Verbs of agency denote relations between behavioural and mental states. Thus, ‘Jim is looking for X’ goes beyond a behavioural description, to take a mentalistic construal whereby Jim's desire for success, and his beliefs about how to search, explain his observed actions. Greek has two verbs of agency that can be used somewhat interchangeably by adults to mean ‘to look for’. The hypothesis is that young children will obey the principle of contrast to diagnose that one verb is mentalistic and the other verb is to be construed behaviourally. Following a study of mothers' verb-use, two studies with 238 children aged three to five years confirmed that the verb preferred in home use gave below-chance performance on a false-belief test whilst the less-established verb gave above-chance success, with children giving appropriate justifications. Thus, Greek preschoolers seem sometimes to have an adult-type understanding and sometimes fail to match the adult understanding. The proposal is that the children initially convert an adult verb-use pragmatic difference into a semantic contrast.