This study tested the constructivist hypothesis that the acquisition of domain-specific conceptual knowledge (declarative knowledge) requires use of general procedural knowledge. More specifically, it was hypothesized that use of a general pattern of hypothetico-deductive reasoning is necessary for the acquisition of novel domain-specific concepts. To test this hypothesis 314 high school biology and chemistry students were first tested to determine whether or not they were skilled in the use of hypothetico-deductive reasoning. Based on this test, students were classified as reflective, transitional, or intuitive thinkers. All students were then presented with a series of four concept-acquisition tasks. It was predicted that reflective (hypothetico-deductive) thinkers would acquire the concepts while intuitive (empirico-inductive) thinkers would not. Transitional thinkers were expected to be partially successful. These predictions were confirmed as skill in hypothetico-deductive reasoning (developmental level), but not age, was highly correlated with performance on the concept acquisition tasks (X2 = 71.14, p < 0.00001). This result was interpreted to be supportive of the constructivist hypothesis.