Motivation and emotion/Book/2020/Cortisol and motivation

Overview
Everybody experiences stress at some point throughout their life. Some people may experience it more than others. Have you ever thought about how some people can regulate stress more than others? Why can stress sometimes encourage behaviours and other times cause avoidance behaviours? This chapter explores the affect of cortisol (the stress hormone) on reward-directed behaviour (motivation). It will look at the neurological affects of cortisol and provide examples of how cortisol affects motivation to exercise and engage in gambling behaviours. Focus questions:
 * What is cortisol?
 * What is the relationship between cortisol and motivation?
 * Cortisol and exercise: Is there a link with motivation?
 * Is there a connection between glucocorticoid hormones and drug and alcohol abuse?

What is cortisol?
Cortisol is a hormone which has long been used as a biological marker of stress,anxiety and depression (Levine et al., 2007). Cortisol plays a critical role in metabolism because of its ability to mobilse energy resources to provide “fuel” for the body (Dickerson & Kemeny, 2004). In the presence of a physical or psychological threat, cortisol levels increase to provide the energy needed to cope with stress-provoking stimuli or to help an individual escape from danger (Hannibal & Bishop, 2014). The activation of the hypothalamic-pituitary-adrenal axis (HPA axis) causes an increase in cortisol secretion in the adrenal cortex (Drogos et al., 2019). In healthy adults, cortisol levels quickly increase after waking in the morning and then slowly reduce across the morning hours. Cortisol secretion occurs in a diurnal cycle and the morning increase in levels is known as the cortisol awakening response (CAR). Increased cortisol has been linked to weight gain (Vicennati et al., 2009). It is also responsible for adrenal fatigue, where an individual is physically exhausted but unable to rest. Adrenal burnout effects moods, causes poor sleep and makes it difficult to concentrate or remember things (Yaribeygi et al., 2017).



What is motivation?
Due to the impact cortisol has on the fight-or-flight response, it also has an affect on motivation and reward-directed behaviour. To be motivated means to be moved to do something. An individual could be motivated by attaining a separable outcome, extrinsic motivation, or an activities inherent satisfactions, intrinsic motivation (Ryan & Deci, 2000). Therefore, a person who feels no inspiration to act on a thought or emotion is characterised as unmotivated, and someone who is activated toward completing a task is considered motivated.

What is the relationship between cortisol and motivation?
Exposure to stress has profound, but complex, affects on motivated behaviour and decision-making. Stress does not have a single affect on motivated behaviour as differences in the intensity, duration, intermittency, controllability and nature of a stressor produces different behavioural endpoints (Hollon, Burgeno & Phillips, 2015). Extensive research into the affect of cortisol on motivation has found that inflated levels of cortisol over a long period of time were problematic for motivation, however a small increase in cortisol levels can lead to heightened motivation (Wirth, 2011). This could occur after semi-intense exercise or in the morning when the CAR is high. It has been demonstrated that individuals with increased cortisol levels displayed an increase in reward-seeking behaviour (Putman et al., 2010). Consistently high cortisol levels can lead to anxiety disorders and susceptablitly to addiction, but it has been concluded that the high cortisol levels measured after exercise created a boost in attentiveness, a desire to perform, and motivation that lasts 20 to 30 minutes (Buddle et al., 2015). During the time period where cortisol is spiked, individuals are more likely to engage in activities that require more motivation and complete them with better accuracy.

Neuroscience of cortisol and motivation


Glucocorticoids that are secreted in response to stress have been shown to accentuate reward sensitivity and may therefore promote engagement in an activity (Kinner, Wolf & Mertz., 2016). Glucocorticoid-receptors (GRs) are extensively found in the dopaminergic reward system making the pathways highly susceptible for glucocorticoid regulation (Ironside et al., 2018). Dopamine is the chemical that motivates an individual, however, cortisol affects the way dopamine travels through the brain and can therefore have a negative influence on dopamine levels (‌Yaribeygi et al., 2017).

