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Behavioral indices of threat and challenge in Hispanic adolescents and hemodynamic responses to a speech stressor
International Journal of Psychophysiology 55 (2005) 343 – 348 www.elsevier.com/locate/ijpsycho
Behavioral indices of threat and challenge in Hispanic adolescents and hemodynamic responses to a speech stressor Keith A. Klinea,*, Patrice G. Saabb, Maria M. Llabreb a
Department of Psychology, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115-2214, USA b Department of Psychology, University of Miami, PO. Box 248185, Coral Gables, FL 33124-2070, USA Received 2 October 2003; received in revised form 20 January 2004; accepted 14 September 2004 Available online 18 October 2004
Abstract Behavioral ratings of performance and nervousness during a speech were used to divide participants (n=54) into threat and challenge groups. Comparisons on cardiac output, Heather index, heart rate, vascular resistance, and blood pressure reactivity indicated greater myocardial responses for the challenge group. This study extends the threat–challenge literature by employing behavioral definitions of constructs and examining a Hispanic adolescent sample. D 2004 Elsevier B.V. All rights reserved. Keywords: Cardiovascular reactivity; Threat; Challenge; Hemodynamic; Behavioral ratings
Individuals vary considerably in patterns of hemodynamic responses to laboratory challenges (Manuck et al., 1993), and this interindividual variability may confer differential risk (e.g., Obrist, 1981; Saab and Schneiderman, 1993). These patterns include myocardial and vascular responses, with blood pressure elevations driven primarily by heightened cardiac output (CO) or total peripheral resistance (TPR), respectively. Also reflective of a myocardial response
* Corresponding author. Tel.: +1 216 875 9751; fax: +1 216 687 9294. E-mail address: [email protected] (K.A. Kline). 0167-8760/$ - see front matter D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.ijpsycho.2004.09.003
are indices of inotropic and chronotropic influences on the heart. Individual or group differences in response patterns may be due in part to variability in appraisals, emotions, or behaviors. In a series of studies, Tomaka, Blascovich, and colleagues have demonstrated differential associations of threat and challenge states with hemodynamic patterns (Blascovich et al., 1999, 2001; Mendes et al., 2001, 2002, 2003; Tomaka et al., 1993, 1997). Tomaka et al. (1993) originally defined overall threat appraisal as high-perceived threat or demand relative to coping ability and overall challenge appraisal as low threat relative to ability. Studies using ratios of self-reported threat or demand to coping ability to divide participants into threat–challenge
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K.A. Kline et al. / International Journal of Psychophysiology 55 (2005) 343–348
groups have associated myocardial reactivity with challenge appraisals and vascular or mixed responses with threat appraisals (Tomaka et al., 1993, 1997). While appraisals are typically regarded as setting the stage for subsequent affective, behavioral, and physiological responses (e.g., Lazarus and Folkman, 1984), most recently, it has been argued that, in active coping (Obrist, 1981) or performance situations, threat and challenge may reflect motivational–behavioral states conceptually similar to effort vs. distress responses (Frankenhaeuser, 1982) and behavioral approach vs. inhibition motivation (Tomaka and Blascovich, 1994; Tomaka and Palacios-Esquivel, 1997). Furthermore, threat may involve joint activation of approach and inhibition systems (Tomaka and Palacios-Esquivel, 1997). Studies including manipulation of these types of states have generally replicated the response patterning observed with appraisals (Blascovich et al., 1999; Tomaka and PalaciosEsquivel, 1997). Recent investigations have conceptualized threat and challenge in terms of such diverse phenomena as social comparison (Mendes et al., 2001), interactions with stigmatized others (Blascovich et al., 2001), and emotional expression (Mendes et al., 2003). In the present study, threat and challenge were defined in terms of behavioral ratings of nervousness and performance during a speech. Consistent with Tomaka and Blascovich’s (1994) suggestion that task performance b. . .serves as a proxy. . .Q (p. 738) for the effectiveness of behavioral coping efforts, performance was viewed as a measure of behavioral coping ability. In addition, extending Tomaka et al.’s (1993) appraisal ratio concept to behavior, we defined overall threat and challenge responses in terms of ratios of nervousness to performance. A potential advantage of this behavioral definition is that appraisals may be unconscious (Lazarus, 1999). Furthermore, a recent finding of lower threat appraisals for men was interpreted as suggestive of a response bias (Quigley et al., 2002). This problem might be bypassed through the use of observer ratings. The presentation portion of the speech stressor used in the present study has been shown to permit substantial heterogeneity in hemodynamic responses (Llabre et al., 1998), and studies employing the same (Baggett et al., 1996) or similar (Tomaka et al., 1999)
tasks have demonstrated reliable behavioral assessment of performance and nervousness. While Baggett et al. (1996) did not explore associations between behavioral and cardiovascular measures, Tomaka et al. (1999) found that a composite behavioral index of performance and nervousness did not mediate associations between self-reported assertiveness and hemodynamic responses. The present investigation explored the utility of behavioral ratings of performance and nervousness during a speech for the study of threat and challenge responses. The primary purpose was to examine whether threat and challenge groups, formed on the basis of behavioral responses to the speech task, differ in concomitantly assessed hemodynamic measures. Participants in this research were 54 healthy adolescents (38 boys and 16 girls) between the ages of 15 and 17 years. The sample was composed of English speaking high school students of Hispanic ethnicity, initially identified as having elevated blood pressure on two occasions during a blood pressure screening at school [i.e., systolic blood pressure (SBP)z135 mm Hg and/or diastolic blood pressure (DBP)z85 mm Hg]. Participants received no compensation. At an initial screening appointment, parents and students were provided with an overview of the study and asked to complete written informed consent/ assent forms. Participants’ height and weight were assessed, and casual blood pressure was determined via mercury sphygmomanometer (three readings from each arm, at 2-min intervals, following 5 min of rest). In addition, parents’ casual blood pressure and selfreported medical history were obtained to ascertain students’ parental history of hypertension (see Saab et al., 2001, for further description of data collection). The session concluded with scheduling of stress reactivity appointments and notification of the following restrictions: (a) no caffeine, alcohol, or exercise for 2 h prior to the appointment; (b) no nicotine for 3 h; and (c) no other drugs or medications for 48 h. At the second appointment, participants’ casual blood pressure was assessed from the right arm using the aforementioned procedure, and compliance with restrictions was confirmed. Next, students were instrumented for the recording of the electrocardiogram, impedance cardiogram, phonocardiogram, and blood pressure (see Saab et al., 1992).
