Motivation and emotion/Book/2019/Episodic memory and planning

Episodic memory and planning:
What role does episodic memory play in planning?

Overview

Memory is an important tool that most living things use to survive. We, as human beings, have an extraordinary ability to use memory to consciously recall fine details from past events and to use them to approach and plan out future tasks.

Episodic memory is the aspect of memory that allows us to attach emotions and feeling to memories, and it also plays a crucial role in planning for the future.

This chapter will discuss the development of episodic memory, particularly the contributions made by the concept's founder, Endel Tulving, as well as discussing other branches of memory and emphasising what sets episodic memory apart from them.

Then we look at the role of the hippocampus and the impact that damage to the hippocampus can have on memory, before finally having an in-depth look at how exactly episodic memory works into our process of planning.

Focus questions

What is Episodic Memory?
What contributes to Episodic Memory?
How does Episodic Memory affect Planning?

How was episodic memory originally developed?

Signs of episodic memory have been seen in children as young as three, however the ability of an infant to retain such a large amount of new information is not feasible, although as we age and our capacity to absorb and retain information improves, so to does our ability to utilise the tool that is episodic memory in day to day operation, as well as for planning ahead. (Scarf, D., Gross, J., Colombo, M., Hayne, H., 2011). Understanding how episodic memory works and furthering our understanding of its relation to planning allows us the opportunity to the concept of episodic memory is a relatively new idea, not only within the scope of psychology as whole but even just within the study of memory, the modern beginning of which started with experiments conducted by Wundt in 1879 and built upon by Herman Ebbinghaus in 1885.

Endel Tulving

Endel Tulving is a Canadian psychologist, most well known, among other things, as being the original developer of the concept of episodic memory. He believed it was a memory system that specialised in storing idiosyncratic experiences. This concept helped in being able to measure learning and memory performance. (Pause, et al., 2013). His most notable work is that of a 1972 paper he wrote, in which he discussed the evidence suggesting that explicit memory (declarative memory) can be split into two sub-categories; semantic and episodic. (Tulving, 1972). His studies into the area of episodic memory are still be undertaken today and his past works are well-regarded amongst his peers as being highly reliable and relevant to modern studies.

Empirical evidence

Figure 1. Different forms of memory utilise different parts of the brain.

Proof of Endel Tulving's hypothesis became apparent during studies of a patient suffering from amnesia as a result of brain damage. This patient was left unable to recall personal feelings in relation to past events, as well as being unable to confidently predict his own reactions to past and future events. Despite this lapse in memory, the patient had no discernible issues answering questions relating to objective factors across a broad variety of topics, from both recent and long term periods of time (Klein,et al., 2002). This study suggests that the content of an event is is split into multiple categories when being stored in long-term memory, and that these forms of memory can be utilised independent of one another (see Figure 1).

What types of memory are there?

Just as there are different types of muscles, in the body, each with their own unique function, so too are there different forms of memory stored within our brains. Memory as a whole can be divided into two categories; explicit and implicit.

Explicit memory (which incorporates semantic and episodic memory) describes memories that can be consciously recalled, typically detailing physical events such as the time, location and weather in which an event occurred.

Implicit memory, which will not be further discussed in this chapter, defines memories that are generally subconscious, such as muscle memory, eating, walking, and be able to complete tasks without consciously focusing on them.

Semantic memory

Figure 2. Various parts of the brain used in memory formation

The main difference between semantic and episodic memory is not the detail of the retained memories so much as the personal interpretation of them. This is because semantic memory is used to define a person's basic knowledge of the world, this could be society's rules, as well as facts or any other knowledge that does not invoke any significant personal connection to the individual.

