12 5Interleaving
Another concept that has developed over the past decade is the concept of interleav-
ing. Interleaving is defined by the mixing of topics during learning sessions, instead
of a single topic in isolation being taught at each learning session [ 25 , 26 ]. This can
be diagrammed by the interleaving group having one session consisting of topics
ABCD, another session BADC, etc. with each letter corresponding to a different
topic. The standard, traditional blocked learning would accordingly look like
AAAA, BBBB, CCCC, etc.
Studies have shown that the traditional blocked learning may provide superior
immediate retention of information, but in the acquisition of long-term memory,
interleaving is superior [ 25 ]. Rohrer and Taylor studied math students that were
placed in a blocked group or mixed group and evaluated their performance on sub-
sequent tests. The blocked group (traditional) performed well on the immediate
practice test, averaging 89%, with the mixed group behind at 60%. However, once
it came to the final retention test several weeks later, the mixed group averaged 63%,
much higher than the blocked group’s average of 20% [ 25 ].
It is thought that interleaving improves long-term memory by allowing the
learner to discriminate between different topics when asked about them in the
future. Blocked learners have difficulty discriminating between topics and are there-
fore unable to move on to the correct solution that may involve more complex or
varied tasks or combinations thereof [ 26 , 27 ].
Feedback-Enhanced Testing
Test-enhanced learning has brought on the use of quizzing as a tool to enhance
learning and long-term memory. Question banks and practice tests that involve mul-
tiple choice questions are readily available to residents and cover many medical and
surgical topics. Although these quizzes have been shown to improve retrieval and
long-term memory, studies have shown that quizzes with multiple choice questions
can lead to negative effects with incorrect information. For example, a resident is
stumped on a multiple choice question and takes an educated guess. That guess
could be based off of false information, leading the learner to misinterpret key con-
cepts. This is why feedback is imperative with test-enhanced learning [ 28 , 29 ].
Feedback allows students to correct mistakes and misinterpreted concepts and
then solidify correct concepts in their memory. Types of feedback include a simple
one-line response to the correct answer, detailed explanations of correct responses,
or study materials to help delineate the correct response [ 28 ]. Karpicke and Roediger
have shown that feedback during repeated testing enhances retrieval and long-term
memory by 25% or more when compared to no feedback [ 30 ].
Feedback is typically presented immediately after the test to ensure effective
retention. This can be done after each individual question or at the end of the quiz.
Recent literature has even shown that delayed feedback may have more benefit. It is
7 Teaching Residents to Teach: Why and How