We may think that our beliefs are based on solid facts and reason, but, in the words of George Gershwin’s old song, “It ain’t necessarily so.” The way our minds work actually limits our ability to discern the truth or make rational decisions. Psychologists have been studying the way we think for many years, and have identified several biases that cause this.
Prejudices and preconceptions
We all tend to pick and choose information that supports our prejudices and preconceptions while ignoring a heap of evidence to the contrary. Right or wrong, climate change deniers provide the most obvious example today, focusing on a tiny minority of expert opinion and brushing aside the overwhelming consensus of climate scientists. Similarly, most of us don’t listen carefully to politicians’ speeches or analyze their policies in detail. Instead we pick up the fragments of information that reinforce our party preference.
This “confirmation bias” even penetrates scientific thinking. For instance, the evidence for the reality of paranormal phenomena is far stronger than the evidence for the effectiveness of many pharmaceutical drugs. And yet most scientists reject out of hand any suggestion that psychic abilities are real because they don’t believe they’re possible. In less-dramatic ways, confirmation bias distorts our thinking and decisions about many aspects of life. Despite my high level of education and career as an academic, I frequently catch myself doing this.
The attraction effect
Another source of bias in our thinking is the “attraction effect.” Imagine you’re comparing smart phone options, and are drawn to the cheaper Basic contract rather than the more expensive Advanced one because it meets your needs adequately. Now suppose that you’ve been offered a third Luxury alternative that costs more but provides no more benefits than the Advanced contract. Research shows that the presence of this third option increases the probability that you’ll choose the Advanced contract. One possible explanation is that the Luxury option makes it easier to justify your choice by claiming you’ve got a bargain — perhaps our decisions are normally biased towards ones we can easily justify rather than what is best for us?
The framing effect
Three decades ago, a third type of bias was identified. The “framing effect” leads us to make choices depending on how the information is presented. In one classic experiment, people were asked to imagine an outbreak of disease threatening a village of 600 people. Plan A would definitely save 200 lives, whereas Plan B would have a 1 in 3 chance of saving An example of how bias affects rational thinking everyone, and a 2 in 3 chance of saving no one.