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Cited by 149Social and Intergroup PsychologyRacial and Ethnic Identity ResearchNeural and Behavioral Psychology Studies

Propranolol reduces implicit negative racial bias

Open access
Terbeck, Sylvia, Kahane, Guy, McTavish, Sarah, Savulescu, Julian, Cowen, Philip J., Hewstone, Miles·2012·Psychopharmacology
DOI 10.1007/s00213-012-2657-5PMC PMC3395337
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Abstract

Background: Implicit negative attitudes towards other races are important in certain kinds of prejudicial social behaviour. Emotional mechanisms are thought to be involved in mediating implicit “outgroup” bias but there is little evidence concerning the underlying neurobiology. The aim of the present study was to examine the role of noradrenergic mechanisms in the generation of implicit racial attitudes. Methods: Healthy volunteers ( n = 36) of white ethnic origin, received a single oral dose of the β-adrenoceptor antagonist, propranolol (40 mg), in a randomised, double-blind, parallel group, placebo-controlled, design. Participants completed an explicit measure of prejudice and the racial implicit association test (IAT), 1–2 h after propranolol administration. Results: Relative to placebo, propranolol significantly lowered heart rate and abolished implicit racial bias, without affecting the measure of explicit racial prejudice. Propranolol did not affect subjective mood. Conclusions: Our results indicate that β-adrenoceptors play a role in the expression of implicit racial attitudes suggesting that noradrenaline-related emotional mechanisms may mediate negative racial bias. Our findings may also have practical importance given that propranolol is a widely used drug. However, further studies will be needed to examine whether a similar effect can be demonstrated in the course of clinical treatment.

AI snapshot

Written from the paper’s full text.

TL;DR

In a double-blind, placebo-controlled study of 36 white healthy volunteers, a single 40 mg oral dose of propranolol reduced implicit racial bias on the IAT without changing explicit racial prejudice or subjective mood. The authors conclude that noradrenergic/β-adrenoceptor mechanisms may mediate implicit negative racial attitudes.

Key findings

  • Propranolol significantly lowered heart rate relative to placebo (main effect of treatment: F(4, 30)=6.56, p=0.02; time × treatment: F(4, 30)=4.62, p=0.00).
  • Propranolol abolished the implicit racial bias effect: the IAT effect was smaller in the propranolol group (M=0.26, SD=1.09) than placebo (M=1.02, SD=0.84; t(33)=2.3, p=0.03, d=0.8), with a significant congruency × treatment interaction (F(1, 33)=6.20, p=0.02).
  • Explicit racial prejudice did not differ between groups, and no significant differences were found for religious, sexual, or drug-addiction prejudice (all p>0.2).
  • Propranolol did not alter VAS ratings of tense, angry, happy, sad, tired, or alert (all p>0.2); 34% of propranolol participants had a “negative” IAT score versus 0% of placebo participants (χ²(1, n=37)=7.2, p=0.02).

Methods

  • Randomized, double-blind, parallel-group, placebo-controlled design; 36 healthy volunteers of white ethnic origin, mostly British students, received either propranolol 40 mg orally (n=18) or placebo (n=18).
  • Participants completed an explicit prejudice feeling thermometer at 70 min and a computerized racial picture version of the IAT at 120 min after drug administration; heart rate and subjective mood were monitored.
  • IAT data were analyzed using Greenwald et al. (2003) improved algorithm; ANOVA was used for IAT, heart rate, and VAS, with post hoc unpaired t-tests, and Mann–Whitney U-tests for explicit prejudice scores.

