Psychological Stress and Physiological Reactions: How Both Affect Cognition

Stress is strongly implicated in both physical and psychological health problems. As noted by Sapolsky (2004), disruptions of homeostasis cause a stress-response, and the stressresponse can lead to stress-related diseases. These negative aspects of stress on health are commonly the focus of research. Of particular interest are the physiological effects of stress, and how it affects the body and mind. Social stress in particular is one of the most well-known and robust factors for physiological reactivity. A well-known paradigm to induce acute social stress in a lab setting is the Trier Social Stress Task (TSST; Kirschbaum, 1993), which includes a timed speech and math task in front of evaluators. The TSST reliably as social evaluative stress and physiological reactivity (for review see Dickerson & Kemeny, 2004). Social stress subsequently affects cognitive performance, as evinced in previous studies involving stress and memory (Kuhlman, 2005). To investigate both the psychological and physiological influences of social stress on cognitive performance, related factors must also be assessed. For college students, variables such as student year, social feedback condition, and social support could affect cognitive performance all in different ways. With these factors in mind, how does stress affect freshmen as opposed to seniors? STRESS AND PERFORMANCE 3 Psychological Stress and Physiological Reactions: How Both Affect Cognition There is a wealth of evidence explicating the biochemical, physiological, and behavioral changes that are associated with stress (Bruns, 2016). The literature on acute stress, of which social stress is classified as, can be measured by the steroid hormone, salivary cortisol, the gold standard of assessing acute stress in a lab setting (Kirschbaum, 1993). The Trier Social Stress Test (TSST) is a standardized experiment that consistently induces a stress response in the hypothalamus-pituitary-adrenal-axis (HPAA), resulting in significant increases of cortisol in the saliva (Kirschbaum, 1993). Findings have also shown that there is a relationship between stress and cognitive control (Plessow, 2011). While there have been previous studies on how acute social stressors affect cognitive performance, none were found that specifically targets college students. Students in college have both a wide range of social support and daily stressors that could reveal differences in how stress is managed. Specifically, factors of student year and college experience have not been explored in their relation to stress and cognitive performance, critical to high-performing college students. Stressors for College Students and Acute Stress The goal of this project has been to determine the psychological and physiological influences on cognitive performance before and after an acute social stress task, by assessing salivary cortisol levels at three assessment occasions and with continuous cardiovascular indices. The primary factor of interest has been the college status of each student. It was hypothesized that there would be statistically significant differences in the acute stress response and subsequent cognitive performance of freshmen and seniors versus that of sophomores and juniors. Freshmen could have a more negative response due to the shock of being in a new place STRESS AND PERFORMANCE 4 with new expectations and limited social support from not knowing many people. Seniors, while more likely adjusted to their college environment, may have high stress levels because of facing uncertainty in the prospects of their future job searching, moving to a new environment, and independence. Alternatively, self-reported survey data may contradict with this idea and portray freshmen on the lower end of the stress spectrum with seniors enduring a higher level depending on these various reported factors. Determining which factors cause or alleviate the most stress could be used to create programs and spread knowledge that helps students better manage stress. Stress has been extensively investigated due to its debilitating effects on mental and physical health (Bruns, 2016; Sapolsky, 2004). The American Psychological Association (APA) now defines stress as “any uncomfortable emotional experience accompanied by predictable biochemical, physiological, and behavioral changes” (Alvord, 2016). Stress is created by stressors, which O’Brien (2017) defines as “the events that trigger our stress response, because they are perceived/appraised as overwhelmingly challenging, threatening, and/or harmful. ” Stress is generally considered to be associated with negative states and its effects are broadly considered deleterious (Bruns). Acute stress can be characterized as exposure to short term stressors and the effects of acute stress can include but are not limited to muscle tension, nausea, psychological damage, increased sympathetic nervous system activity, increased respiration, and increased