Alexa Kightlinger
“Sorry, I’ve got the memory of a goldfish” has been a common adage to express one’s extreme forgetfulness. It has been a longtime myth that goldfish only have a memory that lasts for approximately seven seconds. Since then, a plethora of studies have disproved this misconception. One of the most notable studies was conducted by Oxford researchers who trained goldfish to swim across a tank for a food reward while changing the starting position and strip pattern of the tank. Researchers concluded that goldfish used optic flow, the motion of objects in a scene caused by the observer moving, to aid in navigation and remember visual cues (Sibeaux et al., 2022). Many land-bound species are known to use optic flow, but goldfish process the information differently, instead relying on contrast changes to make it to their destination (Sibeaux et al., 2022). Many other researchers have also shown that goldfish are not the simple-minded creatures we once thought them to be (Davis & Agranoff, 1966 & Givon et al., 2023).
Goldfish aside, imagine how your life would be impacted if you were only capable of living within a seven-second window. That would not be living, merely surviving as you constantly place “catch-up” in regards to your own life. While memory exists on a spectrum of sorts, the function it provides us with is insurmountable.
Learning: Through the encoding of new memories when experiencing novel situations, we can store and retrieve information later to learn new information and skills.
Language and Communication: Memory helps us use the proper vocabulary, grammar, and syntax allowing for more effective communication.
Social Interaction: Remembering past interactions, faces, and names of others allows us to build and maintain relationships.
Problem Solving: Drawing on our past experiences or failures can help us approach issues from a new and different perspective.
These are just a few key skills one may lose when memory is impacted. There are several types of memory, all of which come together to help us perform everyday tasks. I’ve briefly summarized them below so that we can better understand how memory is far more complex than most people think.
Sensory: Short-term storage of sensory information gained from the five senses.
Echoic: Information from auditory senses.
Iconic: Information from visual senses.
Haptic: Information from touch.
Short-Term: Retains information for about 30 seconds.
Working: Deals with the storage, maintenance, and manipulation of information and is used in processes such as learning and reasoning.
Long-Term: Technically has no limit as to how long this memory can last.
Implicit (Non-Declarative): Memories that cannot be expressed in words.
Procedural: Involves memory for actions.
Explicit (Declarative): Memories that can be put into words.
Episodic: Memories of events; autobiographical.
Semantic: General facts and knowledge.
(Camina & Güell, 2017)
I’m sure by now it wouldn’t be surprising to know this is just a consolidated list of the general categories of memory. However, if I were to go into every single type we would be here quite a while. Losing any single one would certainly impact the way you went about your normal life. The idea that memory, an aspect so important and closely tied to one’s identity can be tampered with is certainly a frightening idea. Imagine experiencing a memory lapse more severe than simply forgetting to submit a homework assignment during a busy workweek or misplacing your keys for a few minutes. Now imagine losing, not just one type of memory, but almost every type of memory and being confined to only remembering life in a a seven to thirty second window.
That’s the life of Clive Wearing. A talented musician and brilliant scholar who became infected with herpes simplex encephalitis, causing damage to his medial temporal lobe (Cavaco et. al., 2014) as well as decimating his hippocampus (Suddendorf et. al., 2009). This damage resulted in him developing chronic forms of anterograde and retrograde amnesia. Despite this, his procedural memory remains intact as his ability to sight-read music and play the piano continues to remain strong (Cavaco et. al., 2014). While he can still at large communicate effectively and recognize his life, much of his life is lived in the present (Suddendorf et. al., 2009). Continually, Wearing is under the impression he has just woken up or recovered from being dead which his wife, Deborah Wearing, captures in her book, Forever Today. While his case is inherently unique, the damage he sustained to his hippocampus which resulted in episodic memory deficiency but a retention in semantic memory tracks with other cases and implies that these types of memories have distinct mechanisms, making them double dissociates (Suddendorf et. al., 2009). Damage to the bilateral hippocampus suggests that it plays a critical role in the retrieval of details used to aid in episodic memory which can play roles in both real and imaged scenarios (Suddendorf et. al., 2009).
Wearing’s case has been an important source of information for researchers studying the role the hippocampus plays in memory formation as well as showing the distinction between short and long term memory. Not only has it shined a light on a neuropsychological perspective, but also forces us to think about our own sense of identity and perception. Wearing is forced to experience every moment as if it is the first time he has experienced it. Not only has this been a challenge for him, but for his family and loved ones who he has forgotten. Those who have lost or are currently experiencing a loved one suffering from Alzheimer's or dementia can state first hand how daily life changes and the frustration that comes with it. And yet, despite these challenges, Clive Wearing still finds joy in music and connecting with his loved ones, even if the memory only lasts for seconds. His story should serve as a reminder to cherish and nurture the relationships between our loved ones.
References
Cavaco, S., Feinstein, J. S., van Twillert, H., & Tranel, D. (2014). Musical memory in a patient with severe anterograde amnesia. Journal of Clinical and Experimental Neuropsychology. 34(10), 1089-1100. https://doi.org/10.1080/13803395.2012.728568.
Davis, R. E. & Agranoff, B. W. (1966). Stages of memory formation in goldfish: evidence for an environmental trigger. Proceedings of the National Academy of Sciences of the United States of America 55(3), 555-559. https://doi.org/10.1073/pnas.55.3.555.
Givon, S., Altsuler-Nagar, R., Oring, N., Vinepinksy, E., & Segev, R. (2023). Lateral and medial telencephalic pallium lesions impair spatial memory in goldfish. Brain Research Bulletin, 204(1), 110802. https://doi.org/10.1016/j.brainresbull.2023.110802.
Sibeaux, A., Karlsson, C., Newport, C., & Burt de Perera, T. (2022). Distance estimation in the goldfish (Carassius auratus). Proceedings of the Royal Society B: Biological Sciences. 12:289. https://doi.org/10.1098/rspb.2022.1220.
Suddendorf T., Addis, D. R., & Corballis, M. C. (2009). Mental time travel and the shaping of the human mind. Philosophical Transactions of the Royal Society B 364, 1317-1324. https://doi.org/10.1098/rstb.2008.0301.
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