Imagine being born unable to remember personal experiences. Would you be able to describe who you are to someone without any accessible repertoire of experiential information? At the very least, you could maybe stand in front of a mirror and describe the human being that you see, which is the physical embodiment of who you are. But without being able to store information from your personal experiences, the ones from which you learn, both as they happen and in retrospection, the experiences which shape and influence your beliefs, thoughts, and actions, could you claim to have an identity beyond the inherent physical characteristics of your species? Likely not.
Visualize your first kiss, a delicious meal, a traumatic ordeal, any mental imprint of a personal experience. The individual and private recollection of these events are what we call episodic memories. Episodic memories are categorized as declarative or explicit memories (i.e. memories that can be explicitly stated or conjured). Nevertheless, while episodic memories heavily substantiate our autobiographical memory, they are not equivalent. Autobiographical memory also depends on another type of explicit memory: semantic memory, which pertains to the storage of less subjective information (i.e. facts) such as your birth date, your blood type, the name of your parents, etc. To write your memoir or autobiography, you would need to rely on both types of explicit memories to provide a complete picture.
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Another key distinction between semantic and episodic memory is the dependency on different types of consciousness. Unlike semantic memory, episodic memory is dependent upon one’s conscious awareness of one’s self. This means that while semantic memory can be classified as “common knowledge” (e.g. historical dates, the steps to frying an egg) that remains the same whether in your head or your friend’s, episodic memory is unique to you. For example, your memory of your wedding is bound to be different from your husband’s, although the fact of the date remains the same to both of you. Consequently, I would argue that the principal source of autobiographical information influencing our sense of self comes from our episodic memories.
How would you answer the question “Who am I?” Whatever your answer, it is necessarily based on your self-concept or identity. Your self-concept or identity is constructed from your self-knowledge, self-esteem, self-concept, and your social self. In other words, identity encompasses the qualities, beliefs, personality, looks and/or expressions that identify you as you (to yourself and to others). This self-knowledge, self-esteem, self-concept, and the identity you embody in a social context are dependent on your ability to store information about your experiences. Your idiosyncrasies are developed throughout your lifetime by the interplay of your genetics and personal experiences, but only by being able to chronologically store information about what you’ve done, felt, and learned through these episodic memories can you construct a sense of identity.
(Image copied Wikipedia: By TGageND - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=73936530)
The formation and initial storage of episodic memories depends on a subcortical structure called the hippocampus (located in the medial temporal lobe). This structure is essential for spatial navigation and new memory formation, specifically episodic memory. Damage to it or removal of the hippocampus will result in anterograde amnesia (i.e. inability to form new lasting episodic memories) while retaining long-term episodic, semantic, and procedural memories from the past, as in the famous case of H.M. If you want to protect your episodic memory, among many other cognitive functions, some ways to do so are to exercise regularly, seek education or actively try to keep learning new things, and, most importantly, avoid situations where your head might suffer trauma or injury.
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When we look back at our lives, we mentally “travel” through our subjective experiences, which stream in our heads framed by the semantic memories of the factual context of those events. However, it is our unique experience and memories of the incidents in our past and present that shapes how we derive meaning and develop our idiosyncratic perspective of our narrative. We develop tastes, opinions, ideas, beliefs that are our own because of how our personal experiences change and inform us. Thus, our episodic memory is essential to our sense of identity as it is the ability that allows us to access the narratives of our lives and the important information about events that shaped us into who we are.
References:
Hofstra University, Hempstead, NY, United States. “Episodic Memory.” Encyclopedia of Neuroscience, edited by Georgia Institute of Te
chnology, Atlanta, GA, United States, Elsevier, 2009, pp. 1167–72, www.sciencedirect.com/science/article/pii/B9780128093245027966.
Mcleod, Saul. “Self Concept | Simply Psychology.” Simply Psychology, 2008, www.simplypsychology.org/self-concept.html.
Halber, Deborah. “The Curious Case of Patient H.M.” Brainfacts.Org, 28 Aug. 2018, www.brainfacts.org/in-the-lab/tools-and-techniques/2018/the-curious-case-of-patient-hm-082818.
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