by David L. Dickinson, Dept. of Economics, Appalachian State University, and Todd McElroy, Dept. of Psychology, Appalachian State University
People differ in their diurnal (time of day) preferences: some are morning-types and others are evening-types. These differences are explored in a unique experiment design in which subjects are randomly assigned to produce paper airplanes at either 8:00 a.m. or 10:00 p.m. Our results show that evening-types, at their optimal time of day (10:00 p.m.), produce planes that fly statistically significantly further than those produced by morning-types at their optimal time of day (8:00 a.m.). Evidence also indicates that planes produced by evening-types fly straighter.
Paper airplane flight design is a competitively pursued endeavor that boasts a key role in the world of aeronautical engineering.1 The current world record holder for time aloft of a paper airplane (27.9 seconds), Takuo Toda, is part of a funded research team preparing to launch paper airplanes from the International Space Station.2 Paper airplane competitions are hosted by many student branches of the American Institute of Aeronautics and Astronautics, and Red Bull sponsored the Paper Wings World Finals 2009 competition, which included over 37,000 competitors from several hundred qualifying tournaments from around the globe.
Paper airplane flight distance is a commonly considered outcome measure in the world of paper airplanes, though not the only one: other measures include time aloft, flight stability, and aerobatics. Our experiments examined how one’s diurnal preferences (i.e., morning-types versus evening-types) affected the flight distance and accuracy of the airplane they constructed. Modern society often requires performance at non-preferred times-of-day (e.g., evening- types in the early morning), and some limited research has shown that such “circadian mismatch” affects decision- making (Bodenhausen, 1990; Kruglanski and Pierro, 2008; Dickinson and McElroy, 2009).3 Thus, we hypothesize that circadian mismatch may deplete cognitive resources and harm important paper airplane outcome measures.
[caption id="attachment_49963" align="aligncenter" width="494" caption="Figure 1: Data generation diagram. Sample flight. NOTE: Airplane shown in figure is classic “dart” design. Lightning bolts are for illustrative purposes only, and were never witnessed during our research flights."][/caption]
Our experiment design was aimed at examining decision effects of optimal versus suboptimal times-of-day. A prescreen survey utilized a validated reduced-form questionnaire (Adan and Almiral, 1991) to score the diurnal preferences of each respondent (see Horne and Ostberg, 1976). We then randomly assigned morning- and evening- types to be recruited for a morning (8–9 a.m.) or evening (10–11 p.m.) experiment session. Thus, our 2x2 experiment design includes morning-type subjects both matched (8 a.m.) and mismatched (10 p.m.) to their optimal time-of-day, and similarly for evening-type subjects. Subjects were compensated for participation and for other task outcomes unrelated to the paper airplane task. They were informed in advance that their airplanes would be saved, flown later, and the data would be collected from the flights. Subjects were given up to two minutes to make their paper airplane from a single 8.5x11 inch sheet of paper, on which the experimenter wrote the subject’s ID code. No add-ons (e.g., tape, paper clips,) were allowed. All airplanes were stored loosely and safely until “flight day”, when each airplane was flown three times by different research assistants utilizing a standardized flight technique. All planes were flown at late afternoon times when the flight hallway was largely clear of foot traffic. Each plane flight generated data on flight distance from origin to final resting spot, as well as distance off-center, as described in Figure 1.4
We present results averaged across the three research assistants’ flight data of the 79 airplanes produced for this study.5 Table 1 shows summary data from each of the four experiment cells: morning-matched (MM), morning-mismatched (MMM), evening-matched (EM), and evening-mismatched (EMM) subjects. (Recall, an EMM subject, for example, refers to an evening-type subject in an 8 a.m. experiment session.) Results reported are from one-sided t-tests.
[caption id="attachment_49965" align="aligncenter" width="460" caption="Figure 2: Cumulative distribution functions vs. paper airplane flight distances."][/caption]
Flight distances (in inches) do not significantly differ for the unconditional match vs. mismatch comparison. However, conditional on being circadian “matched”, EM subjects’ mean flight distance was 36% greater than that of the MM subjects’ airplanes (p=.03). The cumulative distribution functions of flight distance are shown in Figure 2 (circadian matched subjects in bold lines), and we see that almost 40% of evening-type subjects
in the night sessions (EM) had flights of 200 or more inches, compared to only 10% for MM subjects. Multivariate regression analysis bears out the same results (available on request).
Results: Flight Trajectory
We also generated data on how far off-center each flight was compared to a straight forward flight, and then standardized the data (using the mathematical laws of right triangles) to determine an average “degrees off at departure” for each plane (see Figure 1). Thus, this variable proxies flight inaccuracy. All airplanes, on average, significantly departed from a straight forward flight line.
However, evening-type subjects made airplanes that flew significantly straighter than the average plane made by a morning-type person (p=.03). This was especially so when people made planes at what was, for them, circadian mismatched times.
