Belief and bias

Are couples who adopt a child subsequently more likely to conceive than comparable couples who have also been trying to conceive but who do not adopt? The belief that they are is widespread.

Also widely-held is the idea that more effective admissions or employment decisions, for example, concerning an undergraduate institution, a graduate school, or a corporate training programme, etc., can be carried out in the case that each candidate is met in a brief, personal interview.

Furthermore, there has been a pervasive view that more babies are born in hospital maternity units or that there are more psychiatric ward admissions on a night when the moon is full.

As the reader may already suspect: though each of these beliefs is well-known and commonly-accepted none is true: people are mistaken about the claims. (see: “conventional wisdom”)

Can we attribute such errors to a lack of exposure to relevant evidence? Or might they be due to a certain carelessness to consider the evidence? Both laypeople and experienced professionals are stricken by such questionable beliefs. Not knowing about or failing to pay attention to the available evidence, generally speaking, is not what’s happening.

Are people simply stupid or gullible? Quite the reverse. We are equipped with formidable abilities to perceive, process information, and understand the world. Erroneous beliefs principally stem from a misapplication or overextension of such intellectual resources. So many lapses and missteps do not result from trying to satisfy important psychological needs, but rather have cognitive origins involving limitations in the human capacity to process information (bounded rationality) and to arrive at good conclusions, for example, see: heuristics. There are certain types of situations and circumstances in which we are particularly exposed, such as decision-making under conditions of uncertainty. When people reach faulty conclusions the determination nevertheless seems sensible and consistent with the evidence at hand. High-intelligence individuals are, like the rest of us, not immune from such mistakes. Rather than referring to this imperfect thinking as irrational, it is better seen as flawed rationality.

The strategies people apply to deal with the disordered ‘data’ of the real world don’t always “measure up”, for example, we exhibit a tendency to recognize order and regularity in chance events and random data sets. Actors often find difficulties coming to grips with incomplete and unrepresentative information while showing a distinct willingness to interpret ambiguous and mixed evidence in light of their preconceptions and expectations. Having adopted a belief, changing or rejecting it is usually not so readily accomplished. We frequently display an excellent facility for defending our beliefs, irrespective of whether or not they are accurate or true.

In addition to these cognitive biases other factors, motivational and social, play a role: for example, wishful thinking and self-serving biases such as social desirability bias, and overestimates such as the false consensus effect. Vividness and salience effects are also implicated.

When forming beliefs, generally the goal is to believe what is true. And so this should mean that people are looking to adopt beliefs which are compatible with the evidence available. When there is time to think carefully and clearly alternatives to and evidence against the beliefs being considered would also be sought. Acting in this way would be a good approach to counteract and contain biases towards favoured beliefs – a kind of rational belief formation. And in addition to increasing our chances of holding true beliefs, the approach suggests we will be more likely to have appropriate confidence allowing us to make better decisions.

Ever-present is the human mind’s capacity and appetite to engage in self-deception, which provides something of a complication. Sometimes the benefits of self-deception will outweigh the costs, but more often it will get in the way of effective thinking and action, and can be harmful. A patient having been ill who pleads with his or her doctor that “if it’s bad, don’t tell me” may not be completely reassured if the doctor then says that they have nothing to worry about.

Should we have a concern about “bad beliefs” and make a concerted effort to take a rational approach? This is for the reader to decide. What are the reader’s goals and epistemic† values?