Dear Dr. McLaren, Thanks for your interpretation. I am also interested in this area and I would like to ask three questions. The first one: in a 2 (G, between-group) by 2 (C, within-group) design, if the main effect of G or C were found at p < 0.001 (uncorrected) level, while the interaction effect was found at p < 0.01 (uncorrected) level, could I only discuss the main effect without mention the interaction if the significant threshold was set at p < 0.001 (uncorrected)? Could I say that the difference between C1 and C2 were consistent across G1 and G2 at the p < 0.001 (uncorrected) level? The second question: in a 2 by 2 within-group design, if I found a significant interaction effect (e.g. p < 0.001, uncorrected) at some regions and I would like to do post-hoc analysis to know the details of such interaction effect (i.e. C11-C12 and C21-C22, respectively), could I do two t-test in the inclusive mask defined by the significant interaction effect with some loose threshold (i.e. p < 0.01 than < 0.001)? I ask this is because I found sometimes the significant interaction effect with strict significance threshold appeared near to but not exactly at the regions I was interested, while some looser significance threshold for the interaction effect could involve the ROIs. The third question: there are two kinds of analysis within ROIs. a) post-hoc t-test within the inclusive mask defined by interaction effect; b) analysis of percent-signal changes (fMRI) or mean/peak amplitude of some electrode (ERP) within ROIs. If the two kinds of analysis give different results, for example, a) significant while b) no significance, how to interpret the results? Bests, Sun Delin