In a way, all psychologists are “evolutionary” psychologists, as the only alternative views are Creationism and seeding theory (extraterrestrials having seeded our planet with humans). So really, any scientific ado must be about what evolved inside of our big primate heads, not whether human psychology has evolved.
Prior to evolutionary psychology, the dominant social science view assumed our heads contained a blank slate—humans were designed by evolution to simply learn (nearly) everything from our local environment. Several developments over the latter part of the last century led some psychologists to seriously question this social science orthodoxy, including findings that humans naturally learn some things much more easily than others, that many aspects of human psychology are universal across cultures and are often shared with similar species, and that just about every psychological trait shows an appreciable level genetic heritability.
Rooted in this new scientific reality, psychologists in the 1980s bravely started to look at human thought and behavior as potentially resulting from not just one blank slate learning mechanism, but many evolved mechanisms. Perhaps some human proclivities like easily learning to fear snakes and preferring physically symmetrical mating partners are psychological adaptations, specially designed biases of thought and behavior evolved in our ancestral past as hunters and gatherers.
Like other sciences, evolutionary psychologists utilize theories and weigh the value of empirical evidence for determining which psychological adaptations are likely to exist. Unlike most other perspectives in psychology, evolutionary psychologists gather evidence from a vast range of sciences, including cultural and physical anthropology, population and molecular genetics, evolutionary biology, neuroscience, and comparative psychology. Despite this methodological sophistication, evolutionary perspectives on humanity are viewed by some as controversial. This is partly due to mistakes made when thinking about the implications of humans as an evolved species.
The most common mistake is falling victim to Naturalistic Fallacy thinking—believing that because something is natural, it is therefore good. Evolutionists do not argue that what is natural is also necessarily good. Lots of very bad things exist in the natural world, with many species adaptively designed for committing morally atrocious acts such as murder and rape. Humans are probably not exempt from possessing some rather nasty evolved mental and behavioral tendencies. What evolutionary psychologists do argue is that we need to fully understand our natural psychological design in order to most effectively create the good world we all desire. Much of our natural design will help with this task, as the capacity for trust and love among friends and family are likely just as evolved as our more malicious sides.
A related mistake is thinking that evolutionary psychologists are conservative ideologues who wish to maintain the status quo found in traditional societies. Josh Tybur and his colleagues studied the political attitudes of graduate psychology students in 2007 and found that evolutionists were equally liberal to those from other perspectives. Evolutionary psychologists are just as interested as others in creating a progressive social world, they just believe that knowing our natural, evolved tendencies provides the brightest path forward in making that world possible.
Read more in this debate: Volkmar Sigusch.