Context: I'm testing a hypothesis for a paper I have to write. I suspect that higher trait authoritarianism (sca) will positively predict greater support for US Supreme Court Justice Roberts (data gathered post affordable care act ruling) on its own, but will increase the negative effects of conspiratorial ideation (CI) in an sca x CI interaction. I tested the interaction in the model below and it was significantly negative. I'm not sure though whether the results suggest that sca buffers/offsets the negative effects of CI or intensifies them. Can someone take a look and explain to me how to interpret it?
At the moment, you cannot tell by examining the interaction. All that you currently know is that SCA positively predicts support for Roberts with C.I and the interaction in the model, and that C.Ideation negatively predicts support for Roberts with SCA and the interaction in the model. These to effects are, however, qualified, by the higher order SCA x CI interaction (-.6398, t = -4.15,p < .001). So, you know that they interact, but you do not know what that interaction looks like. You would need to decompose this interaction into its two simple slopes to examine if either is significant. Use Aiken & West, 1991 as a conceptual guide, and then use some of the online excel calculators (e.g., Jeremy Dawson has an easy one) to plot the simple slopes.