K.A. Kline et al. / International Journal of Psychophysiology 55 (2005) 343–348
The portion of the protocol relevant to the present discussion consisted of a 15-min pretask resting baseline period, 3 min each of speech preparation and presentation, and a 15-min posttask rest period. Following removal of equipment, the participant was debriefed. The evaluated speaking task (Saab et al., 1989) entails participants preparing and presenting a story based on a scenario, with the knowledge that the speech will be videotaped and evaluated. Three scenarios were randomized across participants. Students were required to defend themselves to a store manager after being wrongfully accused of shoplifting, confront an inefficient grocery store checkout clerk, or approach a cinema manager about noisy moviegoers. Mean arterial pressure (MAP), SBP, and DBP were recorded using a Critikon Dinamap (Model 1846SX) monitor, while basal thoracic impedance (Z o) and impedance rate-of-change (dZ/dt) were measured via a Minnesota Impedance Cardiograph (Model 304B). Signal quality was monitored with a Grass polygraph (Model 7D). Impedance data were sampled in 55- and 30-s epochs during the task and rest periods, respectively, and were then ensemble-averaged and scored. Parameters derived from these data included the following: heart rate (HR; bpm), Heather index (HI; V/s2; an indicator of cardiac contractility), CO (l/ min), and TPR (pru). For a more detailed account of these procedures, see Saab et al. (1992). Blood pressure readings were initiated at 30 s, 2 min, 3 min 30 s, 5 min, 7 min 30 s, 10 min, 11 min 30 s, 13 min, and 14 min 30 s into each rest period. During both the preparation and presentation portions of the speech task, readings were taken at 15 s, 1 min 15 s, and 2 min 15 s. Derivation of TPR necessitated matching blood pressure values with impedance samples occurring proximally in time. Heart rate, HI, CO, TPR, SBP, and DBP data were averaged over the last three samples for the pretask rest period and over all three samples for the presentation portion of the speech stressor. Task reactivity was operationalized in terms of change scores (Ds), computed as mean speech presentation level mean pretask baseline level. Separate scales were developed for global behavioral ratings of performance and nervousness during speech presentation. Ratings were made using Likert-
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type scales ranging from 1 (very poor performance; not at all nervous) to 11 (excellent performance; extremely nervous). Although global scales were used, raters were trained to consider specific criteria in making their evaluations. Elements comprising the global rating of speech performance included clarity, continuity, convincingness, quality/quantity of points, and following instructions. Clarity referred to the comprehensibility and consistency of the main point and supporting details, while continuity reflected progression from one complete thought to the next, as opposed to fragmented speech. Convincingness was defined as appearing engaged in the task and convincing or assertive in portraying the role required by the scenario. The quality/quantity of points denoted generation of distinct, original points vs. repetition of the same or similar points. Finally, following instructions signified the degree of adherence with the experimenter’s instructions. Components of the global rating of nervousness included nervous smiling/laughter, overt signs of discomfort/fidgeting, gaze aversion, stammering/ shaky voice, and reluctance to speak. Nervous smiling/laughter was operationalized as any smiling or laughter judged as inappropriate (e.g., not reflecting sarcasm or humor). Overt signs of discomfort/fidgeting referred to the tapping of fingers or feet or any noncommunicative movement, verbalizations (e.g., sighing), or the appearance of discomfort. Gaze aversion was indicated by avoidance of eye contact with the camera, excluding brief glances at a card containing points to be addressed. Stammering/shaky voice included evidence of an unsteady or quivering voice, stumbling, or the use of nonfluencies. Lastly, reluctance to speak was defined as showing hesitancy or unwillingness to speak. An additional measure was the number of times the participant had to be prompted by the experimenter to continue speaking. This variable could reflect nervousness (e.g., reluctance to speak) or performance (e.g., disengagement). Two independent raters coded videotaped speeches for performance and nervousness. The mean interrater correlation for these two measures was high (r=0.97). Table 1 shows demographic and baseline characteristics of threat and challenge groups. Chi-square tests of independence indicated that the groups were comparable in terms of parental history of hyper-
