Reward responsiveness and anxiety predict performance of Mount Everest climbers

Journal of Research in Personality 47 (2013) 111–115

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Brief Report

Reward responsiveness and anxiety predict performance of Mount Everest climbers Greg Feldman a,⇑, Claudia Zayfert b, Luis Sandoval c, Emily Dunn a,1, James A. Cartreine d,2 a

Simmons College, Department of Psychology, Park Science Center, 300 the Fenway, Boston, MA 02114, United States Department of Psychiatry, The Geisel School of Medicine at Dartmouth, Hanover, NH, United States c Department of Education, University of Texas at Austin, Austin, TX, United States d Department of Psychiatry, Harvard Medical School, Brigham and Women’s Hospital, Boston, MA, United States b

a r t i c l e

i n f o

Article history: Available online 12 October 2012 Keywords: BIS FFFS BAS Anxiety Excitement Persistence Performance Extreme environments

a b s t r a c t The present prospective study examined whether individual differences in threat and incentive sensitivity (BIS–FFFS and BAS) and affective states predict performance in a sample of Mount Everest climbers. Climbers higher in reward responsiveness and lower in pre-climb anxiety were more likely to reach higher altitudes. Climbers lower in pre-climb anxiety were also more likely to reach the summit. Results extend existing research on threat and incentive sensitivity and associated affective states by demonstrating their role in predicting persistence in extreme environments. Ó 2012 Elsevier Inc. All rights reserved.

1. Introduction Climbing Mount Everest and other high altitudes is an exceptional human endeavor that requires peak physical fitness, psychological endurance, and behavioral perseverance. At an emotional level, climbers experience the excitement of extreme physical challenge with the reward of summiting the highest peaks on earth. However, such climbs can also be anxiety provoking due to the risks of serious injury and death. On Everest, climbers pass the bodies of those who have died during previous attempts and refer to the final portion of the climb as the ‘‘death zone’’ due to low oxygen levels and frigid temperatures. Only a subset of individuals attempting high altitude climbs reaches the summit. Understanding factors that predict achievement of high altitude climbs is valuable for successful mountain climbing and other activities performed under challenging conditions. For instance, astronauts and military aircraft pilots also work in extreme environments with analogous threats including low oxygen levels, sleep deprivation, and fatigue (Orasanu & Lieberman, 2011). Although a climber’s technical skills and experience are important determinants of success, various other factors, (e.g., weather conditions, team dynamics) can be critically important to the outcome of a high altitude summit attempt. Personality traits and affective states may prove

⇑ Corresponding author. Fax: +1 617 521 3199. 1 2

E-mail address: [email protected] (G. Feldman). Emily Dunn is now at Hunter College (New York, NY). James Cartreine was formerly named James Carter.

0092-6566/$ - see front matter Ó 2012 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jrp.2012.10.001

equally critical for mission safety and success in high-altitude and other extreme environments yet have received little empirical study (Bolmont, 2007). These were the subjects of the present study of individuals attempting to summit Mt. Everest. Success in high altitude climbing may be influenced by individual differences in incentive and threat sensitivity—traits described in the revised Reinforcement Sensitivity Theory (rRST, Gray & McNaughton, 2000) and measured by the Behavioral Inhibition System/Behavioral Activation System (BIS/BAS) scales (Carver & White, 1994). Threat sensitivity is conceptually linked to the tendency to experience negative affect (e.g., fear/anxiety) and exhibit avoidance behavior in response to aversive stimuli. In the BIS/BAS scales, threat sensitivity is captured by a scale measuring the rRST constructs of Behavioral Inhibition System (BIS) and Fight-FlightFreeze System (FFFS)3. The BIS–FFFS scale is positively correlated

3 The Carver and White (1994) BIS/BAS scale used in the present study and in many of the studies reviewed here was developed prior to Gray’s influential revision of the Reinforcement Sensitivity Theory (Gray & McNaughton, 2000), which retains the construct of BAS but has modified the conceptualization of the response to threat. Specifically, the original RST model assigned this role largely to a behavioral inhibition system (BIS) whereas the revised model discusses threat sensitivity in terms of a fight-flight-freeze system (FFFS) that generates fear in the face of threat. In contrast, BIS is now conceptualized as a system that generates anxiety and inhibition in response to conflicts between goals originating in the BAS and FFFT systems. The full-length and abbreviated versions of the BIS/BAS scales were based on the original RST. As such, the threat sensitivity scale was referred to simply as a measure of BIS. More recently, some have argued that these items tap both the revised notion of BIS and FFFS (e.g., Heym, Ferguson, & Lawrence, 2008). As such, we will use the term BISFFFS for this scale (see also Tull, Gratz, Latzman, Kimbrel, & Lejuez, 2010).

