Chapter 13. How Would You Know If Hot Temperatures Cause Aggression?

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C. Nathan DeWall, University of Kentucky

David G. Myers, Hope College

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Note: You will be guided through the Intro, Design, Measure, Interpret, Conclusion, and Quiz sections of this activity. You can see your progress highlighted in the non-clickable, navigational list at the right.

Watch this video from your author, Nathan DeWall, for a helpful, very brief overview of the activity.

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So, how would you know if hot temperatures cause aggression? To study this question effectively in your role as researcher, you need to DESIGN an appropriate study that will lead to meaningful results, MEASURE aggression, and INTERPRET the larger meaning of your results, considering how your findings would apply to the population as a whole.

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Case Studies:

Correlational Studies:

Experiments:

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You have chosen a Case Study design, which means that you want to study one individual or a small group of individuals in depth. For example, researchers interested in increasing our understanding of the minds of extremely violent people have spent years conducting interviews, personality inventories, and other research assessments with small groups of these individuals.

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What could we learn from these participant choices?

A small group of people who eat at restaurants every night. This option does not tell you about your participants’ weight or the size of the dinner plates they use. To know whether using larger dinner plates make us fat, you would need to study a group of individuals who have average body weight. This way you can determine whether changing the size of the plates they use causes them to behave in ways that will increase their weight.

A small group of people who are obese. This option tells you about your participants’ weight but not about the size of the dinner plates they use. To know whether using larger dinner plates makes us fat, you would need to study a group of individuals who have average body weight (not just people who are obese), and then vary the size of the dinner plates they use to see if that causes them to increase their weight.

A small group of people who are thin. This option tells you about your participants’ weight but not about the size of the dinner plates they use. To know whether using larger dinner plates makes us fat, you would need to study a group of individuals who have average body weight (not just people who are thin), and then vary the size of the dinner plates they use to see if that causes them to increase their weight.

A small group of people who have average body weight. You were right to choose people who have average body weight, but this option doesn’t tell us about the size of the dinner plates they use. To know whether using larger dinner plates makes us fat, you would need to study a group of individuals who have average body weight, and then vary the size of the dinner plates they use to see if that causes them to increase their weight. Also, you would need to study a large group, not a small group as in this Case Study approach, in order to determine whether the idea of using larger dinner plates making us fat may apply to the larger population.

Trying to choose a sample of participants helps us realize that the CASE STUDY IS NOT THE BEST RESEARCH DESIGN to test this question. In addition to the issues noted with the participant samples above, it’s important to recognize that although a case study approach may be informative, it would not allow us to determine if hot temperatures can cause aggression. (Do you remember which design method allows you to determine causality?) We need to be able to systematically change the temperature people experience and then measure their aggression. This way we can determine whether hot temperatures cause aggression.

Click “Next” to go back and try again to select the most effective research design.

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You have chosen a Correlational design, which means you want to examine the relationship between two or more variables. For example, suppose researchers are interested in knowing whether having an aggressive personality predicts actual aggressive behavior. They would measure aggressive characteristics in participants’ personality, as well as their actual aggressive behavior, and then examine whether these two factors are related. (They are: Having an aggressive personality does predict greater aggressive behavior.)

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You might correlate the average temperature in different geographical regions with how much people in those regions behave aggressively. The result would tell you whether hot temperatures relate to greater aggression. But that correlational study result would not tell you whether hot temperatures cause aggression. In order to determine causality, you would need to systematically change the temperature that people experience and then measure their aggression.

So, CORRELATIONAL IS NOT THE BEST RESEARCH DESIGN for this study.

Click “Next” to go back and try again to select the most effective research design.

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Nice work! You have correctly chosen to use an Experimental design for your study.

Next, you need to choose the most appropriate study participants.

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You chose A group of people who live in Death Valley, California—one of the hottest places on Earth, but this is NOT CORRECT.

In Death Valley, it is hot most of the time. These people might have a very unusual perception of what temperature constitutes “comfortable”! To know whether hot temperatures cause aggression, you would need to study individuals from the general population who are exposed to different temperatures—cold and hot.

Click “Next” to try again to choose the most appropriate study participants.

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You chose A group of people who live in Yakutsk, Russia—one of the coldest places on Earth, but this is NOT CORRECT.

