With personality or, more generally, individuality we take as our level of analysis the person (not necessarily a human person). But personality could just the consistent, differentiated behavior of a particular system.
So this is one of those I-haven’t-seen-the-paper-yet-just-the-pop-sci-summary but
[Researchers] then asked [MZ and DZ twins] if they would find the same [altruistic] qualities desirable in potential mates.
Statistical analysis of their responses suggested that, in our evolutionary past, those with a stronger mate preference towards altruistic behaviour mated more frequently with more altruistic people.
That means that altruistic genes would be more prevalent than selfish genes.
This could be true only if couples who breed assortatively for high altruism have greater reproductive success than other types of couples, which is a pretty big leap (neverminding potential disconnects between stated preferences and actual mating behavior).
A genetic correlation between preferences and altruistic behavior is potentially interesting if the trait is neutral, as in this case assortative mating can increase the heritability of a trait (Lande 1977).
PS The target article is Phillips, Ferguson and Rijsdijk (in the press) A link between altruism and sexual selection: Genetic influence on altruistic behaviour and mate preference towards it. British Journal of Psychology.
(Source: telegraph.co.uk)
The drink-moderately-for-long-life prescript is making the rounds again with a new study showing the relationship is not explained by health status, social behaviors, or demographic variables:
even after adjusting for all covariates, abstainers and heavy drinkers continued to show increased mortality risks of 51 and 45%, respectively, compared to moderate drinkers.
This still doesn’t resolve weather moderate drinking is the cause or just a symptom of some other individual difference (intelligence, personality, covitality) that influences survival (Deary et al).
On this business, last night I had the most singular Imperial Double Extra Stout. The reviewers complaining about it probably didn’t drink it with a meal.
One limitation (or one might say, one advantage of) personality trait measures is that they try to assess how a person usually is or is perceived to be. To get at basic dispositions in how we think and act, what we feel and desire, you’d like to smooth over situational and contextual effects as much as possible. This procedure has the side effect of smothering most within-person variation in personality.
Allan Clifton presented data in a symposium organized by @hardsci on the nifty idea that other people provide a powerful context for the expression of personality.
The study involved getting participants (who first gave self-reports of their gross personality) to list 30 members of their social network (friends, classmates, family, roommates, coworkers). They then assessed what their own personality was like when they interacted with each person in their social network. While most of these self-perceptions agreed with the initial assessment of the target’s own “usual” personality, there was some variability. For example, one participant might rate themselves as normally agreeable but highly disagreeable when they are with either of their roommates.
The next step was to get a sample of the people in a target’s social network to in turn rate the target. It turns out that these informant reports converged with the target’s own assessment. The two roommates rated the participant as highly disagreeable while everyone on their sports team assessed the target as agreeable.
So it seems that other people are strong contexts in which our personalities are expressed, perceived, and understood. This goes some way toward being more specific in the debate over situations and behavior. One criticism of this research program–an agenda that explores within-person variability in personality and the environment in which it is expressed–is that it has never been very exact in what exactly a situation is, how they are defined and classified. Clifton’s study gives the specifics. This makes sense particularly if we think that personality variation is an adaptive individual difference to different social niches.
If you have an eye for such things, you will have noticed that in addition to changing the domain name of the Reader I have also switched from hosting on Posterous to Tumblr.
Why? The main motivation was that I’ve grown bloody tired for making blog posts using email editors. Emailing content to Posterous was certainly easy but it leadens you with whatever HTML your email client decides to give you, and both Postbox and Gmail are pretty bad at it. If the clients are not inserting extraneous div’s or line break tags, they are adding in their own CSS directives. Enough.
I’ve been tumblelogging (as _why defined it) since 2007 but in the last year I’ve noticed more content on Tumblr that goes beyond “curation”. I have been thinking of switching for the past 6 months (by crossposting to both services) but several other factors prompted me to effect a full move.
There are one or two things missing in the move. The most important is comments. Posterous did them out of the box. Here I’ll have to set up something like Disqus—if I decide to have comments at all. I’d love to hear your thoughts.
Studies based on the Gallup-Healthways Well-Being Index of the US are starting to trickle out. Researchers have used this data to replicated a well-known finding: global measures of well-being are U-shaped, peaking when you are young and old, with the inflection point at around age 54. Hedonic measures of negative affect (such as stress and worry), on the other hand, consistently decrease as we age.
