Raising An Issue in Indian Psychology

A recent literature search threw up an interesting-looking paper; a randomised controlled trial (RCT) on the effect of yoga on gunas (personality) in healthy volunteers (free to read). I was surprised as I rarely come across academic papers on yoga, that too with explicit reference to 'gunas' in the title. . I couldn’t help noticing at the outset that the study appeared to have been carried out at the Department of Yoga Research, Swami Vivekananda Anusandhana Samsthana, a deemed-to-be yoga university. The study was also published in the International Journal of Yoga, which appears to be the university’s own journal publication. So there is plenty of scope for bias to creep in.

Despite that RCTs are the 'gold standard' of psychological research when done properly, the stated aims of this paper didn't exactly fill me with confidence. The study itself wasn't what interested me, but rather one of the tools that the researchers used to assess the participants' personalities. In psychology, personality is assessed using specific scales or questionnaires that have been designed to measure a particular construct, say, anxiety or depression. The Beck Depression Inventory is probably the best known and widely used example of a scale to measure depression, and you can find information about other scales at Wikipedia.

An important concept in the construction of such scales is known as construct validity, the ability of the scale to measure what it is supposed to measure. Using the BDI as an example, can it be that a set of questions is capable of measuring the presence and intensity of depression in a person? All other things being equal, the answer is that it is probably the most reliable tool we have for measuring depression at the moment and that it has been consistently used in a number of different medical fields. Much research has been done in the field of personality psychology in an attempt to construct a real-term workable scale with which to assess personality. Many scales exist, but generally speaking researchers have come to agree that personality can be defined in terms of the "Big 5" factors: Neuroticism, Extraversion, Agreeableness, Conscientiousness and Psychopathy, and that all of our personalities can be measured in different ratings of these. The Reliability of such scales is another important issue that also means something different to the popular sense of the word, and we'll get to that at some point.

For this study the research team wanted to analyse the effects of a yoga course on personality and self-esteem, and they measured these with Karunanidhi's Self-Esteem Inventory (1996) and, wait for it, the Gita Inventory of Personality (Das, 1991). According to this paper, the GIP (referred to as GIN within the paper) was to measure three dimensions of personality: Sattva, Rajas and Tamas.

There is reason to suspect that, at least in the case of the GIP, something mischievous is afoot in the name of psychology. The Gita referred to is of course the Bhagavad-Gita, a Hindu scripture (traditionally believed to be 5000 years old), and the three personality dimensions being assessed are described in the 14th chapter of the text. I'm aware of issues of sensitivity surrounding cross-cultural research in psychology, the importance of accepting cultural boundaries, and so on. If you were to rely on Wikipedia, cross-cultural psychiatry (or transcultural psychiatry) is that which is "concerned with the cultural and ethnic context of mental disorders and psychiatric services".

I have to wonder, though, are cases like this something that ought to be a concern or to be praised? On one hand we have here a different outlook on personality that is independent of Western-oriented psychology, but on the other we have to wonder about the appropriateness of assessing people's individual personality traits on the basis of definitions provided in an antiquated religious text. Psychological research is frequently slighted or condemned (depending on who you listen to) as being overly WEIRD - analysing and assessing people that are dominantly Western, Educated, Industrialised, Rich, and Democratic, and that is a fair criticism in context. In general, the field is crying out for fresh perspectives.

However, it remains unclear if ethnically contextual research from the other end of the spectrum will be able to provide new insight into the field of personality psychology if little to no effort is made to work collegially, and using similar standards of measurement with which to assess people and carry out much needed research.

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Deshpande S., Nagendra H.R. & Nagarathna R. (2009). A randomized control trial of the effect of yoga on Gunas (personality) and Self esteem in normal healthy volunteers., International Journal of Yoga, 2 (1) 13-21. PMID: 21234210

What is "Self Transcendence"?

A recent study by Italian researchers uncovered the fact that neurosurgery involving certain brain structures can effect personality changes that make one feel more "spiritual". 88 patients underwent pre- and post-surgical personality assessments while treated for tumours, and the results were combined with lesion mapping procedures (to precisely locate lesions) after surgery to measure changes in a personality construct called Self-Transcendence (ST). It was found that patients with posterior lesions experienced a considerable increase in 'spirituality' after the surgical removal of their tumours than those with anterior lesions, and that those with more aggressive types of tumour were most likely to describe themselves as religious. For a fuller report and discussion of this fascinating study, please see Mo Costandi's Neurophilosophy.