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with measures of negative affectivity and harm avoidance (Carver & White, 1994). Conversely, incentive sensitivity (measured as BAS) is presumed to be responsible for the strength of an individual’s tendency to experience positive affect (e.g., excitement) and exhibit approach behaviors in response to appetitive stimuli. The BIS/BAS scales have three BAS facets: Reward Responsiveness (BAS:RR, positive affective experience in response to rewards), Drive (BAS:D, highintensity pursuit of desired goals) and Fun-Seeking (BAS:FS, attraction to novel rewards and spur-of-the-moment goal pursuit). All three scales are associated with positive affectivity (Carver & White, 1994) and extroversion (Heym et al., 2008). In addition, BAS:RR is uniquely associated with emotion regulation; BAS:D with aggression/hostility; and BAS:FS with emotion dysregulation, psychoticism, and impulsive sensation-seeking (Carver, 2004; Heym et al., 2008; Tull et al., 2010). BIS–FFFS and BAS have been associated with persistence during challenging tasks and disengagement from distressing life experiences in non-climbing contexts. In laboratory studies, longer persistence with stressful tasks was predicted by lower BIS–FFFS and higher BAS:RR (Dunn et al., 2012) and higher BAS:D and BAS:FS (Tull et al., 2010). In a naturalistic study of breast cancer survivors, lower BAS:RR and higher BIS–FFFS were associated with greater tendency to disengage from active coping among women who expected relapse (Carver, Meyer, & Antoni, 2000). Given that a high-altitude climb like Mt. Everest requires considerable persistence, BIS–FFFS and BAS might be especially relevant to predicting performance; however, they have not been assessed in a study of extreme athletic endeavors. Egan and Stelmack (2003) examined psychoticism, extroversion, and neuroticism (PEN) as predictors of Mt. Everest climbers’ performance (N = 39) and found none of these traits significantly differentiated climbers who reached the summit of Mt. Everest from those who did not. However, effect size analysis of descriptive statistics reported by these authors reveal that summiters reported lower extroversion (d = .25) and psychoticism (d = .38) than non-summiters (Neuroticism: d = .00). The PEN traits and BIS/BAS subscales overlap (especially BIS–FFFS with N, BAS and E) yet are not redundant conceptually or psychometrically (Carver & White, 1994; Heym et al., 2008) thus may produce a distinct pattern of associations with performance. In addition to assessing BIS/BAS, we extend this prior study by also assessing relevant affective states (anxiety and excitement) as predictors of performance measured both categorically (summit or not) and continuously (highest altitude attained). Affective states have been examined both as correlates and consequences of BIS–FFFS and BAS and as predictors of athletic performance. BIS–FFFS is associated with the tendency to experience negative affect such as anxiety; whereas, BAS has been shown to be associated with a tendency to experience positive affect such as excitement in daily life (Jorm et al., 1999) and in response to laboratory rewards and punishments (Carver & White, 1994). In sports psychology literature, a pre-competition positive affective state (‘‘vigor’’) has been shown to predict superior performance across a range of athletic endeavors (Lane, 2007). Pre-performance anxiety/tension, however, has been linked with both enhanced and debilitated performance (Lane, 2007). In a small study of rock climbers in an elite competition (N = 19), higher pre-climb somatic anxiety was associated with successful climb performance (Sanchez, Boschker, & Llewellyn, 2010) in part because those with higher anxiety climbed more slowly over a challenging stretch of the course. It is unclear, however, whether such advantages of pre-climb anxiety would generalize to longer climbs such as summiting Mt. Everest where slower climbing driven by anxiety could be expected to reduce the likelihood of reaching the summit before frigid temperatures and hypoxia require turning back.

