Friday, August 22, 2008

Exploration/ Exploitation == Maximisers/ Satisficers?

There is an interesting research coverage at We are Only Human blog regarding whether people may have two different cognitive styles- one based on exploration of novel ideas and the other based on exploitation or focus on a particular familiar idea. The study employs evolutionary concepts and theorizes that these different cognitive styles may be a reflection of the different foraging styles that might have been selected for and relevant in EEA.

Specifically, while foraging for food in a habitat where the food supply and resources are unpredictable , one is faced with a choice when one has discovered a food source: whether to exploit this food source (a jungle area having sparse edible leaves) or to move ahead in search of a potentially better food source (a jungle area having abundant edible and nutritious fruits) . Both strategies , that of exploring or exploiting can be advantageous and may have been selected for. It is also possible that humans can use either of the strategies based on the environment- (food source distribution) , but may be inclined towards one strategy or the other. The authors of the study surmised that both the strategies have been selected for and we have the potential to use either of the strategy. Moreover, the same foraging strategy we use or are primed of, would also be visible in the cognitive strategy we use.

They used an ingenious technique to prime the subjects with either of the foraging strategies (go read the excellent We are only human blog post) and found that humans were flexible in the use of the appropriate strategy, given the appropriate context, and that the foraging strategy primed the corresponding cognitive strategy. To boot, those primed with an exploratory foraging strategy would be more prone to using exploratory cognitive strategies when confronted with a cognitive task and vice versa. They also found systematic differences between individuals cognitive and foraging styles- some were more exploratory than the others.

This reminds me of the Maximizers/ Satisficers distinction in decision-making style that Barry Scwatrz has introduced and brought to public attention. Basically a Maximizer , when faced with a decision and choice, would go on computing the utility of different choices and try to choose the option that maximizes his utility and is the 'best'. A Satisficer, on the other hand would also explore options, but stop his exploration, when he finds an option that is 'good enough'. I wonder, if just like the exploratory/ Exploitative cognitive and foraging styles, this is just another dimension of the same underlying phenomenon- whether to explore more - or to exploit what is available. To take an example, for marriage, a satisficing strategy may work best - as told in "The Little Prince" one should stop searching for more flowers if one has already had the fortune of possessing a flower.


"People where you live," the little prince said, "grow five thousand roses in one garden... yet they don't find what they're looking for..."

"They don't find it," I answered.

"And yet what they're looking for could be found in a single rose, or a little water..."


An interesting experiment would be to see, if the foraging style, the cognitive style, and the decisions style are all correlated within individuals and if priming one can influence the outcome of the other style.

If so, could there be an underlying neural phenomenon , common to all?

Wray, the author of We are only human blog makes a bold conjecture and relates this to the finding that dopamine levels.

Exploratory and inattentive foraging—actual or abstract—appears linked to decreases in the brain chemical dopamine.


He even relates this to cognitive disorders like Autism and ADHD.

By analogy, in conditions where baseline dopamine is more, like in bipolar and psychosis, one may be more inclined to a more staisficing/ 'I'm feeling Lucky' strategy in which the very first option is acceptable. This may explain the 'jumping-to-conclusions' bias in schizophrenia/ psychosis.

To make things more explicit, though the leading dopamine theory in vogue now is of 'error-prediction' , a competing, and to me more reasonable, view of dopamine function is incentive salience i.e. what 'value'/ importance does the stimuli have for the person in question. The importance can be both positive and negative and thus we have found that dopamine is involved in both dread and desire. The dominant reward prediction theory faces many challenges, the least of which is response of dopamine neurons to novel events. A dopamine burst is also associated with 'novel' events and thus dopamine is somehow involved in/ triggered by Novelty. Baseline dopamine may constrain the dopamine surge felt on a novel event. Thus, in schizophrenia/ psychosis , with baseline dopamine high, a dopamine burst on novelty detection may be high enough so that it is meaningful and may not lead to more exploratory behavior. While in the disorders where baseline dopamine is low, one may require a more profound dopamine burst before the stimuli becoming meaningful and thus may go on seeking novel stimulus till one finds one 'big enough to trigger salience'.

We may extend the salience argument to other domains than incentive. If the chief function of dopamine is to mark salience, then it may also be instrumental in memory and attention. Only what is Salient gets attention, and only what is salient gets into Working Memory. Thus,a high dopamine level may predispose to treating almost everything as salient, leading to delusions of reference (everything is meaningfully related to self etc) etc. Working Memory may be taxed due to everything trying to get in- and thus poor WM in people with schizophrenia. Also, every trivial thing may grab attention- leading to poor sensory gating and conditions like lack of pre-pulse inhibition. On the flip side, while making sense of ones experience, one may accept the first possible explanation and do not search further - thus leading to persistence of delusions.

An opposite scenario would be when one keeps exploring the environment and nothing seems novel due to low dopamine levels. This would be the classical Autistic repetitive and stereotype behaviors. There would be sensory over stimulation, as nothing is salient and one needs to explore more and more. On the other hand, WM capabilities may be good/ savant like, as not every piece of information grabs attention. Everything should seem insignificant and the only way to arrive at decision / choose action would be via exhaustive enumeration and logical evaluations of all options. even after obvious explanations for phenomenon, one may keep looking for a better explanation. No wonder , as per my theory, more scientists would be autistic.

Perhaps, I am stretching things too far, but to me the dopamine connection to Salience/ Meaning/ Importance is sort of worth exploring and I will write more about that in future. For now, let us be willing to associate Salience not just with stimuli related to motivation, but also with stimuli relevant in sensation, perception,learning and memory. If so the common underlying mechanism responsible for differentiating us as a exploratory and expolitatory forager (food) may also be related to our different cognitive styles, our different decision-making styles and our different baseline dopamine levels.

Dopamine though is most strongly related to food and sex. I could even stretch this argument and say this may be related to r and K reproductive styles (note these styles are species specific, but I believe individuals in a specie may also vary on the reproductive strategy along this dimension). Thus, while explorers may have r type of reproductive style, the exploiters may have a K reproductive style.

At one extreme are r-strategies, emphasizing gamete production, mating behavior, and high reproductive rates, and at the other extreme are K-strategies, emphasizing high levels of parental care, resource acquisition, kin provisioning, and social complexity.


If K-strategy is what humans have chosen, maybe exploitation in all areas (cognitive, decision-making, foraging) is more relevant and in tune with our nature. Maybe that's why I'll always be on the side of Psychosis than Autism!! Though, to put things in perspective, maybe humans have evolved to use both strategies as the situations demands , and the best thing would be to use the strategy situation-specific and not lean towards either extremes.

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1 comment:

Ward said...

another good post. I have been exploring a similar idea. Really glad I found your blog.

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