Do beliefs add meaning to our lives? Do they create prejudice or conflict? Do they lead people to commit acts which are destructive to the self and others? How can they be defined and studied? Psychologists are tackling the subject of “belief” by relating this topic to advances that have been made over the last two decades in the understanding of memory systems, and by studying individuals with neurological injuries who develop strange beliefs.
According to Eichenbaum & Bodkin (2000) knowledge may be defined as information that is flexible and can be changed in the face of contradictory evidence, while belief is less amenable to change, and at its extreme is completely resistant to change. Delusions, for example, differ in terms of content and the perceptual abnormalities that are often associated with strange content, but resistance to change is their defining feature.
Davies and Coltheart (2000) have discussed the concept of “conservatism and observational adequacy” in belief revision. Basically, the idea is that we tend to reject ideas that are at odds with our belief system as a whole (conservatism); however refusing to alter one’s beliefs in the light of compelling new experiences (observational adequacy) is unwise. The acceptance of a strange or unusual belief (as in the acceptance of a delusion) would imply a failure of conservatism; and the refusal to alter that belief in the light of evidence which strongly opposes it represents a failure of observational adequacy.
What sort of neuroanatomical and neurochemical change would lead to the resistance of a semantic memory (a belief or delusion) to both integration with past knowledge and change in response to new information? Eichenbaum and Bodkin (2000) have suggested that hippocampal damage leads to inflexible learning. However, individuals suffering from strokes, particularly of the right hemisphere, sometimes develop strange, delusional beliefs about their bodies or their identities (Young, 2000), but these lesions do not always include hippocampal damage. Similarly, while there are neuroanatomical changes in schizophrenia (DeLisi et al., 1991), it is not clear how these relate to the formation and strict maintenance of delusions.
It may be that the interaction of emotional factors with the encoding and retrieval process has much to do with the formation of beliefs. In the medial temporal lobe, the amygdala lies in close proximity to the hippocampus and likely interacts to facilitate the production of memories or block access to memories in response to emotional factors. For example, while our identities may be viewed as a collection of facts about the self that are highly resistant to change, individuals in a dissociative state may “forget” their own identity.
Mishara (2009), in reviewing older concepts of psychiatrist Klaus Conrad (1905-1961), has pointed out that not only are the delusions of schizophrenia often experienced as emotionally satisfying, but they are also subjectively experienced as tying things together after an uncomfortable period in which perceptions are filled with strange and random meanings (in the period of “delusional mood”). Therefore, while we would expect delusions to result in feelings of cognitive dissonance, this does not appear to occur – disagreement between the delusion and the “learned regularities” of life (Frith, 1992) does not appear to create any cognitive conflict for the deluded individual. Contrary to expectation, the delusion may bring an increased sense of calm.
Perhaps the understanding of how memory becomes inflexible and resistant to change will be one of those discoveries that changes how humankind views itself.