Interesting example with 'guilt' as an emotion that may help to foster cooperation. This reminds me of an idea of evolution being treated as a thermodynamic process and 'punishment' as a crucial mechanism in the evolution of cooperation. The authors argue that "punishment acts like a magnetic field that leads to an 'alignment' between players, thus encouraging cooperation."[1]

[1] https://www.technologyreview.com/s/608139/new-model-of-evolu...