As I read through various articles detailing this announcement, I became intrigued at the constant mention of ST as a measure of personality. In his paper, Cosimo Urgesi describes ST as reflecting "the enduring tendency to transcend contingent sensorimotor representations and to identify the self as an integral part of the universe as a whole." ST is among several other personality dimensions in the psychobiological Temperament and Character Inventory (TCI) that was devised by C. R. Cloninger and colleagues in 1994. The TCI has been used in genetics to show ST as a heritable trait, and in molecular neurosciences to show ST related to the functioning of the serotoninergic system. According to Cloninger et al. (1993) their model followed on from previous research that confirmed four dimensions of temperament; novelty-seeking, harm avoidance, reward dependence, and persistence, and added three more dimensions that mature in adulthood; self-directedness, cooperativeness and self-transcendence.

In their discussion of ST, Cloninger et al. begin with the amusing sentence: "Most people meditate or pray daily, which is more frequent than sexual intercourse according to population surveys". They go on to note the lack of spirituality-related traits from personality inventories including the well-known Five Factor Model, which is odd considering that spirituality is an integral aspect of people's lives and mental activity. In describing their definition of spirituality, they say:

"Self-transcendence refers generally to identification with everything conceived as essential and consequential parts of a unified whole. This involves a state of 'unitive consciousness' in which everything is part of one totality. In unitive consciousness, there is no individual self because there is no meaningful distinction between self and other—the person is simply aware of being an integral part of the evolution of the cosmos. This unitive perspective may be described as acceptance, identification, or spiritual union with nature and its source ... The person may identify (or feel a sense of spiritual union) with anything or everything. They may experience the feeling that they are part of or being guided by a wonderful intelligence, which is possibly the divine source of all phenomena. Ultimately, there may be loss of all distinctions between self and other by identifying with the concept of an immanent God as one-in-all."

So it all sounds rather New-Agey (the paper mentions Buddhism and nirvana, Taoism and Advaita Vedanta), but I was still curious about the actual questions themselves. In formulating questions to measure personality dimensions, care is taken to ensure that they accurately represent the concepts they try to measure. Moreover, statistics such as Cronbach's Alpha are employed to ensure that the measure has a high level of internal consistency; the higher, the better it is at measuring a personality construct. In this context ST consisted of three sub-scales; Self-forgetfulness vs. self-consciousness, transpersonal identification, and spiritual acceptance vs. materialism, all three exhibiting a Cronbach Alpha of above 0.7. This indicates that each of the three sub-scales were reliable in excess of 70% in measuring what they claimed to measure.

PsychMaven kindly helped me aquire a copy of the TCI. Bearing in mind that the "questions" are actually statements that one ought to rate on a 5-point scale (1 = Definitely false, 5 = Definitely true), here is the complete list (in order of appearance) that purport to contribute to the ST dimension of personality:

12. I often feel a strong sense of unity with all the things around me.

25. Often I have unexpected flashes of insight or understanding while relaxing.

29. I sometimes feel so connected to nature that everything seems to be part of one living process.

32. I think that most things that are called miracles are just chance.

42. Sometimes I have felt like I was part of something with no limits or boundaries in time and space.

43. I sometimes feel a spiritual connection to other people that I cannot explain in words.

52. Sometimes I have felt my life was being directed by a spiritual force greater than any human being.

56. I have had moments of great joy in which I suddenly had a clear, deep feeling of oneness with all that exists.

68. I often become so fascinated with what I’m doing that I get lost in the moment – like I’m detached from time and place.

73. I often feel a strong spiritual or emotional connection with all the people around me.

91. I have made real personal sacrifices in order to make the world a better place – like trying to prevent war, poverty and injustice.

95. It often seems to other people like I am in another world because I am so completely unaware of things going on around me.

99.I often feel like I am a part of the spiritual force on which all life depends.

106. I have had personal experiences in which I felt in contact with a divine and wonderful spiritual power.

112. Often when I look at an ordinary thing, something wonderful happens – I get the feeling that I am seeing it fresh for the first time.

118. Religious experiences have helped me to understand the real purpose of my life.

143. I believe that all life depends on some spiritual order or power that cannot be completely explained.

148. I often feel so connected to the people around me that it is like there is no separation between us.

151. I am often called “absent-minded” because I get so wrapped up in what I am doing that I lose track of everything else.

