Daydreaming in Humans and Machines: A Computer Model of the Stream of Thought

by Erik T. Mueller

The revised version of a UCLA doctoral dissertation in computer science. Mueller presents a theory of human daydreaming implemented as a computer program called DAYDREAMER. This program models the daydreaming (and to a lesser extent, the overt behavior) of a human in the domain of interpersonal relations and common everyday occurrences. Price to individuals, $32.50. Acidic paper. Annotation copyright Book News, Inc. Portland, Or.

Genres: Artificial Intelligence

Hardcover

First published June 28, 2012

Reviews

[Kevin K · Rating 4 out of 5]

This book describes a 1980s-vintage AI model of daydreaming. Unlike today's AI based on neural networks and deep learning, this model (called DAYDREAMER) explicitly "thinks" using rules written in a variant of English. It's an impractical approach for building large, powerful AIs, but a good way to theorize about daydreaming because it forces the theorist to be explicit about mechanisms.

Mueller presents a number of interesting hypotheses:

Emotions: Accounts of daydreams and nightdreams are rich in emotions of all kinds: frustration, lust, anger, surprise, embarassment, etc. So it's natural to wonder: What role do emotions play in dream-like mental processes? Mueller's hypothesis (derived in part from previous research) is very interesting: Humans must always juggle a profusion of competing goals, and emotions allow us to prioritize. We have to make snap decisions, without overthinking, and emotions handle that task perfectly (although, of course, reasoning may come into play in more important, long-range decisions). This theory has an interesting consequence. If Mueller's hypothesis is correct, it's actually quite easy to endow a machine with emotions. We just need a system for quickly prioritizing goals without thinking. In fact, we might take it a step further: Any machine which prioritizes at high-speed among multiple real-world goals must be quasi-emotional.

Planning: In Mueller's model, daydreaming is planning. Plans can be as simple as what you're going to say at a job interview, or as elaborate as the lurid revenge fantasies of murderers. Planning episodes are triggered by emotions, and employ strategies similar to defense mechanisms that Mueller calls "daydreaming goals." When faced with strong negative emotions (anger, frustration, grief, worry) brought on by a goal failure, DAYDREAMER mitigates the negative emotion via rationalization (e.g., blaming others), roving (shifting attention to a positive memory or fantasy), revenge (planning retaliation for the goal failure), reversal (imagining an alternate past or imaginary future with adjustments to prevent failure), recovery (thinking of ways to achieve a goal which failed in the past) , rehearsal (virtual practice to lessen the chance of failure in reality), or repercussions (examining the consequences of future situations).

The utility of daydreaming: Practical uses include: planning for the future (improving real-world success/efficiency by learning in the virtual environment of fantasy); drawing lessons from successes and failures; reinterpreting past events; enhancing creativity (relaxation of constraints, serendipity in recognition of connections/analogies, inspiration through fantasies of success); emotional regulation (controlling negative mood/emotion); boosting recall of important information; and staying entertained and alert in boring situations.

Use of downtime: The brain, like a computer, consumes a lot of energy (20% of bodily energy usage each day). It would be wasteful to expend that energy doing nothing. Daydreaming and nightdreaming allow the brain to contribute to survival, even when not solving problems immediately at hand.

Repetitive thoughts: I've often been baffled by repetitive thoughts. What does a person gain from repeatedly thinking the same thought? It's as though a computer were to read in information from a disk, parse the info, and store it in memory, and then keep repeating that same read-in operation over and over again. What purpose would that serve? Mueller sheds some light on this issue:

A striking example of the plan rehearsal aspect of daydreaming occurred in a case where a friend (F) of the second author was stung by a bee, whereupon F experienced a strong allergic reaction to the bee venom. F was rushed to the hospital and treated in time to avoid anaphylactic shock. F stated that, for an entire year after this experience, F would spontaneously daydream about being stung. These daydreams were not repetitions of the original event, but began by imagining being stung in various situations, e.g., by a pool, at the beach, while at a party, while biking, while alone at home, etc. Each daydream consisted of imagining what F would do in case F's bee sting kit was inaccessible, in case the phone was out of order, in case the car broke down, and so on. F claims now to have rehearsed plans for a large number of hypothetical circumstances, e.g., using ice from the refrigerator, knowing where a hospital is and driving at breakneck speed to a hospital before collapsing, etc. This case is rather dramatic because the original goal threat was to a very high-priority goal, i.e., a health preservation goal. The function of daydreaming in this case was to rehearse and examine plans in imagined situations. Clearly, daydreaming here provides an advantage over planning systems which only initiate planning when posed with the actual occurrence of a goal threat or goal failure. Preparation-based daydreams tend to be triggered by emotions of fear. Thus, generating this class of daydreams involves specifying a process model of what might be called "worrying" when observed in people.

Repeated thoughts can yield new information because each iteration occurs in a new context. You may be stumped by a problem when you daydream about it on Tuesday, but by Wednesday you have new, relevant information that allows you to solve it. (Mueller uses the term "serendipity" for these fortuitous connections between repeated thoughts and new contexts.) Infinite loops of obsessive thought might occur when a problem with strong emotional charge has no solution.

This is the best book I've read on the mechanics of dreaming (daydreaming + nightdreaming). It's clear and full of interesting ideas. Mueller's surveys of the literature on daydreaming and nightdreaming are useful. On the downside, around half of the book is devoted to antique programming details that aren't relevant anymore. Probably best skimmed or skipped by the contemporary reader.