A B S T R A C TUnderstanding the development of moral attitudes toward unrelated individuals from different social groups may provide insights into the role of biological and cultural factors in prosocial behavior. Children (3-11 years old, N=80) were presented with moral dilemmas describing a conflict of interests between a con-specific (human) and another species (animals or aliens). Participants were asked to evaluate the behavior of a human in terms of 'good' and 'bad' , and to choose whom they would help: a human aggressor who benefits at the expense of a victim in vital need, or the victim. Results showed that the older children preferred to help non-human victims significantly more often than the younger children. The evaluation of human actions was related to the proportion of such preferences. These findings are discussed from the perspectives of kin selection theory, group selection theory and the system-evolutionary approach. The implications of the study for moral education are suggested.

Recent research strongly supports the idea that cardiac activity is involved in the organisation of behaviour, including social behaviour and social cognition. The aim of this work was to explore the complexity of heart rate variability, as measured by permutation entropy, while individuals were making moral judgements about harmful actions and omissions. Participants (N ¼ 58, 50% women, age 21-52 years old) were presented with a set of moral dilemmas describing situations when sacrificing one person resulted in saving five other people. In line with previous studies, our participants consistently judged harmful actions as less permissible than equivalently harmful omissions (phenomenon known as the "omission bias"). Importantly, the response times were significantly longer and permutation entropy of the heart rate was higher when participants were evaluating harmful omissions, as compared to harmful actions. These results may be viewed as a psychophysiological manifestation of differences in causal attribution between actions and omissions. We discuss the obtained results from the positions of the system-evolutionary theory and propose that heart rate variability reflects complexity of the dynamics of neurovisceral activity within the organism-environment interactions, including their social aspects. This complexity can be described in terms of entropy and our work demonstrates the potential of permutation entropy as a tool of analyzing heart rate variability in relation to current behaviour and observed cognitive processes.

The goal of the present research was to investigate psychophysiological bases of moral dilemmas solving by children. We assessed the heart rhythm of Russian children aged 4—11 (N=75) during interview, solving moral dilemmas, and subsequent questionnaires. We compared data of two age group: 4—7 years old and 8—11 years old. The task of moral dilemma was to choose who would take a resource: an in-group member (resource is needed for an optional benefit) or an out-group member (resource is needed for survival). questionnaires. There was a significant decrease of heart rate moral decisions in younger children (4—7 years old). There was no differences of heart rate moral decisions in elder children (8—11 years old). We speculate that younger children have no mismatch during decision making due to scarcity of their new experience. They do not have to activate the adaptation processes during moral dilemmas solving. The results are discussed from the position of the system evolutionary approach and the notions of changes in heart rate variability as an indicator of adaptation processes.