Effects of Afternoon Nap and Bright Light on Flow, Sleepiness, and Performance - Prof. Cor, Apuntes de Psicología Fisiológica

¡Descarga Effects of Afternoon Nap and Bright Light on Flow, Sleepiness, and Performance - Prof. Cor y más Apuntes en PDF de Psicología Fisiológica solo en Docsity! Industrial Health 2012, 50, 189-196 Original Article The Relationship between Flow, Sleepiness and Cognitive Performance: The Effects of Short Afternoon Nap and Bright Light Exposure Kosuke KAIDA!*, Yuji TAKEDA! and Kazuyo TSUZUKI' Human Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Japan Received September 30, 2011 and accepted Janiary 25, 2012 Published online in J-STAGE March 28, 2012 Abstract: “Flow” is a positive emotional state which typically occurs when a person perceives a balance between the challenges associated with a situation and his or her capabilities to accomplish these demands. While flow often occurs along with positive feelings and high introspective perfor- mance, only a few studies have investigated how itis associated with cognitive performance (i.e., ob- jective performance). In the present study, we investigated the relationship between flow, emotions, and cognitive performance. A short nap (0 min) and bright light (2,000 lux) techniques were used as experimental manipulations to enhance flow. Fifteen participants (31.3 + 7.19 yr old) took part in four experimental conditions: rest, short nap, bright light, and nap and bright light. Pearson's correlation coefficients were calculated for flow and other indices using standardized data. Results showed that flow scores significantly increased after a short nap and under bright light exposure. The correlations between flow and reaction time were also significant. Flow was significantly associ- ated with positive emotion and sleepiness. These results suggest that a short nap and bright light can be employed as a flow facilitator and that flow status can be used as an indicator in evaluating work efficiency and occupational mental health. Key words: Sleepiness, Nap, Bright light, Flow, Emotion Introduction “Flow” is a positive emotional/affective state that typi- cally occurs when a person perceives a balance between the challenges associated with a situation and his or her capabilities to accomplish or meet these demands (p824)>. Flow is often experienced in various activities, such as sports?, musical performance?, car driving?, and Internet use”, At work, flow is defined by characteristics such as *To whom correspondence should be addressed. E-mail: kaida-kosukeQumin.ac jp 02012 National Institute of Occupational Safety and Health absorption, work enjoyment, and intrinsic/autotelic work motivation”. During flow, workers” subjective perfor- mance (i.e., introspective performance) and occupational mental health improve, and thus flow is thought to be an important factor in maintaining workers” subjective well- being”. While the relationship between flow and subjective per- formance (i.e., questionnaire scores) has been reported? 9, relatively few studies have investigated the relationship between flow and objective performance (e.g., cognitive skills) due to difficulties evaluating objective performance in natural settings, such as during sports activities”. Evaluation of objective performance with flow, however, would be an important research topic in light of not only 190 workers” well-being but also work efficiency and injury prevention in the workplace. The present study therefore focused on the relationship between flow and objective (i.e., cognitive) performance in a quiet laboratory setting. The present study also focused on the relationship be- tween flow and sleepiness. Previous studies have demon- strated that sleepiness may relate to low levels of positive emotion and high levels of negative emotion in a sleep- restricted condition”, and that treatments to reduce sleepi- ness (e.g., napping, bright light) not only improve cogni- tive performance! **? but also increase positive mood'?. According to the cognitive-energy model proposed by Zohar et al. (2005), sleep loss would reduce “cognitive energy” to cope with a goal-disturbing event, and positive emotion for a goal-enhancing event would also be reduced by sleep loss!”. The cognitive-energy model seems to fit with the flow theory because challenging tasks would re- quire high cognitive energy (i.e., less sleepiness) through which stronger flow experiences would be induced”. In the present study, a short nap (20 min) and bright light (22,000 lux) were used as countermeasures to sleepiness. Many previous studies have reported that a short nap (see reviews!*9) and bright light!? 12D reduce/improve sleepi- ness and performance, while some studies failed to demon- strate an effect of bright light on performance!?2%?D_ More- over, it has been reported that a short nap and bright light enhance positive feelings (i.e., pleasantness, satisfaction, and relaxation)!”