A study investigated the finding that metacognitive ability and reading level are related, and examined the effects of both presentation and response modes on young children's ability to detect ambiguity in messages. An ambiguity detection test was completed by 74 first grade children (who also completed a reading pretest), 26 second graders, and 20 third graders. Children were randomly assigned to oral or oral-plus-written presentation conditions, and point or verbal response conditions. Nine messages containing three levels of ambiguity were presented, and then the children were asked to choose the geometric shape described by the message. Unambiguous messages had only one correct referent, while partially ambiguous messages referred to two of the four shapes, and ambiguous messages referred to all four shapes. After indicating their responses, the children were asked if they had been told enough so that they could choose just the one shape that the experimenter had been thinking of, and were also asked to specify what further information they required to choose just one. Findings indicated a positive correlation between reading and performance on the ambiguity detection test. Message type, grade level, and response mode had significant effects on ambiguity detection, while mode of presentation did not. Of the first graders who responded correctly to all nine messages, all but four were able to specify what further information was necessary to choose correctly one of the four shapes presented. These findings provide further support for the link between metacognitive awareness and reading development. (A table of data and four references are included.) (NKA)