Limitations

  • The paper states that explicit and implicit prejudice measures were given in a fixed order with a time gap, which might have produced a confounding effect whereby prior explicit testing interacted with propranolol to affect the IAT.
  • The paper notes that further studies are needed to determine whether the effect persists with sustained propranolol treatment, whether it modulates implicit bias outside the laboratory, and whether the action is peripheral or central.
  • Evident from the text: the sample was small (n=36), all white and mostly from a British student population, and the study used only behavioral measures; the authors also note that the IAT effect in the propranolol group was not significant, and the chi-square test reports n=37 despite 36 participants.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1007/s00213-012-2657-5

Cites

32 of 32 references verified0 citation errors · 0 not checkable

Statistics

Claims the paper makes

0 of 32 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    The subjective ratings do not suggest that propranolol caused sedation relative to placebo.

    “Our subjective ratings do not suggest that propranolol caused sedation relative to placebo.”
    Quote in the paperSubstantial claim
  • Findingown data

    Propranolol (40 mg orally) abolished or reduced implicit racial bias as measured by the IAT relative to placebo.

    “Relative to placebo, propranolol significantly lowered heart rate and abolished implicit racial bias, without affecting the measure of explicit racial prejudice.”
    • Also stated in: § Results · plain
      “However, an unpaired t-test showed the difference between congruent and incongruent trials (the IAT effect) was significantly smaller in the propranolol (M=0.26, SD=1.09) as compared to the placebo group (M=1.02, SD=0.84) (t(33) = 2.3, p=0.03; d=0.8)”
    • Also stated in: § Discussion · plain
      “The main finding of our study is that propranolol significantly reduced implicit but not explicit racial bias.”
    Quote in the paperSubstantial claim
  • Findingown data

    Propranolol (40 mg orally) did not affect explicit racial prejudice relative to placebo.

    “without affecting the measure of explicit racial prejudice”
    • Also stated in: § Results · plain
      “We found no effect of propranolol on the measure of explicit prejudice as judged using the Mann–Whitney U-test for independent, non-parametric data.”
    • Also stated in: § Discussion · plain
      “propranolol significantly reduced implicit but not explicit racial bias”
    Quote in the paperSubstantial claim
  • Findingown data

    Propranolol did not affect explicit prejudice against religious, sexual, or drug-addicted groups.

    “no significant difference between the propranolol and placebo groups was found for religious prejudice, sexual prejudice, or prejudice against drug addicted individuals (all p>0.2)”
    Quote in the paperNot a substantial claim
  • Findingown data

    The proportion of participants with a negative IAT score was significantly higher in the propranolol group (34%) than in the placebo group (0%).

    “in the propranolol group 34% of the participants had a “negative” IAT score (they were faster in the “bias”-incongruent as compared to the congruent condition). In the placebo group no subject had such a score. This difference was significant (χ2(1, n=37) = 7.2, p=0.02).”
    Quote in the paperSubstantial claim
  • The quote only partly states this claim. 1
  • May combine two claims. 10
  • Classified as probably not a substantial claim. 18

  • The quote only partly states this claim.

    Findingown data

    Propranolol (40 mg orally) significantly lowered heart rate relative to placebo in healthy white volunteers.

    “Relative to placebo, propranolol significantly lowered heart rate and abolished implicit racial bias, without affecting the measure of explicit racial prejudice.”
    • Also stated in: § Results · plain
      “Propranolol significantly lowered heart rate (calculated as change from baseline) as shown by a significant main effect of treatment on the ANOVA (F(4, 30) = 6.56, p=0.02), as well as a time × treatment (F(4, 30) = 4.62, p=0.00).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    In the placebo group, a significant IAT effect was present in both practice and main trials.

    “Paired t-tests also revealed that an IAT effect (a significant difference between the congruent and incongruent trials) could be determined for both practice (M=112.13, SD=111.06) and main (M=161.05, SD=244.53) trials in the placebo group (t(17) = 4.30, p=0.001; t(17) = 2.80, p=0.01)”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The physiological effect of propranolol (significant drop in heart rate) was present and similar throughout the relevant testing period (60-120 min).

    “our finding that the physiological effect of propranolol (a significant drop in heart rate) was present and similar throughout the relevant testing period (60–120 min).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The IAT is a widely used method to assess implicit attitudes to which individuals may have limited introspective access.