At a neuronal level, motivation-related phenomena have been linked to the value judgement and decision-making in the orbitofrontal cortex and executive function and cognitive control in the anterior cingulate cortex and the dorsolateral prefrontal cortex (DLPFC) (Kim, 2013). Stress response is controlled by neurocircuitries connecting the prefrontal cortex and the amygdala. It has been proposed that the DLPFC has inhibitory projections to the amygdala during stress anticipation to facilitate the confrontation with the upcoming actual stressor (Pulopulos et al., 2020).

Inline with the Neurocognitive Framework for Regulation Expectation, cortisol regulation processes depends on the goal-relevant information associated with a sustained activation of the DLPFC (De Raedt and Hooley, 2016). As the sustained activation of the DLPFC reduces the activation of the amygdala, individuals can be motivated to complete tasks due to reduced fear.

Reinforcement theory
Reinforcement theory of motivation, as proposed by B.F Skinner, refers to a behaviour being the function of its consequences and results in an individual developing a behaviour after performing certain actions due to the rewarding (positive) or punishing (negative) outcome (Skinner, 1963). It is believed that, due to the rewarding effects a behaviour can have on reducing stress and cortisol levels, the behaviour is positively reinforced (Hamidovic et al.,2010). As activation of the HPA axis increases the sensitivity of a stressor in order to respond to it, the rewarding effects of overcoming the stressful event is heightened and individuals are more likely to participate in those behaviours again. It is difficult to determine whether cortisol production due to stress leads to more habitual behaviours either weakening the process of goal-directed behaviours or strengthening the process of the habit. It is also possible that the affect of stress on behaviour might vary depending on whether the result of previous behaviour was positive or negative (Cavanagh et al., 2011). Therefore, stress may boost the neural signals related to decision-making differently depending on the magnitude of the outcomes.

A study conducted by Putman et al (2010) tested the acute effects 40 mg cortisol on motivated decision making in 30 healthy young men. After the cortisol increase, the subjects had to choose between two gambling options with the aim of earning as many game credits as possible. It was found that cortisol reduced the influence of the perceived probability of losing on performance of the gambling task. Although individuals typically avoid gambles with a high probability of losing compared to gambles with a low probability of losing, this risk-avoidant behaviour was reduced by cortisol. The behavioural pattern reflects the combined effect of reduced sensitivity to cues of punishment and increased sensitivity to reward thereby motivating an individuals choices. Other studies have also suggested that stress diminishes one’s ability to make adaptive choices in multiple aspects of reinforcement learning (Park et al., 2017).

Social self-preservation theory
It has long been argued that the need to belong to a social group is a fundamental human motivation and individuals are encouraged to behave in ways that enhance their belongingness to groups (Rohleder et al., 2007). Some researchers argue that just as the activation of the HPA axis and the production of cortisol preserves the physical self, an individuals cortisol levels can increase when the social self is being threatened (Dickerson & Kemeny, 2004). This theory argues that there is a social self-preservation system that assesses threats to an individuals social status and responds in a spike in cortisol levels to provide energy and motivation fight the threat.

A study by Rohleder et al (2007) measured cortisol levels in ballroom dancers before and after competition to assess whether social-evaluative threats increased cortisol responses. Due to the fact that high levels of performance are important to a dancers self-identity and that their goal of becoming an elite dancer could be inhibited by a negative evaluation from another person (eg. a judge), the recorded spike in cortisol was deemed to be a response to a social-evaluative threat. The small rise in cortisol provided a quick burst of energy and heightened memory for the dancers which would have improved their outcome. However, this study did note that the repeated activation of the HPA axis without the correct recovery would have a negative impact on the dancers as their self-esteem and image of themselves would begin to be altered. Social support from a group, which motivates behaviour, was found to reduce cortisol levels and activation of the HPA axis thereby positively reducing physiological responses to stress and benefiting overall health. By being validated by a group, an individual can set clear goals and be motivated to achieve them as their reward is group and social acceptance.

