To see how killing can lead to more killing, a team of researchers got their volunteers to witness and join in the (faked) extermination of invertebrates. Pill bugs, similar to the woodlouse in the picture, were used.
In my words, not the authors' (except for the quotes), this is why they did what they did.
THE ARGUMENT
• killing is a horrible thing to do, and thus "provokes psychological discomfort or threat in the killer".
• this "cognitive dissonance" (Leon Festinger's term) prompts the killer to try to stop feeling so bad.
• One way to ease the misery is to try to justify the killing.
• Justifications can look to an external source, e.g. obeying orders; or, more frivolously, the T-shirt slogan: My rice krispies made me do it.
• Killing someone, however, is such a powerful expression of personal agency that blaming the boss, the cereal (killer?) or anyone else, can seem an inadequate response. So what to do?
• Well, the killer may reinterpret the killing, "to view it as other than it is". E.g. ethnic cleansing; massacres in El Salvador described as La Limpieza (the Clean-up); and so on.
• However it's done, if the behaviour is justified it tends to be maintained, or even reinforced.
The basic idea is that if people are persuaded (in a lab environment, with all the pressure to be helpful-and-obedient-to-scientists that Milgram noted) to commit an initial killing, this is a threat to their self-image as nice guys or gals.
How big a threat? That depends on how much they care about bugs. One aspect of this is perceived similarity: did the volunteers see themselves and the bugs as part of a unified creation sharing the earth, or were they more in the Réné Descartes animals-are-soulless-machines camp? The greater the perceived similarity (cunningly measured by questionnaire some weeks earlier), the greater the threat, so goes the theory.
Eighty-two volunteers (psychology students) were recruited. Those of you who love pill bugs will be glad to know that two refused even to start. Six more reckoned (correctly) that the bugs weren't really being killed. That left 74 woodlouse-mashers. Some were persuaded to feed a bug into the (fake) shredder; others only saw it being done. Then they were left alone with a row of bugs in cups and instructions to get exterminating.
THE HYPOTHESIS
Participants who experienced more threat from doing the initial killing would work harder to justify themselves, and so be readier to carry out the self-paced killings
Those who didn't initially kill, and who felt some similarity with the bugs, would be more reluctant to kill
Thus the researchers predicted an interaction between perceived similarity and numbers of bugs killed during the (self-paced) extermination task.
THE FINDINGS
Sure enough, when people didn't do the first killing, those who felt more like bugs were more reluctant to mash the little critters. But when they had already killed, perceived similarity didn't matter (no relationship with numbers killed). In a second experiment, the initial death toll was upped from 1 to 5 bugs, and that made 'similars' kill more, not fewer bugs. They also killed more than did people who didn't see themselves as like bugs. Perhaps most disturbingly of all, among participants who initially killed 5 bugs, more self-paced killing was associated with higher scores on a measure of mood. In other words, killing more made them feel better.
This isn't just about brutality desensitising people, because participants who saw themselves as more like their victims killed more than people who didn't. Nor is it just that participants were 'primed to kill' by the initial killing - because, again, similarity mattered.
The researchers acknowledge their study's limitations. Bugs aren't people; labs aren't battlegrounds. But they think their method could be useful, and they say the findings shed light on what we know from the study of genocides and other mass killings. Killing once can make future killing easier. Much better not to start at all.
Reference:
Martens, A., S. Kosloff, et al. (2007). "Killing begets killing: Evidence from a bug-killing paradigm that initial killing fuels subsequent killing." Personality and Social Psychology Bulletin 33(9): 1251-1264.
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