Chapter 6, page 102
Figure 6.7: Which are uncles?
This figure has three photos of males.
The first male is middle aged and has a graying beard. Its caption says: Bob is Sarah’s
father’s friend.
The second male is a teenage boy. Its caption says: Sam is Sarah’s father’s brother.
The third man is middle aged and has graying hair and a moustache beginning to turn
gray. Its caption says: Jim is Sarah’s father’s brother.
When students are begin to learn to solve problems in areas such as arithmetic, chemistry, or
physics, they organize their knowledge as novices do, by surface similarity. Experts organize knowledge
by the underlying principles of how to solve the problems. Consider the following simple arithmetic
problems.
#1. Julio has 3 apples, and then his mother gives him 8 more. How many apples does he have now?
#2. Shelby had 11 dollars but spent 6 dollars to buy a CD on sale. How many dollars does he have now?
#3. Nadia gave 7 of her 9 oranges to her brother. How many oranges does Nadia have now?
#4. Pam has saved 5 dollars, and now she earns 4 dollars by doing her chores. How many dollars does
she have now?
An expert (anyone very familiar with arithmetic problems) would typically classify these problems
according to the deep similarity of how to solve the problems: #1 and #4 are similar because both are
solved using addition, and #2 and #3 are similar because they are solved using subtraction. In contrast, a
typical novice would classify these problems by surface similarity: #1 and #3 are similar because they are
about fruit, and #2 and #4 are similar because they are about money. The expert immediately focuses on
the underlying solution procedure. The novice has more trouble getting beyond the surface level of the
story.