    “The implicit association test (IAT) (Greenwald et al. 2009) is a widely used method to assess implicit attitudes to which individuals may have limited introspective access (Nosek et al. 2007).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Greenwald et al. 2009 source

      Not checked in the free run.

    • cites Nosek et al. 2007

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The dominance of political norms of equality and tolerance in Western democracies limits the overt expression of prejudice.

    “The dominance of political norms of equality and tolerance in Western democracies limits the overt expression of prejudice in such countries (Schuman et al. 1997).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Schuman et al. 1997

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductown data

    Only data from blocks with less than 15% errors were analysed; one participant was excluded due to more than 20% errors, and for three others only main trials were analysed.

    “Only data from blocks with less than 15% errors were analysed (one participant was excluded due to more than 20% errors on practice and main trials, for three other participants only the main trials were analysed due to too many errors in the practice trials).”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductown data

    The study used a randomised, double-blind, parallel-group, placebo-controlled design.

    “in a randomised, double-blind, parallel group, placebo-controlled, design.”
    • Also stated in: § Procedure · plain
      “Participants were randomly allocated to take either propranolol (40 mg orally) or placebo in identical capsules in a parallel group, double-blind design.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductcitation

    The IAT was analysed according to the improved algorithm of Greenwald et al. (2003).

    “The IAT was analysed according to the improved algorithm as provided by Greenwald et al. (2003).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Greenwald et al. (2003) source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    The measures of explicit and implicit prejudice were given in a fixed order with a time gap, which might have produced a confounding effect whereby previous explicit testing interacted with propranolol to affect the IAT.

    “It should be noted that our measures of explicit and implicit prejudice were given in a fixed order with a time gap between the two in order to try to avoid the tests influencing each other (e.g., to reduce awareness that “prejudice” was tested). This might have produced a confounding effect whereby previous explicit testing of prejudice interacted with propranolol to affect the IAT.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    The IAT design followed the original version used by Greenwald et al. (1998).

    “The design of the task followed that of the original version used by Greenwald et al. (1998).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Greenwald et al. (1998) source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    The IAT is a reliable measure of implicit attitudes towards social outgroups, whether based on race, sexual orientation, gender, or political preference.

    “There is now extensive evidence that the IAT is a reliable measure of implicit attitudes towards social outgroups, whether based on race, sexual orientation, gender, or political preference (Nosek et al. 2007).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Nosek et al. 2007

      Not checked in the free run.

  • May combine two claims.

    Study design and conductown data

    The groups were well matched in demographic measures and mood.

    “The groups were well matched in terms of demographic measures as well as measures of mood (Table 1).”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductown data

    Participants were screened to be free of Axis 1 Psychiatric Disorder and medical contraindications to propranolol.

    “They were screened by a trained clinician to be free of any Axis 1 Psychiatric Disorder using the Structured Clinical Interview for DSM-IV (SCID-IV); they also underwent a brief medical examination which included an ECG and blood pressure measurement to exclude those suffering any medical contraindication to propranolol administration (epilepsy, asthma, heart disease).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The IAT is a consistently better predictor of discrimination against out-group members than measures of explicit prejudice.

    “A recent meta-analysis further suggests that the IAT is a consistently better predictor of discrimination against out-group members than measures of explicit prejudice (Poehlman et al. 2004).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Poehlman et al. 2004

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductcitation

    The explicit prejudice measure used a feeling thermometer, an established tool (Converse and Presser 1986).

    “A feeling thermometer, an established tool for measuring explicit prejudice (Converse and Presser 1986), was used”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Converse and Presser 1986

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Propranolol can reduce amygdala response to visual stimuli associated with negative emotions such as fear and anger.

    “prior studies have shown that propranolol can reduce amygdala response to visual stimuli associated with negative emotions such as fear and anger (Van Stegeren et al. 2005)”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Van Stegeren et al. 2005 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    A single patient with bilateral amygdala damage exhibited an intact IAT effect.

