Day: February 11, 2019

By Emma Young

As every parent knows, gentle rocking helps a baby to fall asleep. Now a new study, published in Current Biology by researchers in Switzerland, shows that a rocking bed also benefits adults, extending the time that they spend in deep, slow-wave sleep, helping them sleep more soundly, and increasing their memory consolidation through the night. A related rocking study on mice, conducted by a team involving some of the same researchers, and published in the same journal issue, helps to reveal how rocking might have these effects. 

Laurence Bayer at the University of Geneva and colleagues had previously found that continuous rocking during a 45-minute nap helped adults to fall asleep and to sleep more deeply. For the new study, they wanted to explore the effects of rocking during an entire night. 

Eighteen healthy young adults spent a first night getting used to the custom-built bed, which swayed back and forth every four seconds, moving a total of 10.5 centimetres. Next came two experimental nights. One was spent in the rocking bed, and one in a standard bed. During both nights, EEG was used to monitor their brain activity. 

Rocking didn’t help the participants enter the first stage of early, light sleep any faster, nor was their REM sleep affected. But they did spend less time in the first few stages of sleep, and nearly a quarter more time in deep slow-wave sleep.

Bayer and her colleagues also noticed that rocking increased the number of “sleep spindles” during slow wave sleep. These bursts of coherent brain activity are known to help prevent a sleeper from briefly waking – and on the nights the participants were rocked, there was an association between an increase in the “fast” form of sleep spindles and reduced awakenings. (Though brief arousals are common during sleep, they do interfere with normal cycling between the various sleep stages.)

Spindle activity during slow wave sleep is also known to relate to the replaying of memories, which is important for memory consolidation. On the evening before each of the experimental nights, the participants were given a series of word pairs to learn before being tested immediately and then again when they woke in the morning. They performed better on the morning memory test after a night of rocking than after a night in a normal bed. In fact, after a rocking night they did even better on the test than they had the previous evening (this overnight improvement didn’t occur after a night in a standard bed). “This increase in overnight memory accuracy was supported by a decrease in the number of errors and an increase in the number of correct responses only during the rocking night,” the researchers note. 

How might rocking increase slow-wave sleep duration and reduce disruptive waking? “While the exact underlying neuronal mechanism cannot be fully elucidated here, we hypothesize that the rocking effect would be driven by the vestibular system,” they write. 

Evidence for this comes in part from the companion study on mice. All-night rocking had slightly different impacts on mice vs. people: when their cages were rocked, the mice fell asleep faster and stayed asleep for longer, but there was no evidence that they slept more deeply. The effects of rocking vanished, however, in mice bred to lack functional otolithic organs. These organs, which form part of the vestibular system, sense forward/backward and sideways motion. 

The researchers think rhythmic rocking may exert a kind of synchronising action in the brain, inducing a rhythmic pattern of activity in neural pathways from the thalamus, which receives signals from the vestibular system, on into the cortex, directly influencing the appearance of fast sleep spindles.

More work is clearly needed to establish exactly what’s going on. But as far as the observed sleep effects themselves are concerned, as the researchers conclude, “These results may be relevant for the development of non-pharmacological therapies for patients with insomnia or mood disorders or even for ageing populations, who frequently suffer from decreased sleep and/or from memory impairments.” 

—Whole-Night Continuous Rocking Entrains Spontaneous Neural Oscillations with Benefits for Sleep and Memory

—Rocking Promotes Sleep in Mice through Rhythmic Stimulation of the Vestibular System

Image via Giphy.com

Emma Young (@EmmaELYoung) is Staff Writer at BPS Research Digest

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By guest blogger Tomasz Witkowski

The profession of “criminal profiler” is one shrouded in secrecy, even giving off a hint of danger. Yet when the American psychiatrist James A. Brussel began profiling a particular suspect in the 1950s, law enforcement officers were not entirely inclined to trust him. However, it turned out Brussel accurately defined the suspect’s height, clothing and even religion. This spectacular success was the beginning of the profession of the profiler. The FBI formed its Behavioral Science Unit in 1974 to study serial predators. Since then, the art and craft of criminal profiling have become the subject of numerous books, TV shows and iconic films such as The Silence of the Lambs. Criminal profilers are not, however, just characters created to make interesting films and books – in the real world the accuracy of their expert opinions is often key to protecting the safety and lives of others.

