Wiltermuth, S. S. & Heath, C.  (2009). Synchrony and cooperation. Psychological Science, 20, 1-5.

What is “muscular bonding” and how might it explain why armies still march together even though such action would be foolish on modern battlefields?


What is “collective effervescence” how does it contrast with muscular bonding?


What question(s) was this study designed to address?


Describe the different conditions used in each study. What variables were these conditions intended to manipulate?


Describe the measures used to assess cooperation


Describe the important results of each study and what this indicates about group ritual, social bonding, and cooperation


Did the mechanisms of muscular bonding or collective effervescence appear to account for the results of these studies?


What role might group ritual have played over the course of our evolutionary history?


How do cultural rituals involving synchrony provide an evolutionary advantage over those that do not?


Provide some examples of various types of synchronous activities (e.g., chanting, dancing) and describe recent research suggesting why both are similar in enhancing cohesion and cooperation.


Describe the evidence presented in the article that suggests that positive emotions are not necessary for enhancing cooperation through synchronous activities.

How did individuals who previously engaged in synchronous activities perform in the public-goods game and how does this relate to the Miracle in the Andes?


Explain how the existence of the parasites among the survivors runs contrary to the synchrony-cooperation hypothesis.