Tag Archives: Psychology

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:

Sleep deprived judges hand out longer sentences

20 Feb

This study just appeared in the journal Psychological Science:

The degree of punishment assigned to criminals is of pivotal importance for the maintenance of social order and cooperation. Nonetheless, the amount of punishment assigned to transgressors can be affected by factors other than the content of the transgressions. We propose that sleep deprivation in judges increases the severity of their sentences. We took advantage of the natural quasi-manipulation of sleep deprivation during the shift to daylight saving time in the spring and analyzed archival data from judicial punishment handed out in the U.S. federal courts. The results supported our hypothesis: Judges doled out longer sentences when they were sleep deprived.

The Monday after the shift to day light savings time is associated with about 40 minutes of lost sleep. Other studies have found an increased number of car accidents on that day. The authors of this study report that sentences are 5% longer than those on comparison Mondays.

An interesting result, although I do have some skepticism about how well confounding variables can be controlled statistically.

Psychological explanations of physical illness: Time for some skepticism?

17 Oct

A startling paper in Perspectives on Psychological Science:

In some patients with chronic physical complaints, detailed examination fails to reveal a well-recognized underlying disease process. In this situation, the physician may suspect a psychological cause. In this review, we critically evaluated the evidence for this causal claim, focusing on complaints presenting as neurological disorders. There were four main conclusions. First, patients with these complaints frequently exhibit psychopathology but not consistently more often than patients with a comparable “organic” diagnosis, so a causal role cannot be inferred. Second, these patients report a high incidence of adverse life experiences, but again, there is insufficient evidence to indicate a causal role for any particular type of experience. Third, although psychogenic illnesses are believed to be more responsive to psychological interventions than comparable “organic” illnesses, there is currently no evidence to support this claim. Finally, recent evidence suggests that biological and physical factors play a much greater causal role in these illnesses than previously believed. We conclude that there is currently little evidential support for psychogenic theories of illness in the neurological domain. In future research, researchers need to take a wider view concerning the etiology of these illnesses.

From the paper’s conclusion:

Given our current limited understanding of medical disease and its markers, it is perhaps not surprising that not all physical complaints can be associated with a specific, well-recognized disease process. In these circumstances, it is tempting to offer a psychological explanation. However, in this review, we have argued that such explanations are not currently supported by the evidence, at least not in the domains considered here. Further, these explanations may be harmful for the patient. To find better treatments for these illnesses, researchers and practitioners may need to retire those overworked psychological explanations that are commonly invoked in the face of uncertainty and instead adopt a completely fresh perspective. Such an approach may lead to a much deeper understanding of this perplexing collection of illnesses.

Interesting video on the therapeutic use of psychedelic drugs

19 Sep

(hat tip to boingboing)

Why is the full moon myth so powerful?

22 Aug

I was reading this paper in the journal Teaching Psychology about how evidence can help dispel common myths about human behavior, when I came across this sentence:

“In the second case, the superstition that a full moon increases erratic behavior remained impervious to change. Unfortunately, students maintained a strong belief in lunar lunacy at the beginning of the course, and the belief did not change at the end of the course.”

It conforms to my experience, many students at all levels, including doctoral students, are absolutely convinced of the influence of the full moon on human behavior. Students have actually gotten angry when I point out the contrary evidence.

In their paper, McCarthy and Frantz offer a possible explanation:

“We believe this particular misperception is especially difficult to change because people continually employ confirmation bias as a way to retain their belief.”

I suspect that cultural factors might also be involved. I remember in one class two Asian students were astonished by the debate. They had never heard anyone suggest the full moon as a harbinger of bad tidings. In their respective cultures the full moon is seen as an auspicious omen.


Olympic athletes use transcranial direct current stimulation

19 Aug

According to IEEE Spectrum:

“A handful of athletes competing at the Summer Olympic Games in Rio next week will arrive having tried to boost their performance using an unconventional (and not-yet-banned) technology: brain stimulation. The technique, called transcranial direct current stimulation (tDCS), involves channeling a tiny current through specific regions of the brain, making neurons in that area more likely to fire.”

The athletes are using the Halo tDCS device. Here is the promotional video:

Before you run out and buy one of these devices, I suggest you read “An open letter concerning do-it-yourself users of transcranial direct current stimulation” published in The Annals of Neurology.


Brain training increases grey matter volume

15 Aug

On Friday, I reported on a meta-analysis that presented evidence that working memory brain training does not transfer to other cognitive skills. The most recent issue of Personality and Individual Differences carries a paper titled:  “Gray matter volumetric changes with a challenging adaptive cognitive training program based on the dual n-back task.” The n-back task is the most widely used procedure for working memory training in academic research.

Surprisingly, these results do not, necessarily, contradict each other. As noted in the abstract:

“Changes in the gray matter volume of these clusters were correlated with a) behavioral changes across the training program and b) changes in four psychological factors assessed before and after training (fluid and crystallized intelligence, working memory capacity, and attention control). None of these correlations were statistically significant, and therefore, psychological and biological changes were seen as independent.”

Since there working memory training does improve performance on the trained task, we would expect there to be some kind of measurable physical change in the brain. But this does not mean that the training effects are transferable to other cognitive domains.

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