157. I often do things to help protect animals and plants from extinction.

175. I have a vivid imagination.

190. I would gladly risk my own life to make the world a better place.

206. I think it is unwise to believe in things that cannot be explained scientifically.

212. Often I become so involved in what I am doing that I forget where I am for a while.

223. I have had experiences that made my role in life so clear to me that I felt very excited and happy.

232. Reports of mystical experiences are probably just wishful thinking.

It could be argued that statements such as these are anything but 'transcendent'. As Costandi eloquently put it in his report, Urgesi et al. fall short in their study of truly defining spirituality because it is likely that different patients will hold different ideas of spirituality and how it affects their lives. Furthermore, spirituality is an area that consists of many ideas apart from 'transcendence' which, by all accounts, is generally taken to refer to a state of being philosophically and affectively 'above and beyond' this world and all forms of mundane issues. Although many items deal with experiencing spiritual connections and having a sense of oneness with the universe, items that attempt to measure patients' attempts to save plants and animals from extinction hardly qualify as being transcendent and neither does gladly risking one's life for any purpose do the same. Having a "vivid imagination", however, is certainly a questionable inclusion which is bound to draw some sarcastic remarks.

We may quibble about the exactness of ST items and whether they accurately measure spirituality, the neurological findings nevertheless support the dependence of religious beliefs on brain function and even further increases evidence that religious beliefs can be experimentally studied. Urgesi et al. even go as far as to say that "dysfunctional parietal neural activity may underpin altered spiritual and religious attitudes and behaviours".
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Urgesi, C., Aglioti, S., Skrap, M., & Fabbro, F. (2010). The Spiritual Brain: Selective Cortical Lesions Modulate Human Self-Transcendence Neuron, 65 (3), 309-319 DOI: 10.1016/j.neuron.2010.01.026

Cloninger CR, Svrakic DM, & Przybeck TR (1993). A psychobiological model of temperament and character. Archives of General Psychiatry, 50 (12), 975-90 PMID: 8250684

Thugs left man with half a head

I don't often read tabloids, but I noticed this intriguing report in The Sun lately:

Thugs left man with half a head

By STAFF REPORTER

Published: 11 Sep 2009

VICIOUS thugs who punched this man so hard he was left with HALF A HEAD have got off scot free.

Horrified Steve Gator had to have the front of his skull removed by stunned surgeons after his head was smashed against a pavement in the sickening attack. And now the 26-year-old has been told that the teen attackers who disfigured him will escape justice after his case was dropped.

Steve, of Romford, Essex, was attacked after confronting one of the yobs who had been taunting him about his cousin. Another of the violent louts hit him so hard that he was sent flying and struck his head on the path. Steve plunged into a coma for two weeks as his shattered mum and distraught family kept a bedside vigil at Queen's Hospital, Romford.

His brain quickly began swelling and surgeons were forced to remove the front half of his skull just hours after he was admitted.

Grief-stricken mum Nina Gator was warned her son had just a terrifying 15 per cent chance of survival. Two days later cops charged a pair of teenage boys with the savage attack which shocked the neighbourhood. Steve, who has had to quit his job, was left seriously brain damaged and now suffers frequent seizures, has difficulty talking, and his memory is seriously impaired. Mrs Gator, who is his main carer, last night blasted the shock move. The 47-year-old said: "I can't believe it. Everyone is entitled to their day in court."

CPS lawyers claim they needed more proof before going ahead with the case. But Mrs Gator stormed: "Our boy is walking around with half a head - what more evidence do they need? "His sparkle is totally gone. He used to be so independent but he can't work any more and he can't drive." She added: "He's got half a head and he's completely lost his confidence. There's absolutely nothing protecting his brain now it's just under his skin."

Just from looking at the picture, it seems obvious that with this traumatic brain injury (TBI) his frontal lobes are practically destroyed and quite possibly the front parts of his midbrain. The frontal lobe is an extremely important structure responsible for a variety of functions. It is the 'Command HQ' for emotions, and controls and regulates functions such as memory, language, movement, and problem-solving. It is also responsible for more subtle things like judgment, planning, reasoning, spontaneity or impulse control, and some effects on social and sexual behaviour. As such, the frontal lobe administrates much of our very personality and sense of identity. It is also the largest 'lobe' structure, meaning that there is more of it to carry a greater risk of damage. As the story mentions, Gator's "sparkle is totally gone". It is tempting to draw parallels with the tale of Phineas Gage, another individual dubiously famed for frontal lobe damage.