The goal of the present study was to examine whether BIS–FFFS, BAS and associated affective states (excitement and anxiety) predict performance of climbers attempting to summit Mt. Everest. We hypothesized that BIS–FFFS and anxiety would be negatively associated with altitude attained; whereas BAS and excitement would be positively associated with altitude attained. Due to inconsistent findings with regard to which facets of BAS predict persistence, we did not make specific hypotheses as to which BAS facets would predict climbing success. Age was examined as a control variable as it has previously shown negative relationships with likelihood of summiting Mt. Everest (Huey, Salisbury, Wang, & Mao, 2007) and with BIS–FFFS/BAS scores in an adult community sample (Jorm et al., 1999). 2. Method 2.1. Participants and procedure Participants were climbers recruited at Everest South Base Camp in Nepal [elevation 17,500 ft (5400 m)] prior to making a summit attempt. Climbers were approached by one of the authors (JC) who visited climbing team camps during the spring 2008 season. The study was approved by Beth Israel Medical Center’s Institutional Review Board and the Nepal Health Research Council and informed consent was obtained from participants. Measures were part of a larger battery examining a variety of psychosocial and team variables. In 2008 the climbing season was compressed because climbing routes were closed until early May as a team carried the Olympic touch to the summit for the Summer Olympics in China. From the Everest South Basecamp, it commonly takes 4 days to reach the summit. All summit attempts were made between May 18–29, 2008 and the weather was excellent during that period. Seventy-one climbers completed an initial questionnaire including measures of BIS–FFFS/BAS, affective state, and demographics. Forty-nine participants completed the post-climb follow-up assessment on-line or on paper approximately 1 month later. Participant data was retained in these analyses if they indicated intent to summit at baseline and provided complete data for key study variables at both time points. The resulting sample (N = 42) was 88.1% male and represented a broad range of ages (21–71 years, M = 42.2, SD = 11.1) and countries (38.1% United States, 21.4% United Kingdom, 14.3% European countries other than the U.K. 14.3% Canada, 14.3% other). The sample included self-identified clients of guided expeditions (54.8%), professional guides (21.4%), and independent/self-guided climbers (23.8%). 2.2. Measures An abbreviated version (Carver et al., 2000) of the Carver and White (1994) BIS/BAS scales was used to measure BIS–FFFS (three items) and BAS:RR, BAS:D, and BS:FS (two items each) (a = .62, .62, .73, and .72, respectively). The abbreviated measures demonstrated acceptable psychometric properties in a college student sample (Carver et al., 2000). Excitement and anxiety were assessed with a brief self-report measure in which participants used an eight-point scale (1 = not at all, 8 = extremely) to indicate how they were feeling ‘‘right now.’’ Excitement items were energetic, euphoric, and excited (a = .68); anxiety items were anxious, fearful, and nervous (a = .88). Responses to the three items of each scale were summed, with possible scores ranging from 3 to 24. At follow-up, participants reported the highest altitude (meters) they attained and whether they reached the summit (summit status).

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G. Feldman et al. / Journal of Research in Personality 47 (2013) 111–115 Table 1 Descriptive statistics and associations of predictors with climbing outcomes. Full sample

Climber subgroups

(N = 42)

1. 2. 3. 4. 5. 6. 7. 8. 9. * **

Altitude attained Summit status BIS–FFFS BAS: Reward responsiveness BAS: Drive BAS: Fun seeking Anxiety (pre-climb) Excitement (pre-climb) Age

Independent (n = 10)

M (SD)

Altitude attained

Summit status

8491.60 (672.86) 64.3% (yes) 7.62 (2.06) 6.93 (0.95) 6.62 (1.27) 6.40 (1.36) 8.24 (4.80) 13.21 (3.92) 42.19 (11.13)

– .72** .10 .36* .02 .02 .31* .26 .38*

– .21 .16 .03 .04 .42** .20 .22

Guided (n = 23)

Altitude attained

.03 .67* .33 .30 .26 .40 .39

.15 .30 .14 .33 .33 .34 .44

p < .05. p < .01.