Stone et al. A snapshot of the age distribution of psychological well-being in the United States. Proceedings of the National Academy of Sciences (2010) vol. 107 (22) pp. 9985-9990 doi: 10.1073/pnas.1003744107
When I first studied evolution as a sophmore in college the final exam included an open-ended question about whether humans were still evolving. I cannot remember what I wrote—that was before I really understood how to think about evolution—but my answer was probably all muddled.
Recent genetic evidence has gotten us used to the idea that humans have undergone strong and rabid selection regimes over the past 10,000 years. But there is still much to adapt to
Infectious diseases have the potential to act as strong forces for genetic selection on the populations they affect. We find that an HIV infection similar to that currently affecting sub-Saharan Africa could not yet have caused more than a 3 per cent decrease in the proportion of individuals who progress quickly to disease. Such an infection is unlikely to cause major genetic change until 400 years have passed since HIV emergence. However, in very severely affected populations, there is a chance of observing such major genetic changes after another 50 years.
and (although using ‘adapt’ in the sense of ‘acclimatize’)
Despite the uncertainty in future climate-change impacts, it is often assumed that humans would be able to adapt to any possible warming. Here we argue that heat stress imposes a robust upper limit to such adaptation. Peak heat stress, quantified by the wet-bulb temperature TW, is surprisingly similar across diverse climates today. TW never exceeds 31 °C. Any exceedence of 35 °C for extended periods should induce hyperthermia in humans and other mammals, as dissipation of metabolic heat becomes impossible. While this never happens now, it would begin to occur with global-mean warming of about 7 °C, calling the habitability of some regions into question.
Both of these studies are speculative and theoretical but show that evolutionary biology should look forward just as soon as look backward.
Jonah Lehrer recounts the upsides of travel beyond pleasure:
THE GOOD NEWS…is that pleasure is not the only consolation of travel. In fact, several new science papers suggest that getting away – and it doesn’t even matter where you’re going – is an essential habit of effective thinking. It’s not about a holiday, or relaxation, or sipping daiquiris on an unspoilt tropical beach: it’s about the tedious act itself, putting some miles between home and wherever you happen to spend the night.
The article goes on to discuss studies on temporal and spatial construal and the effects of living abroad on creativity. The article makes it sound like anyone who travels will be more creative without wondering whether there is something different about people who like to travel which is…exactly what the studies controlled for.
The study by Jia where participants were told that either a task was devised by students in Greece or by students in Indiana provided a randomization that allows us to ignore individual differences of the participants. The other study on the Duncker problem and living abroad conditioned on Openness to experience, the personality dimension linked to creativity and divergent thinking.
So, it isn’t just that people who think different are prone to wander. Travel really does change the way you think.
I am all for individual differences but they can be overcome by the main effects of treatment. But because individual differences occur everywhere in psychology, properly conveying research results needs to attend to how traits like personality and intelligence were handled.
Two papers are out in Current Biology cover chimpanzee experiences with death.
The first is on the death of Pansy, a 50+ year-old chimp at the Blair Drummond Wildlife Park. The authors don’t shy away from anthropomorphic language:
During Pansy’s final days the others were quiet and attentive to her, and they altered their nesting arrangements (respect, care, anticipatory grief). When Pansy died they appeared to test for signs of life by closely inspecting her mouth and manipulating her limbs (test for pulse or breath). Shortly afterwards, the adult male attacked the dead female, possibly attempting to rouse her (attempted resuscitation); attacks may also have expressed anger or frustration (denial, feelings of anger towards the deceased). The adult daughter remained near the mother’s corpse throughout the night (night-time vigil)
These behaviours highlight the interest of a comparative evolutionary perspective on death and dying in species without symbolic representations of death or death-related rituals.
The second report is on wild chimpanzees carrying their dead infants:
An obvious and fascinating question concerns the extent to which [the mothers] “understood” that their offspring were dead. In many ways they treated the corpses as live infants, particularly in the initial phase following death.
While these are both small observational studies, it is encouraging that researchers are able to share their impressions of what they’ve seen. Because we know death, it is entirely fair to start from our own experience to guide—if not our understanding—at least our questions in investigating these phenomena.
On a happier note, bonobos may sometimes mean “no” when the shake their heads.
photo by Tatyana Humle via Discovery News
Dogs are a great study system for behavior because you have a set of breeds that have undergone recent, strong, and divergent selection for specific behavioral characteristics over a very short period of time (~15ky—we are evolution here, so anything on the order of thousands of years is considered recent). This has also resulted in a great deal of diversity, not only in behavior, but also in morphology and lifespan.
