The Effect of Lighting on Heart Rate
Saginaw Valley State University
Gunner Metzer, Allison Lipinski, and Lyndsie Warden
Dr. Louis Cohen
Presented at Psychology Conference (Saginaw, MI.)
Abstract
Heart rate was tested in light and dark conditions while watching a short horror film. The hypothesis is as follows: Heart rate will be higher when watching a horror film in a dark condition than in a light condition. Results showed insignificant results between the light and dark conditions.
Introduction
The purpose of this study was to look at the effects of having a light on or off with a scary video clip and how it altered heart rate. Previous research on this topic has shown a comparison between the apparent darkness of a space and heart rate. Many factors have an effect on why darkness increases heart rate. This stems from folktales that have been passed on through generations, an overactive imagination, and even gets to how predators that once threatened tribes long ago would attack when they could not be seen. All of these factors could have a possible contribution to why humans react more in darkness than in light. In addition to scary movie studies, the type of fear felt has certain individual differences.
One researcher found that the two different fear responses one may elicit-- fight-or-flight and anxiety --were dependent on the stimuli present (Grillon, 2008). Scary films that are more suspenseful can make viewers more anxious whilst jump-scares can raise heart rate quickly but lower much faster. The way a film feels and sounds also has an effect. Depending on how bright or dim a film was shot in, a mood rating could be gauged (Tarvainen, 2015). Films with darker features and light could be accurately predicted in terms of mood whilst those with brighter features could not be. The sounds that stimulate the nervous system also play a key factor in the increase in heart rate and individual perception of their fear (Calderón, 2018).
So why is fearful media so sought after? Research done on the Psychology of Scary Media saw that those who preferred to watch more scary movies had higher beliefs in the paranormal and preferred more intellectual stimulation (Clasen, 2018). The amount of light seems to cause the heart rate to fluctuate depending on its condition; thus, it is hypothesized that those who watch the scary clip in the dark will have a larger increase in heart rate than those that watch it in a well-lit room.
Method
Design: The experimental design used in this test was an independent samples t-test.
Subjects: The subjects who took part in this test were thirty college-age individuals both male and female.
Materials:
-Computer/Laptop
-YouTube Clips
-NEULOG Heart Rate Monitor
-Informed Consent Form
- Pens
- Room with light switch
Duration: 10 Minutes
Procedure
Prior to the study, participants were given an informed consent form to look over. If they agreed with all of the terms, they then signed the sheet and the experiment began. The participant was then assigned to sit at a seat behind the desktop computer. The video was already loaded and everyone was in their designated positions. After cleaning the participant's finger with an alcohol swab, the heart rate monitor was attached. To allow for correct readings, a baseline heart rate needed to be established. The headphones were then put on and the video began. Throughout the video, the participant's heart rate was tracked on a laptop. After finishing the first video, a calmer second video was played. After the conclusion of the second video, they were asked if they had any additional questions or comments. If they did not, they were free to leave and the next participant could enter the room.
Results
In order to compare the heart rate of participants when they were exposed to the light condition and the dark condition, results were analyzed using an independent samples t-test. The mean times between the light condition and dark condition are represented in the following figure:
Figure 1. Mean heart rate taken between light and dark conditions. Heart rate is measured in beats per minute. Error bars represent a 95% confidence interval.
When comparing means, the average heart rate was taken for each participant under the different lighting conditions and shows how the mean heart rate for the light condition is not statistically different than the mean heart rate for the dark condition. This is shown in the figure above, as the confidence interval bars do overlap with one another. A within-subjects independent samples t-test was conducted to compare the heart rate of the participants between the two conditions. The independent samples t-test indicated that there was no statistically significant effect of lighting on heart rate when watching a scary short film at the .05 significance level (t(30)=-.998, p=.326, 95% CI [-12.832, 4.410]). These results are summarized in the following table:
Note- N = 32. These results indicate that there is no significant mean difference in heart rate between watching the scary clip in the dark and in the light.
Discussion
After running the experiment and looking at the data, the individuals who were tested in each condition were asked afterward if they had seen the scary video clip that was shown. In a few cases, they said that they had watched the video but did not want to say anything until after the session concluded. To change this, a pre-test/assessment should be given to see the level of excitement the participant usually exhibits during scary media when they watch it under normal conditions. There is not an objective scale to measure how scary a piece of scary content is so our judgment must be based on a subjective basis. The biggest problem that caused the most issues was the heart monitoring device itself. It was very sensitive to any movement of the hand and altered the heart rate readings drastically. In a few participants, when their hands moved, the heart rate showed as 210 beats per minute, which is the highest possible output the machine could show. Not only is that number unrealistic, but the reading itself was instantaneous from an average of 60 beats per minute to 210 beats per minute. In the future, a new heart rate monitor should be tested out to ensure the most accurate output. In conclusion, the results that were gathered from this test proved to be insignificant in relation to our hypothesis.
References
- Calderón, S., Rincón, R., Araujo, A., & Gantiva, C. (2018). Effect of congruence between sound and video on heart rate and self-reported measures of emotion. Europe's Journal of Psychology, 14(3), 621-631.
- Clasen, M., Kjeldgaard-Christiansen, J., & Johnson, J. A. (2018). Horror, personality, and threat simulation: A survey on the psychology of scary media. Evolutionary Behavioral Sciences
- Grillon, C. (2008). Models and mechanisms of anxiety: Evidence from startle studies. Psychopharmacology, 199(3), 421-37.
- Kentleigh. (2014, May 13). Retrieved April 23, 2019, from https://www.youtube.com/watch?v=WQvGmMVBYMw
- Planet, A. (2013, January 11). Retrieved April 23, 2019, from https://www.youtube.com/watch?v=_CA5kgWkA-Y
- Tarvainen, J., Westman, S., & Oittinen, P. (2015). The way films feel: Aesthetic features and mood in film. Psychology of Aesthetics, Creativity, and the Arts, 9(3), 254-265