Rob Dixon, Melanie Cary, Carmen Wilson, Bill Cerbin
Rob Dixon, Melanie Cary, Carmen Wilson, Bill Cerbin

Title: Bystander Intervention: Explaining Behavior in Terms of Multiple Variables

Authors: Bill Cerbin, Melanie Cary, Rob Dixon, Carmen Wilson, University of Wisconsin-La Crosse

Contact: Bill Cerbin,

Discipline or Field: Psychology

Course Name: Introductory Psychology

Date: May 10, 2006

Course Description

General Psychology is an introductory course that examines major areas of psychology. It is open to all students and is one of the first courses taken by psychology majors. In this section of the course there were 35 freshmen, all in their first semester of college. The class met twice a week for 85 minutes each class period.

The topic of the lesson, Bystander Intervention, is related to social psychology which examines how and why a person's behavior is influenced by others. This lesson was the first of several class periods on topics in social psychology. The lesson took place during the 8th week of a 15 week term.

The class met in the early morning; however attendance was excellent and students came to class on time. Most students kept up with the assignments, and there were no significant academic problems. The class atmosphere was noticeably congenial--students were friendly and comfortable with one another.

The class involved significant interactive learning situations. Students were accustomed to in-class exercises, working in groups and in-class writing assignments. Consequently, the research lesson activities did not differ significantly from the everyday activities in the course.

Executive Summary

The lesson topic is the psychology of "bystander intervention" (i.e., why onlookers help or do not help a stranger in need of assistance). Research indicates that a number of factors influence how bystanders interpret an incident and whether they assume responsibility to help (e.g., the number of bystanders present, whether the victim appears to need and deserve help, etc.).

Learning Goals. The immediate academic learning goal of the lesson was to develop students' ability to explain the "bystander effect" and how the presence of other people can affect individual behavior. A broader goal of the lesson was to develop students' ability to explain human behavior in terms of multiple factors or variables, which is an important facet of social science reasoning. This latter goal is important because students often resist the complexity of multiple factors and tend to rely on a single factor to explain behavior--something we call "The One Factor Theory."

Lesson Design. The lesson involved students in developing ideas about why bystanders help or do not help people in need. Prior to the lesson students did a homework assignment (pre-test) in which they read "bystander scenarios" that depict people in need of help. For each scenario they predicted whether the onlooker would help the person in need and then gave reasons why an onlooker would or would not help in the specific situation. In class students compared their answers on the pre-test and compiled a set of factors that influence people in bystander situations. The instructor then introduced a research-based model of bystander intervention, and led a discussion comparing students' ideas to the model. At the end of class each student wrote an individual analysis explaining the similarities and differences between the model and his or her group's ideas of bystander behavior. As a homework assignment, students analyzed another set of bystander scenarios (post-test exercise).

Major findings about student learning. On the pre-test students tended to explain helping behavior in terms of the bystander's character and personality (e.g., compassionate people help others). On post-test exercise personality-based explanations decreased and social psychological explanations (i.e., situational factors) increased. During the lesson students generated a wide range of factors involved in bystander intervention and developed plausible explanations for them. In general, they were able to think in terms of multiple factors on the bystander scenarios. Although the lesson evoked the kind of thinking we hoped for, we do not know whether this single lesson changed students' beliefs about the importance of situational variables as determinants of social behavior. For example, during the group discussion some students maintained that character and "upbringing" are primary determinants of bystander actions. The lesson may have uncovered a belief about human nature that influences students' willingness to accept social psychological explanations of behavior.

Complete Report

Complete Lesson Study Report (Word Format)

Lesson (8 min.) 

The Lesson

Below are links to the lesson plan and the materials used to teach it.


Research Lesson Directions to Students

Bystander Pre-Test

Group Exercise 1

Group Exercise 2

Model of Bystander Intervention

Individual Analysis

Bystander Post-Test

Bystander Studies Handout

Discussion of Lesson (7 min.) 

The Study

Below are links to the study of the lesson.


Example of Group Exercise 1 Summary

Example of Individual Analysis

Example of Student Post-Test Responses

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