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Barbara Drescher

Barbara Drescher taught quantitative and cognitive psychology, primarily at California State University, Northridge for a decade. Barbara was a National Science Foundation Fellow and a Phi Kappa Phi Scholar. Her research has been recognized with several awards and the findings discussed in Psychology Today. More recently, Barbara developed educational materials for the James Randi Educational Foundation. Read Barbara’s full bio or her other posts on this blog.

Is It Irrational to Play the Lottery?

Posted on Jan. 12, 2016 by | Comments (55)

With the recent Powerball mania I thought it would be a good time to talk about how to tell a sucker bet from a fair bet, and whether playing the lottery is a rational behavior.

Whenever the lottery comes up, people tend to discuss the astronomical odds of winning, holding it up as the best reason to avoid buying a ticket. However, it is not simply the odds of winning that determines if a bet is rational, at least the way psychologists define the term. A rational bet is a fair bet, and what determines if a bet is fair is something called the expected return.

An expected return is the payoff that one expects to receive—the amount, in proportion to the bet, that one expects to gain. A fair bet is one in which the expected return, in the long run, is zero. In other words, one expects to break even. If you expect to do better than break even, you are at an advantage. The odds of winning are part of expected return, but the payout-to-bet ratio is equally important in determining advantage.

CONTINUE READING THIS POST…

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Resolving Conflicts in Findings: Vaccine Promotion is Tricky

Posted on Aug. 26, 2015 by | Comments (9)

A few months ago I wrote about the psychology of vaccine denial. In the post I discussed two publications, one of which (Nyhan, et al.) found:

Corrective information reduced misperceptions about the vaccine/autism link but nonetheless decreased intent to vaccinate among parents who had the least favorable attitudes toward vaccines. Moreover, images of children who have MMR and a narrative about a child who had measles actually increased beliefs in serious vaccine side effects.

None of the interventions increased parents’ intent to vaccinate.

Then, a couple of weeks ago, a friend sent me a link to this piece describing research which seems to contradict that finding. The authors (Horne, et al.) concluded that

…highlighting factual information about the dangers of communicable diseases can positively impact people’s attitudes to vaccination.

These two conclusions seem to contradict each other. Which should we believe?

CONTINUE READING THIS POST…

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Why Smart Doesn’t Guarantee Rational, Part III

Posted on Jul. 09, 2015 by | Comments (21)
This is the third post in a three-part series. Read the previous two installments, “Why Smart People Are Not Always Rational” and “More On Why Smart People Are Not Always Rational.”

This post is the third and final in a series I began more than a year ago. The first post discussed how rationality differs from intelligence, how both may be measured, and what may keep intelligent people from behaving rationally. The second describes three of the four broad categories of factors involved in rational thinking while taking a closer look at how one thinking disposition, the need for cognition, affects decision-making and problem solving. I highly recommend reading the first two posts before continuing with this one as the background is important.

In summary, we tend to the think that people are irrational because they lack intelligence or knowledge. Both may contribute to rationality. However, intelligence and education are no guarantees of rationality because other factors such as cognitive laziness and open/closed-mindedness are just as, if not more, important. In other words, human beings tend to be irrational out of stupidity or ignorance, but also out of laziness or arrogance.

The scientific process addresses each of these factors to ensure that the answers we find are as accurate as possible. Although the scientific method itself is inherently intelligent, a good researcher must have a minimum level of intelligence in order to succeed as good research rises above bad through the process of peer review. Scientists conduct very thorough reviews of literature to produce theoretically sound hypotheses (addressing ignorance). Regarding cognitive laziness, science itself is curious; scientists would not be in the business if they were not intellectually curious and willing to do the work to find accurate answers. Finally, science is competitive and interactive, discouraging arrogance. An individual scientist may be overconfident, but the process of peer review and replication beats that arrogance down in order to produce a consensus view.

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What the Empirical Evidence REALLY Says about Rock, Paper, Scissors

Posted on Feb. 05, 2015 by | Comments (9)

Rock, Paper, Scissors banner graphic by Ani Aharonian with Daniel Loxton

(Image by Ani Aharonian with Daniel Loxton.)