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Table 1 Demographic and baseline characteristics of threat and challenge groups Variable Gender* Men Women Parental history of HT Positive Negative Uncertain Age (yr) Mother’s education (yr) Father’s education (yr) Height (in) Weight (lb) Body mass index (kg/m2) Casual SBPa (mm Hg) Casual DBPa (mm Hg) SBPb (mm Hg) DBPb (mm Hg) Heart rateb (bpm) Cardiac outputb (l/min) Total peripheral resistanceb (pru)** Heather indexb (V/s2)
Threat
Challenge
81% 19%
59% 41%
41% 30% 29% 16.4 (0.89) 13.6 (2.4) 12.3 (4.0) 68.6 (3.0) 186.9 (57.4) 27.6 (7.3) 123 (11.2) 75 (6.1) 121.2 (11.7) 64.1 (5.9) 74.1 (9.1) 5.8 (1.24) 0.93 (0.17) 13.1 (3.9)
22% 41% 37% 16.1 (0.85) 12.3 (3.9) 12.0 (5.0) 67.1 (4.3) 191.4 (49.6) 29.7 (7.0) 124 (11.3) 73 (7.3) 120.1 (12.7) 62.4 (3.5) 76.9 (10.3) 6.4 (1.31) 0.83 (0.15) 13.5 (4.2)
Values for age, mother’s and father’s education, height, weight, body mass index, casual SBP and DBP, SBP, DBP, heart rate, cardiac output, total peripheral resistance, and Heather index are means (S.D.). HT—hypertension; SBP—systolic blood pressure; DBP—diastolic blood pressure. a Casual blood pressure averaged across medical screening and stress reactivity appointments. b Initial resting baseline levels of physiological variables observed during the stress reactivity session. * pb0.10. ** pb0.05.
tension, v 2 (2, N=54)=2.17, pN0.10, and showed a trend toward a difference in the gender composition, v 2 (1, N=54)=3.20, p=0.074. A series of independentsamples t-tests performed on each of the remaining variables in Table 1 revealed only a significant group difference for baseline levels of TPR, with the threat group exhibiting higher baseline TPR levels than the challenge group, t(52)=2.14, pb0.05. Performance scores were inversely correlated with nervousness ratings (r= 0.69, pb0.0001) and the number of prompts (r= 0.64, pb0.0001). Conversely, nervousness was positively correlated with the number of prompts (r=0.59, pb0.0001). Behavioral threat and challenge responses were determined by computing ratios of scores on the nervousness scale to scores on the performance scale.
A median-split was then performed on the sample distribution of these ratios. Participants with ratios above the median of 0.78 constituted the threat group (M nervousness=6.5, S.D.=2.35; M performance= 3.5, S.D.=1.95; M ratio=2.45, S.D.=2.68), whereas individuals scoring below the median comprised the challenge group (M nervousness=1.5, S.D.=1.32; M performance=7.3, S.D.=1.80; M ratio=0.33, S.D.=0.21). Speech presentation reactivity change scores for the threat and challenge groups are shown in Table 2. Independent-samples t-tests indicated that, relative to the threat group, the challenge group exhibited greater HI responses, t(31)=2.56, pb0.05, as well as heightened HR responses, t(41)=2.29, pb0.05. There was also a nonsignificant trend toward greater CO reactivity for the challenge group, t(37)=1.91, p=0.064. Although the group difference for TPR also failed to reach significance, t(50)=1.56, p=0.126, it was in the expected direction, with the threat group displaying the greatest TPR responses. No group differences emerged for SBP or DBP, ts(52)=0.77 and 0.07, respectively, psN0.10. Threat and challenge groups were also compared on the mean number of prompts received. An independent-samples t-test revealed that the threat group (M=3.3, S.D.=2.3) required approximately twice as many prompts as the challenge group (M=1.7, S.D.=1.4), t(43)=3.00, pb0.01. The present study demonstrated limited evidence of associations of behavioral indices of threat and challenge with patterns of cardiovascular responses to a speech stressor. Specifically, challenge-related behavior was associated with greater myocardial Table 2 Changes from pretask to speech presentation, for threat and challenge groups Variable
Threat
Challenge
CO (l/min)* TPR (pru) HI (V/s2)** HR (bpm)** SBP (mm Hg) DBP (mm Hg)
0.14 (0.83) 0.22 (0.17) 0.07 (2.15) 8.2 (8.0) 27.4 (12.0) 16.3 (7.3)
0.78 (1.47) 0.14 (0.19) 3.10 (5.52) 14.9 (12.3) 30.2 (15.0) 16.2 (5.6)
Values are means (S.D.). CO—cardiac output; TPR—total peripheral resistance; HI—Heather index; HR—heart rate; SBP— systolic blood pressure; DBP—diastolic blood pressure. * pb0.10. ** pb0.05.
