The Affect Stress on Learning - Coursework Example

Article Summary Lightall et al aimed to study the affect stress has on reinforcement learning of older adults compared to the reinforcement learning in younger adults. Stress is experienced by all in their day to day life and it is a common phenomenon to experience stress while making decisions. In fact, episodes of stress influence the decisive behavior of a person. Most of the decisions taken are based on the perceived or anticipated positive or negative outcomes which are based on previous learning or reinforced learning. Other studies had established an association between reinforcement learning, stress and stress hormones such as dopamine. It has also been established through previous research that some other major effects of stress includes synaptic plasticity in dopamanic neurons and increased cravings for drug. PET studies have supported the hypothesis that with alteration of dopamanic activity, stress can affect the reward-related processing. Previous studies have shown that dopamine promotes reward learning in part by allowing plasticity in the corticostrial circuits but impairs aversion learning altogether i.e. increase in dopamine in the striatum supports slow and gradual learning through determination of expected positive and negative outcomes with experiences and alteration in synaptic plasticity. Therefore, with the increase in dopamine in the striatum the long term memory for positive feedback stimulus is strengthened by the factor of stress while negative feedback association and learning are impaired. Moreover, depending on neural mechanisms stress also has an impact on reinforcement learning. Older studies had shown that the brain activity remains almost same in older adults and in case of reward based learning the striatal region of older people shows significant brain stimulations. Incidental memory pictures that were seen during or after a positive feedback showed no difference between the younger and the older brain. However, most studies shows that the affects of stress is much more on behavior is the later stages of life than during the earlier stages and therefore the present study aimed to compare between the two. More specifically, this study investigated what effect a cold stressor task or control task had on reinforcement learning among young and older adults. The main hypothesis was that the cold stressor that had been applied would result in improved reward learning but impair avoidance learning. Furthermore, the study aimed to measure the relatedness between reinforcement learning between the young and older adults related to alterations induced through stress. For the study 96 participants between the age group of 18-34 years were selected. The study group was recruited through advertisement in print and offline, flyers and snowball recruitment. Exclusion criteria included usage of hormonal birth control, usage of medications such as corticosteroids, beta-blockers and sex replacement medications, diseases such as CVD, Alzheimer’s etc and cigarette smoking. In order to accommodate the effect of stress on menstrual cycle younger participants were divided according to their follicular stages. The study protocol as conducted between 2-6 pm. Post hydration the participants answered a 10 minute questionnaire and then provided baseline saliva sample and pain rating. Immediately after this they were exposed to cold stressor or control task followed by a 2nd pain rating which was then again followed by a 5 minute working memory task. The participants were assigned randomly to cold or control task. The cold stressor consisted of manipulation of stress in which participants were exposed to a cold stimulus for some time and in this case they has been asked to hold their non-dominant hand under ice cold water. The control set up consisted of same procedure in warm water. A 2nd sample of saliva was taken. This was followed by the learning task and the 3rd saliva sample was collected. At the extreme end of the session participants recorded psychological stress ratings. The saliva samples taken served as the primary measure of salivary cortisol in response of stress applied. Likert scaling was done to record the extent of pain the participants had experienced before, during and after application of the stressor. The important part of the experiment was the post-stress learning task that required the participants to learn up 3 pairs of Japanese symbols and which of them predicted positive outcome and which ones predicted negative outcome. After training the participants underwent a test without any feedback. Post this they underwent another training session followed by an evaluation. ANOVA’s were used to measure stress ratings, pain and levels of cortisol. K-S test was done using each sample to test skewed distribution against normal distribution. The final analysis results showed that baseline cortisol levels were higher in younger adults than in older. Most importantly there was significant difference in the stress levels of stressor group and control group and their performances indicating a link between stress and learning and moreover it was also seen that the stress had similar effects on both young and old adults. The results supported the hypothesis that stress enhanced the associative learning with positive outcomes while associative learning with negative outcomes was not enhanced. In the present study the effects was stress on reinforced learning was similar even though stress altered performance on test. The results of the study also indicated that there was a strong correlation between cortisol levels and learning behavior. The study did not study the dopamine levels but helped to establish that even though dopamine system decreased with age, healthy older adults could learn effectively under stress. The drawback of the study conducted was that it did not determine if the effect induced by stress was linear or not since only a moderate stressor was included in the study and hence there was not scope for manipulation of stressor intensity. In conclusion, the study established that acute stress enhanced reinforment learning in both younger as well as older adults. The finding has practical implications on our daily life since stress affects our decisions everyday and therefore choices or decisions made under stress would be more biased towards ones with anticipated positive outcomes or rewarding outcomes. Such decisions may have an impact on our lives. Further research calls for studies on the mechanism of how stress affects reinforced learning. References Lighthall et al (2012). Stress Modulates Reinforcement Learning in Younger and Older Adults. Psychology and Aging. Read More