Black cat... waiting to cross? by Luis Rodero-Merino

I never knock on wood. When I do a test at school, or when I am about to see whether I have passed an exam, I do not resort to such things. I think they are old customs which people used not just to bring themselves luck but also to persuade themselves that in some situations wonders could happen. I never knock on wood because I don’t think that it can change things or be useful to me in the psychological sense.