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(i.e., HI, HR, and a trend for CO) responses to the speech task than threat-related behavior. However, the expected threat–challenge group difference for TPR did not approach significance. This is not the first investigation to demonstrate stronger evidence of threat–challenge group differences with myocardial responses than with vascular responses (Tomaka et al., 1997, Study 1; Tomaka and Palacios-Esquivel, 1997). A small sample size may have dampened the robustness of the findings reported here. Nevertheless, these findings are generally in accord with the growing body of literature indicating that states theoretically consistent with threat and challenge are accompanied by distinct hemodynamic profiles (Blascovich et al., 1999, 2001; Mendes et al., 2001, 2002, 2003; Tomaka et al., 1993, 1997; Tomaka and Palacios-Esquivel, 1997). Furthermore, this study extends the literature in that it is the first investigation to use behavioral measures to classify participants into threat–challenge groups. While preliminary, the present data could be viewed as a first step toward providing behavioral validation of the threat and challenge constructs. Although global behavioral measures were deemed suitable for purposes of this study, they do not provide information on the relative contributions of the individual components to the global ratings. Future studies should attempt to disentangle the relative influence of distinct attributes of performance and nervousness on hemodynamic responses. Relatively few studies examining hemodynamic responses to laboratory stressors have included significant representation of the Hispanic population (e.g., Tomaka and Palacios-Esquivel, 1997). Thus, the present investigation provides much needed data on a rapidly expanding minority population in the United States (U.S. Census Bureau, 2003). Furthermore, this study extends the threat–challenge literature by evaluating an entirely adolescent sample. While the uniqueness of the sample (i.e., Hispanic adolescents initially identified as having elevated blood pressure) is a strength of the study, further research is necessary to establish the generalizability of our findings. The heightened myocardial responses shown by our challenge group suggest greater h1-adrenergic activation of the cardiac muscle (e.g., Sherwood et al., 1986) and/or increased vagal withdrawal (Grossman and Svebak, 1987), relative to the threat group. Regardless of the underlying mechanisms, the
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responses of the challenge group are generally consistent with those previously regarded by Tomaka et al. (1993) as adaptive. Longitudinal data are still needed, however, to establish relationships between hemodynamic patterns and clinical disease.
Acknowledgments This work was supported by Grants HL36588 and HL04726 from the National Institutes of Health. The authors would like to thank the Miami-Dade County Public Schools and the Miami-Dade Division of the American Heart Association. The authors would also like to acknowledge Karen Adler and Jon Yoo for their assistance with data collection.
References Baggett, H.L., Saab, P.G., Carver, C.S., 1996. Appraisal, coping, task performance, and cardiovascular responses during the evaluated speaking task. Pers. Soc. Psychol. Bull. 22, 483 – 494. Blascovich, J., Mendes, W.B., Salomon, K., Hunter, S.B., 1999. Social bfacilitationQ as challenge and threat. J. Pers. Soc. Psychol. 77, 68 – 77. Blascovich, J., Mendes, W.B., Hunter, S.B., Lickel, B., Kowai-Bell, N., 2001. Perceiver threat in social interactions with stigmatized others. J. Pers. Soc. Psychol. 80, 253 – 267. Frankenhaeuser, M., 1982. Challenge–control interaction as reflected in sympathetic–adrenal and pituitary–adrenal activity: comparison between the sexes. Scand. J. Psychol., Suppl. 1, 158 – 164. Grossman, P., Svebak, S., 1987. Respiratory sinus arrhythmia as an index of parasympathetic cardiac control during active coping. Psychophysiology 24, 228 – 235. Lazarus, R.S., 1999. Stress and Emotion: A New Synthesis. Springer, New York. Lazarus, R.S., Folkman, S., 1984. Stress, Appraisal, and Coping. Springer, New York. Llabre, M.M., Klein, B.R., Saab, P.G., McCalla, J.B., Schneiderman, N., 1998. Classification of individual differences in cardiovascular responsivity: the contribution of reactor type controlling for race and gender. Int. J. Behav. Med. 5, 213 – 229. Manuck, S.B., Kamarck, T.W., Kasprowicz, A.S., Waldstein, S.R., 1993. Stability and patterning of behaviorally evoked cardiovascular reactivity. In: Blascovich, J., Katkin, E.S. (Eds.), Cardiovascular Reactivity to Psychological Stress and Disease. American Psychological Association, Washington, DC, pp. 111 – 134. Mendes, W.B., Blascovich, J., Major, B., Seery, M., 2001. Challenge and threat responses during downward and upward social comparisons. Eur. J. Soc. Psychol. 31, 477 – 497.