A friend, The Neurocritic, pointed out that Gator may need several cranioplasties in order to rebuild his skull, and highlighted a recent Neurosurgical Focus literature review that discusses the types of post-operative complications associated with the surgical procesure underwent by Gator. Known as a decompressive craniectomy, and consisting of a partial removal of the skull in order to allow the swelling brain to expand without being squeezed, we start with contusion blossoming; the surgery leaves massive bruises which can be observed via pre-op and post-op CT scans.

Lesions - a mass lesion may develop on the opposite side of the brain to the injury or elsewhere in the brain. As Gator's frontal lobes were destroyed, it is possible that a lesion may develop around the back end and possibly affect the parietal lobes, which deals generally with perception, orientation and recognition.

Herniation - a small protrusion (or more) of neural tissue may remain in the early period after swelling subsides, sometimes through the cranial defect as is observed with 'normal' skin hernias. Gator has no such defect though, as the front of the skull was smashed.

Subdural Effusions - a collection of pus beneath the outer lining of the brain. This condition usually results from bacterial meningitis, but because craniectomies affect the circulation of cerebrospinal fluid (CSF) it is possible that buildups may accumulate. Similar to blood clots. Hygromas may also occur, which are buildups of CSF without blood. To counteract these, a craniectomy should be accompanied with a duraplasty, a reconstructive operation on the dura mater, the outermost and fibrous membrance covering the brain and spinal cord. Duraplasties have been observed to lower the incidence of subdural effusions occurring.

Infection - this may seem a rather obvious effect of any medical procedure, to guard against, but craniectomies (bone removal) will necessitate cranioplasties (bone reconstruction). As such, opening old scars and exposing the brain upto or after a month after the incident runs the risk of contracting infection and delaying healing. The review suggests a minimum wait of 3 months before replacing the bone, and that storage of the bone in a freezer can also increase the risk of infection.

Hydrocephalus - "water on the brain", refers to accumulations of CSF in neural cavities. This is unfortunately a common occurrence beyond a month after the injury, and will need specialised procedures (shunt treatment) to deal with it if it occurs.

Syndrome of the Trephined - another unfortunate common occurrence after decompressive craniectomies, of which common symptoms include dizziness, headaches, concentration difficulties, mood disturbances, irritability, and memory problems. Because Gator's particular situation involved the destruction of his frontal lobes, he will unfortunately suffer much worse symptoms than these. However, in general terms when the motor functions are affected, this then becomes known as motor trephine syndrome.

Bone resorption - when one undergoes a decompressive craniectomy, you're likely to have stray bone fragments swimming around and there's around a 50% chance that bone resorption will occur, which is when bone cells (known as osteoclasts) break down the bone and release minerals like calcium directly into the blood.

Persistent vegetative state - clearly the saddest effect of all extreme brain injuries. While decompressive craniectomies are effective at ameliorating intra-cranial pressure and reducing the risk of death, they offer no guarantee of restoring brain function once the patient suffers a TBI. The risks of surviving into a vegetative or minimally conscious state after undergoing craniectomy range upwards of 15-20%.

It may be that Steve Gator's clinicians need to be vigilant and ensure that his treatment is as risk-free as possible. And of course, wishing him all the best to recover well.
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Stiver, S. (2009). Complications of decompressive craniectomy for traumatic brain injury Neurosurgical FOCUS, 26 (6) DOI: 10.3171/2009.4.FOCUS0965

So Gay, So Very Gay

It's unbelievable what's uncovered sometimes. A recent survey of British psychologists and psychiatrists has uncovered that a sizeable amount have attempted to "convert" homosexual patients or clients to heterosexual orientations!

It's a well-known axiom that (biological) homosexuality is an orientation that cannot be changed, what to speak of the scientific consensus on the matter, and what do you think might happen if any such changes are encouraged? Psychological harm and damage.

After all, what is "normal"? Anyone with even a layman understanding of psychology and/or neuroscience will know that definitions of normality are as subjective as one's colour preferences. And when you have a discriminating society that is ever-willing to ostracise on the slightest grounds of anything perceived as different, it isn't that hard to imagine how seriously this counts as psychological abuse especially concerning a topic so fundamental to someone's 'personhood' as sexual identity.