Everyday exercise
Exercise is perceived by the body as an environmental stressor and stimulates the release of cortisol from the HPA axis. Exercise also represents a physical form of the fight response which is crucial to engage in if cortisol levels are to be rebalanced. The more an individuals fitness improves, the better the body becomes at dealing with physical stress, meaning that less cortisol will be released during exercise and in response to emotional or psychological life stresses (Hill et al., 2008). This reduction in cortisol prevents impediment of other neural mechanisms and hormones needed to evoke motivation, such as dopamine. Similarly, if you experience a lot of psychological and emotional stress that impedes on your capacity to want to do things exercise can help as the periodic spike in cortisol can lead to the stabilisation cortisol levels and the reduction of stress. Although many results discussed in this type of research relate to the problems created through inflated levels of cortisol after long periods of time, a brief increase in cortisol levels leads to heightened motivation after semi-intense exercise (Buddle et al., 2015).

Cortisol levels increase at a rate proportional to the exercise intensity, but reach a final level depending on the total duration of the exercise session (Hill et al., 2008). Therefore, in order to reduce stress through exercise, moderate exercise every day at 30 to 40 minutes is recommended. This is due to the balance in cortisol secreted energy in the body and an individual using all of their cortisol induced energy to help repair the muscles and evoke the recovery process. Sometimes, exercise heightens pre-existing cortisol imbalances. As exercise yields the body's stress response, when cortisol levels aren't in homeostasis, it can cause cortisol levels to just remain high. For an individual who exercises with the purpose of reducing stress and anxiety and does not experience the reward of lower stress levels, the motivation to exercise reduces as there has been no positive reinforcer linked to the reward of the behaviour. Motivation to exercise to seek the reward of a reduction of stress needs to be further explored in literature.

Extreme Sport


Cortisol prepares an athlete for the psychological and physiological demands of competition. The anticipatory increase in cortisol before a sport event can affect performance through its influence on the cognitive process, including its activation and deactivation of the prefrontal cortex-amygdala (van Paridon et al., 2017). It has been established that high cortisol levels can reduce the feedback response of the amygdala resulting in an individual having little fear and looking for ways to feel the emotion. In other circumstances cortisol has been found to increase the feedback of the amygdala, suggesting that some people who participate in extreme sports are simply motivated by the goal of overcoming their fears (Kinner et al., 2018). Social motivation, goal achievement and risk taking have all been considered motives for adventure sport participation (Kerr & McKenzie, 2012).

Reversal theory has been used to understand the participation in risk taking sports. Reversal theory is the notion that an individuals motivation is dependant on the meaning they attach to a situation and the emotions they experience (Filaire et al., 2007). This is considered an individuals current metamotivational state. When an individual is in a paratelic state, they have a desire for high arousal, they focus on the person and often participate in activities that promote instrinic enjoyment and fulfilment. Paratelic-dominant athletes are generally deemed as arousal seekers and enjoy the participation in high risk sports. This could be due to paratelic-dominant people doing well under stress and viewing stress as a challange that needs to be overcome rather than a threat to be avoided. Reinforcement behaviour is also evident in risk-taking and thrill seeking sport as the psychological effects are what encourages repeat participation.

Doug: the mountaineer Case Study

Doug is a mountaineer and rock climber who began climbing in his late 20s to the escape boredom of his job. Now 52, Doug continues to climb but notes that he has always had a fear of heights. The increased cortisol levels Doug experiences during his climb, as a result of heights being a physical and psychological stressor, means that Doug finds motivation to climb by setting a goal of conquering his fears. For Doug, the loss of self-consciousness during his climb is enjoyable and is a positive reinforcer for the behaviour that has continued nearly 30 years. By engaging in an individual risk-taking sport knowing the evaluative pressure of social groups is absent his motivation to continue climbing increased. Assuming Doug takes the time to recover from his significant spike in cortisol whilst climbing, Doug's climbing may be a habitual response to life stressors.

This case study was inspired by the research of Kerr & Houge Mackenzie (2012).

