title: Acute anxiety and social inference: An experimental manipulation with 7.5% carbon dioxide inhalation.
abstract: Positive self-bias is thought to be protective for mental health. We previously found that the degree of positive bias when learning self-referential social evaluation decreases with increasing social anxiety. It is unclear whether this reduction is driven by differences in state or trait anxiety, as both are elevated in social anxiety; therefore, we examined the effects on the state of anxiety induced by the 7.5% carbon dioxide (CO2) inhalation model of generalised anxiety disorder (GAD) on social evaluation learning.
  
  
  
  For our study, 48 (24 of female gender) healthy volunteers took two inhalations (medical air and 7.5% CO2, counterbalanced) whilst learning social rules (self-like, self-dislike, other-like and other-dislike) in an instrumental social evaluation learning task. We analysed the outcomes (number of positive responses and errors to criterion) using the random effects Poisson regression.
  
  
  
  Participants made fewer and more positive responses when breathing 7.5% CO2 in the other-like and other-dislike rules, respectively (gas × condition × rule interaction p = 0.03). Individuals made fewer errors learning self-like than self-dislike, and this positive self-bias was unaffected by CO2. Breathing 7.5% CO2 increased errors, but only in the other-referential rules (gas × condition × rule interaction p = 0.003).
  
  
  
  Positive self-bias (i.e. fewer errors learning self-like than self-dislike) seemed robust to changes in state anxiety. In contrast, learning other-referential evaluation was impaired as state anxiety increased. This suggested that the previously observed variations in self-bias arise due to trait, rather than state, characteristics.
authors.affiliation: Department of Psychology, University of Bath, Calverton Down, Bath, UK k.s.button@bath.ac.uk.
authors.forename: Katherine S
authors.initials: KS
authors.lastname: Button
authors.affiliation: UK Centre for Tobacco and Alcohol Studies, School of Experimental Psychology, University of Bristol, Bristol, UK.
authors.forename: Lucy
authors.initials: L
authors.lastname: Karwatowska
authors.affiliation: School of Social and Community Medicine, University of Bristol, Bristol, UK.
authors.forename: Daphne
authors.initials: D
authors.lastname: Kounali
authors.affiliation: UK Centre for Tobacco and Alcohol Studies, School of Experimental Psychology, University of Bristol, Bristol, UK Integrative Epidemiology Unit, Medical Research Council, University of Bristol, Bristol, UK.
authors.forename: Marcus R
authors.initials: MR
authors.lastname: Munafò
authors.affiliation: UK Centre for Tobacco and Alcohol Studies, School of Experimental Psychology, University of Bristol, Bristol, UK Integrative Epidemiology Unit, Medical Research Council, University of Bristol, Bristol, UK.
authors.forename: Angela S
authors.initials: AS
authors.lastname: Attwood
mesh_terms: D000280:Administration, Inhalation; D000293:Adolescent; D000328:Adult; D001007:Anxiety / Q000139:chemically induced* / Q000523:psychology*; D001008:Anxiety Disorders / Q000139:chemically induced* / Q000523:psychology*; D002245:Carbon Dioxide / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007858:Learning / Q000187:drug effects / Q000502:physiology; D008297:Male; D008603:Mental Health; D008875:Middle Aged; D012119:Respiration; D055815:Young Adult
chemical_list: D002245:Carbon Dioxide
keywords: Anxiety; carbon dioxide inhalation; carbon dioxide levels; learning; negativity; positivity; self-perception; self-referential processing; social anxiety; social judgement; state anxiety; trait anxiety