Context effects in symbolic magnitude comparisons.

Five experiments demonstrate that context has an effect on the ease with which people can determine the relative sizes of pairs of large and small animals. In a standard context, people are faster at choosing the larger of two large animals and the smaller of two small animals. However, when only pairs of small animals are presented (Experiment 1), relatively large pairs (RABBIT-BEAVER) are treated as if they were large animals and are discriminated more rapidly under the choose larger instruction. Similarly, when only large animals are presented (Experiment 2), the smaller of these are now treated as if they were small animals. Several models are presented that account for these effects of context, and these models are examined in subsequent experiments that impose yet other variations in magnitude pairings. The results demonstrate the importance of context in comparative judgement and place important constraints on theories of linear orders.