Determinants of Propranolol’s Selective Effect on Loss Aversion

Abstract

Research on emotion and decision-making has suggested that arousal mediates risky decisions (e.g., Bechara et al., 1997), but several distinct and often confounded processes drive such choices. Here, we used econometric modeling to separate and quantify the unique contributions of loss aversion, risk sensitivity and choice consistency to risky decision-making. We administered the beta-blocker propranolol in a double-blind, placebo-controlled within-subjects study, targeting the neurohormonal basis of physiological arousal. Matching our intervention’s pharmacological specificity with a quantitative model delineating decision-making components allowed us to identify the causal relationships between arousal and decision-making that do and do not exist. Propranolol selectively reduced loss aversion in a baseline- and dose-dependent manner (i.e. as a function of initial loss aversion and body-mass index), and did not affect risk sensitivity or choice consistency. These findings provide evidence for a specific, modulatory, and causal relationship between precise components of both emotion and risky decision-making.

Acute stress does not affect risky monetary decision-making

“…First, we checked the baseline parameter estimates for risk attitudes, loss aversion, and consistency to ensure they replicated previous work (Tom et al., 2007, Sokol-Hessner et al., 2009, De Martino et al., 2010, Sokol-Hessner et al., 2013, Chumbley et al., 2014, Sokol-Hessner et al., 2015, Sokol-Hessner et al., 2015). Computing the mean sample values for each of the group-level baseline parameters and then using Equation (4) to transform those values to value function parameter space produced appropriate values (mean recovered ρ = 0.92, 95%CI = [0.85 0.97]; mean recovered λ = 2.22, 95% CI = [1.88 2.61]; and mean recovered μ = 25.9, 95% CI = [21.3 31.1]).…”

“…Immediately following the conclusion of the CPT (or control), a second saliva sample was collected, and then participants were given an 8-min break during which they were asked to sit quietly without using any digital devices. They then gave a third saliva sample, after which they completed the risky decision-making task which took roughly 23 min (see below; Sokol-Hessner et al., 2009, Sokol-Hessner et al., 2013, Sokol-Hessner et al., 2015, Sokol-Hessner et al., 2015). Finally, participants gave a fourth saliva sample and completed a post-study questionnaire.…”

“…The basic model was identical to that used previously (see Equations (1), (2), (3); Sokol-Hessner et al., 2009, Sokol-Hessner et al., 2013, Sokol-Hessner et al., 2015, Sokol-Hessner et al., 2015). $$u\left(x^{+}\right)=p\left(x\right)\times x^{\rho }$$$$u\left(x^{-}\right)=p\left(x\right)\times -\lambda \times {\left(-x\right)}^{\rho }$$$$p\left(choosegamble\right)={\left(1+e^{-\mu \times \left(u\left(gamble\right)-u\left(guaranteed\right)\right)}\right)}^{-1}$$Equations (1), (2) determine the utility ( u(x) ) of the objective monetary amounts in the risky gamble and the guaranteed alternative.…”

“…Individual differences in HPA axis activity were objectively quantified with four measurements of salivary cortisol per day (Velasco et al., 1997, McRae et al., 2006). Participants' decision-making was also quantified with a risky decision-making task (Sokol-Hessner et al., 2009, Sokol-Hessner et al., 2013, Sokol-Hessner et al., 2015, Sokol-Hessner et al., 2015) that, in combination with an econometric model of valuation and decision-making, allowed the separation of risk attitudes, loss aversion, and consistency in decision-making for each participant on each day. Finally, statistically powerful hierarchical Bayesian analysis methods were used to pool the data from 120 participants, both leveraging individual differences and group-level analysis to identify how acute stress affects or spares the three measured processes contributing to risky decision-making.…”

Emotional arousal predicts intertemporal choice.

“…Future studies should explicitly manipulate arousal, either pharmacologically (e.g., Sokol-Hessner et al, 2015), or through incidental arousing stimuli (e.g., Nassar et al, 2012), to determine whether emotional arousal underlies intertemporal choices in this paradigm. We also acknowledge that physiological arousal is only one component of emotion (Scherer, 2000).…”