Sunday, August 4, 2019

Review: Thomas Gilovich's "How We Know What Isn't So: The Fallibility of Human Reason in Everyday Life"

Thomas Gilovich has been researching what he sums up as "human judgment" for nearly four decades. He is currently the Chair of the psychology department at Cornell University and has written four books, one of which I chose to read for this class, entitled "How We Know What Isn't So: The Fallibility of Human Reason in Everyday Life". In a nutshell, "How We Know What Isn't So" examines common cognitive errors and biases found in various human beliefs and understandings. The book does so by analyzing Gilovich's own extensive research in this field, and referencing research done in the same fields by his peers.

Gilovich breaks down the causes of the questionable beliefs that we've developed in the modern era into two major categories - cognitive determinants and motivational/social determinants. The cognitive determinants are related to the "Ways of Thinking" lecture from our class and revolve around things like misinterpreting data, finding patterns where none exist, and making poor decisions based on ambiguous information. We've seen several examples of this in our lectures covering psychic crime detectives and cold readings. The motivational and social determinants include generally self-serving beliefs - "believing what we want to believe" - and, moreover, believing what we think others will believe; the "false consensus effect".

What I found to be the most interesting part of the book, however, is when Gilovich pulled all of his research and reasoning together and explained some of the "questionable and erroneous beliefs" that are most commonplace today, and how they are potentially negatively affecting people and, perhaps, society as a whole. Gilovich touches on three major topics: belief in ineffective "alternative" health practices, belief in the effectiveness of questionable interpersonal strategies, and belief in ESP. What I found the most interesting and relevant, however, was his analysis of belief in ineffective health practices, and why the field of medicine and health is where the most harm is done to the human race as a result of erroneous beliefs. From "psychic surgeons" to faith healers to baseless healing rituals and unproven medications, humans continue to defy even the most basic logic by forsaking proven, scientifically researched medical treatments in favor of perceived positive outcomes and the anecdotal evidence of quasi-medical procedures and treatments.

Our very first lecture touched on a simple but major example of a pseudoscientific "medical device", the "Q-RAY bracelet" that "balances negative ions and positive ions" to improve wellness and performance. The entire sales pitch for this bracelet is based on vague descriptions, no clinical evidence, and the subjective, anecdotal response from actual users, who "cannot believe" how great they feel and call it "magic". Later in our lecture series, we learned about many of the tactics used by psychics and mediums that perform "cold readings", and as it turns out, nearly everything in the Q-RAY sales pitch fits the characteristics of a cold reading - vague claims, testimonial/opinion based statistics, and "shotgunning", or spreading the possible positive effects of the bracelet out so widely that no one can really determine if it is helpful or not. The bracelet supposedly "optimizes bio-energy" (though they don't even explain what "bio-energy" is), "promotes a more active, better lifestyle (with no explanation of what the general "better" even refers to), and "provides an overall sense of well-being". Could these "benefits" possibly be any more vague when one uses scientific thinking rather than fast thinking? Not surprisingly, clinical studies found that the bracelet had essentially the same effect as a other words, no effect whatsoever.

Though, as humans, we've come a long way from what would today be considered archaic, almost ridiculous medical practices like lobotomies and trephination (where doctors cut holes in the skull or sever parts of the brain to treat mental disorders), the anti-vaccination movement - based almost solely on fear mongering and erroneous conclusions - shows that we really haven't learned much when it comes to associating scientific evidence with perceived outcomes. Gilovich's book was published nearly 30 years ago, yet the "post hoc" fallacy (the Latin "Post hoc ergo propter hoc", "after this, therefore because of this") is as relevant as ever; an outcome is associated with a perceived treatment, so it must be because of that treatment. As Gilovich points out, almost any outcome can appear to support a treatment's effectiveness...or ineffectiveness, for that matter. Ironically, we again tie back to the "believing what we want to believe" hypothesis when it comes to why we, as humans, continue to make these cognitive errors in the first place. Three decades later, this fallacy has reared its ugly head again, and the very phenomenon that Gilovich researched and wrote about has brought about a major regression in modern medicine.

The causes of autism are not yet 100% understood, though researchers are making great strides in understanding both its causes and effects. Unfortunately, since medical science has not yet established a cause with certainty, many have speculated that vaccines have caused autism, and have made the irrational decision to not vaccinate their children. Those supporting the anti-vaccination movement have little to no science to base their decision on; the only studies that have purported to find a link between vaccinations and autism have been proven to be fraudulent. Nevertheless, "anti-vaxxers", as they are known, have remained steadfast to their convictions, claiming that vaccines can and have caused autism, despite no evidence supporting this fact; post hoc ergo propter hoc. What was thought to be an innocent, personal decision is now putting the lives of children at large in jeopardy. Diseases like measles - which was essentially eradicated in the United States as of 2000 - have returned and have infected thousands of children and killed many in this country alone. As one can clearly see, erroneous human reason can literally cost lives.

As Gilovich points out, "what is most important, then, is not dispelling particular erroneous beliefs (although there is surely some merit in that), but creating an understanding of how we form erroneous beliefs". If we understand how and why we form erroneous beliefs, and if we think more slowly - more scientifically - rather than relying solely on fast thinking and cognitive heuristics, we will undoubtedly be better off as individuals and, subsequently, better off as human beings. Think critically, employ all of the elements of thought, and have the courage and confidence to be a fair-minded thinker.

I've compiled a few relevant and interesting videos that supplement my report and complement Gilovich's book. I hope you find them as interesting as I did!

Tom Gilovich on why it's worth studying human judgment and decision making: 

Ethan Lindenberger, a vaccinated teenager who was unvaccinated as a child, explains the dangers of misinformation and how erroneous thinking can put lives at risk:

Tom Gilovich lecture covering many of the topics he researched and wrote about in his book: 


Cherry, K. (2019, June 17). How Heuristics Help You Make Quick Decisions or Biases. Retrieved from

Kahneman, D. (2012, June 15). Of 2 Minds: How Fast and Slow Thinking Shape Perception and Choice. Retrieved from

Post hoc ergo propter hoc. (2019, July 26). Retrieved from

The anti-vaccination movement. (2018, September 13). Retrieved from

Tom Gilovich. (n.d.). Retrieved from

No comments:

Post a Comment