A popular YouTube channel called Numberphile has published a video in which they claim to have a good strategy for winning at Rock, Paper, Scissors, gleaned from a paper on the topic. The video was only posted on January 27th, but it has already been viewed well over a half million times and is popping up in blog posts at popular sites. It’s got some cute animation and the material is presented by a charming mathematician named Hannah Fry who is clearly no dummy.

But several statements she made bothered me and I found the whole thing a confusing jumble when it came to presenting the findings of the paper, so I read the paper myself, did some additional research, and found what I think are some nontrivial problems with the way the paper has been interpreted. The paper was published online nearly a year ago and has been covered on dozens of academic review, popular news, and other websites, at least one of which is likely the source of what Fry presents. Reports range in quality from getting the research completely wrong to a rather good explanation with a ridiculously wrong title.

Nearly every report of this paper got the most crucial detail wrong.

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More On Why Smart People Are Not Always Rational

Posted on Oct. 24, 2014 by | Comments (55)

This is the second post in a three-part series. Read the first post, “Why Smart People Are Not Always Rational” and the final installment, “Why Smart Doesn’t Guarantee Rational, Part III.”

In a previous post I discussed the fascinating case of Paul Frampton who, as the website News Observer put it, “instantly was transformed from superstar particle phenomenologist with three Oxford University degrees to international tabloid fodder” when he fell for a honey trap drug smuggling scam. In it, I talked about irrationality in Mensa, the “high IQ society”, and the fact that rational behavior is not, as most of us assume, a direct product of intelligence.

If rationality is not a product of intelligence, then what is it a product of?

CONTINUE READING THIS POST…

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The Logic of Causal Conclusions: How we know that fire burns, fertilizer helps plants grow, and vaccines prevent disease

Posted on Oct. 03, 2014 by | Comments (14)
This post was originally published at Drescher’s personal ICBS Everywhere blog on October 1, 2014.

I usually cringe when I read a comment by a skeptic arguing that “correlation does not prove causation.” Of course, it’s true that correlation does not prove causation. It’s even true that correlation does not always imply causation. There are many great examples of spurious correlations which demonstrate clearly just how silly it is to extrapolate cause from correlation. And the problem is not trivial. Headlines in popular press articles alone can be very damaging as most people simply accept them as true.

BUT…

I cringe because I am afraid that this oversimplification leads people to think that correlation plays no role in causal inference (inferring that X causes Y). It does. In fact, it plays a very important role that skeptics should be just as aware of as the sound bite “correlation does not imply causation.” And that is that causation cannot be logically inferred in the absence of a correlation.

What’s more, that sound bite does nothing to educate people about how and when we should infer cause. So let’s take a look at both problems.
CONTINUE READING THIS POST…

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Why Smart People Are Not Always Rational

Posted on Sep. 21, 2014 by | Comments (56)
NOTE: Most of the content of this post was included in a talk at The Amaz!ng Meeting in 2013 titled “Why Mensa Will Never Eliminate World Hunger”. It is the first of a series of posts on the difference between intelligence and rationality. Read the next two installments, “More On Why Smart People Are Not Always Rational” and “Why Smart Doesn’t Guarantee Rational, Part III.”

Paul Frampton

Paul Frampton. Image from Wikimedia Commons, used here under Creative Commons Attribution-Share Alike 3.0 Unported license.

Paul Frampton fell for a “honeytrap”*. A divorced man of 68, he had begun corresponding online with a woman named Denise Milani in November of 2011. Milani was a bikini model in her early 30s. Although he had never spoken with her over the phone or Skype, in January of 2012 he set out to meet her in Bolivia, where she was doing a photo shoot. Two weeks later he was sitting in a jail in Buenos Aries, arrested for transporting two kilos of cocaine into the country.

Here is what happened in a nutshell: Frampton was sent a ticket from Chapel Hill, North Carolina to Bolivia, by way of Toronto. When he got to Toronto, he discovered that the ticket for the second leg was invalid. So he waited in Toronto for another ticket. Four days later, he arrived in Bolivia, but Milani was no longer there. She was in Brussels on another photo shoot. She would send him a ticket, but would he mind bringing her a bag she’d left in Bolivia?

CONTINUE READING THIS POST…

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