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Mendes, W.B., Blascovich, J., Lickel, B., Hunter, S., 2002. Challenge and threat during social interactions with white and black men. Pers. Soc. Psychol. Bull. 28, 939 – 952. Mendes, W.B., Reis, H.T., Seery, M.D., Blascovich, J., 2003. Cardiovascular correlates of emotional expression and suppression: do content and gender context matter? J. Pers. Soc. Psychol. 84, 771 – 792. Obrist, P.A., 1981. Cardiovascular Psychophysiology: A Perspective. Plenum Press, New York. Quigley, K.S., Feldman Barrett, L., Weinstein, S., 2002. Cardiovascular patterns associated with threat and challenge appraisals: a within-subjects analysis. Psychophysiology 39, 292 – 302. Saab, P.G., Schneiderman, N., 1993. Biobehavioral stressors, laboratory investigation, and the risk of hypertension. In: Blascovich, J., Katkin, E.S. (Eds.), Cardiovascular Reactivity to Psychological Stress and Disease. American Psychological Association, Washington, DC, pp. 49 – 82. Saab, P.G., Matthews, K.A., Stoney, C.M., McDonald, R.H., 1989. Premenopausal and postmenopausal women differ in their cardiovascular and neuroendocrine responses to behavioral stressors. Psychophysiology 26, 270 – 280. Saab, P.G., Llabre, M.M., Hurwitz, B.E., et al., 1992. Myocardial and peripheral vascular responses to behavioral challenges and their stability in black and white Americans. Psychophysiology 29, 384 – 397. Saab, P.G., Llabre, M.M., Ma, M., et al., 2001. Cardiovascular responsivity to stress in adolescents with and without persistently elevated blood pressure. J. Hypertens. 19, 21 – 27.
Sherwood, A., Allen, M.T., Obrist, P.A., Langer, A.W., 1986. Evaluation of beta-adrenergic influences on cardiovascular and metabolic adjustments to physical and psychological stress. Psychophysiology 23, 89 – 104. Tomaka, J., Blascovich, J., 1994. Effects of justice beliefs on cognitive appraisal of and subjective, physiological, and behavioral responses to potential stress. J. Pers. Soc. Psychol. 67, 732 – 740. Tomaka, J., Palacios-Esquivel, R.L., 1997. Motivational systems and stress-related cardiovascular reactivity. Motiv. Emot. 21, 275 – 296. Tomaka, J., Blascovich, J., Kelsey, R.M., Leitten, C.L., 1993. Subjective, physiological, and behavioral effects of threat and challenge appraisal. J. Pers. Soc. Psychol. 65, 248 – 260. Tomaka, J., Blascovich, J., Kibler, J., Ernst, J.M., 1997. Cognitive and physiological antecedents of threat and challenge appraisal. J. Pers. Soc. Psychol. 73, 63 – 72. Tomaka, J., Palacios, R., Schneider, K.T., Colotla, M., Concha, J.B., Herrald, M.M., 1999. Assertiveness predicts threat and challenge reactions to potential stress among women. J. Pers. Soc. Psychol. 76, 1008 – 1021. U.S. Census Bureau, 2003, June 18. Young, diverse, urban: Hispanic population reaches all-time high of 38.8 million, new Census Bureau estimates show. United States Department of Commerce News. Retrieved August 24, 2004, from http:// www.census.gov/Press-Release/www/2003/cb03-100.html.
Behavioral indices of threat and challenge in Hispanic adolescents and hemodynamic responses to a speech stressor Keith A. Klinea,*, Patrice G. Saabb, Maria M. Llabreb a
Department of Psychology, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115-2214, USA b Department of Psychology, University of Miami, PO. Box 248185, Coral Gables, FL 33124-2070, USA Received 2 October 2003; received in revised form 20 January 2004; accepted 14 September 2004 Available online 18 October 2004
Abstract Behavioral ratings of performance and nervousness during a speech were used to divide participants (n=54) into threat and challenge groups. Comparisons on cardiac output, Heather index, heart rate, vascular resistance, and blood pressure reactivity indicated greater myocardial responses for the challenge group. This study extends the threat–challenge literature by employing behavioral definitions of constructs and examining a Hispanic adolescent sample. D 2004 Elsevier B.V. All rights reserved. Keywords: Cardiovascular reactivity; Threat; Challenge; Hemodynamic; Behavioral ratings
Individuals vary considerably in patterns of hemodynamic responses to laboratory challenges (Manuck et al., 1993), and this interindividual variability may confer differential risk (e.g., Obrist, 1981; Saab and Schneiderman, 1993). These patterns include myocardial and vascular responses, with blood pressure elevations driven primarily by heightened cardiac output (CO) or total peripheral resistance (TPR), respectively. Also reflective of a myocardial response
* Corresponding author. Tel.: +1 216 875 9751; fax: +1 216 687 9294. E-mail address: [email protected] (K.A. Kline). 0167-8760/$ - see front matter D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.ijpsycho.2004.09.003
are indices of inotropic and chronotropic influences on the heart. Individual or group differences in response patterns may be due in part to variability in appraisals, emotions, or behaviors. In a series of studies, Tomaka, Blascovich, and colleagues have demonstrated differential associations of threat and challenge states with hemodynamic patterns (Blascovich et al., 1999, 2001; Mendes et al., 2001, 2002, 2003; Tomaka et al., 1993, 1997). Tomaka et al. (1993) originally defined overall threat appraisal as high-perceived threat or demand relative to coping ability and overall challenge appraisal as low threat relative to ability. Studies using ratios of self-reported threat or demand to coping ability to divide participants into threat–challenge