Careau and colleagues tie these strands together:
Here we tested whether proactive [dog] personalities (high levels of activity, boldness, and aggression) are related to a fast “pace of life” (high rates of growth, mortality, and energy expenditure). Data from the literature provide preliminary evidence that artificial selection on dogs (through domestication) generated variations in personality traits that are correlated with life histories and metabolism. We found that obedient (or docile, shy) breeds live longer than disobedient (or bold) ones and that aggressive breeds have higher energy needs than unaggressive ones.
They posit a correlated response to selection on personality as the explanation for these changes in life-history parameters.
There is something fundamentally Darwinian in this study: looking at artificial and unconscious selection by humans as a complex evolutionary process.
Photo cc-by shinkusano
Over at The Hardest Science, Srivastava is gearing up to teach a course on SEM and thinking about how to warn students against the pixie dust approach to modeling and analysis.
This is definitely not easy, and something I struggle with, even when I have the time to prepare and know better. Last week I was helping someone learn how to do multi-level modeling in SPSS, a software package that apparently I am supposed to be competent with. I was so happy when I figured out the MIXED function to get the output I wanted, that this is all I was able to focus on. I totally forgot about conveying the higher level concepts of model formulation, such as writing out equations for each of your models and plotting regression lines for each of the subjects or treatment levels to get a feel for where modeling energy should be expended. Part of the problem is that I don’t know anything about plotting in SPSS. A poor excuse, I know.
Our tools do constrain us, and while knowing the principles and concepts is important, there is another aspect of statistical literacy, which is making your tools do what you want.
Photo cc-by FordRanger
For ethical reasons, psychological participants must be given a consent form that details what the experiment is about and what will be required of them. Unfortunately, these participant information sheets often turn into a page or two of turgid prose that winds up with the feel and finish of the end user license agreements you see during software installation. Like a EULA or the contract you sign for a flat, these documents are not actually designed to be read, digested, and understood. The point rather, is to make the researcher feel like they are being responsible and informative and to get the participant to “click agree” at the bottom as quickly as possible.
A nice counter example are the instructions given to participants during a set of experiments about self-other knowledge of personality characteristics (more on these findings in time):
These 10 minutes are completely unstructured, it’s up to you guys how you want to get to know each other. Try to give everyone a chance to talk and try to get to know everyone, but other than that, just do whatever you would normally do when trying to get to know a group of new people.
Participants are humans, not lawyers.
image cc-by doctorow
Chasing pregnant women, congressional district × budgeting shenanigans, Big Science (with a capital B and a capital S) comes to child health and development as the National Children’s Study seeks to following children from birth to age 21. The ambition and scope is a bit staggering, but they intend to collect hundreds of phenotypic, genotypic, and environmental measurements for each participant and compare them against outcomes in pregnancy, development, behavior, and health with a particular focus on asthma, obesity, and injury.
I guess we have 21 years to look forward to the results of gene × environment interactions on temperament and emotional regulation, though from the wording in the research plan on exposures and outcomes (pdf) I cannot tell if they intend to collect personality data on the parents as well.
But the big problem the Times is reporting is with recruitment. Mothers and communities are wary of investing in the project when it isn’t clear how the data are to be used or what the benefit will be. This is a problem in smaller scale research, too, such as with the hapless psychology study participant who might get some cake, or £5, or even as little as 5¢ if they wander into the peat bog of Mechanical Turk. There is no reason to invest because there is no way to track your returns. And with an enterprise as massive as the National Children’s Study, carried over such an extensive period of time, we have to be comfortable with the possibility that the study will affect the very exposures it is designed to detect. Mother’s are right to ask: what’s in it for me and my baby?
A report from the folks at Hunch (Mac vs PC People: Personality Traits & Aesthetic/Media Choices) tells us what we already knew: Mac users like to be different while PC users prefer to stick with what they’re comfortable with. While the questions are nominally about aesthetics, media and consumer choices, and “personality,” for the most part they’ve actually made a questionnaire that captures several facets of the personality dimension Openness to experience.
A lot of the questions hit on the facet of Artistic interests (“Which type of art do you prefer?”, mostly through the choice of Modernism, and I would hazard that most folks who chose the Impressionist painting were picking ‘flowers’ rather than ‘Monet’; all of the items about aesthetic or design preferences) although there are a few questions related to Extraversion (“How often do you throw parties?”) and Agreeableness (attitude to authority). Other questions probably hit on both high Openness and low Conscientiousness at the same time (task preference).
NB: the sample size for some of these items is huge! (N > 50,000) Of course, as I tell my students, a little more methodological details would be nice:
Summary findings in this report are noted when there is a statistically significant difference in the answers of the two subsets being compared.
graphic cc-by Rétrofuturs