Table 2 Regression analyses predicting altitude attained and summit status. Linear regression predicting altitude attained B

SE

21.72 46.83 254.91 53.31 11.70

8.12 48.25 116.58 20.11 26.47

Age BIS–FFFS BAS:RR Anxiety Excitement *

Final b

t

0.36 0.14 0.36 0.38 0.06

Logistic regression predicting summit status sr

2.67* 0.97 2.19* 2.65* 0.44

2

0.12 0.02 0.08 0.11 0.00

B 0.06 0.24 0.47 0.22 0.22

SE

Wald

Odds ratio (95% CI)

Inverse odds ratio

0.04 0.24 0.51 0.09 0.12

2.69 0.96 0.85 5.41* 0.43

0.94 0.79 1.60 0.80 1.08

1.06 1.27

(.87–.1.01) (.49–1.27) (.59–4.37) (.67–.97) (.85–1.37)

1.25

p < .05.

2.3. Analysis plan Bivariate correlations were performed to examine the associations of BIS–FFFS, BAS scales, and affective states with altitude attained (Pearson correlations) and summit status (point-biserial correlations). Multivariate analyses were performed to examine which variables uniquely predicted altitude attained (linear multiple regression) and summit status (logistic regression). Cohen’s (1988) guidelines for interpreting effect sizes was used for r [.1– .3 = small, .3–.5 = medium, >.5 = large)]; Cohen’s d (>.2 = small, .2–.5 = medium, and >.8 = large) and R2 in multiple regression analyses with multiple independent variables (.02–.12 = small, .13– .25 = medium, >.25 = large).

3. Results 3.1. Preliminary analyses Descriptive statistics are presented in Table 1. Independent sample t-tests revealed that participants included in the analyses (n = 42) did not differ significantly (ps > .20) from those who were excluded (n = 26–27) in terms of baseline measures of BIS–FFFS, BAS subscales, excitement, or anxiety (d = |.04| |.15|, suggesting trivial to small group differences). Of the 42 participants included in analyses, 64.3% (n = 27) reached the summit. 3.2. Prediction of altitude attained and summit status In predicting altitude attained (Table 1), BAS:RR showed a medium, positive correlation; excitement a small-to-medium, positive correlation; whereas age and anxiety showed medium, negative correlations. In terms of summit status, anxiety showed a medium-to-large, negative correlation, BIS–FFFS and age smallto-medium, negative association, and BAS:RR and excitement small-to-medium, positive associations (see on-line supplement for full correlation matrix of study variables).

Regression analyses were conducted to examine the unique effect of the predictors on altitude attained and summit status (See Table 2). BAS:D and BAS:FS were not included in these models as they exhibited virtually no bivariate association with either dependent variable. First, a linear multiple regression analysis was performed to predict altitude attained. Age was entered in the first step as a covariate (R2 = .141, p = .014). BIS–FFFS, BAS:RR, anxiety, and excitement were entered in the second step (DR2 = .272, p = .007). BAS:RR and anxiety emerged as significant unique predictors of altitude attained. Analyses were repeated with only BAS:RR and anxiety entered in the second step after controlling for age in Step 1. Results of this analysis (DR2 = .254, p = .001) suggested that these two variables together had a large effect which accounted for nearly all of the variance explained by the four individual differences predictors included in the original model. A logistic regression was performed to predict summit status (Table 2). In the first step age did not significantly predict summit status (X2 = .200, df = 1, p = .16, Nagelkerke R2 = .064). When BIS– FFFS, BAS–RR, anxiety, and excitement were added in a second step, the block of variables significantly predicted summit status (X2 = 12.59, df = 4, p = .013, Nagelkerke DR2 = .343). For all negative logistic regression coefficients, inverse odds-ratios were calculated to facilitate interpretation of results. Only anxiety was a significant unique predictor of summiting. For each one-point reduction on the anxiety scale, a climber’s odds of attaining the summit increased 25%. As an exploratory follow-up analysis (see Table 1), we examined correlations between predictors and altitude attained in two subgroups: independent/self-guided climbers (those without a professional guide) and climbers in a guided expedition4. Independent 4 We wish to thank an anonymous reviewer for suggesting these exploratory analyses. Professional guides were excluded from these sub-group analyses for two reasons. First, guides were considerably more experienced than either group in terms of both years of high-altitude climbing [M = 20.00 (9.29)] and lifetime high-altitude climbs [M = 81.67 (71.15)]. Second, task demands are different for guides as are the factors affecting summiting (e.g., they may forego a chance to summit to assist a client).