344
K.A. Kline et al. / International Journal of Psychophysiology 55 (2005) 343–348
groups have associated myocardial reactivity with challenge appraisals and vascular or mixed responses with threat appraisals (Tomaka et al., 1993, 1997). While appraisals are typically regarded as setting the stage for subsequent affective, behavioral, and physiological responses (e.g., Lazarus and Folkman, 1984), most recently, it has been argued that, in active coping (Obrist, 1981) or performance situations, threat and challenge may reflect motivational–behavioral states conceptually similar to effort vs. distress responses (Frankenhaeuser, 1982) and behavioral approach vs. inhibition motivation (Tomaka and Blascovich, 1994; Tomaka and Palacios-Esquivel, 1997). Furthermore, threat may involve joint activation of approach and inhibition systems (Tomaka and Palacios-Esquivel, 1997). Studies including manipulation of these types of states have generally replicated the response patterning observed with appraisals (Blascovich et al., 1999; Tomaka and PalaciosEsquivel, 1997). Recent investigations have conceptualized threat and challenge in terms of such diverse phenomena as social comparison (Mendes et al., 2001), interactions with stigmatized others (Blascovich et al., 2001), and emotional expression (Mendes et al., 2003). In the present study, threat and challenge were defined in terms of behavioral ratings of nervousness and performance during a speech. Consistent with Tomaka and Blascovich’s (1994) suggestion that task performance b. . .serves as a proxy. . .Q (p. 738) for the effectiveness of behavioral coping efforts, performance was viewed as a measure of behavioral coping ability. In addition, extending Tomaka et al.’s (1993) appraisal ratio concept to behavior, we defined overall threat and challenge responses in terms of ratios of nervousness to performance. A potential advantage of this behavioral definition is that appraisals may be unconscious (Lazarus, 1999). Furthermore, a recent finding of lower threat appraisals for men was interpreted as suggestive of a response bias (Quigley et al., 2002). This problem might be bypassed through the use of observer ratings. The presentation portion of the speech stressor used in the present study has been shown to permit substantial heterogeneity in hemodynamic responses (Llabre et al., 1998), and studies employing the same (Baggett et al., 1996) or similar (Tomaka et al., 1999)
tasks have demonstrated reliable behavioral assessment of performance and nervousness. While Baggett et al. (1996) did not explore associations between behavioral and cardiovascular measures, Tomaka et al. (1999) found that a composite behavioral index of performance and nervousness did not mediate associations between self-reported assertiveness and hemodynamic responses. The present investigation explored the utility of behavioral ratings of performance and nervousness during a speech for the study of threat and challenge responses. The primary purpose was to examine whether threat and challenge groups, formed on the basis of behavioral responses to the speech task, differ in concomitantly assessed hemodynamic measures. Participants in this research were 54 healthy adolescents (38 boys and 16 girls) between the ages of 15 and 17 years. The sample was composed of English speaking high school students of Hispanic ethnicity, initially identified as having elevated blood pressure on two occasions during a blood pressure screening at school [i.e., systolic blood pressure (SBP)z135 mm Hg and/or diastolic blood pressure (DBP)z85 mm Hg]. Participants received no compensation. At an initial screening appointment, parents and students were provided with an overview of the study and asked to complete written informed consent/ assent forms. Participants’ height and weight were assessed, and casual blood pressure was determined via mercury sphygmomanometer (three readings from each arm, at 2-min intervals, following 5 min of rest). In addition, parents’ casual blood pressure and selfreported medical history were obtained to ascertain students’ parental history of hypertension (see Saab et al., 2001, for further description of data collection). The session concluded with scheduling of stress reactivity appointments and notification of the following restrictions: (a) no caffeine, alcohol, or exercise for 2 h prior to the appointment; (b) no nicotine for 3 h; and (c) no other drugs or medications for 48 h. At the second appointment, participants’ casual blood pressure was assessed from the right arm using the aforementioned procedure, and compliance with restrictions was confirmed. Next, students were instrumented for the recording of the electrocardiogram, impedance cardiogram, phonocardiogram, and blood pressure (see Saab et al., 1992).