. Thus, it can be assumed that a short nap and bright light could facilitate positive feelings in flow experience, which would then improve performance. The hypotheses of the present study are: (1) a short nap and bright light facilitate flow, and (2) flow will be signifi- cantly related to task performance, sleepiness, and positive emotions. Methods Participants and experimental design Fifteen healthy volunteers (8 males; 31.3 + 7.19 yr old) participated in the study. All participants met the following criteria: a normal sleep-wake cycle not classified as ex- treme “evening type” or “morning type” according to the Momingness-Eveningness questionnaire”, no physical or mental health problems (less than 15 points on the Center for Epidemiological Studies-Depression Scale; CES-D), no travel to a different time zone within 3 months before the experiment, no shift work within 3 months before the experiment, no use of medication, non-smoker status, and body mass index (BMI) less than 25. Participants” Morn- K KAIDA el al. ingness/Eveningness score, CES-D score, and BMI (mean + SD) were 48.3 + 6.31, 6.9 + 4.79, and 21.0 + 1.78kg/ mí, respectively. Conditions Participants carried out four experimental conditions following one preparation day, which were afternoon short nap (NAP), bright light (BLT), bright light and afternoon nap (BLT+NAP), and control (CNT, i.e., neither bright light nor nap) conditions. The order of the conditions was counterbalanced among the participants. A sleep diary was recorded by participants in order to monitor their sleep- wake cycles during the experimental days. The days of each condition were separated by at least three days to avoid accumulation of sleep restriction or sleep debt. The experimental protocol was approved by the Ethics Committee in Research Involving Humans at the National Institute of Advanced Industrial Science and Technology, Japan. Flow check list (FCL) The Flow Checklist (FCL), which was originally de- veloped by Ishimura (2008) in Japanese, was used. The FCL is composed of 10 items (7-grade Likert scales rang- ing from 1 = “does not apply at all” to 7 = “applies very much”) which are categorized into three independent fac- tors, namely, “confidence in competence,” “challenge to goals,” and “positive emotion and absorption.” Each factor consists of 2 to 4 items: “Everything is going well,” “I am able to control situations,” “I am confident in managing matters,” and “I behave/move with everything in contro!” for the first factor (i.e., Confidence); “I feel my work is challenging” and “I am getting ahead toward goals” for the second factor (i.e., Challenge); “I feel time flies,” “I am in a state of complete concentration,” “I am completely im- mersed,” and “I am enjoy ing work” for the third factor (¡.e., Immersion). The reliability of the FCL has been confirmed in an earlier study (Cronbach's a=0.663)?>. Participants were asked to circle the scale number indicating their feel- ings at the moment. Positive and negative affect schedule (PANAS) The positive and negative affect schedule (PANAS) was used to measure positive affect (PA) and negative affect (NA)?”. The Japanese-translated PANAS scale used in the present study consists of 20 items (interested, excited, strong, enthusiastic, proud, alert, inspired, determined, active, attentive, jittery, afraid, distressed, upset, guilty, scared, hostile, irritable, ashamed, and nervous). Items Industrial Health 2012, 50, 189-196 FLOW, SLEEPINESS AND COGNITIVE PERFORMANCE Flow checklist A significant main effect of “NAP” was observed in the “general flow score” [F(1, 14)=13.07, p<0.05]. Interac- tions between “NAP” and “BLOCK” [F(1, 14)=19.98, p<0.01] and between “BLT” and “BLOCK” [F(1, 14)4.93, p<0.05] were also significant, as shown in Fig. 3A. For “confidence in competence” factor, the main effect of “NAP” [F(1, 14)=5.79, p<0.05] and the interaction between “BLT” and “BLOCK” were significant [F(1, 14)=6.14, p<0.05] (See Fig. 3B). For “challenge to goals” factor, a significant main effect of “NAP” [F(1, 14)20.09, p<0.01] and an interaction between “NAP” and “BLOCK” were observed [F(1, 14)=23.54, p<0.01] (Fig. 3C). For the “positive emotion and absorption” factor, the significant main effect of “NAP” [F(1, 14)=6.91, p<0.05] and the interaction between “NAP” and “BLOCK” were observed [F(1, 1455.66, p<0.05] (Fig. 3D). Results indicate that all three subcategories of flow scores increased after the short nap, while only one sub- category (“confidence in competence”) increased under the bright light exposure. Correlation coefficients Table 1 shows the Pearson's product-moment correla- tion coefficients (i.e. rs) between the flow scores and other indices (significant level was set at p<0.05). The flow scores were correlated with the search time of the con- textual cueing task (rs ranged from 0.26 to -0.45); the correlation between general flow