Children's ambiguous utterances: a re-examination of processing limitations on production

The ability to convey the optimal amount of information during conversation is a fundamental aspect of language use. In this study the relationship between children's failures to produce unambiguous utterances and the mental effort demands of the communication task was investigated. Five-, six-, seven- and nine-year-old children performed a message production task and a finger-tapping task both separately and simultaneously. The decrease in finger-tapping frequency during the simultaneous performance was used as an estimate of effort demands of the message production task. Working memory capacity was assessed by means of a spatial memory test and an object features identification task. Children's intuitions about message adequacy were recorded in two message evaluation tasks. By age six children proved to be able to select the relevant information when they were explicitly asked to do so, indicating that effort demands of the communication task did not exceed their computational resources. However, results suggested that the relative effort requirements of the communication task decrease with increasing age. These findings support a performance theory of communication development in which effort demands are a determinant of children's message adequacy.