Table 2.

Dietary health challenge success by Pupil Dilation Index and task order.

Population-level effects	Beta estimate	Standard deviation	95% Credible interval
(Intercept)	61.96	5.81	[50.88; 73.89]
Pupil Dilation Index	12.47	4.40	[3.39; 21.08]
Task order	1.39	8.48	[− 15.58; 17.81]
Bayes factor	4.07

Dietary health challenge success modelled with a Bayesian linear regression as a function of Pupil Dilation Index and task order (Eq. 4): the individual dietary health challenge success level (measured over all challenging trials in percentage points) is explained by the standardized and mean-centred Pupil Dilation Index (PDI). Compared to the average level of PDI in the group, an increase of 1 standard deviation (SD) in pupil dilation explains an additional 12.47% of dietary health challenge success on top of the 61.96% health challenge success that an individual with average PDI would show. The analysis is controlling for a factor representing Task Order (emotion regulation or dietary choice task first). Task order does not explain variation in dietary health challenge success levels (95% credible interval for the estimate includes zero).

Model fits are given as the population level mean of the posterior distribution ± standard deviation (SD) and the 95% credible interval. The Bayes factor is given for a comparison of the model against an intercept-only model.