The researchers determined from key experiments that the asymmetry of nerve connections between the right and left brain is an important factor that leads to differences in behavior. Accordingly, fruit flies with symmetrical nerve cell connections head more indirectly towards objects than animals with asymmetrical brains. The authors assume that this additional variability factor enables animals to develop heading differences even with the same or similar genetics, thereby increasing the likelihood of survival of the population.

Why every person and every animal differs in behavior from its peers is one of the central questions of neurobiology and psychology. The answer to this question is often given as an interplay of genetic differences and environmental factors. Many studies have shown the importance of both factors. To illustrate this: genetics and environmental factors can be comprehensively used to explain the similarities in behavior of identical twins. They are genetically identical and grow up in most cases under very similar environmental conditions. However, both factors are much less suitable to explain the differences in behavior of identical twins. A third factor, the influence of developmental noise is in that context much better suited to explain the differences.