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Questioning the implicit association test

7 Jul

New York Magazine has published a devastating critique of the widely cited implicit association test (IAT). The creators of the IAT claim that it can ferret unconscious biases. From the point of view of psychometrics, the first important question we must ask about any instrument is its reliability, that is, does the measure yield consistent results if the measured phenomenon has not changed. It is a basic law of measurement that an unreliable measure can not be valid.

Here is what the article says about reliability:

What constitutes an acceptable level of test-retest reliability? It depends a lot on context, but, generally speaking, researchers are comfortable if a given instrument hits r = .8 or so. The IAT’s architects have reported that overall, when you lump together the IAT’s many different varieties, from race to disability to gender, it has a test-retest reliability of about r = .55. By the normal standards of psychology, this puts these IATs well below the threshold of being useful in most practical, real-world settings.


How effective is nudging?

23 Jun

Nudging, in this context, means social policy designed to encourage desirable behavior without restricting choice. A paper in the most recent Psychological Science looks at the effectiveness of nudging:

Governments are increasingly adopting behavioral science techniques for changing individual behavior in pursuit of policy objectives. The types of “nudge” interventions that governments are now adopting alter people’s decisions without coercion or significant changes to economic incentives. We calculated ratios of impact to cost for nudge interventions and for traditional policy tools, such as tax incentives and other financial inducements, and we found that nudge interventions often compare favorably with traditional interventions. We conclude that nudging is a valuable approach that should be used more often in conjunction with traditional policies, but more calculations are needed to determine the relative effectiveness of nudging.

Here is Cass Sunstein defends the idea of nudging:

And, of course:

Documentary: “Resurrect Dead”

10 May

Over the weekend, my wife and I watched the documentary Resurrect Dead: The Mystery of the Toynbee Tiles.

Toynbee tiles are mysterious plaques that are embedded into the asphalt on many streets in a number of cities. There are two of them in Cleveland. Most of the tiles carry the message:

IN MOViE `2001

The tiles all appear to be carved by the same individual. The documentary is the utterly adsorbing story of a group of men who try to discover the origin of the tiles.

As a psychologist, I was fascinated both by the tiler himself who appears to have schizotypal traits and by the obsession of his pursuers. The film does not disappoint and the we do discover the identity of the tiler. But not until we have pursued leads including a David Mamet play, Larry King, historian Arnold Toynbee, and pirate radio stations.

Prisoner’s Dilemma Videos

19 Apr

Last night I was teaching the prisoner’s dilemma to my students. Turns out there are a lot of entertaining videos on the topic. For example:

My students found these especially enjoyable:

For a more serious look at the background:

My numerology paper published

12 Apr

Just off the presses “A Test of Numerology: Do Birth Numbers Predict Nobel Prize Winners?” published in The Journal of Articles in Support of the Null Hypothesis. Here is the abstract:

This paper tests a claim made by numerologists – the belief that the digits of a person’s birth date summed to a single integer, called the birth number, has predictive power. In order to test this claim the birth number was calculated for persons winning Nobel Prizes between the years 1901 and 2010. The distribution of birth numbers for prize winners did not differ significantly from chance (χ2 = 4.92, df = 8, p = 0.77). The distribution of birth numbers between winners of different prize categories also did not differ significantly from chance (χ2= 28.9, df = 40, p = .90). These results provide no support for the claims of numerology

You can find the paper here.

People who never forget

5 Apr

Read about them in this Guardian article.

Crypto-spiritualism: The return of facilitated communication

8 Mar

Spiritualism is the belief that it is possible to communicate with the death through trance mediums. While there are historical antecedents, modern spiritualism began in 1848 in New York state, when the young Fox sisters claimed the power to produce raps from the spirit world.

Spiritualism promised communication with the  dead, and for the bereaved this was often an irresistible  hope.  Fraudulent mediums were happy to provide solace, for a price. Exposures of fraud, probably contributed to the decline of spiritualism, but even today there are believers.

Sunday’s Washington Post brought the sad news of a revival of the discredited technique called facilitated communication. Facilitated communication is supposed to allow people with severe autism and other developmental disabilities to communicate. It is easy to see why parents would want to believe that their non-verbal children could actually communicate, but our evidence shows that that facilitated communication does not work and that the messages are actually authored by the facilitators via the ideomotor effect.

Here is the American Psychological Association’s statement on facilitated communication.

And here is the powerful Frontline documentary on the subject.

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