Lies, Damned Lies, and Statistics (39): Availability Bias

example of availability bias on a newspaper’s frontpage

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This is actually only about one type of availability bias: if a certain percentage of your friends are computer programmers or have red hair, you may conclude that the same percentage of a total population are computer programmers or have red hair. You’re not working with a random and representative sample – perhaps you like computer programmers or you are attracted to people with red hair – so you make do with the sample that you have, the one that is immediately available, and you extrapolate on the basis of that.

Most of the time you’re wrong to do so – as in the examples above. In some cases, however, it may be a useful shortcut that allows you to avoid the hard work of establishing a random and representative sample and gathering information from it. If you use a sample that’s not strictly random but also not biased by your own strong preferences such as friendship or attraction, it may give reasonably adequate information on the total population. If you have a reasonably large number of friends and if you couldn’t care less about their hair color, then it may be OK to use your friends as a proxy of a random sample and extrapolate the rates of each hair color to the total population.

The problem is the following: because the use of available samples is sometimes OK, we are perhaps fooled into thinking that they are OK even when they’re not. And then we come up with arguments like:

• Smoking can’t be all that bad. I know a lot of smokers who have lived long and healthy lives.
• It’s better to avoid groups of young black men at night, because I know a number of people who have been attacked by young black men (and I’ll forget that I’ll hardly ever hear of people not having been attacked).
• Cats must have a special ability to fall from great heights and survive, because I’ve seen a lot of press reports about such events (and I forget that I’ll rarely read a report about a cat falling and dying).
• Violent criminals should be locked up for life because I’m always reading newspaper articles about re-offenders (again, very unlikely that I’ll read anything about non-re-offenders).

As is clear from some of the examples above, availability bias can sometimes have consequences for human rights: it can foster racial bias, it can lead to “tough on crime” policies, etc.

More posts in this series are here.

The Causes of Human Rights Violations (36): Anchoring Effect

The anchoring effect is a psychological bias that leads us to rely too heavily on one piece of information – often even information that is totally irrelevant – when making decisions. Once the anchor is set, there is a bias toward adjusting or interpreting other information to reflect the “anchored” information. I can best explain this with an example. It’s well known that judges do not simply apply legal rules to the facts of a case in a purely rational or mechanical manner. In fact, the decisions of judges are influenced by political, social and psychological biases, one of those being the anchoring effect.

German judges with an average of more than fifteen years of experience on the bench first read a description of a woman who had been caught shoplifting, then rolled a pair of dice that were loaded so every roll resulted in either a 3 or a 9.  As soon as the dice came to a stop, the judges were asked whether they would sentence the woman to a term in prison greater or lesser, in months, than the number showing on the dice.  Finally, the judges were instructed to specify the exact prison sentence they would give to the shoplifter.  On average, those who had rolled a 9 said they would sentence her to 8 months; those who rolled a 3 said they would sentence here to 5 months; the anchoring effect was 50%. (source)

What does this have to do with human rights or with the causes of human rights violations? Well, if you replace the loaded dice in the quote above with the sentencing demands of prosecutors or even the demands of the “public”, you will not be surprised to find unfairness in sentencing:

The results of a recent study of ours (Englich & Mussweiler, 2001) indicate that accomplished trial judges with an average of more than 15 years of experience were influenced by sentencing demands, even if the demands were made by non-experts. In fact, the magnitude of this influence proved to be dramatic. Judges who considered a high demand of 34 months gave final sentences that were almost 8 months longer than judges who considered a low demand of 12 months. A difference of 8 months in prison for the identical crime. Notably, this influence occurred although both demands were explicitly made by a non-expert. (source)

Sentencing demands can be an effective “anchor” leading to violations of those human rights that require fairness in criminal trials. Skilled but ruthless prosecutors can use this in order to influence even experienced judges and to have them impose unfair sentences.

Obviously, the anchoring effect isn’t limited to criminal trials, and it’s not just the anchoring effect that can introduce a bias in judges’ rulings. I’m not sure if I already mentioned this incredible finding:

The percentage of judges’ rulings that are favorable to the accused drops gradually from about 65% to nearly zero within each decision session and returns abruptly to 65% after a break. This indicates that judges are swayed by things that shouldn’t have any bearing on their decisions.

I’m still looking for other examples of rights violations caused by the anchoring effect, but in the mean time I should mention that it must also be possible to use the effect to improve respect for human rights.

Something about the related topic of unconscious priming is here. More posts in this series about the causes of rights violations are here.

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Why Do We Need Human Rights? (25): Human Rights and the Endowment Effect

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Why do we say that people fighting for their rights are in fact fighting for the recognition of their rights? That people have rights even when the law doesn’t recognize these rights? That, in other words, people have moral rights that precede their legal rights? And that these moral rights can be used to evaluate and, if necessary, create their legal rights?

At first sight, such statements imply the dubious ontological claim that moral rules have an objective reality, independent of what people believe or do, and that these rules populate a parallel and invisible universe of morality. These days, we usually think that rights and rules are the products of human beings, rather than natural or God-given entities. On closer examination, however, denying that there are such independent rights creates a problem and ignores an opportunity.

• The problem: without independent moral rights, all we’re left with are the existing legal rights, which more often than not are insufficient or even complicit in human rights violations. In other words, we’re left with legalism and legal positivism, rather unattractive worldviews.
• The missed opportunity: without independent moral rights, we ignore the strategic advantages of the endowment effect: people are much more eager to fight when they believe they are fighting to keep what is theirs already, than when they fight in order to get what isn’t theirs already. Usually, the endowment effect is considered to be a cognitive bias (in economics, the value of something shouldn’t change just because you already have it), but in this context all means to make the fight for rights more successful are welcome.

Lies, Damned Lies, and Statistics (29): How (Not) to Frame Survey Questions, Ctd.

Following up from an older post on the importance of survey questions, here’s a nice example of the way in which small modifications in survey questions can radically change survey results:

(source, source, source)

Another example:

Our survey asked the following familiar question concerning the “right to die”: “When a person has a disease that cannot be cured and is living in severe pain, do you think doctors should or should not be allowed by law to assist the patient to commit suicide if the patient requests it?”

57 percent said “doctors should be allowed,” and 42 percent said “doctors should not be allowed.” As Joshua Green and Matthew Jarvis explore in their chapter in our book, the response patterns to euthanasia questions will often differ based on framing. Framing that refers to “severe pain” and “physicians” will often lead to higher support for ending the patient’s life, while including the word “suicide” will dramatically lower support. (source)

Similarly, seniors are willing to pay considerably more for “medications” than for “drugs” or “medicine” (source). Yet another example involves the use of “Wall Street”: there’s greater public support for banking reform when the issue is more specifically framed as regulating “Wall Street banks”.

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What’s the cause of this sensitivity? Difficult to tell. Cognitive bias probably has some effect, and the psychology of associations (“suicide” brings up images of blood and pain, whereas ”physicians” brings up images of control; similarly “homosexual” evokes sleazy bars, “gay” evokes art and design types). Maybe the willingness not to offend the person asking the question. Anyway, the conclusion is that pollsters should be very careful when framing questions. One tactic could be to use as many different words and synonyms as possible in order to avoid a bias created by one particular word.

More on DADT and homosexuals in the military. More on assisted suicide. More on lying with statistics.