The Halo Effect – A Pernicious Illusion of Knowability that Teachers Need to Understand


Home / The Halo Effect – A Pernicious Illusion of Knowability that Teachers Need to Understand

The Halo Effect suggests: She is beautiful, so she must also be clever. Image copyright Janet Cameron, used with permission.

Nassim Taleb, who introduced the notion of The Halo Effect in his book, The Black Swan, explains that we constantly deceive ourselves about the past.  We take on board sparse data – and then we assume that this is all there is, and there is nothing more.  We feel the need to make events coherent to simplify our world, so we construct our stories on such flimsy evidence.  Having created faulty and flawed past events in our minds, we come to believe that they are true.

So what effect does this have on adults in education?

The Halo Effect Starts with a Narrative Fallacy

The narrative fallacy, says Nobel Prizewinner, Daniel Kahneman, in his book Thinking Fast and Slow, “…describes how flawed stories from the past shape our view of the world and our expectations for the future.”  

These fallacies arise from a fundamental human need, and that is to make some sense of our lives. It is no wonder that, by the time we are adults, we are sometimes confused about our abilities and whether we can succeed in our chosen field of study. As Daniel Kahneman says, “Outcomes that are almost certain are underweighted relative to actual certainty. The expectation principle, by which values are weighted by their probability, is poor psychology.”

How We Seek Coherence in the World

The following properties appeal to our need for coherence in our confusing and frightening world.

  • The stories are concrete rather than abstract.
  • The event most focused on is the most challenging, or most impressive.
  • They ascribe little to matters of luck or chance.  Instead they focus on human qualities, for example, talent, intention, gullibility, stubbornness.
  • They focus of what happened, not on what actually failed to happen, in other words, they ignore non-events.

To summarise, it is the challenging, causal events that become the kernel of our stories. We perceive, in another person, one most prominent or remarkable characteristic or quality, and then we generalise it.  We attribute it to the personality of that person. This can become a trap for novice teachers, and, indeed, even experienced teachers, especially those teaching adults. Adults are already indoctrinated with false and often negative beliefs, and teachers need to be constantly aware and guard against hurried judgements.

Errors of Judgement

Andrew Coleman, in the Oxford Dictionary of Psychology, explains how a US psychologist, Edward Lee Thorndyke (1874-1949) coined the term “halo error” in 1920 to describe this phenomenon, which “…leads to an overvaluation of the personality as a whole.”

It is also sometimes termed “trait centrality” – and described by Polish born US psychologist Solomon E. Asch (1902-1996) as “…a tendency of certain personality traits to have an overwhelming effect in impression formation, even influencing the interpretation of other traits associated with the person being judged.”

Asch conducted a fascinating experiment. He picked a target person and described him in two different ways.  Firstly, he used the adjectives: intelligent, skilful, industrious, warm, determined, practical and cautious.  Then, again, he described the person as all of the above, except that he replaced the property “warm” with the property “cold.”

This particular trait contrast affected people’s impression of the target person.

“When the list of traits contained “warm,” 91% of judges guessed that the target person was also “generous,” compared with only 8% when the list contained “cold.” When the stimulus list included “warm,” the target person tended to be perceived as also being “happy, humorous, sociable and popular,” but when the stimulus list included “cold,” most judges thought the stimulus person would not have those traits but would be “persistent, serious and restrained.”

Andrew Coleman likens the phenomenon to that of Gestalt, a counselling technique in which “…the whole is more than the mere sum of its parts.”

Adult students often under-rate their own potential. Photo by Janet Cameron, with permission.

Adult students often under-rate their own potential. Photo by Janet Cameron, with permission.

Positive and Negative Aspects of the Halo Effect

Daniel Kahneman says that halos can be positive.  “If we think a baseball pitcher is handsome and athletic, for example, we are likely to rate him better at throwing the ball too.”  On the other hand, the effect can also be negative. “If we think a player is ugly, we will probably underrate his athletic ability.” 

We can be greatly unsettled by inconsistencies that go against the grain of our human feelings:  Kahneman quotes a disturbing example in his book:  He says, “Hitler loved dogs and little children,” is shocking no matter how many times you hear it, because any trace of kindness in someone so evil violates the expectations set up by the halo effect.”

The fact that bad people do good things, and good people do bad things, doesn’t gel with how we tend to view our world.

Luck and Non-Events

Daniel Kahneman uses, as an example, the stunning success of that superlative giant of technology, Google.  It started with two students in the computer science department at Stanford University. Now these men are among the richest people in the world.  What amazing role models!  However, while we might be happy for them and wish them well, are we deluding ourselves by assuming that their rise to power was inevitable and predestined, because of their particular modus operandi? 

Kahneman says, “A detailed history would specify the decisions of Google’s founders, but for our purposes it suffices to say that almost every choice they made had a good outcome. A more complete narrative would describe the actions of the firms that Google defeated. The hapless competitors would appear to be blind, slow and altogether inadequate in dealing with the threat that eventually overwhelmed them.”

These successes are the back-stories that students are likely to bring to a class or course, whether they are involved in the arts, business, technology or science. Role models can be inspirational, but for people with specific issues about their own abilities, they can also create unrealistic goals.  Caring, empathetic teachers can help adult students to focus on and value their own special skills.

Knowability?  Is it Real or Imagined?

There were, says Kahneman, a number of people who claimed, shortly after the 2008 financial crisis, that they knew it would happen.  Kahneman raises a strong objection to the word knew which he feels should be removed from our vocabulary when we are talking of major events.  He says, “Some people thought well in advance that there would be a crisis, but they did not know it. They now say they knew it because the crisis did, in fact, happen.”  This, says Kahneman, is “a misuse of an important concept.”

If something is known, then it is true, and it can be shown to be true.  There were, actually, many people who didn’t believe that the crisis was inevitable. In reality, it was not possible to know, beyond all doubt, that the crisis would happen and to claim that this,  “…implies that the world is more knowable than it is. It helps perpetuate a pernicious illusion.”

Semantics, Knowability, and Understanding Affect Learning

We need to clean up our language, says Kahneman.  For example, sentences such as the following sound odd:  “I had a premonition that the marriage would not last, but I was wrong.” 

We understand far less about the past than we think we do!  Therefore, we also know less about each other than we think we do, and remembering that can help us defer judgement and assist others in achieving their potential.

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