Why do people fall for utter nonsense? Marketeers, psychics, con artists, politicians, quacks, pundits, mystics – the list seems endless of people who essentially make their living by lying through their teeth to everyone else. And it's not as if they are particularly crafty about it or that their lies are that sophisticated. There aren't even very sneaky about it. Most, if not all, of the ridiculous claims made by these people can easily be discounted by one or two relatively simple follow-up questions or straight forward logic. Why then are they still so successful at manipulating people? How can a group of our leaders go so far as to ridicule 'the reality-based community' (who prefer to make decisions in a somewhat logical manner) knowing full well that a majority won't know the difference or at least not care enough to be concerned? A corollary question is why people are immune to some of these cons but vulnerable to others? Why can one person see through the absurdity of an ancient mythology and still fall for the slight of hand of a psychic con artist? Since both are selling the same logic-free wares why accept one and reject the other? How do we compartmentalize logic in one arena and throw it away we read a fortune cookie? Why can our species articulate splendid methods of deductive and logical reasoning and yet rarely implement them in day to day practice.
Simple; humans make decisions using heuristic methods that are highly vulnerable to cognitive biases. A thorough assessment of our biases will take a number of installments but a discussion of 'Availability Heuristics' is a good place to start.
What are Heuristics and Availability Heuristics? Heuristics are “strategies using readily accessible, though loosely applicable, information to control problem-solving in human beings and machines” (Pearl, 1983) . They are remembered patterns that can be used to make educated guesses or invoke 'common sense' in decision-making. Availability heuristics are a form of well studied cognitive bias where greatest decision-making weight is applied to the most easily remembered pattern or heuristic rather than the most precise or accurate ones which may be less easily recalled. And that is a bit of a problem because heuristics are often generated through experiences that are colored by whatever circumstances surround the event which triggers them. Why is that such a problem? Because we incorporate coincident associations into these pearls of wisdom which will affect future decisions regardless of whether true causality exists or not. Causality (or true cause and effect linkage from one event to another) is not something that bothered our ancestors trying to avoid perils. Better for them was to recall vivid patterns of information that they 'associated' with perilous circumstances regardless of causality. The price of over calling peril was usually not that great, while the cost of under-triage could be death. This may explain our tendency to read much more into simple coincidences (to the great delight of con artists) than is warranted by reality. All this of course presupposes that our minds are an ad hoc collection of bits and pieces of re-purposed animal behaviors rather than unique souls endowed by a higher being. Holy texts may argue the latter but behavioral studies overwhelmingly support the former.
It is a fact that for every incidence of true causality, there are countless coincident events whose only real association is created, and subsequently faithfully defended in our minds. The human mind is loathe to tolerate uncertainty (another cognitive bias) and readily substitutes coincident events into heuristics and applies them with the same zeal whether they contain any fragments of cause and effect or not. As time goes on we stop trying to use the heuristic to predict future events and begin to search for situations which conform to the circumstances defined by the heuristic. This reinforces its power over our thoughts, whether real or imagined, but also destroys any true predictive value that might have been associated with it in the first place (yes, that last paragraph is essentially my personal definition of religion...). Such is the associative power of available heuristics that almost nothing can change their perceived power shy of death or significant personal cost.
How do Heuristics and Availability play out in real world examples? As it turns out nature provides numerous opportunities to study these phenomena. One of the wonderful examples of evolutionary convergence is mimicry – a species which evolves characteristics that confer survival advantage presumably through similarities to recognizably dangerous species. Theoretically these similarities confer at least some of their advantage through reduced predation. But for this to be the case at least 3 things must be true: 1) predators must depend upon heuristics in prey selection ; 2) these heuristics must be subject to availability bias; and 3) the mimic must have evolved these characteristics after the dangerous species being imitated. Let's defer the discussion of the third criteria for now.
The case of the coral snake and its presumptive mimic the scarlet king snake is a great example of heuristics and availability in action in nature. The coral snake is North America's cobra cousin possessing powerful neurotoxic venom and sporting a jaunty livery of yellow black and red bands. These distinctive bands alternate 'yellow, red, yellow, black, yellow red...' and so on. The scarlet king snake also has yellow, red and black bands but these occur in the pattern of 'yellow, black, red, black, yellow...'. In other words the venomous reptile's red bands touch only yellow bands and the harmless one's red bands only touch black ones. This mimicry is clearly only an approximation to the dangerous species. If you see each side by side the differences are easy to spot (preferably through glass ...). This has lead to the heuristic of 'yellow and red and you're dead', etc.
Here's where availability comes into play. Consider 4 possible heuristics regarding these snakes: 1) avoid snakes with alternating yellow, red and black bands where the black bands are bordered in yellow; 2) yellow and red and you're dead; 3) avoid yellow, red and black stripped snakes; or 4) avoid snakes. Number '4' is clearly the simplest to remember (and probably the people's choice...) so it benefits from 'availability'. For a species that routinely eats snakes, '3' would probably be the heuristic of choice and an explanation as to why the mimicry need not be that precise since animals in nature are unlikely to pull out a book on identifying features of prey. Yeah, you may pass on an occasional meal but you live to eat another day. Choices '1 or 2' would only be of interest to herpetologists or the occasional amorous king snake.
Remember that logical assessment and deliberate consideration of options is a very recent luxury enjoyed, as far as we can tell, only by technologically advanced humans. Most decisions in nature need to be rapid and decisive if one wishes to avoid being eaten or killed. Close is generally good enough in horse shoes, hand grenades and almost all decisions in nature. (As an aside it is interesting to hypothesize that the general human aversion to snakes might be a behavioral artifact inherited from our African ancestors who more routinely encountered nasty's like the cobra, puff adder, mamba, etc. as they traveled the African plains and a general serpent aversion heuristic might have been a good strategy. With no particular survival advantage associated with a love of snakes, this trait may well have persisted. Could this be the instinctive origin of Satan as a serpent?)
Doubt the significance of availability heuristics to cognition? Try to recall the pattern difference between the coral and king snakes. Which one(s) come immediately to mind? Availability heuristics are heavily leveraged in all of our intensive training programs. How many time have you heard military trainers talk about repetitive training so that recruits will 'act instinctively' in combat. The goal of these programs is to overcome existing availability heuristics (such as self-preservation) and replace them with military useful ones. (In heuristic terms 'cowardice' might be better termed either inadequate reprogramming of availability or reversion to primary heuristics under severe stress.) Everyone in government may not believe in evolution but they surely leverage its implications to accomplish their goals... Think of the GOP strategy of creating availability heuristics like, McCain = patriot and security, while Obama = socialist, terrorist, Muslim. The persistence of such are clear examples of the power and persistence of availability heuristics to decision-making including such important topics as national leadership. Marketeers may not study neurochemistry and human evolution but they put availability to work creating all those little ditties that clog our minds and create that brand loyalty that translates to a healthy corporate bottom line.
So why should any of this be of any interest beyond behavioral psychologists and a few geeks, such as myself, working in machine intelligence research? Nothing could be more important. We are facing modern problems and complex global decision environments with cognitive processes evolved to handle snap decisions in situations where the stakes were that of individual (or small cohort) survival. Our technological advantages over predators and many historical environmental dangers reduces the need for these snap decisions. But the cost is that these same technical advantages require the application of deliberate logic approaches in order to avoid more generalized and extensive species dangers created by these technologies and we don't have time to evolve them. If we are to survive we must understand how our genes guide our cognition and create societal memes to mitigate our limitations before we make a snap decision to destroy ourselves.