An
examination of recall protocols provides a second useful approach to the study
of mathematical understanding (Hegarty et al., 1995; Mayer, 1982). In our
research, we asked student to read a series of arithmetic word problems. For
each problem, students were assigned to treatment groups that required them
either to write down the key information, draw a picture, construct a diagram,
or compute an answer. Then they were given memory tests such as cued recall and
recognition.
Mayer (1981) has shown that word
problems consist of assignment statements and relational statements. Assignment
statements specify a numerical value for a variable, such as “At Lucky, butter
costs 65 cents per stick”. In this case, the value is 65 and the variable is
the cost (in cents) per stick at vons. The assignment can be expressed as LUCKY
= 65. A relational statement expresses the quantitative relation between two
variables such as “This is two cents less per stick than butter at vons.” In this
case, the relation can be expressed as an equation, LUCKY = 2 + VONS, where
LUCKY is the cost (in cents) per stick as Lucky and VONS is the cost (in cents)
per stick at Vons.
Prediction 3 : students make more
errors in remembering relational statements than in remembering assignment
statements. The construction of situation model requires special attention
be paid to relations among the variables, particularly as expressed in the
relational statements. Therefore, if a student uses a problem model approach,
then the student should remember the actual relation between the two variables
described in a relational statement. For example, the crucial relation in the
relatiomal statement in the butter problem is that butter at vons cosrs more
that butter at lucky. In contras, if a student uses a direct translation
strategy, a primary goal is to assign values to variables. Therefore,
thestudent is less likely to correctly remember relational statements. It
follows that when students make errors in remembering word problems, the will
be more likely to make errors in remembering relations than assignments.
In order to test this prediction, we
asked college students to read and later to recall to recall a series of eight
problems. The student had 2 minutes to read each problem, and was asked to draw
a picture, write an equation, or summarize the main information. As predictes,
students made 3 times as many errors in recalling relational statements than in
recalling assignment statements that had appeared in the problems. Furthermore,
an analysis of errors revealed 20 cases in which students remembered a relation
as an assignment, but only one case in which an assignment was recalled as a
relation. For example, one student changed the relational statement “The steamer’s
engine drives in still water at a rate of 12 miles per house than the rate the
current,” to an assignment statement, “its engines push the boat at 12 mph in
still water.” These result suggest that students have more difficulty in
representing, storing, or retrieving relations (or any combination thereof)
than assignments, and point to the difficulty some students may face in using a
problem model approach on problems invcving relational statements.
Prediction 4: successful problem
solvers are more likely to remember the relation between two variables and less
likely to remember the exact wording of the relational term than are the
unsuccessful problem solvers. We can make a more specific prediction
concerning the retention performance of unsuccessful and successful problem
solbers. We define successful problem solvers as those who use a correct
solution plan in solving a set of word problems and unsuccessful problems as
those who make errors in solving a set of word problems. If successful students
use a direct translation approach, we expect them to remember the key word
(e.g., “less” or “more”), but not necessarily to remember the correct relations
among the variables (e.g., that butter costs more at vons than lucky),
especially students use a problem model approach, we expect them to remember
the correct relations among the variables, but not necessarily to remember the
exact wording of the key word.
To test this prediction, we asked
college students to solve a series of 12 word problems that contained four
targer problems, which were two-step problems with relational statements such
as the butter problem. Then we asked students to recall the problems and to
take a recognition test.
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