This article traces the contributions of mirror neuron theories in neuroscience to debates on literature and related theories of mimesis or, as Erich Auerbach defined it, the representation of reality. The “ensemble” descriptor used for the visualization technologies on which we currently depend to chart the neuronal firing in the human brain is also an apt term for an additional translational issue between structure and what one might call the philosophical domain. The most carefully established data of brain activity is empirically confirmable on the micro level. Moving from it to the so-called “higher order” or more complex issues of meaning and use by humans, not least in cultural life, requires in effect a translation from micro evidence to ensemble evidence. Within the neurosciences, such translational processes are objects of seduction and suspicion at once. Yet an “ensemble” principle is not only active in brain mapping evidence, but in the “single brain” to “social brain” evidence field for neural mirroring. The brain in isolation represents only a slice of the field of the dialogic brain, the brain performing social cognition of others, the brain bringing the other’s existence into the individual’s embodied space through the individual’s internal simulation. This essay moves from the concept of the social brain to the suggestion of an ontological priority of representation in the mirror neuron paradigm. Is literature itself a relative of brain mirroring processes, and thus a form of biomimesis? And if we recognize literature and other representational processes as a part of “the human ensemble,” should we also recognize the capacity of literature and other art forms to mimetically influence our performance of physiological being?

Humans have an automatic tendency to imitate, as illustrated by unconscious mimicry during social interactions and behavioral interference effects in the laboratory. Automatic imitation is thought to arise from activation of the imitative motor representation during action observation, which is likely mediated by the overlapping representation of observed and executed actions in the mirror neuron system. In contrast to mechanisms of automatic imitation, models attempting to explain how automatic imitative tendencies are brought under intentional control are incomplete. In this dissertation, I use functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) to measure and disrupt neural activity during imitation interference tasks to expand current models of imitation control. In particular, I focus on dissociating imitation control from control over a related prepotent response tendency--spatial compatibility--to determine (1) whether control mechanisms involved in overcoming automatic response tendencies evoked by action observation utilize a dedicated mechanism and (2) whether imitation control involves modulation of the mirror neuron system. In addition, I explore the hypothesis that imitative control mechanisms may differ depending on whether control is exerted in reaction to a stimulus (after the automatic response tendency has been evoked) or in advance of a stimulus (reducing the degree of automatic response activation in the first place).

Results indicate that neural systems involved in reactive control of imitation are dissociable from those involved in controlling spatially compatible response tendencies. I propose a model of reactive imitation control involving interactions between prefrontal control regions and the mirror neuron system. In contrast to reactive control, I found no evidence of a dissociable preparatory imitation control mechanism in an fMRI study. However, TMS results suggest that preparatory control of imitation involves suppression of MNS activity, which can be reconciled with neuroimaging results through a general control that reduces the influence of visual input on the motor system. Thus, regardless of the timing, imitation control seems to involve modulation of MNS activity through interactions between general cognitive control systems and the more specific imitation circuits.

Humans and other social animals seem to place a positive reward value on the welfare of others. Many believe that this “prosocial inclination” is driven by empathy for others, though the mechanisms underlying this relationship remain unclear. An important subprocess within empathy is our ability to share in the internal and behavioral states of others, a process we will refer to as self other resonance. Evidence suggests that this ability is heavily driven by neural resonance, a brain mechanism in which the perception of internal states and behavior in others triggers correlated activity in motor, somatosensory and affective brain systems, potentially creating shared information states between individuals. Self-other resonance may foster prosocial inclinations by a simulation mechanism according to which the more we share in others’ states, the more we may be inclined to treat them as we would ourselves. Conversely, contextual factors that inhibit or enhance our degree of self-other resonance with others, like their group affiliation, their social distance, their race or their perceived character, also seem to modulate our prosocial inclinations towards them, suggesting common control mechanisms.

We hypothesize that individual differences in the neural correlates of self–other resonance and its control can predict individual differences in the behavioral correlates of prosociality and its modulation in response to context. We first examined which neural data during self-other resonance tasks was most informative about prosocial behavior in the Dictator Game, a task in which subjects decide how to allocate real money between themselves and 24 players (represented with a neutral-expression headshot, a name and a yearly income) of high and low incomes (Experiment 1, n=20). We then attempted to causally elucidate the relationship between self-other resonance and control by the use of a behavioral intervention (Experiment 2, n=34) and disruptive neuromodulation (Experiment 3, n=58), designed to enhance self-other resonance and disrupt top-down control, respectively. Finally, since all 78 subjects from experiments 1 and 3 underwent identical neuroimaging and behavioral protocols, we investigated gender differences in trait empathy and neural correlates of self-other resonance, including functional connectivity among regions implicated in self-other resonance and its control.

In Experiment 1, we found that individual differences in subjects’ vicarious activation in regions associated with self-other resonance (limbic system and somatosensory cortex), and regions associated with top-down control of pain, motor behavior and affect (temporoparietal junction, medial and dorsolateral prefrontal cortex) was correlated with individual differences in subjects’ prosocial decisions as well as their tendency to modulate these decisions in response to contextual information. Furthermore, we found evidence for functional connectivity between these self other resonance and top-down control areas, and found that this functional connectivity was also correlated with prosocial decisions. These findings suggest that self other resonance drives greater prosocial inclinations, while top-down control results in inhibition of prosocial inclinations, at least in the experimental setting we adopted. Indeed, disruptive neuromodulation of two putative control areas resulted in reliable increases in prosocial decisions (Experiment 3). The behavioral intervention designed to engage self-other resonance, on the other hand, did not show evidence of increasing prosocial decision-making (Experiment 2), though it did significantly alter the distribution of subjects’ offers to low-income players (increased normality and reduced variance). This null finding cannot exclude that more effective or longer interventions may indeed boost prosocial inclinations. Last, in examining gender differences, we found evidence for increased top-down control in males and increased bottom-up perceptual processing in females. This is consistent with previous findings in empathy research suggesting that females are more prone to vicariously respond to the states of others, while males are more prone to engage top-down control of affect and vicarious responding.

These results jointly suggest that self other resonance and control processes may be an important component of prosocial decision-making, by modulating the extent to which we put others’ welfare on par with our own, even when social cues typically associated with self other resonance are very limited. An important theoretical question is why self other resonance and its control seem to play such a crucial role in prosocial decision making in these conditions (when social cues are limited). We suggest that the embodied cognition framework provides a plausible functional mechanism that accounts for these findings.