Alcohol addiction
Addiction to alcohol and gambling is the result of the altered functioning of psychological motivation systems. Cortisol is thought to play a role in the vulnerability to addictive behaviour because of its role is the mesolimbic reward pathway (Li et al., 2014). It has been suggested that a person dependant on alcohol may show chronic activation of the HPA axis especially during heavy periods of consumption (Lovallo, 2006). Brkic et al (2016) examined the relationship between high and low cortisol levels in participants after being presented with an acute stressful situation and the respective responses to alcohol consumption. They found that alcohol had a higher sedentary effect on individuals who had higher cortisol levels in response to a stressful event. The effect was more evident in when high doses of alcohol were consumed. This puts high cortisol responders to stimuli at high risk of addiction as the depressant effects of alcohol is positively reinforced when it calms stress.

Gambling addiction
Similarly in individuals with gambling addictions, the HPA axis' response to stressors have appeared as atypical suggesting the chronic exposure to gambling dampens the response of the HPA axis (Paris et al., 2010). As gambling has stress-like psychological effects, motivation to gamble could be the attempt to restore cortisol homeostasis in pathological gamblers. A study conducted by Li et al (2014) looked at the association between cortisol levels with an increased response to monetary and non-monetary rewards in pathological gamblers. In line with other literature, they found higher cortisol levels were associated with a increased response to monetary rewards suggesting that cortisol may contribute to addictive process in pathological gamblers by enhancing gambling-related cues. As gambling-related cues triggers gambling urges in pathological gamblers, there is a supportive link between increased cortisol and a gamblers motivation to engage in activities producing monetary rewards.

Smoking addiction
The effect of smoking on cortisol levels was explored in a cross-sectional study which concluded there was high probability that the increased level of cortisol release found in the participants can be linked to nicotine. Specifically, the nicotine found in smoking cigarettes. This is in line with the key findings regarding the effect of other vices on cortisol levels such as gambling and drinking. This ‘myth busts’ the claim that ‘smoking reduces stress’ as the cross-sectional study does not concur with this, rather alludes to the opposite. In participants that smoked there was an increased cortisol level 30 minutes after waking up when compared to the control group of non-smokers. This change in cortisol levels is another piece of evidence that cortisol impacts addiction levels and can be considered one of the enablers of the addiction behaviour patterns in affected individuals (Steptoe & Ussher, 2006).

Quiz
{Activation of the HPA axis results in the secretion of what hormone? - Dopamine - Serotonin + Cortisol - Testosterone {Cortisol is known as being: - The happy hormone + The stress hormone - The depressive hormone {What theories are related to cortisol's affect on motivation: + Reinforcement theory - Risk taking theory + Social self-preservation theory - Increased exercise theory + Reversal theory {Can motivation to exercise be influenced by cortisol levels? + Yes - No
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Conclusion
The rise and fall of cortisol levels can have a vast impact on motivation levels. Small increases in cortisol levels have proven to give bursts of energy to induce a fight response to stimuli and can enhance cognitive function for a short time to ensure a threat is overcome. The inhibitory effect cortisol can have on the amygdala reduces the fear involved in participating in a task to achieve a goal. As activation of the HPA axis increases the sensitivity of a stressor and therefore the rewarding effects of overcoming the stressful event is also heightened making individuals are more likely to participate in those behaviours again. Positive reinforcement of activities is a key way cortisol can influence motivation. Threats to one's social appearance also spikes cortisol levels, driving an individual to behave and perform in a way that is valued by a group. In line with reinforcement theory, exercise is a positively reinforced and motivated activity due to its ability to calm the brain and return cortisol levels to homeostasis. Some people who engage in extreme sports use the spike in cortisol to purposefully conquer their fears and periodically enjoy the inhibition of cognitive function. Chronic activation of the HPA axis results in addiction tendencies and in this behaviour is also evident in the role reinforcement has on repeat behaviour. Chronic activation of the HPA axis can lead to brain dysfunction and the permanent rewiring of systems. Whilst cortisol is important for responding to stressful stimuli, levels should always be brought down to homeostasis and an individual must let their bodies fully recover to prevent the long-term damage to the brain.