The mid to late 1990s saw a series of negative media events in the United Kingdom (UK) related to biotechnology. According to the trust asymmetry hypothesis, such events ought to cause public trust in risk managers of biotechnology to fall quickly but rise slowly. We present evidence from the Eurobarometer surveys that from 1996 to 1999 public trust in the UK declined, but it increased sharply between 1999 and 2002. We seek to explain this apparent contradiction to the asymmetry hypothesis. We use canonical discriminant analysis of public trust to show that whether people trust or distrust risk managers of biotechnology depends significantly on the amount of knowledge people have about science. We speculate that knowledge of science moderates the trust asymmetry effect.