bayesian t-test - hypothesis
I`m a bit unsure whether to conduct/report one-sided or two-sided bayesian t-tests.
In short - We have conducted an experiment, in which participants performed keypresses and were presented with effects that were either congruent or incongruent with prior acquired action-effect associations. Participants performed four blocks of 48 trials each. We expected shorter reaction times in congruent than in incongruent trials (But of course if the effect is the other way around (shorter reaction times incongruent trials than congruent trials) we would like to interpret this as well.
So if i conduct a one-sided bayesian t-test with the hypothesis A (congruent) < B (incongruent)
I get moderate evidence for a congruency effect (congruent < incongruent) in block 1 (BF = 4), but no evidence for such an effect in Block 2-4 (BFs are somewhere between 0.05 and 0.09). And using this approach, there is no way to obtain any evidence for an reversed effect (incongruent < congruent) if there is one.
However if I conduct a two sided bayesian t-test with the hypothesis A(congruent) ≠ B(incongruent) than I get only anecdotal evidence (BF = 2.03) for a congruency effect in block 1, but moderate evidence for a congruence reversal (incongruent < congruent) in block 4 (BF = 7.7)
So, If I
m strictly adhering to my hypothesis choosing a one-sided approach I get some evidence for my original hypothesis (in the first block), but I wont "detect" the congruency reversal in the last block. If a choose a two-sided approach, the evidence towards my original hypothesis is quite weak (BF of 2 instead of 4 in the first block) but I "detect" that over time (block 4) the opposite of which I had expected can be observed.
Are there any ideas on how to solve this?