Journal of Research in Innovative Teaching - National University

Memory retention is related to the spacing effect discussed above because, if the study
sessions are spaced too far apart, memory retention will be poor and the spacing effect will lose
its potency. Rohrer and Pashler (2007) argue that the spacing effect depends jointly on two
intervals: the interval between study sessions (the intersession interval, ISI) and the interval
between study sessions and the test (the retention interval, RI). These researchers suggest that the
optimal ISI for the spacing effect is roughly 10–30 percent of the RI. In other words, if the
interval between study and test (the RI) is ten days (not uncommon for accelerated classes), the
ISIs should be spaced somewhere between one and three days apart. If the retention interval is
one month (common for semester classes), the optimal ISI would be between three and nine
days. Rohrer and Pashler (2007) reported that mathematics students in traditional classes who
spaced practice problems across a one-week period performed better on a subsequent test than
math students who massed the practice problems into one session. If their formulation is correct,
we should see the same improvement with math students taking accelerated classes and spacing
their practice over one or two days rather than a week.
Proactive and Retroactive Interference
Classical verbal learning theory proposed two types of interference—proactive and retroactive
(Underwood, 1957). Proactive interference occurs when prior learned material interferes with
and creates forgetting of the current material under study. Retroactive interference refers to
subsequent learning that interferes with and causes forgetting of the to-be-remembered material.
Just how interference theory relates to the accelerated versus traditional education debate is
difficult to pin down. On the one hand, interference theory might suggest that it is not a good
idea to take shorter, accelerated courses in a sequential fashion (as done, for example, in some
nontraditional colleges and universities) because earlier and later classes might interfere with
learning of the current class. On the other hand, taking courses concurrently over an extended
time period (as is done in more traditional semester sessions) might create proactive and
retroactive effects when students try to study one subject but experience interference from
material learned in the other classes. What little evidence exists seems to indicate that whether
classes are taken in sequence or concurrently does not effect learning performance (Boddy, 1985;
Tatum & Parker, 2007).
Multiple Testing Effects
If students are tested regularly (e.g., once per week), they tend to study more and space their
studying more evenly during the class (Bangert-Drowns, Kulik, & Kulik, 1991; Leeming, 2002).
Moreover, Roediger and Karpicke (2006a, 2006b) have shown that testing alone, independent of
the effect of studying, can have a positive impact on long-term retention of the study material.
These facts suggest that the longer, more traditional forms of course delivery should produce
better learning and retention than accelerated classes because more time is available to test
students. As discussed below, the research evidence is equivocal on this point, with most studies
showing no difference between accelerated and extended learning on long-term retention.
Although no difference is typically the cases, a handful of studies show better retention for the
extended classes, while a few other studies show slightly better retention for accelerated classes.
Focused Attention
Most of us have experienced situations in which we have become deeply immersed in an
activity, losing self-consciousness and feeling highly productive and satisfied afterward.
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