For a long time, behavioral scientists and psychologists thought that we could learn about the behaviors of our species by just studying any humans and then generalizing findings to all the rest of humanity. For example, if we study the way that US-American college students think and behave, then we would know what “normal” human behavior is, and how all humans should think and behave. 

In the 21st century, psychologists joined ethnologists and anthropologists and realized that human thinking and behavior is much more diverse and much more shaped by culture than was assumed, and so scientists started to carry out more cross-cultural research. 

Through cross-cultural research, we realize how flexible the human mind is and that we humans organize our communities in many diverse ways through norms, traditions, beliefs, language, technologies. Our culture and the language we speak influences everything from how we teach and learn, how we perceive colors, space, time, our social environment and our place in it, how we interact with family and strangers, the kinds of personalities that we might develop, the kinds of things we value, and our judgment of right and wrong. Historic factors like how our ancestors made a living, their experience of conflict and cooperation, or epidemics still influence our cultural minds today. 

But through cross-cultural research we also realize what all humans have in common, no matter their cultural background, and hence what it means to be human.