Peanut Butter, Jelly, and the Diathesis-Stress Model


Covering abnormal psychology and a variety of disorders in Introductory Psychology may be interesting and exciting to students; however, explaining the causes of disorders can be quite a challenge. When instructors describe genetic predispositions and environmental influences, students often understand these concepts independently. Consequently, when these concepts are combined as an interrelated idea (e.g., the diathesis-stress model), confusion and sometimes doubt arise. Graphs and charts can be used to make the point, but blank stares still persist.

This demonstration can be used to explain the diathesis-stress model in a "hands-on" experience that is easy to prepare and execute.

Materials Needed: 8 slices of bread (4 slices cut into 3 pieces each), creamy peanut butter, jelly, 8 baking cups, 4 butter knives, watch with a second hand.

Instructions: First, explain that the diathesis-stress model emphasizes the joint occurrence of maladaptive behavior and high levels of stress. Next, select four volunteers to represent the following levels of functioning. (a) Low Predisposition-Low Stress, (b) High Predisposition-Low Stress, (c) Low Predisposition-High Stress, (d) High predisposition-High Stress.

In the demonstration, each student, one at a time, will be given two slices of bread, a baking cup full of peanut butter, a baking cup full of jelly, and a butter knife. Each student will be assigned to his/her level of the diathesis-stress model and instructed to make the best possible peanut butter and jelly sandwich. The resulting sandwich should represent the condition of the person functioning at each level of the model. In other words, the student will see what possibly caused the development of a disorderly sandwich (ie., a mental disorder).

To facilitate the low or high predisposition or the low or high stress, the following conditions should be implemented. A person with low predisposition will be given perfect ingredients for his/her sandwich. A student with the high predisposition category will be given perfect peanut butter and jelly, but each slice of his/her bread will be cut into three pieces. Those participants in the low stress category will be given all the time they need to make their sandwich. Participants in the high stress condition will be given only 25 seconds to make their sandwich. (Hint: Do not give the participant the ingredients until his/her turn. Following this procedure reduces the opportunity for prior planning or strategy development in making the sandwich.)

The conditions for making the sandwiches and the hopeful results at the four levels are as follows:

  1. Low Predisposition-Low Stress – Ingredients are perfect and the participant has as much time as needed. The result should be a perfectly normal sandwich.
  2. High Predisposition-Low Stress – The participant has perfect ingredients except for the cut-up bread. He/she has ample time to make the sandwich. Even though the bread is cut up, the result should resemble a common sandwich.
  3. Low Predisposition-High Stress – The ingredients are perfect, but the participant only has 25 seconds to make the sandwich. Although the sandwich may not be flawless, it is near normal.
  4. High Predisposition-High Stress – The participant has perfect ingredients except for the cut-up bread, but he/she only has 25 seconds to put all the ingredients together. The result should not be normal; it should be pieces of what could be a typical sandwich, if the high predisposition or high stress were not present.
The resulting sandwiches tend to illustrate the degree of disorderliness possible. In other words, the degree and development of mental disorders is the joint action of predisposition and stress. The participants can easily digest the results.