Context effects in recognition have played a major role in evaluating theories of recognition. Understanding how context impacts recognition is also important for making sound trade mark law. Consumers attempting to discriminate between the brand they are looking for and a look-alike product often have to differentiate products which share a great deal of common context: positioning on the supermarket shelf, the type of store, aspects of the packaging, or brand claims. Trade mark and related laws aim to protect brands and reduce consumer confusion, but courts assessing allegations of trade mark infringement often lack careful empirical evidence concerning the impact of brand and context similarity, and, in the absence of such evidence, make assumptions about how consumers respond to brands that downplay the importance of context and focus on the similarity of registered marks. The experiments reported in this paper aimed to test certain common assumptions in trade mark law, providing evidence that shared context can cause mistakes even where brand similarity is low.