Research has revealed a variety of left–right asymmetries among vertebrates and invertebrates. In many species, left- and right- lateralized individuals coexist in unequal numbers (‘population-level’ lateralization). It has been argued that brain lateralization increases individual efficiency. However, individual efficiency does not require the alignment of the direction of lateralization in the population. It has thus been hypothesized that the alignment of lateralization at the population level may arise as an evolutionarily stable strategy when individually asymmetrical organisms must coordinate their behavior with that of other asymmetrical organisms. Game-theoretical models in which asymmetric individuals engage in intraspecific and interspecific interactions suggest that population-level lateralization is more likely to evolve in social than in non- social species. Empirical data supporting the hypothesis come from studies comparing social and non-social species of bees.
Elisa Frasnelli is completing her PhD work at the Center of Mind and Brain Sciences, University of Trento, Italy, focusing her interest on brain lateralization, i.e., the differential functional specialization of the left and right sides of the brain. She is investigating lateralization both from a theoretical point of view, using her mathematical training (she graduated in Physics and Biomedical Tecnologies) and from an experimental point of view, focusing on lateralization in insects. On these topics she published four peer- reviewed papers. She has been a visiting student in the Centre for Neuroscience and Animal Behaviour at the University of New England in Australia.