score and performance is depicted in Fig. 4). Correlations between flow indices and PA were significant (rs ranged from 0.32 to 0.71), while relatively low in NA (rs ranged from —0.01 to 0.26). Flow indices were negatively associated with sleepiness (15 ranged from —0.31 to -0.46). Discussion The present study revealed that flow scores became sig- nificantly higher in short nap conditions relative to other conditions, that is, a short nap induced a flow experience. In addition, flow scores were positively associated with positive emotion and negatively associated with subjective sleepiness and search time in the contextual cueing task. These results suggest the following: (1) flow tends to be induced after a short nap or in a less sleepy condition; and (2) flow experience is associated not only with subjective feelings (i.e., positive emotion and sleepiness) but also with objective performance (i.e., visual search time). 193 These results imply that workers exp eriencing flow can make more use of their capabilities in their tasks, and that this contributes to better performance at work. Such workers would possibly increase their work satisfaction, and thus flow can be thought as an important factor to influence occupational mental health at work. While the original flow theory asserted that flow experience enhanc- es objective performance”, few studies have supported this based on a behavioral experiment. A clear association between flow and objective performance demonstrated in the present study could serve to help workers understand that flow experience could improve work efficiency. As mentioned earlier, low cognitive energy in sleep- deprived conditions could decrease motivation and weaken one's ability to cope with disturbing events!”. Consistent with this, “challenge,” one of the subcategories of flow, namely, the motivation-related category, was the most strongly correlated with performance (1=-0.45) compared with the other subcategories (“confidence,” /=-0.26; and “immersion,” 7=0.34). Interestingly, “challenge” also showed the strongest correlation with sleepiness (—=-0.46) and positive affect (0.71) compared with the other flow subcategories. These results imply that the feeling of be- ing challenged, which is associated with motivation, is a key aspect of flow in improving performance that could contribute to reduced sleepiness. Contrary to our expectations, significant correlations were not found between flow and implicit learning amount. This result, as well as the negative correlations between flow and visual search time, could be due to type of task or type of abilities*”. Although previous studies reported that positive emotion facilitates flexible think- ing? and verbal ability??, implicit learning in contextual cueing might occur almost independently from emotional responses, including flow. It has also been shown that positive emotion impedes a logical** 3% and careful way of thinking??, The present results, on the other hand, dem- onstrate that the influence of positive emotion on implicit learning is neutral (i.e., it neither improves nor impedes). The advantages and disadvantages of positive emotion or flow should be systematically investigated in future stud- ies, which could identify ways to achieve better emotional balance at work. In relation to emotional balance, Fredrickson (2009) proposed that experiencing positive emotion in a 3-to-1 ratio with negative emotion is the appropriate balance for maintaining well-being*”. In this view, a positive ratio of balance would lead us to a tipping point beyond which we natural ly become more adaptive to our modern society. 194 K KAIDA el al. A B 455 5 E re MA Post sp $ ¿ 4 3 Á E 35 pb E 30 + E? 25 > ENT BET NAPBLINAP CNT BL NAP BLI+NAP Condition Condition : D 5r 5 E z Za IN 5 3 2 = 2 3 2 3 2 3p E 3 a » B E 2 2 CONTO OBLTO NAPBLT-NAP Condition CNT BLT NAPBLT+NAP Condition Fig. 3. (A) Score of “general flow.” The “general flow score” was calculated by the addition of scores of the three factors of the flow check list (FCL). (B) Score of “confidence in skills.” (C) Score of “challenge to goals.” (D) Score of “positive emotion and absorption.” Bars on the figures show standard errors (SEs). Pre: pre-treatment (white bar). Post: post-treatment (black bar). CNT: control condition. NAP: nap con- dition. BLT: bright light condition. BLT+NAP: bright light and nap condition Table 1. Pearson's product moment correlation coefficient Performance PANAS —— ——— Sleepiness Implicit learning — Reaction Time PA NA Flow General 0.12 0.45 0.58 0.08 -0.35 Confidnece 0.22 -0.26 0.58 0.26 -0.33 Challenge 0.10 0.41 071 010 -0.46 Immersion 0.13 0.34 0.32 -001 0.31 Bold types are significant at p<0.05. General: competence”” Challenge: NAS; the positive and negative affect schedule. To keep emotional balance in this ratio is of particular importance from the evolutionary perspective as explained in the “broaden