Social selection

Social selection is an alternative theory to sexual selection proposed by the evolutionary biologist Joan Roughgarden.

Overview
Roughgarden first began thinking Darwin may have been in error about sexual selection after she attended a 1997 gay pride parade in San Francisco. According to Roughgarden:

I was just stunned by the sheer magnitude of the LGBT [Lesbian, Gay, Bisexual, Transgender] population. Because I’m a biologist, I started asking myself some difficult questions. My discipline teaches that homosexuality is some sort of anomaly. But if the purpose of sexual contact is just reproduction, as Darwin believed, then why do all these gay people exist? A lot of biologists assume that they are somehow defective, that some developmental error or environmental influence has misdirected their sexual orientation. If so, gay and lesbian people are a mistake that should have been corrected a long time ago. But this hasn’t happened. That’s when I had my epiphany. When scientific theory says something’s wrong with so many people, perhaps the theory is wrong, not the people.

Roughgarden began to look for sexual anomalies which contradict the sexual selection theory and wrote it can’t explain the homosexuality that’s been documented in over 450 different vertebrate species. In 2004 she published a challenge to sexual selection titled Evolution's Rainbow which offered a critique of Darwin's sexual selection theory based on instances in which animals do not follow traditional sex roles where the male attempts to impress the female, and the female chooses her mate. It also contains a literature survey on unexpected sexual behavior in many species of animals.

She published another paper in 2006 with two other scientists criticising sexual selection and proposing an alternative replacement termed social selection. In response many scientists criticised the paper writing that Roughgarden's theory of social selection contains many flaws and should not be considered a new theory as her data does not contradict sexual selection. Roughgarden and her colleagues replied to the criticism and wrote "[our theory] is about the number of offspring successfully reared and is not an extension of sexual selection theory."

In her book The Genial Gene: Deconstructing Darwinian Selfishness (2009) the case against sexual selection theory is continued by Roughgarden and social selection is presented as an alternative. The book lists 26 phenomena not explained by the current sexual-selection theory that are better explained by social selection. According to Roughgarden, sexual selection derives from a view of natural behavior predicated on the selfish-gene concept, competition and deception, whereas the social selection derives from teamwork, honesty, and genetic equality.

Criticism
PZ Myers, a biologist at the University of Minnesota wrote "I think much of what Roughgarden says is very interesting. But I think she discounts many of the modifications that have been made to sexual selection since Darwin originally proposed it. So in that sense, her Darwin is a straw man. You don’t have to dismiss the modern version of sexual selection in order to explain social bonding or homosexuality." In response to criticism Roughgarden has written "I think many scientists discount me because of who I am. They assume that I can’t be objective, that I’ve got some bias or hidden LGBT agenda. But I’m just trying to understand the data. At this point, we have thousands of species that deviate from the standard account of Darwinian sexual selection. So we get all these special case exemptions, and we end up downplaying whatever facts don’t fit. The theory is becoming Ptolemaic. It clearly has the trajectory of a hypothesis in trouble."

Despite Roughgarden's comments about sexual selection being in trouble, most scientists have disagreed with her theory and have written she has exaggerated the importance of homosexuality in animals.