Please also provide the following information in addition to your question:

- Operating System: OSX 10.14
- brms Version: 3.5

Imagine that I am interested in the Bayes Factor in favour of brightness having an effect on response time to shapes. Do the null and alternate hypotheses have to have the same random effects structures? For instance, is this okay?

```
m1 <- brm(RT~Brightness + (1+Brightness|Subject) + (1|Item))
m0 <- brm(RT~(1|Subject) + (1|Item))
bf <- bayes_factor(m1,m0)
```

Or is it a problem that the alternate hypothesis has a random subject slope?