In class, we have been discussing the effects of drugs, stress and emotion on the autonomic nervous system (the ANS). One of bodily functions that the ANS controls is heart rate. In this way, it can influence the rate of delivery of oxygen and nutrients to the cells of the body. In times when the body is stressed, or pharmacologically aroused, increased heart rate (and other changes induced by the sympathetic branch of the ANS, in conjunction with the endocrine system) increases the delivery of nutrients to cells, as well as increasing the rate of disposal of waste products.

Arousal of the sympathetic division of the ANS, and hence, increased heart rate, occurs whenever an organism is undergoing physical exertion. But it can also be produced by events that the organism interprets as stressful--typically, novel events, or something that represents a change from the usual routine. While ANS arousal allows the organism to mobilize its physiological resources to deal with potential physical demands, it also allows for high and potentially damaging levels of sympathetic activation, based on chronic anxiety or mental tension. And a college campus is a place rife with chronic mental tension!

Typically we think of our ANS as "automatic," largely outside of our voluntary control. Certainly it would be helpful if we could learn to control it, at least a little bit, during those times that we find particularly stressful (like exams, meetings with important people, conflicts with sweethearts or employers). In fact, emotions can have a huge effect on the body--including heart rate! In this assignment, you will investigate these effects.

Methods:

Equipment Needed: Stopwatch or watch with a second indicator

Number of Subjects: Minimum of three

Time Per Subject: Fifteen minutes

Time for Experimenter: About an hour

BEFORE BEGINNING, READ THESE DIRECTIONS CAREFULLY. Make sure that your subject is seated comfortably, has been relaxing for at least ten minutes, and did not engage in any strenuous exercise in the last half hour. Before reading the instructions, make sure that you can find your subject's pulse on his or her wrist. The unit for recording of the heart rate will be a thirty-second interval. You will record the number of beats every thirty seconds on the data sheet that you can download here. Allow fifteen seconds to pass between each thirty-second interval of recording so that you will have enough time to record the pulse and give instructions. If you have an instruction to give to the subject (ex. "Relax," or "Think Anger"), give the instruction as soon as you have recorded the pulse rate from the previous instruction, but wait the full fifteen seconds before beginning to count the new number of heartbeats.

Read these instructions to your subject:

"This is a short, fifteen-minute experiment to determine how emotion can affect the rate of the beating of your heart. When I say "Begin," you should close your eyes and relax, while I take your pulse. After a minute, I will say "Think Anger," and you should think about a situation in which you were extremely angry. After I record your pulse I will say "Relax," and you should stop thinking about that angry situation and relax again. I will take your pulse for another minute, and then I will say "Think Fear." This time, you should think of a time when you were extremely fearful. Following this one-minute episode I will say "Relax," and you should stop thinking of this fearful situation. This time, you should try to decrease your heart rate by thinking of something that is relaxing or calming to you. I will take your pulse for one final minute.

Before you begin the experiment, decide on each situation you will think about for the anger activity and the fear activity. Let me know when you have decided, and are ready to begin. After you have decided, stop thinking about the images until I give you the instruction during the actual experiment."

Give your subject a few minutes to decide on the images, and then to stop thinking about them before you begin the experiment. Wait one minute after the subject has selected the images, to allow any effect that this may have produced to subside. Then, begin. Record your data on the attached data sheet. Be sure to list for each subject in the appropriate place on the data sheet the basic situation that they imagined in each of the conditions. Since heart rate is usually expressed as beats per minute, double each of the numbers you have recorded to get the subjects' heart rates in each condition. Be sure to turn in your data sheet with your summary. A summary that does not include the data sheet will not be graded.

Plot the data for each of your subjects on a graph and include that with your summary and data sheet. Use a different symbol for each subject, and connect the symbols for each subject by lines.

Do all of your subjects show an ability to increase their heart rate by thinking about a time when they were angry? Which procedure, anger or fear, was more effective? Generally, lowering heart rate is much more difficult. Can all of your subjects decrease their heart rate? What are the implications of your findings for our ability as humans to control some of our bodies response to stressful emotions?

Documents You Will Need:

Heart Rate and Emotion Data Sheet (you will need a computer that can download and open a data sheet in MS Excel to use this document). Turn this data sheet in with your summary.

References:

Jonides, J. & Rozin, P. (1983). Study Guide for Gleitman's Basic Psychology. New York, NY: W.W. Norton & Company.