    “Phelps et al (2003) found that a single patient with bilateral amygdala damage exhibited an intact IAT effect”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Phelps et al (2003) source

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    Increased amygdala activation is associated with implicit prejudice but not with explicit racial attitudes.

    “previous neuroimaging studies found that increased amygdala activation was associated with implicit prejudice but not with explicit racial attitudes (Phelps et al. 2000).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Phelps et al. 2000 source

      Not checked in the free run.

  • May combine two claims.

    Premisereasoning

    Previous studies on amygdala and implicit bias are largely correlational and cannot establish causal mechanisms.

    “However, these previous studies are largely correlational in nature, and cannot establish the causal mechanisms that underlie implicit bias.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The ability of oxytocin to facilitate socially reinforced learning is mediated via beta-adrenergic mechanisms in the amygdala.

    “Hurlemann et al. (2010a, b) have suggested that the ability of oxytocin to facilitate socially reinforced learning is mediated via beta-adrenergic mechanisms in the amygdala.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Hurlemann et al. (2010a, b)

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Oxytocin increases in-group favouritism.

    “De Dreu et al (2011) reported that in-group favouritism was increased by oxytocin”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites De Dreu et al (2011) source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Noradrenergic transmission in the basolateral amygdala plays a role in emotional processing, as demonstrated in animal studies.

    “the role of noradrenergic transmission in the basolateral amygdala in emotional processing has also been demonstrated in animal studies (McGaugh 2000).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites McGaugh 2000 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Memory for emotional stimuli is impaired by propranolol but not nadolol, suggesting a central location for the relevant β-adrenoceptors.

    “Van Stegeren et al (1998) found that memory for emotional stimuli was impaired by propranolol but not nadolol, suggesting a central location for the relevant β-adrenoceptors.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Van Stegeren et al (1998) source

      Not checked in the free run.

23 of 23

  • The paper relies on this without support.

    Negative evaluations of minority groups are a central source of avoidance, discrimination, and conflict.

    “Negative evaluations of minority groups are a central source of avoidance, discrimination, and conflict — problems which are of particular importance in today’s increasingly cosmopolitan world.”

  • The paper relies on this without support.

    Implicit negative attitudes towards other races are important in certain kinds of prejudicial social behaviour.

    “Implicit negative attitudes towards other races are important in certain kinds of prejudicial social behaviour.”

  • The paper relies on this without support.

    There is extensive evidence that implicit bias remains a live and potent influence.

    “There is, however, extensive evidence that implicit bias — automatic negative attitudes associated with out-group members (Greenwald et al. 1998) — remains a live and a potent influence.”
3 of 3

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Statistics recomputed

Every reported test result, recomputed from its test statistic and degrees of freedom. A result shows as not adding up only once an independent check has confirmed it.

  • ConsistentF(4, 30) = 6.56reported p = .02 · recomputed p < .001

    “F(4, 30) = 6.56, p = .02”

    The paper states a correction for multiple tests

  • ConsistentF(4, 30) = 4.62reported p = 0 · recomputed p = .005

    “F(4, 30) = 4.62, p = .00”

  • Consistentt(33) = 2.51reported p = .02 · recomputed p = .017

    “t(33) = 2.51, p = .02”

  • Consistentt(34) = 2.4reported p = .02 · recomputed p = .022

    “t(34) = 2.4, p = .02”

  • ConsistentF(1, 33) = 13.6reported p = .001 · recomputed p < .001

    “F(1, 33) = 13.60, p = .001”

  • ConsistentF(1, 33) = 6.2reported p = .02 · recomputed p = .018

    “F(1, 33) = 6.20, p = .02”

  • ConsistentF(1, 33) = 0.26reported p = .61 · recomputed p = .614

    “F(1, 33) = 0.26, p = .61”

  • Consistentt(33) = -1.85reported p > .05 · recomputed p = .073

    “t(33) = −1.85, p > .05”

