One critical distinction is between the direct effects tests have on retention
and the indirect effects provided by tests (Roediger & Karpicke,
2006b). We will refer to this distinction throughout the chapter.
Briefly, as the name implies, direct effects arise from the test itself. So,
for example, if a student is asked ‘‘Which kings fought in the Battle of
Hastings in 1066?’’ and she correctly answered the question, her retrieval
of this fact would lead to it being better recollected again later than if she
had no practice or had simply studied the answer. This is an example of the
direct effect of testing (e.g., Carrier & Pashler, 1992). Incidentally, in case
you need it, the answer is that the forces of Duke William II of Normandy
overwhelmed King Harold II’s English forces at Hastings, hence ‘‘the
Norman conquest.’’
The indirect effects of testing refer to other possible effects that testing
might have. For example, if students are quizzed every week, they would
probably study more (and more regularly) during a semester than if they
were tested only on a midterm and a final exam. Thus, testing would have