Dear community,
We have liking ratings on a 1–5 Likert scale of images, each in one of two conditions (asymmetrical vs. symmetrical) and belonging to one of six stimulus sets. We are interested in the effect of set on symmetry preference (whether liking more symmetrical or asymmetrical images). This is the head and structure of our dataset:
Here is our model configuration:
prior_m1 ←
#fixed
set_prior(“normal(0,1)”, class = “Intercept”) +
set_prior(“normal(0,1)”, class = “b”, coef = “symmetry1”) +
#error
set_prior(“gamma(1,2)”, class = “sd”)
m1Part ← brm(sliderL.response ~ symmetry + (symmetry|participant) + (symmetry|set),
data = Data,
family = cumulative(link = “probit”, threshold = “flexible”),
iter=20000, warmup=2000,
prior=prior_m1,
chains=4, cores=4,
init=‘0’, control=list(adapt_delta=0.99, max_treedepth = 10),
seed = 111)
Then, we run
conditional_effects(m1, effect = “set”, categorical=TRUE, re_formula = NULL)
This yields the probabilities for each level of liking per set:
We would very much appreciate a response to the question:
Do these probabilities refer to symmetry1 (in contrast with the intercept) or symmetry0 (the intercept)?
Many thanks and kind regards,
Ana