How deliberate, spontaneous and unwanted memories emerge in a computational model of consciousness

Abstract

“And as soon as I had recognized the taste of the piece of madeleine soaked in her decoction of lime-blossom which my aunt used to give me ... immediately the old grey house upon the street, where her room was, rose up like a stage set to attach itself to the little pavilion opening on to the garden which had been built out behind it for my parents ...; and with the house the town, from morning to night and in all weathers, the Square where I used to be sent before lunch, the streets along which I used to run errands, the country roads we took when it was fine ...” ---Marcel Proust, Remembrance of Times Past () In these words the novelist Marcel Proust described a flood of unbidden memories evoked by the taste of what must be the most famous cookie in the world, Proust’s madeleine soaked in lime-blossom tea. It is of course an experience of spontaneous recall. Judging by numerous thought-monitoring studies, spontaneous recall is the norm in everyday thought. But because it is more difficult to study experimentally than deliberate recall, we know much less about it. In this chapter we describe how a current theory of conscious cognition, global workspace theory, leads naturally to a model of both deliberate and spontaneous recall. Deliberate recall is intended; spontaneous memories are not. They can be divided into two categories: 1. acceptable spontaneous recall (ASR), like Proust’s famous rush of memories evoked by the taste of the madeleine. Such memories are interesting or pleasant or at least tolerable; 2. unwanted spontaneous recall (USR), such as painful traumatic events, an annoying recurrent melody, or a the memory of an unresolved argument with a loved one. We therefore have three categories altogether, deliberate recall (DR), spontaneous recall that is acceptable (ASR) and unwanted spontaneous recall (USR). A large-scale computational model of global workspace theory called IDA has been developed by Franklin and co-authors (Franklin et al, 2005). IDA allows the detailed modeling of GW theory, together with other well-studied cognitive mechanisms, in challenging real-world tasks (Franklin et al, 1998; Franklin and Grasser 2001; Franklin 2001a; Ramamurthy et al, 2003, 2004; Franklin et al, 2005). This chapter will only focus on the question of consciousness and voluntary control as they apply to recall. Because IDA is able to simulate human functioning in at least one type of highly trained expertise, our approach here is to furnish a working proof of principle, showing that the basic computational mechanisms are adequate to generate human-like cognitive functioning in a real-world task. No added theoretical constructs are needed to show three kinds of recall we discuss here: deliberate, spontaneous and unwanted. They emerge directly from the original model. Unwanted memories are important in post-traumatic “flashbacks,” as reported in the clinical literature. While there is controversy about the accuracy of claimed memories, for example, there is little debate that repetitive thoughts and fragments of memories can occur. Wegner has been able to evoke unwanted words in an “ironic recall” paradigm, that is, an experimental method in which subjects are asked not to think of some category of ideas, such as white bears or pink elephants (1994). Unwanted memories can be annoying, or in the case of obsessional thinking, they may become disabling. In everyday life, one can simply ask people to bring to mind an intensely embarrassing personal memory, which can be quite uncomfortable. A number of clinical categories (the Axis I disorders) involve unwanted thoughts, feelings, actions, or memories. These conditions are at the more dysfunctional pole of unwanted mental events, and the study of unwanted memories may help provide some insight into them.