By Anna Choi
Photo by Steinar Engeland on Unsplash
Introduction
With the recent new developments and complex networks, people are required to receive, understand and process a plethora of information flowing in their daily lives- especially in highly intellectual and demanding environments such as workplaces and academia. Indeed, pressure and stress come as a set to maintain oneself in this society. Stress may act as a positive stimulus to motivate individuals to work harder by creating an adequate amount of tension, but otherwise, it may cause harmful consequences, leading to an imbalance in one’s well-being. Likewise, it is crucial to grow the ability to control stress factors. In this regard, numerous academic research has explored key determinants of one’s stress levels, including external factors such as global issues, as well as internal factors like mood shifts and minor psychological stimuli.
Definition of Stress
By definition, “stress” refers to the physiological and psychological reaction triggered by a stressor, either external or internal, creating an unstable, tension-induced mental state (Ness and Calabrese, 2016). Starting from students who are raised in stressful academic environments with the demands of assignments and grades to fully grown adults in workplaces who are responsible for their own households, it is apparent that stress is now simply a part of daily life. In recent years, the number of reports of unhealthy life patterns and changes in behavior has elevated. For example, in the United Kingdom, up to 49% of adults have spotted changes in behavior due to stress, while 51% and 61% of adults felt either anxious or depressed due to stress respectively (Mental Health Foundation).
Emotional and physical well-being is crucial to sustaining a balanced, healthy life. “Well-being” refers to having a positive and satisfying life, often including workload balance with social life, connecting with other people, and maintaining a regular daily routine. If stress is not regulated and managed properly, well-being definitely would be hard to establish, therefore resulting in psychological effects.
Types of Memory
Memory, also crucial to functioning in a healthy life, is defined to be “the ability to use the past in the service of the present” (Karpicke and Lehman, 2013). Psychologists mainly subdivide memory into two categories- implicit memory and explicit memory.
Implicit memory is a form of memory that is relatively long-lasting and does not require conscious retrievals, such as general knowledge or common logic that many uses in their everyday lives (Schott, et al., 2005). Explicit memory refers to conscious recollection of past experiences or episodes, often used when asked to remember an event that occurred on a specific date (Schott, et al., 2005).
Memory includes steps to be processed in the brain- sensory memory, short-term memory, and long-term memory.
Sensory memory simply refers to the moment sensory receptors take in information from the environment and send it immediately to the brain, which lasts half of a second if it is iconic, visualizing images and symbols, and around three to four seconds if it is echoic, meaning that the memory is stored in the form of sound (Weiten, 2003). During this stage, it can be said that almost no information is stored in the brain because it is so brief.
Short-term memory, also known as working memory, has limited capacity and can hold a couple of pieces before the information is disposed of (Weiten, 2003). It is easily misconceptualized that short-term memory only is the memory capacity before the information is stored in long-term memory, but short-term memory also acts as a space to retrieve data from long-term memory to bring into the conscious level while conducting a specific task. Afterward, it is sent back to long-term memory.
Unlike short-term memory, long-term memory has limitless storehouse capacity, meaning it can hold as many items as possible (Weiten, 2003).
There are several processes required when transitioning into these memories, which is called encoding (Weiten, 2003). Through various encoding strategies that one may acquire, such as using mnemonic devices, priming, and many others, information is encoded into the brain, which is how memory is consolidated. However, in the process of memory smoothly transitioning through and consolidating in long-term memory capacity, stress often interferes by intensifying emotional memory, being called “a strong modulator of memory function”(Luethi, 2008).
Past Studies
The relationship between the two factors has long been studied in the field of general sciences. However, findings drawn from each study seem to still differ, making it more difficult to reach a consensus about the explicit impact of stress on working memory and performance.
A study was conducted to test working memory-related task performance in 31 healthy male subjects after exposing them to varying stressors (Gärtner, et al., 2014). Researchers found that acute stress decreases frontal theta activity, which overarches to a variety of behavioral functions crucial in our daily lives such as attention, alertness, and orientation, usually important in highly demanding tasks (Stylios and Chen, 2016). To support the such conclusion, another study conducted in 2015 yielded results that presented poor working memory and overall performance based on frontal-theta activity in the hippocampus, with anxiety and stress both taken into account (Shi, et al., 2015).
Nevertheless, more studies argued otherwise. In a study assessing the effects of stress and cortisol levels on a comprehensive variety of memory tasks in male human subjects which require the usage of all three types of memory, verbal working memory was found to have imposed performance while areas in perceptual priming and contextual priming showed no differences (Luethi, et al., 2008). Overall, findings indicated that social stressors certainly do play a role in memory impairment, but not always in general performance.
Another meta-analysis study claimed that the impact of acute stress is “case by case”. In contrast to implicit memory, which can easily be influenced, the effect of prior acute stress in explicit memory is less apparent, frequently displaying neither performance nor short-term memory immediately after training (Sandi, 2013). Furthermore, other studies have shown evidence parallel to the hypothesis that stress and glucocorticoids impair the retrieval of memory which is primarily dependent on the hippocampus (Sandi, 2013).
Conclusion
It is clear that the relationship between stress and working memory and performance certainly does exist. However, there are still disagreements and questions raised regarding how exactly stress affects the two most crucial functions of our bodies. It cannot be denied that finding the distinct cause-and-effect relationship between the two factors is certainly complex and difficult with the amount of information unveiled at the moment. Some studies are especially hard to generalize because of the limitations in the variety of subjects and other confounding variables. Yet, scientists and researchers are still striving to investigate more on the relationship between the two factors through creative approaches even at this moment.
References
Gärtner, M., Rohde-Liebenau, L., Grimm, S., & Bajbouj, M. (2014). Working memory-related frontal theta activity is decreased under acute stress. Psychoneuroendocrinology, 43, 105–113. https://doi.org/10.1016/j.psyneuen.2014.02.009
Karpicke, J. D., & Lehman, M. (2013). Human memory. Oxford Bibliographies Online Datasets. https://doi.org/10.1093/obo/9780199828340-0107
Luethi, M. (2008). Stress effects on working memory, explicit memory, and implicit memory for neutral and emotional stimuli in healthy men. Frontiers in Behavioral Neuroscience, 2. https://doi.org/10.3389/neuro.08.005.2008
Ness, D., & Calabrese, P. (2016). Stress effects on multiple memory system interactions. Neural Plasticity, 2016, 1–20. https://doi.org/10.1155/2016/4932128
Sandi, C. (2013). Stress and cognition. WIREs Cognitive Science, 4(3), 245–261. https://doi.org/10.1002/wcs.1222
Schott, B. H., Henson, R. N., Richardson-Klavehn, A., Becker, C., Thoma, V., Heinze, H.-J., & Düzel, E. (2005). Redefining implicit and explicit memory: The functional neuroanatomy of priming, remembering, and control of retrieval. Proceedings of the National Academy of Sciences, 102(4), 1257–1262. https://doi.org/10.1073/pnas.0409070102
Shi, Z., Gao, X., & Zhou, R. (2015). Frontal theta activity during working memory in test anxiety : NeuroReport. LWW.
Stalling, R. B., & Weiten, W. (2003). Weiten’s psychology: Themes and variations (10th ed.). Wadsworth Publishing Company.
Stress: Statistics. (n.d.). Mental Health Foundation. Retrieved February 5, 2023, from https://www.mentalhealth.org.uk/explore-mental-health/mental-health-statistics/stress-statistics
Stylios, G. K., & Chen, M. (2016). Theta Power - An overview. ScienceDirect Topics. https://www.sciencedirect.com/topics/engineering/theta-power
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