The Ash Twins Blog

From a piece on neuroscience and philosophy by Patricia Churchland, published in Neuron, November 2008:

[H]uman groups can be large and… kindly behavior may extend beyond the circle of kin and even beyond the community. Traditional moral philosophers are apt to attribute this phenomenon to a unique relationship with God, to the greater intrinsic goodness of humans, to our greater intelligence, or to some combination of these. Though these may be implicated, it is worth considering that biologically rooted dispositions explain extending social attachment beyond kin and clan.

Bowles (2006) has argued that altruism and lethal competition between human groups coevolved. Just as a chimp troop is apt to expand its territory and resources by killing off members of a neighboring troop, early hominins probably found it paid to raid weaker hominin clans and divide the spoils in a sufficiently fair-ish way to ensure loyalty. Able manpower to defend and attack would be an important consideration in enlarging the group and extending attachments.

Even so, amalgamation is a risky business, since problematic newcomers could undermine the welfare or stability of the group. Will they be a social boon or burden? Before accepting a newcomer, the group needs assurance that he can bond normally and is not socially or emotionally handicapped. The hypothesis is that, as a first-pass filter for trustworthiness, unconscious mimicry serves rather well.

Psychological studies on unconscious mimicry in humans show that the posture, mannerisms, prosody,  and words of the experimenter are unknowingly mimicked by the experimental subject as the two engage on a shared task. Additionally, subjects whom the experimenter mimics tend to evaluate the experimenter more favorably than if they were not mimicked (Chartrand and Dalton, 2008). Subjects who experience social stress before beginning the task display a higher level of unconscious mimicry than otherwise. Casual observation of humans getting to know each other supports the science, indicating that unconscious mimicry functions as ‘‘social glue.’’ The production and detection of mimicry requires energy, implying that the brain cares enough to spend the resources on a regular basis. Why? Is it possible that humans use imitative behavior as evidence of normal social capacities?

Humans appear to be vastly more imitative than other primates (Tomasello et al., 2005). When infants begin to imitate, a deeper level of bonding seems to emerge. Why does infant imitation bring such joy to parents? One factor among others is that imitative performance predicts that the child has the neural wherewithal to learn what he needs to learn to survive, both socially and in the wider world. Negatively put, if the infant fails to imitate, the failure is a worrisome predictor that the brain lacks what the infant needs to get on in the social world. In the ancestral condition, parental investment may be reduced accordingly. Mimicry, I suggest, serves as a social signal because it indicates the presence of a crucial social capacity, namely the capacity to ‘‘read minds’’—know what others intend, believe, expect, and feel. If mimicry can be used to evaluate infants, so also strangers.

The idea is that adults respond positively to mimicry in social situations because imitative behavior is a powerful signal of social competence that inaugurates trust or assures the continuation of trust. If the newcomer is trustworthy, in this sense, he will probably behave in a way that is consistent with good citizenry. This means that mimicry, even if unconsciously produced and unconsciously detected, is a safety signal. The level of [oxytocin], and hence the level of trust, probably increase; defensive behavior and autonomic arousal decrease. Mimicry is not a fail-safe predictor of social competence, and full acceptance will be gradual. As a first-pass filter, however, it may weed out the worst. As a first-pass filter, it may also set the stage for trade and cooperation with other clans. Some strangers with evil intent may pretend so thoroughly that they do unconsciously mimic. Others may not, thus tipping off the insiders that something is amiss. The occasional sociopaths may easily gain entry, though the old hands may read groveling behavior as too good to be true.