8% retention, 5 lost to follow-up). Participants (mean age: 30.8 years, SD = 9.6) had experienced and/or witnessed an average 10.1 types (SD = 5.9, range = 1-27) of traumatic events. We applied a single-blind design in which independent assessors of pre- and posttreatment indices were masked in relation to participants' treatment allocation status. Primary outcomes were symptom scores of Post Traumatic Stress Disorder (PTSD), Complex PTSD (CPTSD), Major Depressive Disorder (MDD), the 5 scales of the Adaptive Stress Index (ASI), and a measure of resilience (the Connor-Davidson Resilience Scale [CDRS]). Compared to CBT, an intention-to-treat analysis (n = 331) at 6-week posttreatment follow-up demonstrated greater reductions in the IAT arm for all common mental disorder (CMD) symptoms and ASI domains except for ASI-3 (injustice), as well as increases in the resilience scores. Adjusted average treatment effects assessing the differences in posttreatment scores between IAT and CBT (with baseline scores as covariates) were -0.08 (95% CI: -0.14 to -0.02, p = 0.012) for PTSD, -0.07 (95% CI: -0.14 to -0.01) for CPTSD, -0.07 for MDD (95% CI: -0.13 to -0.01, p = 0.025), 0.16 for CDRS (95% CI: 0.06-0.026, p ? 0.001), -0.12 (95% CI: -0.20 to -0.03, p ? 0.001) for ASI-1 (safety/security), -0.10 for ASI-2 (traumatic losses; 95% CI: -0.18 to -0.02, p = 0.02), -0.03 for ASI-3 (injustice; (95% CI: -0.11 to 0.06, p = 0.513), -0.12 for ASI-4 (role/identity disruptions; 95% CI: -0.21 to -0.04, p ? 0.001), and -0.18 for ASI-5 (existential meaning; 95% CI: -0.19 to -0.05, p ? 0.001). Compared to CBT, the IAT group had larger effect sizes for all indices (except for resilience) including PTSD (IAT, d = 0.93 versus CBT, d = 0.87), CPTSD (d = 1.27 versus d = 1.02), MDD (d = 1.4 versus d = 1.11), ASI-1 (d = 1.1 versus d = 0.85), ASI-2 (d = 0.81 versus d = 0.66), ASI-3 (d = 0.49 versus d = 0.42), ASI-4 (d = 0.86 versus d = 0.67), and ASI-5 (d = 0.72 versus d = 0.53). No adverse events were recorded for either therapy. Limitations include a possible allegiance effect (the authors inadvertently conveying disproportionate enthusiasm for IAT in training and supervision), cross-over effects (counsellors applying elements of one therapy in delivering the other), and the brief period of follow-up. CONCLUSIONS:Compared to CBT, IAT showed superiority in improving mental health symptoms and adaptative stress from baseline to 6-week posttreatment. The differences in scores between IAT and CBT were modest and future studies conducted by independent research teams need to confirm the findings. TRIAL REGISTRATION:The study is registered under Australian New Zealand Clinical Trials Registry (ANZCTR) (http://www.anzctr.org.au/). The trial registration number is: ACTRN12617001452381.
Project description:The present study investigates the formation of new word-referent associations in an implicit learning scenario, using a gender-coded artificial language with spoken words and visual referents. Previous research has shown that when participants are explicitly instructed about the gender-coding system underlying an artificial lexicon, they monitor the frequency of exposure to male vs. female referents within this lexicon, and subsequently use this probabilistic information to predict the gender of an upcoming referent. In an explicit learning scenario, the auditory and visual gender cues are necessarily highlighted prior to acqusition, and the effects previously observed may therefore depend on participants' overt awareness of these cues. To assess whether the formation of experience-based expectations is dependent on explicit awareness of the underlying coding system, we present data from an experiment in which gender-coding was acquired implicitly, thereby reducing the likelihood that visual and auditory gender cues are used strategically during acquisition. Results show that even if the gender coding system was not perfectly mastered (as reflected in the number of gender coding errors), participants develop frequency based expectations comparable to those previously observed in an explicit learning scenario. In line with previous findings, participants are quicker at recognizing a referent whose gender is consistent with an induced expectation than one whose gender is inconsistent with an induced expectation. At the same time however, eyetracking data suggest that these expectations may surface earlier in an implicit learning scenario. These findings suggest that experience-based expectations are robust against manner of acquisition, and contribute to understanding why similar expectations observed in the activation of stereotypes during the processing of natural language stimuli are difficult or impossible to suppress.