Development of scientific reasoning in college biology: Do two levels of general hypothesis-testing skills exist?

The primary purpose of the present study was to test the hypothesis that tw o general developmentally based levels of hypothesis-testing skills exist. The first hypothesized level presumably involves skills associated with tes ting hypotheses about observable causal agents; the second presumably invol ves skills associated with testing hypotheses involving unobservable entiti es. To test this hypothesis, a hypothesis-testing skills test was developed and administered to a large sample of college students both at the start a nd at the end of a biology course in which several hypotheses at each level were generated and tested; The predicted positive relationship between lev el of hypothesis-testing skill and performance on a transfer problem involv ing the test of a hypothesis involving unobservable entities was found. The predicted positive relationship between level of hypothesis-testing skill and course performance was also found. Both theoretical and practical impli cations of the findings are discussed. (C) 2000 John Wiley & Sons,Inc.