Brain and cognitive processes of imitation in bimanual situations: Making inferences about mirror neuron systems

The relationship between mirror neuron systems and imitation is being widely studied. However, most if not all, studies on imitation have investigated only the mirror mode. The present study examined whether imitation in a mirror (specular) mode is likely to reflect similar or distinct neural processes and psychological principles as imitation in a non-mirror (anatomical) mode. Experiment 1 examined whether altering sensory information may reverse the typical mirror mode advantage, resulting in superior performance in the non-mirror mode. Experiment 2 examined whether the two different modes of imitation rely differentially on target selection (goals) and effector selection (means). Experiment 3 examined whether spatial translations are likely to occur in a typical non-mirror imitation mode. Experiment 4 examined whether non-mirror imitation would be the naturally selected mode of imitation under some situations. Findings from all experiments demonstrated marked differences between mirror and non-mirror modes of imitation. The implications of these findings may raise challenges for theories and models of mirror neurons.