A problem facing investigations of implicit and explicit learning is
the lack of valid measures of second language implicit and explicit
knowledge. This paper attempts to establish operational definitions of
these two constructs and reports a psychometric study of a battery of
tests designed to provide relatively independent measures of them. These
tests were (a) an oral imitation test involving grammatical and
ungrammatical sentences, (b) an oral narration test, (c) a timed
grammaticality judgment test (GJT), (d) an untimed GJT with the same
content, and (e) a metalinguistic knowledge test. Tests (a), (b), and (c)
were designed as measures of implicit knowledge, and tests (d) and (e)
were designed as measures of explicit knowledge. All of the tests examined
17 English grammatical structures. A principal component factor analysis
produced two clear factors. This analysis showed that the scores from
tests (a), (b), and (c) loaded on Factor 1, whereas the scores from
ungrammatical sentences in test (d) and total scores from test (e) loaded
on Factor 2. These two factors are interpreted as corresponding to
implicit and explicit knowledge, respectively. A number of secondary
analyses to support this interpretation of the construct validity of the
tests are also reported.This research was
funded by a Marsden Fund grant awarded by the Royal Society of Arts of New
Zealand to Rod Ellis and Cathie Elder. Other researchers who contributed
to the research are Shawn Loewen, Rosemary Erlam, Satomi Mizutani, and
Shuhei Hidaka.The author wishes to thank Nick Ellis, Jim Lantolf, and two
anonymous SSLA reviewers. Their constructive comments have helped
me to present the theoretical background of the study more convincingly
and to remove errors from the results and refine my interpretations of
them.