EDUCATIONAL PSYCHOLOGY

Chapter 7, page 143

found that the more explanations that students in the explanation group provided, the more they learned.
Students in the explanation group who generated many explanations were particularly successful at
developing an accurate model of how blood goes from the heart to the lungs, back to the heart, and then to
the rest of the body.
An important characteristic of the explanations of students in the explanation group was that their
explanations often enabled them to infer the function of body structures. Here is an example:

TEXT: The septum divides the heart lengthwise into two sides. The right side pumps blood to the lungs, and

the left side pumps blood to the other parts of the body.

STUDENT EXPLANATION: So the septum is a divider so that the blood doesn’t get mixed up. So the right

side is to the lungs, and the left side is to the body. So the septum is like a wall that divides the heart into two

parts... it kind of like separates it so that the blood doesn’t get mixed up. (Chi et al., 1994, p. 454)

Note that the parts of the explanations in italics are inferences that the student makes about the function of
the septum; the septum’s function to keep blood separate is not explicitly mentioned. By generating
explanations, the students develop a better understanding of what the text says because they add important
information that was not explicitly stated in the text.

Based on this study, the researchers concluded that generating explanations is an highly effective means
of learning. Many other studies also support the usefulness of explanations in learning (Bielaczyc et al.,
1995; Ferguson-Hessler & de Jong, 1990; Mevarech & Kramarski, 2003; Ozgungor & Guthrie, 2004;
Rittle-Johnson, 2006). Hence, explanations appear to be a particularly powerful comprehension strategy to
teach to students.

Problem 7.5

Understanding students’ thinking: Explanations

I have found that my educational psychology students often have difficulty

diagnosing whether students are self-explaining or not. Consider the following

example:

A high school mathematics teacher has assigned students to work in pairs to

solve rate problems. Each student in the class has exhibited some difficulties in

solving these problems correctly. The teacher has instructed students to

explain answers to each other as they work together. As the teacher walks by

the different groups, she listens to what students are saying. Put yourself in

the teacher’s position and evaluate whether the students in each example

have given a good explanation.

1. Word problem. Samantha drives an average of 20 miles per hour to go to a
   movie. The movie theater is 5 miles from her house. How long did it take
   Samantha to get there?
   Student 1: I always get confused on these rate problems.
   Student 2: I think we have to use the definition of rate.
   Student 1: Oh yeah. So, rate equals distance divided by time. OK, so that
   means that, let’s see, 20 equals 5 divided by time. I forget how to get
   rid of the time exactly. I guess it’s a matter of flipping both sides over.
   OK, so that’s time divided by 3 equals 1 over 20. So the answer is 3/20
   of the time.