CSB #8: Effect of Videos on Heart Rate

This experiment was conducted by me, Helen, and Kelly Most of us have laughed so hard watching a video that we've gone out of breath. Surely, our heart rate must have increased, right? This experiment is intended to test whether videos affect our heart rate and which ones do not.

Through this experiment, we assessed the change in people’s heart rate when watching certain videos. We created a play list of five videos: a video of a talented street dancer, an eerie video, a funny “fail” video, a song (music video), and a video of a sleepy kitten, all of which you can see here. Using a heart rate grip monitor and Logger Pro 3.0, we monitored the change of heart rate in five different people while they were watching the videos.

We hypothesized that if the videos initiated any change in heart rate at all, then the first three videos, which were fast-paced, scary, and humorous videos, would result in an increase in heart rate, while the last two, cute and relaxing videos, would lower the heart rate. Each playlist included one advertisement about insurance, which we predicted would also result in a lower heart rate. Our five test subjects were Catherine, Mr. Contini, Vivian, Sabrina, and Andrew, a variety of races, ages, and genders. The general trend that we predicted was (1) an increase in heart rate during the dance video, (2) a lowered heart rate during the ad, (3) an increase in heart rate during the “scary” video, (4)a further increase during the funny video, and finally (5) a sharp decline in heart rate during both the song and the video of the kitten.

First, before we started collecting data on Logger Pro, we made sure that the subject's heart rate was being steadily recorded, and then we began playing the playlist. The videos were played in one-minute intervals, so if they were longer than a minute, we stopped them in the middle and switched to the next video. To make sure we were comparing the change in heart rate with the correct videos, we recorded the intervals on the graph on Logger Pro which corresponded to the start and end times of each video. After the playlist was done, we stopped collecting data and started a new Logger Pro file for each test subject. After repeating this procedure for all five of our subjects, we analyzed the results.

Contrary to our hypothesis, 3 people’s heart rate increased during the music video, and 3 other people’s heart rates increased during the video of the sleepy kitten, while one person’s heart rate decreased during the scary video. In addition, one person’s heart rate decreased during the dance video and two people’s heart rates went up during the advertisement. Although there were a few exceptions, the data collected generally supported our initial hypothesis for the first three videos. More experimentation is needed to know why results varied so much during the music video, kitten video, and advertisement. The first video of a street dancer may have caused an increase in heart rate because of the loud beat, fast pace, and sharp dance moves, all possible contributors to excitement in the subjects. While watching the second video, the unsettling art style and eerie music may have triggered fear and increased the heart rate. During the humorous video, the increase in heart rate could be attributed to laughing or excitement, which would make the heart speed up. The advertisement sometimes lowered and sometimes increased heart rate, possibly showing that some people were intrigued and others were bored by it. Some of our test subjects, like Catherine, whose heart rate increased by approximately 14 BPM during the ad, smiled or laughed at the advertisement, and their heart rates went up. It is possible that measuring a person’s heart rate during an ad can measure their level of interest towards it. During the music video, people’s heart rates both increased and decreased at random intervals, which contradicted our hypothesis; we had initially expected the subjects’ heart rates to decrease because of the slow pace of the song. Although the music was calming, the some of the heart rates, like Vivian's, whose increased approximately 8 BPM, may have increased because of the nature of the song (love song) and/or because the people in the video were attractive. Additionally, the majority of the subjects’ heart rates increased during the video of the sleepy kitten, although there were a few exceptions where the heart rate decreased. This may have been because the kitten was “cute”, which may have triggered a small adrenaline rush and caused increased heart rate. For those whose heart rates went down, it could have been that they are part of that group of people who are unaffected by “cute” things or maybe it was relaxing for them.

For further experimentation, we could ask our test subjects to write down their emotions while watching the videos to see what emotions are associated with increasing and decreasing heart rate. Also, we could take a bigger and more varied group of people to be sure that our results apply to a larger scale of people as opposed to just the select group we chose. It would help to be able to control when the advertisement played because it might make a difference if it was in between two intense videos or in between two calming videos. In addition, having more time to play more videos and being able to play the entire videos might have an effect on our results as well.

Here is our data:

(Click to enlarge)


Here are the graphs:

(Click to enlarge)

CSB #7 Resilience and Treatment

After being in a stressful situation, such as a family member dying or fighting in a bloody war, the ability to bounce back to normal after the event is what we call resilience. Nobody knows for sure the science behind it, but neurologists and psychologists are trying to figure out what causes it and how to treat those who are having a hard time resiling (yes, that is a word). When someone is in a stressful situation, his hypothalamus reacts, sending out a hormone called CRH (corticotropin-releasing hormone). Then, the pituitary gland responds by releasing ACTH (adrenocorticotropin hormone), which causes the release of cortisol from the adrenal glands. Cortisol helps you decide "fight or flight" and execute your plan fast. If a person is put under stress too much, the body keeps pumping out cortisol, which can damage parts of the brain that control memory and emotion, "[s]o you end up an emotional and physical wreck." Resilient people tend to send out hormones and chemicals that counteract the stress signal faster and "more readily." DHEA (dehydroepiandrosterone) and neuropeptide Y are among the many chemicals which lessen the effects of cortisol. George A. Bonanno (heh) of Teachers College at Columbia University took videos and analyzed the emotions and facial expressions of some who had recently lost a loved one. He saw "sadness but also anger and happiness." However, different people respond differently afterwards stressful situations to cope with them. Some of them behaved in a way "that, in other circumstances, may have bordered on narcissism" to prove to themselves that they could not have done anything to prevent the tragic event from happening. Others denied their feelings and some "repressed negative thoughts and emotions" and "convinced themselves that they could handle whatever came their way." It is believed that 90% of all people can cope naturally by themselves without any long-term damage to their emotional health.This leads researchers to think about new ways they could treat (or not treat) people to overcome or even train them to be less impacted by stressful situations. There have been cases where people have suffered longer and more pain than they had to because they were told that it was normal to feel sad for that long. Also, studies show that the classic "talk-it-out" psychology therapy may not be as helpful as previously thought and might actually make the person feel worse. The National Center for PTSD has "developed an approach designed to encourage a person's own coping abilities rather than introspective delving into psychopathological reactions." All in all, the process of resilience is different for everyone, our "innate capacity to bounce back means that most of the time things turn out all right."

Stix, Gary. "The Neuroscience of True Grit." Scientific American Mar. 2011: 
     29-33. Print.
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