Annie Bartlett and her colleagues sent postal questions to members of the British Psychological Society, the British Association for Counselling and Psychotherapy, the United Kingdom Council for Psychotherapy and the Royal College of Psychiatrists, in which they were asked to give their views on "conversion treatment" and to describe up to six patients they may have treated accordingly. Of the 1328 examinable anonymous responses received, a flabbergasting 17% reported having assisted in reducing, changing, suppressing their gay or lesbian desires. Of these 17% (222 practitioners), 159 of them (72%) thought that a "service" should be available for homosexuals who wish to change their orientation.

Am I missing something here? Did I suddenly enter the Twilight Zone and wind up in Iran or something? This is England 2009! And it was back in 1973 that homosexuality was removed as a mental disorder from the Diagnostic and Statistical Manual of Mental Disorders (DSM), so why are these attitudes still prevailing in psychotherapeutic practice? Do old habits die hard? Because of the anonymous nature of the survey there is no information provided as to the average age of the sample, even when the authors selected a random sample of responses from the members of each organisation. Even though only 4% (55 respondents) of the total sample said they would consider therapy to change patient orientations upon requests for such therapy, it is much more worrying that the aforementioned 17% have actually attempted to do so. Considering the absense of compelling evidence that patients can even be successfully treated, trying to force or encourage such a change can only heighten and intensify the emotional conflicts that homosexuals may undergo (due to peer pressures, etc.) and cause lasting psychological damage.

This study appears to follow on from earlier 2004 research (also by the same authors) in which an oral history of homosexual patients was gained. 29 homosexuals who had received treatment for their "disorder" were interviewed about their experiences, which revealed a nominal amount of coercive and peer pressures and also resulted in lasting emotional distress.

What can I say? It's sad that these professionals appear to have no real knowledge of social identity issues. And I'd hate to be cynical, but what's the betting that serious conflict of interest issues are responsible for this grave failure of psychotherapeutic services? The type of conflict of interest that arises from personal convictions and beliefs?

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Bartlett, A., Smith, G., & King, M. (2009). The response of mental health professionals to clients seeking help to change or redirect same-sex sexual orientation BMC Psychiatry, 9 (1) DOI: 10.1186/1471-244X-9-11

Smith, G., Bartlett, A., & King, M. (2004). Treatments of homosexuality in Britain since the 1950s--an oral history: the experience of patients BMJ, 328 (7437) DOI: 10.1136/bmj.37984.442419.EE

Does Religion Make You Nice?

HOT OFF THE PRESS! (3 Oct 2008)

The very latest issue of the Science journal has published a review of religious prosociality.

This is an issue that has an indirect connection with my recent Masters thesis. What a pity this wasn't published a little earlier, as I could have incorporated some of this data into my thesis.

But never mind, I'll read this review and criticise it here soon.

In plain English (as per the abstract): This review examines the evidence for religious prosociality, in other words, the extent to which religion goes in ensuring you're a "good guy". Do you help people and do favours for them because of your natural niceness, or because your religion tells you to? While surveys find a correlation between religiosity and helpful behaviour, experiments have found that this correlation occurs mainly in context where the reputation of the 'helper' is enhanced. In other words, religiously-motivated helpers want to do good and be seen doing good. Other experiments find that religious thoughts reduce the inclination to cheat and increase helpful behaviour towards random strangers.

I don't know what the rest of it means (re devotion and trust, morally concerned deities, etc) as I'll have to read it to find out. But this is a taste!

How Representative are Volunteers?

As if by magic, another item at the BPS Research Digest which is also relevant to my recent forays discusses the question of whether participants in psychology studies are "representative" of the total sample under review. It seems like the majority of those who take part in psychology studies are generally more "stable and outgoing", which begs questions about whether said studies are reliable in their testing of depression measures, for example.

To give some background, the popular five-factor model measures personalities in terms of five separate factors (known as the "Big 5" model): Neuroticism, Conscientiousness, Agreeableness, Extraversion and Psychoticism. A depressed person, for instance, might have a higher Neuroticism (or even Psychoticism!) measurement than most people and a lower Extraversion rating. On the opposite end, an outgoing and popular person is likely to have high ratings for Extraversion, Agreeableness, perhaps even Conscientiousness. It is easy to see how personalities can be generally rated and measured according to these five factors.