[caption id="attachment_49964" align="aligncenter" width="499" caption="Table 1. Summary data. Note: Flight Distance and OffCenter are given in inches "][/caption]
The most significant determinant of paper airplane outcome measures in our experiments was one’s diurnal preference. Evening-types seem to be the wise choice for these tasks, no matter the time of day. As an example of the implication of this result, consider that EMM planes diverged at 12° from departure.6 Now consider a flight from New York’s JFK airport to the Seattle–Tacoma airport (2405 miles flight distance). At 12° divergence, assuming a linear flight path, the plane would be approximately 500 miles from Seattle when reaching the West Coast (near Chico, CA, for example). All else equal, had that plane been designed by an MMM engineer, diverging 18.7° from departure, it would end up about 800 miles from Seattle (between Fresno and Bakerfield, CA.). Modest assumptions about the time and resource costs per passenger to correct that 300-mile difference, multiplied by over 40 weekly flights from JFK to Seattle, show how quickly the impact of this effect could add up.7
Policy prescriptions for the airline industry are straightforward. Job recruitment practices could be modified to discriminate against morning-types, as our results indicate that evening-type workers should produce better aircraft. If airline production schedules are also altered to disproportionately utilize evening shifts, the industry would further benefit from improved aerodynamics design of the type that led to increased paper airplane flight distances in our study. While the prevailing wisdom is that “the early bird gets the worm,” this research argues that night owls are getting the worms in this particular paper airplane task. Future research might consider expansion of the outcome measure (e.g., aerobatics, flight stability), and the study of sleep personality effects on broader classes of engineering or manufacturing outcomes.
(Image credit: Flickr user Gianluca [Miche])Acknowledgements
The authors wish to thank John Whitehead, Tim Perri, Pete Groothuis, and Mark Strazicich for comments, as well as Jonathan Corbin, Natasha Brown, Dana Larson, Patrick Figuerado, and especially Katie Lambert for their valuable research assistance. We thank Appalachian State University for unknowingly offering the 2nd floor hallway of Smith–Wright Hall for the paper airplane flights.
Adan, A., and H. Almiral. “J. Horne and O. Ostberg Morningness–Eveningness Questionnaire: A Reduced Scale,” Personality and Individual Differences, vol. 12, 1991, pp. 241–53.
Bjerner, B., A Holm, and A. Swensson, “Diurnal Variation of Mental Performance: A Study of Three-shift Workers,” British Journal of Industrial Medicine, vol. 12, 1955, pp. 103–11.
Bodenhausen, G.V., “Stereotypes as Judgmental Heuristics: Evidence of Circadian Variations in Discrimination,” Psychological Science, vol. 1, no. 5, 1990, pp. 319–22.
Coren, S. 1996. Sleep Thieves. New York: Free Press.
Dickinson, D.L. and T. McElroy, “Naturally-occurring Sleep Choice and Time of Day Effects on P-beauty Context Outcomes,” working paper #09-03, Dept. of Economics, Appalachian State University.
Horne, J.A., and Ostberg, “A Self-assessment Questionnaire to Determine Morningness–Eveningness in Human Circadian Rhythms.” International Journal of Chronobiology, vol. 4, 1976, pp. 97–110.
Horowitz, T.S., B.E. Cade, J.M. Wolfe, and C.A. Czeisler, “Searching Night and Day: A Disassociation of Effects of Circadian Phase and Time Awake on Visual Selective Attention and Vigilance,” Psychological Science, vol. 14, no. 6, 2003, pp. 549–57.
Kruglanski, A.W., and A. Pierro, “Night and Day, You Are the One: On Circadian Mismatches and the Transference Effect in Social Perception,” Psychological Science, vol. 19, no. 3, 2008, pp. 296–301.
Wright, K.P., Jr., J.T. Hull, and C.A. Czeisler, “Relationship between Alertness, Performance, and Body Temperature in Humans,” American Journal of Physiology: Regulatory, Integrative, and Comparative Physiology, vol. 283, no. 6, 2002, pp. R1370–7.
Yamaguchi, M. “Paper Airplane to Fly from Space to Earth: Scientists Say a Successful Flight Could Advance Spacecraft Design.” Associated Press, March 27, 2008.
1 See Paper Airplanes. This site now incorrectly identifies Ken Blackburn as the current world recorder holder for paper airplane time aloft. The record was broken on May 18, 2009 by Takuo Toda (see reference at The Telegraph).
2 Yamaguchi (2008) reports that a prototype has already successfully passed a wind tunnel durability test.
3 Without examining circadian mismatch per se, sleep researchers have documented decreased performance in a variety of arenas at adverse circadian phase times (e.g., Wright et al, 2002; Horowitz et al., 2003; Bjerner et al, 1955)
4 Paper airplane flight objectives include not only distance traveled, but also flight time, and acrobatics. We only explore the first in this paper.
5 We count the final resting point in calculating our total flight distance, while others may choose to count distance to where the plane hits ground. Because planes that fly straighter are more likely to have a longer landing slide, our data probably contain a positive bias on flight distance for straighter flights.
6 Our calculations of degrees off at departure likely underestimate the true degree of divergence, because our estimates assume linear divergence. Our recollection is that many paper airplane flights that were off-center followed a nonlinear divergence path (i.e., a convex flight path that was diverging at an increasing rate)
7 If you are thinking that pilots themselves could correct flight paths, perhaps with the help of air traffic controllers, then you perhaps forget that the culture in both those professions gives rise to sleep deprivation (see Coren, 1996).
(Title image credit: Flickr user Dave Kellam)
_____________________This article is republished with permission from the January-February 2010 issue of the Annals of Improbable Research. You can download or purchase back issues of the magazine, or subscribe to receive future issues. Or get a subscription for someone as a gift!
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