Three studies comparing the respective roles of interlanguage universals and natural language transfer in determining learners' judgments of grammaticality used college students of French in their second, third, and fourth semesters as subjects. In the first experiment, the subjects were exposed to both grammatical and four types of ungrammatical stimuli sentences with basic, familiar vocabulary, and were asked to make nominal judgments of grammaticality based on three error types. In the second, the same subjects were given groups of sentences with similar error types and asked to rank them for grammaticality according to the same criteria. In the third experiment, another group of second-semester French students was given larger groups of sentences and asked to rank them for grammaticality. Overall, the results were consistent with previous research on other languages, but it is proposed that some of the results might be attributable to the property of additivity or to morphological features, and several situations were found that are not accounted for by the distinction interlanguage universal rule vs. transfer rule. In addition, possible factors in the judgment of error that could confound the findings are considered. The researcher is cautioned not to accept wholly the universal-transfer dichotomy, which may be a false dichotomy. (MSE)