This paper explores the use of design patterns and anti-patterns in teaching human-computer interaction principles. Patterns are increasingly popular and are seen as an efficient knowledge transfer mechanism in many fields, including software development in the field of software engineering, and more recently in the field of human-computer interaction. In software engineering a concerted effort is also being made to identify and document "anti"-patterns for recording the experiences of expert software developers to caution novices against potential bad practices. It is, however, essential that we ensure compatibility with the learner's internal knowledge representation and acquisition processes, whether we are attempting to convey the knowledge in the form of a pattern or an anti-pattern. Since teaching with anti-patterns implies using negation, the primary aim of the research reported in this paper is to explore the efficacy of negative, rather than positive, teaching mechanisms. Evidence from theories of mental modelling and knowledge acquisition that highlight significant dangers in the use of anti-patterns to teach novices human-computer interaction principles is presented and supported with empirical findings. We started off by investigating the use of patterns (positive) in teaching, and then carried out experiments to test the use of anti-patterns (negative) in teaching HCI principles. This paper, whilst reporting mainly on our findings with respect to HCI design anti-patterns, will also identify some problems with the structure and use of patterns and anti-patterns in pedagogy.