Acute anxiety and social inference: An experimental manipulation with 7.5% carbon dioxide inhalation

Katherine S Button, Lucy Karwatowska, Daphne Kounali, Marcus R Munafò, Angela S Attwood

Research output: Contribution to journalArticle (Academic Journal)peer-review

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BACKGROUND: 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.

METHODS: 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.

RESULTS: 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).

CONCLUSIONS: 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.

Original languageEnglish
Pages (from-to)1036-1046
Number of pages11
JournalJournal of Psychopharmacology
Issue number10
Early online date4 Jul 2016
Publication statusPublished - Oct 2016

Structured keywords

  • Brain and Behaviour
  • Tobacco and Alcohol


  • Anxiety
  • carbon dioxide inhalation
  • carbon dioxide levels
  • learning
  • negativity
  • positivity
  • self-perception
  • self-referential processing
  • social anxiety
  • social judgement
  • state anxiety
  • trait anxiety

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