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climbers typically assume a greater responsibility for coordinating climb logistics and teamwork than professionally-guided climbers and are often more experienced. In this sample, the independent group had participated in relatively more lifetime high-altitude climbs [M = 12.70 (10.39)] than guided climbers [M = 9.65 (5.92), d = .36]; however, the two groups had comparable years of highaltitude climbing experience [independent M = 9.40 (6.64); guided M = 8.78 (9.32), d = .07]. No association between BIS–FFFS was observed for independent climbers but a small, negative association was observed among guided climbers. BAS:RR showed a large, positive correlation with altitude attained in self-guided climbers and a medium, positive correlation among those in guided expeditions. BAS:D showed a medium, negative relationship with altitude attained in self-guided climbers but a small, positive association for those in guided expeditions. Finally, the relationship of BAS:FS to altitude attained was medium and negative for independent climbers but medium and positive for those in guided expeditions. Results for anxiety, excitement, and age were comparable in both groups.

4. Discussion The present study examined whether reward and threat sensitivity and their associated affective states (excitement and anxiety) predicted performance in an extreme environment as indexed by the altitude achieved by climbers attempting to summit Mt. Everest. Results indicated that, after controlling for age, individual differences in reward responsiveness and anxiety accounted for an additional 25.4% of the variance in altitude attained in the full sample. Furthermore, each point decrease on the 22-point anxiety scale increased a climber’s odds of summiting by 25%. Given the range of other proximal factors that likely contribute to whether an individual reaches the summit (e.g., technical skills, team dynamics, altitude sickness, and accidents), it is remarkable that these individual differences in personality and affect are such robust predictors. We had predicted that higher threat sensitivity (BIS–FFFS) and anxiety would predict poorer performance and that higher incentive sensitivity (BAS) and excitement would predict superior performance. These hypotheses were partially supported. In the full sample of Everest climbers reward responsiveness (BAS:RR) emerged as a significant predictor of altitude attained consistent with prior research on persistence (Carver et al., 2000; Dunn et al., 2012). BAS:RR highlights positive affect occurring in the process of goal pursuit (‘‘When I’m doing well at something, I love to keep at it’’). It is possible that climbers higher in reward responsiveness are energized by the attainment of each smaller goal en route to the summit (e.g., successfully crossing a challenging crevasse) and this helps to fuel continued engagement. Anticipating thrills may draw some individuals to extreme environments. However, these results suggest ability to maintain a reward focus and savor each accomplishment during the relative drudgery and discomfort inherent in tasks like mountain climbing may be crucial to success in such endeavors. Drive (BAS:D) and fun-seeking (BAS:FS) did not predict outcomes in the full sample; however, subgroup analyses revealed a more nuanced picture. In the self-guided sample, higher BAS:D and BAS:FS were associated with lower altitude attained (medium effect size). It is possible that the intensity of goal pursuit captured by BAS:D (sample item: ‘‘When I want something, I go all out to get it’’) leads to impatience and frustration with arduous tasks of long duration and, in turn, impaired performance among self-guided climbers. This would be consistent with prior research linking BAS:D with frustration following a difficult laboratory task (Dunn et al., 2012), hostility/aggression, and anger (Carver, 2004). It is possible that the success of independent climbers hinges more on interpersonal teamwork enhancing the relevance of such emo-

