From classic ethology to modern neuroethology: overcoming the three biases in social behavior research

•Modern social behavior research suffers from species, environment, and sex biases.•This reductionism has enabled great findings but restricted biological complexity.•Applying genetic tools with naturalistic settings provides new mechanistic insights.•Studying both sexes in social behavior research should become a must.

A typical current study investigating the neurobiology of animal behavior is likely restricted to male subjects, of standard inbred mouse strains, tested in simple behavioral assays under laboratory conditions. This approach enables the use of advanced molecular tools, alongside standardization and reproducibility, and has led to tremendous discoveries. However, the cost is a loss of genetic and phenotypic diversity and a divergence from ethologically-relevant behaviors. Here we review the pros and cons in behavioral neuroscience studies of the new era, focusing on reproductive behaviors in rodents. Recent advances in molecular technology and behavioral phenotyping in semi-natural conditions, together with an awareness of the critical need to study both sexes, may provide new insights into the neural mechanisms underlying social behaviors.