EDUCATIONAL PSYCHOLOGY

Chapter 1, page 23

Figure 1.6:

Example materials from Needham & Begg’s study

Two-String

An adventurous explorer traveling through the jungles of Africa decided to stop for the night. Since the

jungle he was exploring was full of snakes, he decided to sleep in a hammock-like device suspended over

a babbling brook. He began unfolding the blanket that would serve as the base for the hammock. When he

finished this, the explorer grabbed two vines hanging down and tied them together. This served as support

for one end of the blanket. However, the two vines that were to support the other end presented some

difficulty. When the explorer grabbed the end of one vine, it was impossible for him to grasp the end of

the other vine at the same time. The two vines simply could not be knotted together in this way. The

explorer thought he would have to give up and move camp elsewhere because these two vines from above

could not be knotted together. Suddenly, an idea struck the explorer and he was able to knot together the

two vines.

Step 1. All students read this problem.

How did he do it?

Half of the students
tried to answer this question.

He took a rock and attached it to the end of one vine. Next, he

grabbed the rock and vigorously swung the vine to which it was

attached in the direction of the other vine. He then ran quickly to

this other vine, grabbed it, and walked as close as possible to the

swinging vine, which was now swinging back and forth. He then

waited until the swinging vine came his way and caught it on the

upswing. Now, while holding both vines, he removed the rock

and knotted the two vines together. He was then able to enjoy a

safe night's sleep.

The other half of the students read about how to solve the problem.

Step 2

In this passage, you are told of a jungle explorer who must tie two vines together to make this sleeping

apparatus. However, when he tries to grab the one vine to bring it over to the other one to tie them, he finds

that he cannot do it. The two vines are too far apart for him to grab onto at the same time. So, he takes a

rock and attaches it to the end of one of the vines. The rock cannot be so heavy that it pulls the vine down

and it cannot be so light that it will not allow him to turn the one vine into a pendulum. So, he sets the vine

to which he attaches the rock in swinging motion. Then, while it's swinging, he runs over to the stationary

vine, grabs it, and walks with it towards the vine that is now swinging. When the swinging vine comes back

to him on the upswing, he can grab it, while still holding the other vine, and attach the two of them together.

Because of the pendulum motion, this solution works. So, by turning one of the vines into a pendulum, the

explorer is able to attach the vines together.

Step 3. All of the students observed an experimenter give this lecture.

Step 4 continues on the next page.