seratonin and morality

Serotonin regulates our moral judgements

By mdbownds@wisc.edu (Deric Bownds) on morality

Crockett et al. have done some fascinating experiments demonstrating that increased serotonin makes individuals less likely to endorse moral scenarios that result in the infliction of personal harm to others. They examine the effects of a single high dose of the selective serotonin reuptake inhibitor (SSRI) citalopram on moral judgment in healthy volunteers using a set of hypothetical scenarios portraying highly emotionally salient personal and less emotionally salient impersonal moral dilemmas with similar utilitarian outcomes (e.g., pushing a person in front of a train to prevent it from hitting five people and flipping a switch to divert a train to hit one person instead of five people, respectively). Here is their abstract:
Aversive emotional reactions to real or imagined social harms infuse moral judgment and motivate prosocial behavior. Here, we show that the neurotransmitter serotonin directly alters both moral judgment and behavior through increasing subjects’ aversion to personally harming others. We enhanced serotonin in healthy volunteers with citalopram (a selective serotonin reuptake inhibitor) and contrasted its effects with both a pharmacological control treatment and a placebo on tests of moral judgment and behavior. We measured the drugs' effects on moral judgment in a set of moral 'dilemmas' pitting utilitarian outcomes (e.g., saving five lives) against highly aversive harmful actions (e.g., killing an innocent person). Enhancing serotonin made subjects more likely to judge harmful actions as forbidden, but only in cases where harms were emotionally salient. This harm-avoidant bias after citalopram was also evident in behavior during the ultimatum game, in which subjects decide to accept or reject fair or unfair monetary offers from another player. Rejecting unfair offers enforces a fairness norm but also harms the other player financially. Enhancing serotonin made subjects less likely to reject unfair offers. Furthermore, the prosocial effects of citalopram varied as a function of trait empathy. Individuals high in trait empathy showed stronger effects of citalopram on moral judgment and behavior than individuals low in trait empathy. Together, these findings provide unique evidence that serotonin could promote prosocial behavior by enhancing harm aversion, a prosocial sentiment that directly affects both moral judgment and moral behavior.
A commentary by Tost and Meyer-Lindgerg notes:
In a broader context, the work by Crockett et al. supports a number of interesting conclusions. It extends prior evidence suggesting that there are at least two major pharmacological routes that modulate human social behavior: a direct route (“bottom-up”) involving prosocial neuropeptides such as oxytocin and vasopressin, which promote prosocial behaviors such as attachment, empathy, and generosity, and an indirect route (“top-down”) involving serotonin, which delimits antisocial behaviors by reducing negative affect and enhancing the aversiveness of harming others (see figure below). If this is true, functional interactions between these transmitter systems are likely. Consistent with this, Crockett et al. report a pronounced impact of serotonin augmentation on social decision making in subjects with high trait empathy, a finding suggestive of additive prosocial effects of both routes. The study also demonstrates that the effects of serotonin on prosocial behavior are relatively specific and are absent under norepinephrine augmentation with atomoxetine.

Habit Formation

How to form a habit

This has nothing to do with nuns' clothing. Habits are those behaviours that have become automatic, triggered by a cue in the environment rather than by conscious will. Health psychologists are interested for obvious reasons - they want to assist people in breaking unhealthy habits, while helping them adopt healthy ones. Remarkably, although there are plenty of habit-formation theories, before now, no-one had actually studied habits systematically as they are formed.

Phillippa Lally and her team recruited 96 undergrads (mean age 27) and asked them to adopt a new health-related behaviour, to be repeated once a day for the next 84 days. The new behaviour had to be linked to a daily cue. Examples chosen by the participants included going for a 15 minute run before dinner; eating a piece of fruit with lunch; and doing 50 sit-ups after morning coffee. The participants also logged onto a website each day, to report whether they'd performed the behaviour on the previous day, and to fill out a self-report measure of the behaviour's automaticity. Example items included 'I do it automatically', 'I do it without thinking' and 'I'd find it hard not to do'.

Of the 82 participants who saw the study through to the end, the most common pattern of habit formation was for early repetitions of the chosen behaviour to produce the largest increases in its automaticity. Over time, further increases in automaticity dwindled until a plateau was reached beyond which extra repetitions made no difference to the automaticity achieved.

The average time to reach maximum automaticity was 66 days, although this varied greatly between participants from 18 days to a predicted 254 days (assuming the still rising rate of change in automaticity at the study end were to be continued beyond the study's 84 days). This is much longer than most previous estimates of the time taken to acquire a new habit - for example a 1988 book claimed a behaviour is habitual once it's been performed at least twice a month, at least ten times. In fact, even after 84 days, about half of the current study participants had failed to achieve a high enough automaticity score for their new behaviour to be considered a habit.

Unsurprisingly perhaps, more complex behaviours were found to take longer to become habits. Participants who'd chosen an exercise behaviour took about one and a half times as long to reach their automaticity plateau compared with the participants who adopted new eating or drinking behaviours.

What about the effect of having a day off from the behaviour? Writing in 1890, William James said that a behaviour must be repeated without omission for it to become a habit. The new results found that a single missed day had little impact on later automaticity gains, either early in the study or later on, suggesting James may have overestimated the effect of a missed repetition. However, there was some evidence that too many missed repeats of the behaviour, even if spread out over time, had a cumulative effect, reducing the maximum automaticity level that was ultimately reached.

It seems the message of this research for those seeking to establish a new habit is to repeat the behaviour every day if you can, but don't worry excessively if you miss a day or two. Also be prepared for the long haul - remember the average time to reach peak automaticity was 66 days.

This research has a serious shortcoming, acknowledged by the researchers, which is that it depended entirely on participants' ability to report the automaticity of their own behaviour. Also, the amount of data made it hard to form clear conclusions about the need for consistency in building a habit. However, the study provides an exciting new approach for exploring habit formation and future research could easily remedy these shortcomings.
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Lally, P., van Jaarsveld, C., Potts, H., and Wardle, J. (2010). How are habits formed: Modelling habit formation in the real world. European Journal of Social Psychology DOI: 10.1002/ejsp.674

Tomasello Interview

Very interesting interview of the american anthropologist Michael Tomasello (Max-Planck-Institut for Evolutionary Anthropology, Department of Developmental and Comparative Psychology, Leibzig, Germany), recorded in October 2008 on the German public channel 3Sat. This is the full version of the interview, which covers a broad range of topics from the notions of (shared) intentionality and its ontogenic emergence in human beings to the origins of human communication (in contrast to the one of the Great Apes), to the biological and cultural dimensions of human social behaviour, and to collaboration and altruism. Enjoy! (For more information on these topics, check Michael Tomasello's website: http://email.eva.mpg.de/~tomas/ , as well as the series of four lectures he gave upon receiving the Jean Nicod 2006 prize: http://www.institutnicod.org/lectures2006_outline.htm)