Many languages have verbal stems like hug and marry whose intransitive realization is interpreted as reciprocal. Previous semantic analyses of such reciprocal intransitives rely on the assumption of symmetric participation. Thus, 'Sam and Julia hugged' is assumed to entail both 'Sam hugged Julia' and 'Julia hugged Sam'. In this paper we report experimental results that go against this assumption. It is shown that although symmetric participation is likely to be preferred by speakers, it is not a necessary condition for accepting sentences with reciprocal verbs. To analyze the reciprocal alternation, we propose that symmetric participation is a typical feature connecting the meanings of reciprocal and binary forms. This accounts for the optionality as well as to the preference of this feature. Further, our results show that agent intentionality often boosts the acceptability of sentences with reciprocal verbs. Accordingly, we propose that intentionality is another typical semantic feature of such verbs, separate from symmetric participation.