tional factors. The negative association between BAS:FS and performance in the self-guided group is consistent with the Egan and Stelmack (2003) finding that extroversion and psychoticism (which both correlate with BAS:FS) were negatively related to performance among Everest climbers. This suggests that more impulsive goal-pursuit may harm performance among self-guided climbers who typically have greater responsibility for coordinating climb logistics than professionally-guided climbers do. In contrast, among climbers in professionally-guided expeditions, higher BAS:D and BAS:FS were associated with superior performance (small and medium effects, respectively), consistent with prior findings that BAS:D and BAS:FS are positively associated with persistence in laboratory stressors (Tull et al., 2010). These differential findings may reflect individual differences between independent climbers and guided-climbers, differences in the task demands of each group, or both. The findings with respect to anxiety are consistent with those of previous research indicating that anxiety may impair performance in athletic endeavors (Lane, 2007). The present results might appear to be at odds with those of a prior study suggesting that anxiety can enhance climb-relevant performance in rock climbing competitions (Sanchez et al., 2010). However, the benefits of anxiety (e.g., accident avoidance) in a shorter duration rock climb may be outweighed by costs that may become evident in longer, highaltitude climbs (i.e., doubt, distress-related physiological depletion). The present data suggest that anxiety can negatively affect performance when speed and efficiency of effort are important to survival and success during lengthy and grueling challenges. Pre-climb state anxiety was a more critical factor both in altitude attained and summit success than the more trait-like BIS– FFFS. This suggests that efforts to modify pre-climb anxiety (e.g., developing anxiety management skills) might enhance the likelihood of climbers’ success in such grueling endeavors as a Mt. Everest ascent, consistent with the goals of interventions that help persons in high-performance situations manage negative emotions and maintain positive moods (e.g., Carter, Buckey, Greenhalgh, Holland, & Hegel, 2005). Excitement also exhibited a small-tomedium effect on performance in the full sample yet this effect diminished in multivariate analyses, suggesting it is better accounted for by other variables measured. The rate of individuals reaching the summit in this sample (64%) is consistent with estimates of the overall rate of summiting Mt. Everest in Spring 2008 (66% of the estimated 290 climbers at Everest South basecamp), as well as summit rates for the subsequent three seasons (2009: 62%, 2010: 71%, and 2011: 67%)5. This suggests that the present sample is representative of recent cohorts of Mt. Everest climbers. The advantageous weather conditions and compressed climbing schedule of the 2008 season may have constrained variability of other factors affecting performance. We were able to study a cohort of individuals performing the same task in a brief period of time under very similar conditions, which may have allowed for individual differences to more clearly emerge as predictors of performance. The present study makes several contributions to our understanding of factors influencing performance in extreme environments. However, there are some limitations that deserve mention. First, the brief version of the BIS/BAS scale (Carver et al., 2000) used here yielded low internal consistency in some subscales, which may have attenuated the magnitude of associations between traits and outcomes. In addition, given that both threats and incentives are highly salient in extreme environments such as Mt. Everest, it would be valuable for future research to 5 We wish to thank Richard Salisbury (personal communication, July 6, 2012) for providing these statistics based upon analysis of the database that he developed and updates each climbing season (See Salisbury & Hawley, 2011).

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assess the processes by which conflict between motivations arising from both threat and incentive sensitivity systems are monitored and resolved, as emphasized in the revised Reinforcement Sensitivity Theory (Gray & McNaughton, 2000). Finally, pre-climb affect may not reflect affect while engaged in climbing. In vivo assessment of affective states periodically during the summit attempt would enable assessment of its effects on performance beyond the effect of anticipatory anxiety and could account for other dynamic factors such as entry into increasingly hypoxic conditions (Orasanu & Lieberman, 2011). 5. Conclusions The present study identified personality and affective factors that prospectively predict performance during a high altitude climb. Pending replication, these findings may inform selection of individuals who must persevere in pursuit of challenging goals in extreme environments and interventions to enhance their performance. More broadly, these results help to expand our understanding of how these widely-studied individual differences influence human performance in real-world contexts. Acknowledgments This study was supported in part by the National Space Biomedical Research Institute (NSBRI) through NASA NCC 9-58. We wish to thank the climbers at Mt. Everest South Basecamp in Nepal in Spring, 2008 who made this research possible. Appendix A. Supplementary material Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.jrp.2012.10.001. References Bolmont, B. (2007). Relationships between mood states and motor performance. What can you learn from high altitude. In A. M. Lane (Ed.), Mood and Human

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