The Role of Emotion Suppression in Reaction Time and Threat Response During Highly Intense Stress. Alan Neider Briarcliff High School

Transcription

1 The Role of Emotion Suppression in Reaction Time and Threat Response During Highly Intense Stress Alan Neider Briarcliff High School

2 Purpose/Introduction This experiments goal was to determine the role of emotion suppression in reaction time during highly intense stress. Stress is the bodies reaction that requires a physical, mental, or social response. Post traumatic stress disorder (PTSD) is an anxiety disorder that can develop after exposure to highly intense stress and traumatic events.

3 Facial Features Changeable aspects of faces social signals show the internal states and intentions of others (Fichtenholtz et al. 2009). The display of fear on a person s face is a cue that an impending threat is present, and a happy expression represents a situation where a reward could be expected (Hillman et al., 2004).

4 Stressors and Cognitive Function Trait ability to remember human faces may be related to how accurately people recall faces that are associated with highly emotional circumstances (Morgan et al. 2007). Stressors that are situations that will elicit a stress response only in certain individuals will cause a response may be mild or pronounced (Lupien et al. 2006).

5 Memory and traumatic stress -ROCF performance was significantly poorer in subjects who reported greater histories of exposure to traumatic stress (threat to life). It is well known in preclinical studies that early exposure to uncontrollable stress can cause sensitization of noradrenergic and dopaminergic systems (Henry et al 1995). (Morgan 2004)

6 Research Question What is the role of emotion suppression in reaction time and threat response during highly intense stress?

7 Hypothesis H1: Participants who suppressed their emotions would perform better under stress than those who didn t suppress their emotions. H0: Suppression of ones emotions will have no effect on performance during stress.

8 Methods (Participants and Study Site) 32 recruited male active duty personnel who were enrolled in military survival school training. The study site of this experiment was Camp Lejeune, North Carolina, which is a United States Military Survival School. In order to establish, which soldiers suppress emotions a psych assessment was administered.

9 Overall Methods Outline Baseline Psychiatric Assessment (testing for emotion suppression) Phases of Survival School Phase 1 (baseline phase): one week of classroom instruction Phase 2 (stress phase): all participants experienced 48 hours of partial food and sleep deprivation. The participants are taken captive in a mock prisoner of war camp.

10 Methods (Task Parameters) Task consisted of 9 runs, each run contained 96 trials, for each of 24 stimulus categories, and lasted 5.6min. Consisted of a dynamic facial cue stimulus that changed both gaze direction (left, right) and facial expression (happy, fearful), followed by presentation of a target object.

11 Methods (Stimuli) Happy Target stimuli consisted of two photos that were chosen from the IAPS affective picture set (Lang et al., 2001) One stimulus was positively-valent and the other was negatively valent. To create realistic dynamic emotional expressions, fearful and happy facial expressions of intermediate intensity were created using the morphing methods outlined in LaBar and colleagues (2003) using MorphMan 2000 software (STOIK, Moscow, Russia). Fearful

12 Results (Reaction time and Accuracy) 1 Participants who suppressed their emotions were the ones who performed the best under stress. 2 Approximately 65% of the participants performed better under stress 3 Approximately 35% of the participants performed worse in the stressful task

13 Results

14 Reaction Time Compared To Accuracy Reaction Time Reaction Time

15 Limitations Since only men are part of the United States Special Operations forces only men were recruited in this study. Most of the soldiers (but not all) who participate in survival school training are considered stress hardy according to military standards

16 Discussion (Lupien et al. 2007) indicated that stressful traumatic emotional circumstances elicit an emotional response. Findings People who suppress their emotions aren t as affected by the decrements caused by stress Can help predict, what soldiers or people are at a higher risk of developing PTSD

17 References Campbell et al: Meanings in motion and faces: Developmental associations between the processing of intention from geometrical animations and gaze detection accuracy. Development and Psychopathology 18(1) (2006): Ekman et al: The facial action coding system. Psychologists Press (1978) Fichtenholtz et al: Happy and fearful emotion in cues and targets modulate eventrelated potential indices of gaze-directed attentional orienting. Social Cognitive and Affective Neuroscience 2 (2007): Fichtenholtz et al: Modulation of reflexive orienting to gaze direction by facial expressions. Visual Cognition 18(3) (2009): Hellhammer et al: Social hierarchy and adrenocortical stress reactivity in men. Psychoneuroendocrinology 22(8) (1997): Hillman et al: Emotion and motivated behavior: postural adjustments to affective picture viewing. Biological Psychology 66 (2004: Kirschbaum et al: Impact of gender, menstrual cycle phase, and oral contraceptives on the activity of the hypothalamus-pituitary-adrenal axis. Psychosomatic Medicine 61(2) (1999): Kirschbaum, et al: Response variability of salivary cortisol under psychological stimulation. Journal of Clinical Chemistry and Clinical Biochemistry 27(4) (1989): 237. Kirschbaum et al: Sex-specific effects of social support on cortisol and subjective responses to acute psychological stress. Psychosomatic Medicine 57(1) (1995): Kudielka et al: Acute HPA axis responses to laborator psychosocial stress in healthy elderly adults, younger adults, and children: Impact of age and gender. Psychoneuroendocrinology 29(1) (2004): Labar et al: Dynamic perception of facial affect and identity in the human brain. Cerebral Cortex 13 (2003): Lieberman Harris et al: Severe Decrements in Cognition Function and Mood Induced by Sleep Loss, Heat, Dehydration, and Under nutrition During Stimulated Combat. BIOL Psychiatry 57 (2005): Lang et al: International Affective Picture System (IAPS): Instruction Manual and Affective Ratings. (Tech. Rep. No. A-5). Gainesville: University of Florida, Center for Research in Psychophysiology (2001). Lupien et al: Beyond the stress concept: Allostatic load a developmental biological and cognitive perspective. Handbook series on developmental psychopathology (2006): Lupien et al: Stress-induced declarative memory impairment in healthy elderly subjects: Relationship to cortisol reactivity. The Journal of Clinical Endocrinology and Metabolism 82(7) (1997): Lupien et al. The effects of stress and stress hormones on human cognition: Implications for the field of brain and cognition. Brain and Cognition 63 (2007): Morgan et al. Accuracy of Eyewitness Identification is significantly associated with performance on a standardized test of face recognition. Law and Psychiatry 30 (2007): Morgan et al. Hormone Profiles in Humans Experiencing Military Survival Training. Society of Biological Psychiatry 47 (2000): Pruessner et al: Self-reported depressive symptoms and stress levels in healthy young men: Associations with the cortisol response to awakening. Psychosomatic Medicine 65(1) (2003): Rohleder et al: Glucocorticoid sensitivity in humans-interindividual differences and acute stress effects. Stress 6(3) (2003): Roy et al: Life events and social support as moderators of individual differenes in cardiovascular and cortisol reactivity. Journal of Personality and Social Psychology 75(5) (1998): Schweinberger et al: Assymetric relationships among perceptions of facial identity, emotion, and facial speech. Journal of Experimental Psychology: Human Perception and Performance 24 (1998):

18 Future Research In order to show the accuracy of the theory that suppression of emotions is predictive of who is at the highest risk of developing PTSD a long-term research study is necessary in the future.