Can we say, after the passage of 40 years since the job of offender profiling (OP) was established, that this profession is a craft worthy of trust, one whose practitioners make use of tried and tested tools, or rather would it be more accurate to describe it as an art-form grounded in intuition that supplies us with foggy, uncertain predictions? Answers to these questions are given by Bryanna Fox from the University of South Florida and David P. Farrington from the University of Cambridge in the December edition of Psychological Bulletin, where they present a systematic review and meta-analysis of 426 publications on OP from 1976 through 2016. 

While Fox and Farrington assure us that the field of offender profiling has made considerable improvement in the scientific rigor of its research, I believe a closer look at their results do not give us much cause for optimism. The problem is OP is a field whose beginnings had such little scientific rigor that even though things have improved there is still such a long way to go. 

For example, the proportion of OP publications using advanced statistical analyses has risen substantially, but while they were at 0 per cent four decades ago, the figure still stands at just 33 per cent. In the past ten years the number of peer-reviewed studies out-paced non-peer reviewed publications by a margin of three to one, which sounds like good news. However, the new review demonstrates that OP has been studied quite poorly and a science that fails after so long to uncover any meaningful effects is arguably nothing more than a cargo cult science.

For instance, despite being applied often in active police investigations, very few evaluations of the profiles’ accuracy or effectiveness have taken place. Less than 10 per cent of all publications contained evaluations of existing profiles or profiling strategies conducted to determine the level of accuracy of these profiles and methods. 

Also, no previous analysis has determined the specific recurring themes or criminal profile categories that exist within the body of publications on OP. Fox and Farrington took up this task, analysing 62 publications that have developed offender profiles. They found considerable variation in the number, characteristics and terminology used to describe otherwise similar profile types, which, by the way, have little in common with the pop culture depiction of the “Organized” and “Disorganized” serial killer profiles originally proposed by agents in the FBI’s Behavioral Science Unit in the 1980s. The recurring profile themes or category types found by Fox and Farrington in the literature included: expressive, instrumental, visionary, hedonistic, power/control, traveling and local homicide offenders.

The wide variety in methods and terminology used across the field is striking. Some authors proposed profiles on the basis of their investigative experience or the modus operandi at the crime scene, while others drew on their reviews of the OP literature or a statistical analysis of all available crime scene information. This wide variety makes synthesis of the findings of OP as a whole very difficult.

Far greater cause for optimism is given by the results of the meta-analysis of case-linkage analysis research from 2002 to 2016. Case linkage is the process of determining whether there are discrete connections, or distinctive behavioural factors, that associate two or more previously unrelated cases by means of crime scene analysis, such as victim selection/targeting, method of approach and attack, location type, nature and sequence of sexual acts, any verbal activity, modus operandi, signature behaviour, and the amount of time spent in the commission of the crime. Results indicate that, in general, case linkage analysis can be used successfully to link crimes in a series of offences committed by a single offender. In fact, well over half of all reported analyses of case-linkage accuracy were statistically in the moderate to strong range, whereas almost 20 per cent were very strong. 

Despite the tremendous strides made by OP in relation to where it began 40 years ago, the results of this new review suggest OP nevertheless mostly still fails to meet the “Daubert standard” – originating from a 1993 case and now employed widely in the USA, this standard defines the scientific credibility that must be passed for evidence to be presented in courtrooms. Specifically, there is no known reliability or error rate for the vast number of methodologies or profiles developed in the OP field. Yet Fox and Farrington remain optimistic. They believe that: ”OP appears to be on a positive trajectory in terms of the use of more scientific and statistical methods, data and analyses, and evaluations of our work. Continuation on this trajectory, particularly in the next 10 years, will help the field of OP transform from a ‘cocktail napkin psuedoscience’ into an evidence-based discipline that produces research used to help police, inform policy, and ultimately, make the world a safer place.”

Hopefully this will be the case. Today, however, our answer to the question posed in 1976 by British forensic psychiatrist Colin Campbell about criminal profiling in an article for Psychology Today  – “Are we better at this than a bartender?” – is a simple, “not necessarily.”

– What Have We Learned From Offender Profiling? A Systematic Review and Meta-Analysis of 40 Years of Research

Post written by Dr Tomasz Witkowski for the BPS Research Digest. Tomasz is a psychologist and science writer who specialises in debunking pseudoscience in the field of psychology, psychotherapy and diagnosis. He has published over a dozen books, dozens of scientific papers and over 100 popular articles (some of them in Skeptical Inquirer). In 2016, his latest book Psychology Led Astray: Cargo Cult in Science and Therapy was published by BrownWalker Press. He blogs at Forbidden Psychology.