K.A. Kline et al. / International Journal of Psychophysiology 55 (2005) 343–348
The portion of the protocol relevant to the present discussion consisted of a 15-min pretask resting baseline period, 3 min each of speech preparation and presentation, and a 15-min posttask rest period. Following removal of equipment, the participant was debriefed. The evaluated speaking task (Saab et al., 1989) entails participants preparing and presenting a story based on a scenario, with the knowledge that the speech will be videotaped and evaluated. Three scenarios were randomized across participants. Students were required to defend themselves to a store manager after being wrongfully accused of shoplifting, confront an inefficient grocery store checkout clerk, or approach a cinema manager about noisy moviegoers. Mean arterial pressure (MAP), SBP, and DBP were recorded using a Critikon Dinamap (Model 1846SX) monitor, while basal thoracic impedance (Z o) and impedance rate-of-change (dZ/dt) were measured via a Minnesota Impedance Cardiograph (Model 304B). Signal quality was monitored with a Grass polygraph (Model 7D). Impedance data were sampled in 55- and 30-s epochs during the task and rest periods, respectively, and were then ensemble-averaged and scored. Parameters derived from these data included the following: heart rate (HR; bpm), Heather index (HI; V/s2; an indicator of cardiac contractility), CO (l/ min), and TPR (pru). For a more detailed account of these procedures, see Saab et al. (1992). Blood pressure readings were initiated at 30 s, 2 min, 3 min 30 s, 5 min, 7 min 30 s, 10 min, 11 min 30 s, 13 min, and 14 min 30 s into each rest period. During both the preparation and presentation portions of the speech task, readings were taken at 15 s, 1 min 15 s, and 2 min 15 s. Derivation of TPR necessitated matching blood pressure values with impedance samples occurring proximally in time. Heart rate, HI, CO, TPR, SBP, and DBP data were averaged over the last three samples for the pretask rest period and over all three samples for the presentation portion of the speech stressor. Task reactivity was operationalized in terms of change scores (Ds), computed as mean speech presentation level mean pretask baseline level. Separate scales were developed for global behavioral ratings of performance and nervousness during speech presentation. Ratings were made using Likert-
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type scales ranging from 1 (very poor performance; not at all nervous) to 11 (excellent performance; extremely nervous). Although global scales were used, raters were trained to consider specific criteria in making their evaluations. Elements comprising the global rating of speech performance included clarity, continuity, convincingness, quality/quantity of points, and following instructions. Clarity referred to the comprehensibility and consistency of the main point and supporting details, while continuity reflected progression from one complete thought to the next, as opposed to fragmented speech. Convincingness was defined as appearing engaged in the task and convincing or assertive in portraying the role required by the scenario. The quality/quantity of points denoted generation of distinct, original points vs. repetition of the same or similar points. Finally, following instructions signified the degree of adherence with the experimenter’s instructions. Components of the global rating of nervousness included nervous smiling/laughter, overt signs of discomfort/fidgeting, gaze aversion, stammering/ shaky voice, and reluctance to speak. Nervous smiling/laughter was operationalized as any smiling or laughter judged as inappropriate (e.g., not reflecting sarcasm or humor). Overt signs of discomfort/fidgeting referred to the tapping of fingers or feet or any noncommunicative movement, verbalizations (e.g., sighing), or the appearance of discomfort. Gaze aversion was indicated by avoidance of eye contact with the camera, excluding brief glances at a card containing points to be addressed. Stammering/shaky voice included evidence of an unsteady or quivering voice, stumbling, or the use of nonfluencies. Lastly, reluctance to speak was defined as showing hesitancy or unwillingness to speak. An additional measure was the number of times the participant had to be prompted by the experimenter to continue speaking. This variable could reflect nervousness (e.g., reluctance to speak) or performance (e.g., disengagement). Two independent raters coded videotaped speeches for performance and nervousness. The mean interrater correlation for these two measures was high (r=0.97). Table 1 shows demographic and baseline characteristics of threat and challenge groups. Chi-square tests of independence indicated that the groups were comparable in terms of parental history of hyper-
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Table 1 Demographic and baseline characteristics of threat and challenge groups Variable Gender* Men Women Parental history of HT Positive Negative Uncertain Age (yr) Mother’s education (yr) Father’s education (yr) Height (in) Weight (lb) Body mass index (kg/m2) Casual SBPa (mm Hg) Casual DBPa (mm Hg) SBPb (mm Hg) DBPb (mm Hg) Heart rateb (bpm) Cardiac outputb (l/min) Total peripheral resistanceb (pru)** Heather indexb (V/s2)
Threat
Challenge
81% 19%
59% 41%
41% 30% 29% 16.4 (0.89) 13.6 (2.4) 12.3 (4.0) 68.6 (3.0) 186.9 (57.4) 27.6 (7.3) 123 (11.2) 75 (6.1) 121.2 (11.7) 64.1 (5.9) 74.1 (9.1) 5.8 (1.24) 0.93 (0.17) 13.1 (3.9)
22% 41% 37% 16.1 (0.85) 12.3 (3.9) 12.0 (5.0) 67.1 (4.3) 191.4 (49.6) 29.7 (7.0) 124 (11.3) 73 (7.3) 120.1 (12.7) 62.4 (3.5) 76.9 (10.3) 6.4 (1.31) 0.83 (0.15) 13.5 (4.2)
Values for age, mother’s and father’s education, height, weight, body mass index, casual SBP and DBP, SBP, DBP, heart rate, cardiac output, total peripheral resistance, and Heather index are means (S.D.). HT—hypertension; SBP—systolic blood pressure; DBP—diastolic blood pressure. a Casual blood pressure averaged across medical screening and stress reactivity appointments. b Initial resting baseline levels of physiological variables observed during the stress reactivity session. * pb0.10. ** pb0.05.
tension, v 2 (2, N=54)=2.17, pN0.10, and showed a trend toward a difference in the gender composition, v 2 (1, N=54)=3.20, p=0.074. A series of independentsamples t-tests performed on each of the remaining variables in Table 1 revealed only a significant group difference for baseline levels of TPR, with the threat group exhibiting higher baseline TPR levels than the challenge group, t(52)=2.14, pb0.05. Performance scores were inversely correlated with nervousness ratings (r= 0.69, pb0.0001) and the number of prompts (r= 0.64, pb0.0001). Conversely, nervousness was positively correlated with the number of prompts (r=0.59, pb0.0001). Behavioral threat and challenge responses were determined by computing ratios of scores on the nervousness scale to scores on the performance scale.
