Reciprocal verbs alternate between unary collective sentences (Carrie and Aidan fought), binary sentences (Carrie fought Aidan) and “with” sentences (Carrie fought with Aidan). There is no agreement in the literature on the semantic account that properly characterizes the reciprocal alternation. Results of the experiments that we reported show that, in contrast to the common assumption in the field, the reciprocal alternation does not show a unidirectional entailment from unary reciprocal sentences to the binary reciprocal. In other words: if it is true that Carrie and Aidan fought, it is not necessarily true that Carrie fought Aidan and Aidan fought Carrie. The reciprocal alternation has a more complex semantics, which is not exhausted by standard logical notions like symmetry. To give a full account of reciprocal verb meaning, we also need to consider the conceptual content of the verb and its sensitivity to typicality effects. We found that in asymmetric events the acceptance of reciprocal sentences is boosted if participants in the event show the relevant emotion or intention, for instance ‘being angry’ in case of an event for the verb ‘fight’. We argued that the semantic relation between the different reciprocal alternates can be accounted for by a Threshold Model, based on the notion of typicality.The new element in our use of the Threshold Model is in accounting for the systematic relations between the argument structure of reciprocal verbs and the conceptual meaning of the verbs.