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By Christian Jarrett

Talk of personality in politics is often dismissed as idle gossip, but politicians’ personalities inform their policy choices, shape their campaigning style and predict their chances of electoral success.

In fact, there has been much speculation that personality may be key to understanding perhaps the biggest electoral shock ever – Donald Trump’s triumph in the 2016 US Presidential election. Many commentators have highlighted Trump’s unusually brash, extraverted and narcissistic personality and proposed that it may partly explain his appeal among some voters. However, before now, there has been little systematic evidence to support this claim.

A new open-access paper in Presidential Studies Quarterly addressed this lack of evidence, surveying  875 international experts about the personality traits of 103 political leaders, including Trump and 20 other populists, who took part in 47 elections in 40 countries around the world between 2015 and 2016. Alessandro Nai and his colleagues found that Trump’s traits were rated at the extremes even in comparison to other populist leaders, suggesting a “truly unique and off-the-charts public persona”.

The participating experts, who had a slight left-leaning political bias, had academic backgrounds in “electoral politics, political communication (including political journalism), and/ or electoral behaviour”. They each evaluated one political candidate using an established Big Five personality questionnaire and a shortened version of a Dark Triad questionnaire to tap less savoury traits (such that each politician was rated by multiple experts – Trump, for instance, was rated by 75 experts). The experts also scored the candidates’ campaigning style.

Nai’s team were careful to explain that “we do not claim to measure the candidates’ actual psychological profile – and even less, the clinical components of their psyche – but rather their perceived personality (reputation).”

According to the judgment of the participating experts, Trump’s personality is extremely extraverted; extremely low on agreeableness; extremely low on conscientiousness; extremely neurotic (i.e. low emotional stability); and also extremely high on narcissism, psychopathy and Machiavellianism. The only trait where he was rated as average was openness.

Even when compared against other populist leaders, Trump came out as having the lowest scores of all on agreeableness, conscientiousness and emotional stability, and the highest scores for narcissism and Machiavellianism. On extraversion he was only outscored by Vladimir Zhironovsky of Russia, and on trait psychopathy only by Arlene Foster of Northern Ireland and Nikola Gruevski of Macedonia. Trump scored significantly higher on all the Dark Triad traits when compared against the average scores of the other populist leaders, making him in the researchers’ words, “an outlier among the outliers”. And when comparing his profile against the average for non-populist leaders, the difference is “staggering”, they added.

In terms of campaigning style, Trump scored very high for the negative tone of his tactics and his use of appeals to voters’ fears, and he had the single highest score for use of character attacks. This fits with the general pattern in the data for traits like low agreeableness and low conscientiousness, and high Dark Triad scores, to correlate with negative campaigning styles.

Overall Nai’s team believe their data show that what is unique about Trump is not his lack of political experience (other world leaders, like Macron, share this background) nor his personal wealth (again there are other examples, like Putin and Berlusconi), but his personality style. “Systematic comparison between Trump’s public persona and the profiles of other mainstream and populist candidates shows that Trump is, indeed, off the charts.”

While this new study provides fairly comprehensive comparative data on Trump’s personality and that of many other global politicians, and also demonstrates that there are meaningful associations between politicians’ personalities and their campaigning styles, what it doesn’t do is provide causal evidence that Trump’s personality was the reason for his electoral success, nor for his subsequent behaviour in office.

Nai’s team do allow themselves to speculate about the future, however. They point out that given previous research on US presidents’ and other politicians’ personalities – suggesting, among other things, that strong extraverts tend to be more successful, narcissists are willing to take more risks, and disagreeable leaders pass more legislation successfully – that they would “advocate for caution when assuming that Trump will necessarily be a president without major achievements at the end of his term(s)”.

On the negative side, past research suggests narcissistic leaders tend to allow more unethical behaviour among their subordinates, and note that Trump scored very low on conscientiousness, a trait previously associated with success among former presidents.

“Overall,” the researchers concluded, “the comparison of [Trump’s] profile with trends in the literature suggests that Trump will continue to be in campaign mode and be relatively successful in (short-term) crisis management, agenda setting, and the setup of new legislative initiatives. At the same time, his profile will undoubtedly drive impulsive decisions … ” They added, “our results could support the prediction that Trump will be a chaotic president.”

—Donald Trump, Populism, and the Age of Extremes: Comparing the Personality Traits and Campaigning Styles of Trump and Other Leaders Worldwide

Christian Jarrett (@Psych_Writer) is Editor of BPS Research Digest

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