  • Consistentt(33) = 0.95reported p > .05 · recomputed p = .349

    “t(33) = 0.95, p > .05”

  • Consistentt(33) = 2.3reported p = .03 · recomputed p = .028

    “t(33) = 2.3, p = .03”

  • Consistentt(17) = 4.3reported p = .001 · recomputed p < .001

    “t(17) = 4.30, p = .001”

    The paper prints p at a floor (such as p < .001)

  • Consistentt(17) = 2.8reported p = .01 · recomputed p = .012

    “t(17) = 2.80, p = .01”

  • Consistentt(18) = -0.53reported p > .05 · recomputed p = .603

    “t(18) = −0.53, p > .05”

  • Consistentt(18) = 1.82reported p > .05 · recomputed p = .085

    “t(18)=1.82, p > .05”

14 of 14

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Negative-IAT analysis reports 37 participants instead of 36

    Major

    The study says it included 36 participants, split equally between treatment groups, but the reported analysis of negative IAT scores gives n=37.

  • IAT between-subject factor is named inconsistently

    Minor

    The statistics section names the IAT between-subject factor as "Time," whereas the reported IAT interaction uses treatment. The described IAT comparison is between propranolol and placebo groups, not time groups.

2 of 2

Cites

Flagged first, then by citations

Research works printed but not linked: 3

  1. Converse JM, Presser S (1986) Survey questions, handcrafting the standardized questionnaire, series: quantitative applications in the social science 63. Thousand Oaks, California: SAGE Publications
  2. Eysenck HJ, Eysenck SBG (1964) Manual of the Eysenck personal inventory. Educational and Industrial Testing Service, San Diego
  3. Poehlman TA, Uhlmann E, Greenwald AG, Banaji MR (2004) Understanding and using the implicit association test: III. Meta-analysis of predictive validity. Eur J Soc Psychol 38:922–934

Cited by

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Related

Authors
Terbeck, S., Kahane, G., McTavish, S., Savulescu, J., Cowen, P. J., & Hewstone, M.
Affiliations
  • University of Oxford (GB)
  • Warneford Hospital (GB)
Corresponding author
Terbeck, Sylvia
ORCID
Venue
Psychopharmacology
Publisher
Springer Science and Business Media LLC
Published
2012-02-28
Volume
222
Issue
3
Pages
419-424
ISSN
  • 0033-3158 (ISSN-L)
  • 1432-2072
DOI
10.1007/s00213-012-2657-5
PMC
PMC3395337
OpenAlex
W2058912915
Semantic Scholar
232df68583e4624a18a8bd0b1ebf6613b2c4219b
Cited by
149
References
32
Citations by year
2026: 5 · 2025: 11 · 2024: 14 · 2023: 20 · 2022: 3 · 2021: 13 · 2020: 5 · 2019: 8 · 2018: 11 · 2017: 13 · 2016: 12 · 2015: 7 · 2014: 10 · 2013: 9 · 2012: 8
FWCI
35.87
Type
journal article
Language
en
Open access
Licence
Locations
  • Psychopharmacology (publishedVersion, cc-by)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
  • PEARL (University of Plymouth) (submittedVersion)
  • PEARL (University of Plymouth) (submittedVersion, other-oa)
Funders
  • Wellcome Trust (087208, WT087208MF, 086041, WT086041MA)
  • Arts and Humanities Research Council (AH/F019513/1)
Topics
  • Social Sciences › Sociology and Political Science › Social and Intergroup Psychology
  • Social Sciences › Sociology and Political Science › Racial and Ethnic Identity Research
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Neural and Behavioral Psychology Studies
Keywords
propranolol, implicit racial bias, racial prejudice, beta-blockers, norepinephrine, emotional mechanisms, Implicit Association Test, heart rate, out-group bias, explicit prejudice
MeSH terms
Adrenergic beta-Antagonists, Double-Blind Method, Female, Heart Rate, Humans, Male, Prejudice, Propranolol, Social Behavior, White People

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Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

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