heart rate (Alvord). Chronic stress, as opposed to acute stress, is longterm exposure to stressors, and magnifies the effects of acute stress, commonly resulting in major, long lasting health problems such as insomnia, high blood pressure, muscle pains, high blood pressure, and a weakened immune system (Bruns). Acute stress can be measured by the hormone cortisol, which can be obtained from saliva for acute assessments using the Salivette system. STRESS AND PERFORMANCE 5 The Trier Social Stress Test The Trier Social Stress Test (TSST) is a seminal laboratory stress task originally designed by Kirschbaum, Pirke and Hellhammer in 1993. To date, it is one of the most reliable methods of inducing social stress and subsequently creating meaningful changes in salivary cortisol levels, all while in a controlled lab setting. It is considered high in both experimental and mundane realism. The protocol of the TSST involves the participant performing a speech and mental arithmetic task, each task for 5 minutes, in front of a panel of two confederate “evaluators. ” The participant is instructed that their performance will be audio-visually recorded for later analysis of performance and non-verbal body language. The evaluators are trained research assistants who are scripted to behave in a stoic or aloof manner and to give little facial and non-verbal feedback to the participants in one condition; in the present study, we also investigated a second condition in which, evaluators begin to offer positive nonverbal feedback approximately 30 seconds into the participant’s performance. The tasks are designed to be difficult and elicit acute stress in the participant, but in a controlled lab environment, where psychological and self-reported data on mood and performance data can be collected (Kirschbaum 1993, Birkett 2011, Dickerson & Kemeny, 2004). Literature Review and Goals of Stress Management The relationship between psychosocial stressors and long-term health detriment is affected by the nature, frequency, and magnitude of the stressors, as well as by the individual's biological vulnerability (i.e., genetics, constitutional or dispositional factors), psychosocial resources, and learned patterns of coping (Schneiderman, 2005). Learning coping methods and strategies could provide valuable help in mitigating future stressors. Additionally, psychosocial interventions have proven useful for treating stress-related disorders and may influence the STRESS AND PERFORMANCE 6 course of chronic diseases (Schneiderman, 2005). It is important to note that psychosocial factors are modifiable and attainable to any college student. If coping methods are to be investigated to illuminate how students can reduce stress levels, said research may suggest that students will benefit with better cognitive performance when exposed to acute stress. Physiological stress reactivity is a response generated by an organism from a stressor such as an environmental condition. Some examples prone to induce stress are fear and social anxiety. In humans, stress is the body's method of reacting to a challenge or threat. One physiological response related to stress is innervated by sympathetic nervous system (SNS) activation, which usually results in the fight-or-flight response. Because the body cannot keep this state for long periods, the parasympathetic system returns the body's physiological conditions to homeostasis (McEwen, 2000). Acute stress can be beneficial as it allows the hypothalamic-pituitary adrenal axis (HPAA) and the SNS to maintain balance and remain active, garner resources to interface with stress, similar to the way in which an influenza vaccination is created from the influenza strand itself. However, cumulative to acute stressors are generally expected to be unhealthy for any individual. Chronic stress can be caused by a change in eating or sleeping habits and from continuous stressors such as work or school. The negative effects of chronic stress can range from muscle and joint pain to high blood pressure and lowered immune system effectiveness. Specifically, the conducted research examined the cognitive effects of stressors in our daily lives. Several studies of a similar nature have been conducted and displayed results showing that there is decreased memory performance in groups who are more stressed as compared to the control (Kuhlman, 2005). STRESS AND PERFORMANCE 7 Hypothetical Results Figure 1: Free salivary cortisol levels in response to the stress or the control condition. Figure 2: Effects of the stress versus the control condition on delayed memory retrieval The data presented above compared young healthy males aged 19-40 years old and shows a negative performance in the individuals who underwent the stressful situation. This study demonstrated the cognitive performance through delayed memory recall in participants that underwent either a stressful situation or a control situation. While this is only one study, it STRESS AND PERFORMANCE 8 provides a thorough ba