Narrative 4: Narrative & The Brain

Posted by PH on April 25, 2008
Narrative

I am currently doing a PhD entitled Narrative Structures In e-Learning. I’m doing it part-time and am about half-way through: that is, 3 years into a 6 year project.

Whilst doing my literature search I became fascinated with the ubiquity of narrative—this amazing facility all humans have to tell stories in various ways—and I spent more than two years researching this problem, writing it up, and then going back over it all again. Eventually it all came together in a paper that will be published later this year in Interactive Learning Environments. What follows is an extract from that paper.

The Origin of Narrative in the Brain
The ability to narrate is generally considered to be available to all human beings regardless of gender, race, colour, or cultural milieu (Barthes 1967), and Bruner has suggested that we have a “predisposition” for narrative (Bruner 2002, p.33). These observations suggest that there is something built-in, something hardwired, that allows for this ubiquity. Reviewing recent research in the fields of cognitive psychology and neurobiology this section is an attempt to offer some explanation for the universal human facility for what we call ‘narrative’.

Our ability to narrate depends entirely upon our having some way of encoding and retrieving time-sensitive memories. These are usually called our episodic memories, that is, memories that include “the detailed sequence of events that constitute an experience and the spatial and temporal context in which the sequence occurred” (Eichenbaum 2003, p.236). Although little is known about our memory systems with absolute certainty, many researchers implicate that part of our Limbic systems called the hippocampus as being instrumental in the encoding and retrieval of episodic memories (Burgess et al 2002; Eichenbaum 2003, 2004; Xu et al 2005). It would seem that the hippocampus was originally specialized for encoding spatial relationships, but in humans the left side has evolved to encode time-based experiences.


Figure 1: The Hippocampus & The Brain

However, having this ability on its own would not necessarily be responsible for the creation of a narrative facility. For this type of higher-order cognitive skill we need to look to certain parts of cerebral cortex, namely the frontal lobes. These are responsible for what are often called the brain’s ‘executive functions’ and are particularly related to language production, decision-making, problem-solving, and socialization.

Wheeler, Stuss, and Tulving (1997) have identified a particular function of the frontal lobes that they explicitly relate to episodic memory, called autonoetic consciousness. This is defined as “…the capacity that allows adult humans to mentally represent and to become aware of their protracted existence across time” (Wheeler et el 1997, p.335). Autonoetic consciousness allows us not only to look back into our past and monitor our present state, it also allows us to project ourselves into the future: “We consider this the most highly evolved form of consciousness […] which provides a fluid link from the individual’s past, through the present, to the future, and back again” (ibid).

Given that we have this relatively primitive organ (the hippocampus) that is actually doing the work of encoding episodic memories, and given that we have developed a time-aware consciousness in our frontal lobes that is exploiting these episodic memories in complex ways, it seems inevitable that a representational form—that is, a means for expressing these experiences both internally and externally—must evolve as well. On this evidence, then, it would seem that what we call ‘narrative’ is an emergent property of the interaction between the hippocampus and the frontal lobes.

Narrative and Memory
Having established a basic description of brain anatomy that offers a mechanism and evolutionary imperative for narrative, I would now like to look in some depth at the human memory system, with the aim of showing how fundamental narrative is to human comprehension.

Our declarative memory is memory for things, events, and experiences that we are able to consciously access and articulate (e.g. Squire 2004, p.173; Baddeley 1999, p.19). This declarative memory is usually considered to be made up of two closely interrelated sub-systems, episodic and semantic memory. Episodic memory, as we have seen, is “memory for personally experienced events set in a spatio-temporal context” (Burgess et al 2002, p.625), whereas semantic memory is concerned only with the storage of ‘facts’ and other knowledge about the world. How these two relate to each other and how they interact—if in fact they are discrete systems at all—bears directly upon our discussion.

Firstly, although there is a good deal of experimental evidence to suggest that episodic and semantic memories are distinct systems, it has to be pointed out that we have no conscious knowledge of them as being discrete, or ability to control them individually. Secondly, although there is a significant body of research implicating the hippocampus in the encoding of episodic memory—as we have discussed—there is no known mechanism for the separate encoding of semantic memory: all memory encoding is mediated by the hippocampus (Eichenbaum 2004, p.109). This suggests that the episodic and semantic memory systems may be different aspects of one larger and more complex system. Eichenbaum (2003, 2004) has developed a model of hippocampal memory encoding that includes and explains both episodic and semantic memory, whilst also allowing for phenomena such as the inferral of new information from existing memories and contextualization.

As we discussed earlier, our perception of the world is as a linear series of experiences: we move through time, gathering sensory input. These experiences will be encoded in episodic memory by the hippocampus. However, an episodic memory of a particular event can be broken down into a series of associative representations that include the people involved, the environment in which it occurred, and the actions that took place. What’s more, these actions are sequentially organized, that is, they occurred in a particular order at this particular event. And because we may have met some of these people before, or been in this environment before, and performed similar actions before, this particular episodic memory may have many features in common with existing episodic memories: this allows the formation of relational networks (Eichenbaum 2004).


Figure 2: After Eichenbaum 2003, 2004

Figure 2 is a schematic diagram of what Eichenbaum calls a “simple memory space” (Eichenbaum 2003, p.236). It shows two episodic memory sequences and the associative representations that make them up. We can see that the two memory sequences have certain elements in common at positions 3 and 4 that could begin to form the basis of a relational network. It may be that activity in the Episode 1 sequence may trigger recall of the Episode 2 sequence. Also, from this commonality certain inferences could be made about the indirect relationship between elements 1 and 2 in Episode 1, and elements 5’ and 6’ in Episode 2, or between elements 1’ and 2’ in Episode 2, and elements 5 and 6 in Episode 1.

