Is the label 'conspiracy theory' a cause or a consequence of disbelief in alternative narratives?

Using the label 'conspiracy theory' is widely perceived to be a way of discrediting wild ideas and unsubstantiated claims. However, prior research suggests that labelling statements as conspiracy theories does not reduce people's belief in them. In four studies, we probed this effect further, and tested the alternative hypothesis that the label 'conspiracy theory' is a consequence rather than a cause of (dis)belief in conspiracy-related statements. Replicating prior research, Study 1 (N = 170) yielded no evidence that the label 'conspiracy theory' affects belief in statements. In Study 2 (N = 199), we discovered that the less people believed in statements, the more they favoured labelling them as 'conspiracy theories'. In Studies 3 and 4 (Ns = 150 and 151), we manipulated the relative believability of statements and found that participants preferred the label 'conspiracy theory' for relatively less believable versus more believable statements. The current research therefore supports the hypothesis that prior (dis)agreement with a statement affects the use of the label 'conspiracy theory' more than the other way around.