In lay terms semantic memory incorporates solely the objective aspect of an event, such as the temperature of a room in which an event took place, the music playing in the back ground, the colour of the walls and the words spoken. It is an evolutionary tool which animals have passively used for millions of years to remember locations and distinguishing features of places and other animals climates and other basic information which is key to survival. Human beings use this once purely survival tool to now develop and refine processes, allowing us to evolve further as a species faster than less cognitive beings. Just as semantic memory is the 'yin' of explicit memory, episodic memory is the 'yang'. Semantic memory provides us with a broad understanding of concepts, facts, and principles that are not tied to specific events. This knowledge can influence our planning by providing a foundation of general information upon which we can build our plans.

Episodic memory

Episodic memory is the other half of explicit memory which covers the more emotional aspects of memories. It is entirely about the personal experience, and how events are stored and recalled in different ways by people. (Yassa & Reagh, 2013)

For example, if you and your friends went on a trip together to the coast, where semantic memory would be used to recall what car you drove down in and what town you stayed in, episodic memory would recall how you felt seeing the beach, which friends you got closer with and which ones started to annoy you.

As an evolutionary tool, episodic memory contributes to the conscious part of our decision-making and problem-solving abilities. In modern times episodic memory is often used during moments of empathy and nostalgia.

Evidence that episodic memory is a useful skill which humans have evolved to naturally learn to use can be seen in conclusions made by Russel, Alexis & Clayton (2010) in a study focused on children aged three to five. This study has these children performing planning tasks and found that three year old children possessed very few planning skills, while five year old children had mostly all developed planning skills for themselves and others, and the four year old children seemed to cover the widest range of development, indicating that four years old is the stage where episodic memory starts to become more accessible part of a person's mind.

How does episodic memory work?

When it comes to the discussion of where in the brain episodic memory most frequently occurs, there is is a large debate. Despite the hippocampus generally being conceived as the location of memory storage, several studies provide contradictory findings. While Aggleton and Brown (1999) found that episodic memory tasks primarily utilised the temporal lobe (inclusive of the hippocampus) and their findings were corroborated by Simons, Graham and Hodges in 2002, Wiggs, Weisberg and Martin (1998) found that use of episodic memory highlighted regions of the temporal lobe and did not make us of the medial temporal lobe in any of their tests. Despite several studies finding discrepancies in how different memory tasks use different areas of the brain, a significant amount conclude that activity surrounding episodic memory takes place in the medial temporal lobe, primarily within the hippocampus itself.

The hippocampus and implications

The Hippocampus plays a major role in the storage and recollection of all memories, including episodic memories. The hippocampus is a part of the brain, specifically a small portion of the medial temporal lobe (see Figure 2). It's primary function is to collect information about an occurrence in order to store it in long term memory (Tulving & Markowitsch, 1998).

When an impairment has occurred that affects a person's episodic memory, they will tend to struggle with recalling details from long-term memories.

This will often be seen when a patient has a neurodegenerative disease such as Alzheimer's disease, Parkinson's Disease, schizophrenia, or even major depressive disorder (Pause, et al., 2013).

Other impairments can be caused by physical trauma to the skull, specifically in cases where an impact to the medial temporal lobe has occurred, in which case a noticeable decrease in the effectiveness of episodic memory can be observed,. This can be viewed as both a psychological and behavioral condition.(Pause, et al, 2013)

How does episodic memory relate to planning?

As episodic memory incorporates long term memories, as well as the emotions associated with them, it follows that episodic memory and planning are closely linked.

The relationship between episodic memory and planning is known as the episodic cognitive system (Shackleford, et al, 2012). Episodic Cognition refers to a person's ability to recall information from 'episodes' or events in the past, inclusive of long term and short term.

This ability allows us to use our past experiences to adapt to changing circumstances in the present , as well as allowing us to prepare, or 'plan' for events in the future.

Future-planning can refer to progressive, conservative and preventative measures that we take in order to improve our own well-being within the scope of our abilities.

Although results are thus far inconclusive, Raby & Clayton (2013) provide a strong basis for the hypothesis that the process which allows us to future-plan stems from the basic instincts of animals to adapt to changing circumstances.

Quiz

Conclusion

Episodic Memory is a concept first developed by Endel Tulving in 1972, as a sub-category of declarative memory, complementary to semantic memory.