In Yakutsk, it is cold most of the time. These people might have a very unusual perception of what temperature constitutes “comfortable”! To know whether hot temperatures cause aggression, you would need to study individuals from the general population who are exposed to different temperatures—hot and cold.

Click “Next” to try again to choose the most appropriate study participants.

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You chose A group of people who have a history of extreme violence, but this is NOT CORRECT.

With this group, it would be difficult to determine if hot temperatures cause aggression, because they are already a generally very aggressive group! To know whether hot temperatures cause aggression, you would need to study individuals from the general population who have different levels of aggressiveness.

Click “Next” to try again to choose the most appropriate study participants.

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Good job! You have correctly chosen to use an Experimental design. You also chose an appropriate sample of participants—a group of people from the general population. Let’s say you randomly assign some of your participants to experience uncomfortably hot temperatures and others to experience average temperatures. Next, how will you MEASURE the relevant behavior or mental process, which in this case is aggression, in each of your two groups?

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You chose Ask participants to report their attitudes toward aggression, but this is NOT CORRECT.

Knowing whether participants have positive attitudes toward aggression is important, but it does not tell you anything about their actual aggressive behavior. To know whether hot temperatures cause aggression, we have to measure participants’ actual aggression.

Click “Next” to try again to select the best way to measure whether hot temperatures cause aggression.

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You chose Ask participants to report their anger level, but this is NOT CORRECT.

Anger is an emotion. Aggression is a behavior. Angry people tend to be more aggressive, but that does not mean that all angry people are aggressive. To know whether hot temperatures cause aggression, we have to measure participants’ actual aggression.

Click “Next” to try again to select the best way to measure whether hot temperatures cause aggression.

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You chose Ask participants to report the number of hours they play violent video games, but this is NOT CORRECT.

Playing violent video games is related to greater aggression, but for the purposes of this experiment, you need to measure actual aggression.

Click “Next” to try again to select the best way to measure whether hot temperatures cause aggression.

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Good job! You have correctly chosen to use an Experimental design, in which you will expose some people to uncomfortably hot room temperatures and other people to average room temperatures. You chose an appropriate sample of participants—a group of people from the general population. You also chose how best to MEASURE the relevant behavior or mental process, which in this case is aggression. You selected the option, Measure to what degree a participant will blast a stranger with noise.

In several studies, Craig Anderson and colleagues have shown that exposure to hot room temperatures does in fact cause aggression (Anderson et al., 2000; Anderson, 2001). In an experiment very similar to yours, some participants sat in a hot, sweat-inducing room, whereas other participants sat in a comfortable room. Next, participants had the opportunity to behave aggressively by blasting a stranger with noise, and those in the hot room blasted the most.

How can you apply what you’ve learned to the larger population—beyond the people you’ve studied? Consider where you might encounter roadblocks to confidence in your results. What factors might keep you from being able to apply what you’ve learned in a broader context?

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You tested whether hot temperatures cause aggression. You exposed some participants to hot temperatures and others to comfortable temperatures. Then you measured their aggression. Several factors influence aggression, and they might not have any relation to hot temperatures. Just think of the many people who lash out even on cold or average-temperature days! Factors that could interfere with our INTERPRETATION of results are called confounding variables.

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Confounding Variables:

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The confounding variables for your study would include those highlighted below:

The highlighted confounding variables relate to your confidence in whether hot temperatures cause aggression. Numerous factors can increase or decrease the likelihood that a person will behave aggressively. Some people are naturally more aggressive than others, which may lead them to get involved in physical fights. Exposure to violence during childhood can also increase a person’s chances of behaving aggressively (Bandura, 1977). Knowing whether someone is male or female is not entirely predictive, but several studies have shown that males do tend to behave more aggressively than females (Wood & Eagly, 2002, 2007).

Note that by randomly assigning participants to either the hot room or the comfortable room, you control for natural aggression variation, childhood exposure, male/female differences, and many other possible confounding variables. With random assignment, each participant has the same chance of being assigned to each group. This should give each of your groups a balanced number of participants expressing these variations.

Click on "Video Hint" below to see a brief animation describing Random Assignment.

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Random Assignment:

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You may do better on the Quiz if you take notes while watching this video. Feel free to pause the video or re-watch it as often as you like.

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