and build theory”*9. According to this theory, negative emotion is essential for keeping us away “general flow score” Confidence: “confidence in challenge to goals” Immersion: “positive emotion and absorption”” PA- PA: positive affect. NA: negative affect from life-threatening dangers but positive emotion is also important in order to feel enjoyment and curiosity, which should help us to function effectively in searching for new resource potential or in building long-term relationships Industrial Health 2012, 50, 189-196 FLOW, SLEEPINESS AND COGNITIVE PERFORMANCE 30 y 3 = A General flow score > 8 -30 -1200 -800 400 0 400 800 1200 AReaction time (ms) Fig. 4. Correlation between the subtracted general flow scores and the subtracted reaction times (search times). with others. Based upon the behavioral point of view, we suspect that flow might be related to speed of skill acquisi- tion (i.e., a learning curve). If the appropriate balance of challenge and skill levels accelerates skill acquisition at work, individuals should feel flow in their assignments. Demonstrating this assumption using behavioral science methods is a compelling future research topic. Many practical methods to keep the “golden ratio” of emotional balance have been proposed, such as exercis- ing?” *% and meditation*”. Naps*? and bright light!'> exposure could also be among these methods. These techniques, however, would presumably influence flow differently. In the present study, bright light improved only “confidence in competence” and no association with bright light was found in terms of “challenge to goals” and “positive emotion and absorption.” In contrast, all three flow components increased after a short nap. The detailed effects of executing these techniques on flow components should be investigated in the future studies. In conclusion, the present study found that flow is facilitated after a short afternoon nap and under bright light exposure during a contextual cueing task and that flow correlated positively with objective performance and negatively with subjective sleepiness. These results suggest that a short nap and bright light can be employed as a flow facilitator and that flow status can be used as an indicator in evaluating work efficiency and occupational mental health. Acknowledgements The authors would like to thank M. Miyagi, K. Inamasu and A. Yasuoka for assistance in subject recruitment and testing. The authors would also like to thank the partici- pants and the reviewers” valuable comments. References 1) Csikszentmihalyi M (1990) Flow: The psychology of optimal experimence. Harper and Row, New York. 2) Jackson SA, Ford SK, Kimiecik JC, Marsh HW (1998) Psychological correlates of flow in sport. J Sport Exerc Psychol 20, 35878. Bakker AB (2005) Flow among music teachers and their students: the crossover of peak experiences. J Vocat Behav 66, 26-44. [CrossRef] Kawasaki M, Kaida K, Kishi H, Watanabe N, Yamada H, Yamaguch Y (2010) [Human theta and alpha EEG oscillations estimate the delight and satisfaction under improvements of driving skills]. Ningen Kogaku 46, 307-16 (in Japanese with English abstract). Pilke EM (2004) Flow experiences in information technology use. Int J Hum Comput Stud 61, 347-57. [CrossRef] 6) Demerouti E (2006) Job characteristics, flow, and performance: the moderating role of conscientiousness. J Occup Health Psycho! 11, 266-80. [Medline] [CrossRef] 7) Salanova M, Bakker AB, Llorens $ (2006) Flow at work: evidence for an upward spiral of personal and organizational resources. J Happiness Stud 7, 1-22. [CrossRef] 8) Bakker AB, Oerlemans W, Demerouti E, Slot BB, Ali DK (2011) Flow and performance: a study among talented Dutch soccer players. Psychol Sport Exerc 12, 442-50. [CrossRef] Dinges DF, Pack E, Williams K, Gillen KA, Powell JW, Ott GE, Aptowiez C, Pack Al (1997) Cumulative sleepiness, mood disturbance, and psychomotor vigilance performance decrements during a week of sleep restricted to 4-5 hours per night. Sleep 20, 267-77. [Medline] Hayashi M, Masuda A, Hori T (2003) The alerting effects of caffcine, bright light and face washing after a short daytime nap. Clin Neurophysiol 114, 2268-78. [Medline] [CrossRef] Kaida K, Takahashi M, Akerstedt T, Nakata A, Otsuka Y, Haratani T, Fukasawa K (2006) Validation of the Karolinska slecpiness scale against performance and EEG variables. Clin Neurophysiol 117, 1574-81. [Medline] [CrossRef] Kaida K, Takahashi M, Haratani T, Ostuka Y, Fukasawa K, Nakata A (2006) Indoor exposure to natural bright light prevents afternoon slecpiness. Sleep 29, 462-9, [Medline] Kaida K, Takahashi M, Otsuka Y (2007) A short nap and natural bright light exposure improve positive mood status. Ind Health 45, 301-8. [Medline] [CrossRef] Zohar D, Tzischinsky O, Epstein R, Lavie P (2005) The effects of sleep loss on medical residents” emotional reactions to work events: a cognitive-energy model. Sleep 3 4 2 9 10) 1 3 13 14)