Paranoia, sensitisation and social inference: findings from two large-scale, multi-round behavioural experiments.

Abstract

1The sensitisation model suggests paranoia is explained by over-sensitivity to 2 perceived threat in social environments. However, this has been difficult to test 3 experimentally. We report two pre-registered studies that tested i) the sensitisation 4 model as an explanation of paranoia, and; ii) the role of purported maintaining 5 factors in supporting social sensitisation. In study one, we recruited a large general 6 population sample (N=987) who serially interacted with other participants in multi-7round Dictator games, matched to fair, partially fair, or unfair partners. Participants 8 rated attributions of harmful intent and self-interest after each interaction. In study 9 two (N=1011), a new sample of participants completed the same procedure and 10 additionally completed measures of anxiety, worry and interpersonal sensitivity. As 11 predicted, paranoid ideation predicted higher and faster overall harmful intent 12 attributions, whereas attributions of self-interest were unaffected, supporting the 13 sensitisation model. Contrary to predictions, neither worry nor anxiety predicted 14 harmful intent attributions while interpersonal sensitivity predicted decreased harmful 15 intent attributions. In a third exploratory study we combined data sets to examine the 16 effect of paranoia on trial by trial attributional changes when playing fair and unfair 17dictators. Paranoia predicted a greater reduction in harmful intent attributions when 18 playing a fair but not unfair dictator, suggesting paranoia may also exaggerate the 19 volatility of beliefs about the harmful intent of others. 20 21

Reduction in social learning and increased policy uncertainty about harmful intent is associated with pre-existing paranoid beliefs: Evidence from modelling a modified serial dictator game

“…Social experiments using interactive game theory tasks have found that paranoia reduces the threshold for attributing harmful intent in ambiguous social exchanges [ 15 – 18 ]. More recently, Barnby et al [ 19 ] extended this work and additionally found that individuals high in paranoia were more likely to reduce high harmful intent attributions after a higher initial peak when interacting with partners who were consistently fair. This finding potentially suggested increased uncertainty of live paranoid social inferences in those with higher baseline pre-existing paranoid beliefs.…”

Dopamine manipulations modulate paranoid social inferences in healthy people

“…Following Barnby et al (2019a), we analysed the data using multi-model selection with model averaging (Burnham & Anderson, 2004;Grueber et al, 2011). The Akaike information criterion, corrected for small sample sizes (AICc), was used to evaluate models, with lower AICc values indicating a better fit (Grueber et al, 2011).…”

“…We developed a within-subjects, multi-trial modification on the Dictator game design used in previous studies to assess paranoia (Barnby et al, 2019a). Each participant played six trials against three different types of dictator.…”

“…We predicted that potentiation of dopamine transmission using L-DOPA in healthy participants would increase attributions of harmful intent and the salience of paranormal beliefs, given increased presynaptic dopamine in those at risk of psychosis (Howes & Kapur, 2009). Following Barnby et al (2019a), we also predicted that haloperidol and L-DOPA would respectively reduce and increase the amount of trials taken to reach a peak level of high harmful intent attribution but not self-interest attributions. All analysis scripts and open data are available on the Open Science Framework (https://osf.io/mr63j/).…”

“…Mohr et al (2005), also using levodopa, found that laterality of lexical decision processing altered as a function of magical ideation. However, belief salience (Barnby et al, 2019a) has yet to be tested.…”