In this model semantic knowledge is not a distinct memory system, it is abstracted from the links in the episodic memory sequences: the commonalities between them become established as ‘general knowledge’. However, because this common knowledge remains embedded within those episodic memories—it remains situated within its original context—it can be used to make inferences about novel experiences, about information that is not explicitly related, or things that have not been experienced directly. Consequently, these simple relational networks can be seen as the basic building blocks of human learning, planning, simulation, and creativity.

Support for this conception of our memory system and the structural networks that underlie it can be found elsewhere in the Cognitive Psychology literature: as long ago as 1932 Bartlett used the general term schemas to describe memories that had been grouped, categorized, and stored as structures and used to rationalize new experiences. More recently researchers have identified schemas that relate to particular types of knowledge:

  • Frames are “knowledge structures relating to some aspect of the world (e.g. a building) containing fixed structural information” (Eysenck & Keane 2005, pp.383-384).
  • A script is a “predetermined causal chain of conceptualizations that describe the normal sequence of things in a familiar situation” (Schank 1975, p.117), the prototypical example of which is his ‘restaurant’ script (ibid).
  • The story schema, which is the “idealized internal representation of the typical parts of a typical story and the relationship between those parts” (Mandler & Johnson 1977, p.111).

These schemas are learnt. They are generalizations about environments, sequences of events, and stories, that over time and through constant exposure have established themselves as stable, yet dynamic, structural elements in declarative memory: in Eichenbaum’s terms, they are relational networks.

Their use offers several distinct advantages. Dijk (1980) suggests that they aid memorization in three ways. Firstly, they allow global organization and the imposition of coherence on the raw data: “Without this kind of global organization in memory, retrieval and hence use of complex information would be unthinkable” (ibid, p.14). Secondly, it allows for a reduction in the amount of data that needs to be remembered: this increases efficiency. Thirdly, the process of actually deriving a schema from the mass of raw data “may involve the construction of new meaning (i.e., meaning that is not a property of the individual constitutive parts)” (ibid, p.15. Italics in the original). These mechanisms are largely unconscious, although we may be able to consciously exploit them, e.g. ‘chunking’ information to aid memorization (Miller 1956).

Whether we call them schemas or relational networks, we should recognize that our memories are largely made up of knowledge structures that create expectation about experience and that aid comprehension. Making meaning can therefore be seen as a negotiation between these existing structures and new experience: this is of course exactly what constructivist theory proposes.

Conclusion
This discussion strongly implicates narrative as one of the most important mechanisms we possess for comprehension and for making meaning. Firstly, because there is a considerable body of evidence to suggest that our entire declarative memory system is time-dependent, and secondly because the three schematization strategies we have discussed here all strongly relate to narrative construction.

References
Baddeley, A.D. (1999) Essentials of Human Memory. Hove, New York: Psychology Press.
Barthes, R. (1977) Introduction to the Structural Analysis of Narratives, in Image-Music-Text. London: Fontana.
Bruner, J. (2002) Making Stories: Law, Literature, Life. New York: Farrar, Straus and Giroux.
Burgess, N., Maguire, E.A. & O’Keefe, J. (2002) The Human Hippocampus and Spatial and Episodic Memory, in Neuron, 35, 625-641.
Dijk, T. A. van (1980) Macrostructures. New Jersey: Lawrence Erlbaum Associates.
Eichenbaum, H. (2003) The hippocampus, episodic memory, declarative memory…where does it all come together? In Ono, T., Matsumoto, G., Llinas, R.R., Berthoz, A., Norgren, R., Nishijo, H., & Tamura, R. (Eds) Cognition and Emotion in the Brain. Elsevier Health Science.
Eichenbaum, H. (2004) Hippocampus: Cognitive Processes and Neural Representations that Underlie Declarative Memory. In Neuron, 44, 109-120.
Eysenck, M.W. & Keane, M.T. (2005) Cognitive Psychology. Hove, New York: Psychology Press.
Mandler, J.M. & Johnson, N.S (1977) Remembrance of Things Parsed: Story Structures and Recall, in Cognitive Psychology, 9, 111-151. From: http://www.sciencedirect.com/ [Accessed 2.3.07]
Miller, G. A. (1956) The Magical Number Seven, Plus or Minus Two, in The Psychological Review, 1956 (63), 81-97.
Schank, R. (1975) Using Knowledge to Understand, in Proceedings of the 1975 Workshop on Theoretical Issues in Natural Language Processing. From: http://portal.acm.org/ [Accessed 24.1.06]
Squire, L.R. (2004) Memory Systems of the Brain: A Brief History and Current Perspective, in Neurobiology of Learning and Memory, 82, 171-177. From: www.sciencedirect.com [Accessed 4.1.06]
Wheeler, M.A., Stuss, D.T. & Tulving, E. (1997) Toward a Theory of Episodic Memory: The Frontal Lobes and Autonoetic Consciousness, in Psychological Bulletin, 121, 3, 331-354.
Xu, J., Kemeny, S., Park, G., Frattali, C., & Braun, A. (2005) Language in context: emergent features of word, sentence, and narrative comprehension, in NeuroImage, 25, 1002-1015. From: www.sciencedirect.com [Accessed 7.9.06]

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