[And for those who think there is much more to personality than these five categories, yes, you would be right, but statistical factor analysis has shown that most personality quirks come under one of the five umbrella factors of the Five-Factor model. Other personality models exist, of course, such as the 16PF Model.]

A study by Lonnqvist et al. (2007) mailed 61 military officers a survey on values (out of the 158 who were originally approached) who had completed personality assessments three years previously as per army recruitment procedures. The results showed that the respondents evidenced lower measures of Neuroticism and higher measures of Conscientiousness, Agreeableness and Extraversion. That's just about what you might expect from a military officer, don't you think? Although I'm only going by the BPS Review, it is reported that measures were established as opposed to those who didn't return the survey. How do they know? Just because 97 officers didn't bother to return the survey doesn't mean that they evidence higher measures of Neuroticism, or even that they have lower measures of Conscientiousness, Agreeableness and Extraversion!

And what about gender differences? All of these military officers were male, could there have been a difference if females were included in the study? And above all, is it appropriate to make a massive generalisation about all or most psychology participants based on a sample of 61 military officers? Don't participants come from different strata of society and from all walks of life? I did a post-hoc power analysis to check the sample size and even though this study seems more than sufficiently powered (.99!), the way that simple criticisms like mine above don't seem to have been properly addressed doesn't exactly scream of reliability to me.

It would make sense, however, if this was some sort of pilot study and a larger and more inclusive study is in the works, but no mention of such has been made.

In any case, a second study (by the same researchers) also used a survey approach: siblings from 15 families assessed the personalities of their brothers or sisters and also asked to volunteer for further tests and interviews. The subsequent sibling ratings showed that 55 participants who volunteered for further testing scored higher for Conscientiousness, Extraversion and Agreeableness than the 29 who declined the option of further testing. This is consistent with the study of military officers, and leads to the general finding by Lonnqvist et al. that volunteers for pyschological studies "are ... better adjusted than nonvolunteers. More specifically, those who are willing to volunteer as research participants tend to be lower in Neuroticism and higher in Conscientiousness than are those who are reluctant to volunteer."

Despite the simple criticisms, the study is reliable enough to be considered carefully since it has implications for psychological research. It means that there is a reasonable-to-good chance that participants who choose to volunteer for studies, who have low Neuroticism levels, are more likely to exhibit positive responses to drug treatments for depression or other things like panic disorders. But more importantly, the results of personality questionnaires are likely to be skewed because of the likely preponderance of volunteers who are not really representative of the full range of Five Factors. This is certainly an issue to take into consideration.

So how to go about trying to find a representative sample? Lonnqvist et al. suggest "acquiring samples comprised of people who are required to serve as experimental participants (e.g. as part of their jobs or academic programs)." This is fair enough; in many universities it is a requirement for 1st-year undergrads to take part in studies of 3rd-year students to acquire course credits. This can be a good thing, but my experience is that such students usually do these things in a rush and are focused more on obtaining the course credits than conscientiously (pun intended) participating in the study. Also, undergraduate students aren't always the sample of choice for most studies.

Another recommendation is that the research should be presented in an "attractive" way in order to attract a wide range of people to take part. This would be a reasonable proposal since the mere increase in sample size may simply mean an increase in volunteers, yet efforts to test a wider range of people would be more likely to yield representative results. This isn't a very solid proposal though, in my opinion. A final recommendation was to "attempt to evaluate the representativeness of the volunteer sample against the relevant population on the variables of interest." Huh? Comparing the sample to the population, basically? Isn't the point of all psychological studies to extrapolate the findings to the general population? So in other words, there really isn't anything (much) you can do to make your sample more representative. Just try and present your study in a more "attractive" way, whatever that means.

I have a tip: Just be nice to people. Talk to them and inform them that you're doing a psychology study, and ask them politely if they'd like to help you by taking part. If you've caught them at a good time, chances are they'll agree to participate. And this isn't necessarily an indication of volunteering. Some participants may find it something of a cathartic experience to complete the BDI-II questionnaire, for example. At least, those I've tested anyway.

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Lönnqvist, J., Paunonen, S., Verkasalo, M., Leikas, S., Tuulio-Henriksson, A., Lönnqvist, J. (2007). Personality characteristics of research volunteers. European Journal of Personality, 21(8), 1017-1030. DOI: 10.1002/per.655