A median-split was then performed on the sample distribution of these ratios. Participants with ratios above the median of 0.78 constituted the threat group (M nervousness=6.5, S.D.=2.35; M performance= 3.5, S.D.=1.95; M ratio=2.45, S.D.=2.68), whereas individuals scoring below the median comprised the challenge group (M nervousness=1.5, S.D.=1.32; M performance=7.3, S.D.=1.80; M ratio=0.33, S.D.=0.21). Speech presentation reactivity change scores for the threat and challenge groups are shown in Table 2. Independent-samples t-tests indicated that, relative to the threat group, the challenge group exhibited greater HI responses, t(31)=2.56, pb0.05, as well as heightened HR responses, t(41)=2.29, pb0.05. There was also a nonsignificant trend toward greater CO reactivity for the challenge group, t(37)=1.91, p=0.064. Although the group difference for TPR also failed to reach significance, t(50)=1.56, p=0.126, it was in the expected direction, with the threat group displaying the greatest TPR responses. No group differences emerged for SBP or DBP, ts(52)=0.77 and 0.07, respectively, psN0.10. Threat and challenge groups were also compared on the mean number of prompts received. An independent-samples t-test revealed that the threat group (M=3.3, S.D.=2.3) required approximately twice as many prompts as the challenge group (M=1.7, S.D.=1.4), t(43)=3.00, pb0.01. The present study demonstrated limited evidence of associations of behavioral indices of threat and challenge with patterns of cardiovascular responses to a speech stressor. Specifically, challenge-related behavior was associated with greater myocardial Table 2 Changes from pretask to speech presentation, for threat and challenge groups Variable
Threat
Challenge
CO (l/min)* TPR (pru) HI (V/s2)** HR (bpm)** SBP (mm Hg) DBP (mm Hg)
0.14 (0.83) 0.22 (0.17) 0.07 (2.15) 8.2 (8.0) 27.4 (12.0) 16.3 (7.3)
0.78 (1.47) 0.14 (0.19) 3.10 (5.52) 14.9 (12.3) 30.2 (15.0) 16.2 (5.6)
Values are means (S.D.). CO—cardiac output; TPR—total peripheral resistance; HI—Heather index; HR—heart rate; SBP— systolic blood pressure; DBP—diastolic blood pressure. * pb0.10. ** pb0.05.
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(i.e., HI, HR, and a trend for CO) responses to the speech task than threat-related behavior. However, the expected threat–challenge group difference for TPR did not approach significance. This is not the first investigation to demonstrate stronger evidence of threat–challenge group differences with myocardial responses than with vascular responses (Tomaka et al., 1997, Study 1; Tomaka and Palacios-Esquivel, 1997). A small sample size may have dampened the robustness of the findings reported here. Nevertheless, these findings are generally in accord with the growing body of literature indicating that states theoretically consistent with threat and challenge are accompanied by distinct hemodynamic profiles (Blascovich et al., 1999, 2001; Mendes et al., 2001, 2002, 2003; Tomaka et al., 1993, 1997; Tomaka and Palacios-Esquivel, 1997). Furthermore, this study extends the literature in that it is the first investigation to use behavioral measures to classify participants into threat–challenge groups. While preliminary, the present data could be viewed as a first step toward providing behavioral validation of the threat and challenge constructs. Although global behavioral measures were deemed suitable for purposes of this study, they do not provide information on the relative contributions of the individual components to the global ratings. Future studies should attempt to disentangle the relative influence of distinct attributes of performance and nervousness on hemodynamic responses. Relatively few studies examining hemodynamic responses to laboratory stressors have included significant representation of the Hispanic population (e.g., Tomaka and Palacios-Esquivel, 1997). Thus, the present investigation provides much needed data on a rapidly expanding minority population in the United States (U.S. Census Bureau, 2003). Furthermore, this study extends the threat–challenge literature by evaluating an entirely adolescent sample. While the uniqueness of the sample (i.e., Hispanic adolescents initially identified as having elevated blood pressure) is a strength of the study, further research is necessary to establish the generalizability of our findings. The heightened myocardial responses shown by our challenge group suggest greater h1-adrenergic activation of the cardiac muscle (e.g., Sherwood et al., 1986) and/or increased vagal withdrawal (Grossman and Svebak, 1987), relative to the threat group. Regardless of the underlying mechanisms, the
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responses of the challenge group are generally consistent with those previously regarded by Tomaka et al. (1993) as adaptive. Longitudinal data are still needed, however, to establish relationships between hemodynamic patterns and clinical disease.
Acknowledgments This work was supported by Grants HL36588 and HL04726 from the National Institutes of Health. The authors would like to thank the Miami-Dade County Public Schools and the Miami-Dade Division of the American Heart Association. The authors would also like to acknowledge Karen Adler and Jon Yoo for their assistance with data collection.
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