Episodic memory is used when an event takes place in order to recall how we felt throughout. Semantic memory, on the other hand, is used to to store objective data about events which aren't associated with the personal experience.

Episodic memory is primarily controlled by the hippocampus. The hippocampus is an organ within the medial temporal lobe of the brain.

A person's ability to utilise episodic memory, especially with regards to planning, increases with age.

Damage to the hippocampus will have an effect on recall ability and memory.

The relationship between episodic memory and planning is the episodic cognition system.

Although current studies are not conclusive and more work is needed before definitive conclusions are drawn, there is substantial evidence in support of the belief that personal experiences held as a result of episodic memory play a crucial role in future planning.

References

Aggleton, J. P., & Brown, M. W. (1999). Episodic Memory, Amnesia, and the Hippocampal–Anterior Thalamic Axis. "Behavioral and Brain Sciences" , 22(3), 425-444.

Klein, S. B., Loftus, J., & Kihlstrom, J. F. (2002). Memory and Temporal Experience: The Effects of Episodic Memory Loss on an Amnesic Patient's Ability to Remember the Past and Imagine the Future. Social Cognition, 20(5), 353-379. doi: 10.1521/soco.20.5.353.21125

Pause, B.M Zlomuzica, A., Mariani, J., Pietrowsky, R., Dere, E., (2013), Perspectives on Episodic-like and Episodic Memory, Frontiers in Behavioral Neuroscience https://doi.org/10.3389/fnbeh.2013.00033

Raby, C. R., & Clayton, N. S. (2012). 12 Episodic Memory and Planning. The Oxford Handbook of Comparative Evolutionary Psychology, 217.

Russell, J., Alexis, D., & Clayton, N. (2010). Episodic Future Thinking in 3-to 5-Year-Old Children: The Ability to Think of What Will be Needed from a Different Point of View. Cognition, 114(1), 56-71.

Scarf, D., Gross, J., Colombo, M., Hayne, H., (2011) To have and to hold: Episodic memory in 3‐ and 4‐year‐old children, Wiley Online Library, https://doi.org/10.1002/dev.21004</nowiki>

Shackelford, T., Vonk, J., Raby, C., & Clayton, N. (2012-02-13). Episodic Memory and Planning. The Oxford Handbook of Comparative Evolutionary Psychology. : Oxford University Press. Retrieved 1 Sep. 2019, from https://www.oxfordhandbooks.com/view/10.1093/oxfordhb/9780199738182.001.0001/oxfordhb-9780199738182-e-12.

Simons, J. S., Graham, K. S., & Hodges, J. R. (2002). Perceptual and Semantic Contributions to Episodic Memory: Evidence from Semantic Dementia and Alzheimer's Disease. Journal of Memory and Language, 47(2), 197-213.

Tulving, E. (1972). Episodic and Semantic Memory. In E. Tulving, & W. Donaldson, Organization of Memory (pp. 381-4502). New York: Academic Press.

Tulving, E., & Markowitsch, H. J. (1998). Episodic and Declarative Memory: Role of the Hippocampus. Hippocampus, 28, 198-204. Doi: 10.1002/(SICI)1098-1063(1998)8:3<198::AID-HIPO2>3.0.CO;2-G

Wiggs, C. L., Weisberg, J., & Martin, A. (1998). Neural Correlates of Semantic and Episodic Memory Retrieval. Neuropsychologia, 37(1), 103-118.

Yassa, M., A Reagh, Z., M, (2013) Competitive Trace Theory: a Role for the Hippocampus in Contextual Interference During Retrieval, Frontiers in Behavioural Neuroscience, https://doi.org/10.3389/fnbeh.2013.00107

External links

Episodic Memory (12 minute youtube.com video)
The hippocampus and episodic memory (7 minute youtube.com video)
Information Processing Model: Sensory, working, and long-term memory (7 minute khanacademy.com video)