The Sexual and Social Intelligence Hypothesis is about sexual behaviour -mate recognition and (repeated) mate preference-. The SSIH states that sexual behaviour is of influence on (biological) evolution. Selection on genotype, phenotype and on sexual behaviour of the mate influences vertical evolution (species origination) by transferring genes and biosemiotic patterns. Sexual selection on sexual behaviour is also of importance on horizontal evolution because it raises social and sexual behavioural and cultural patterns. Cultural behavioural patterns are horizontal transmittable in groups, more or less regardless of genotype or phenotype.

Due to sexual selection on sexual behaviour of the mate the SSIH differentiates between mating by penetration and mating by making love. Making love, more specific bringing the mate to orgasm by sexual actions, is typical for humans (Homo). Most primates, bonobo’s to some extend excluded, mate by penetration. Bonobo’s are presumed to have evolved chronologically after the Pan-Homo split.

Making love demands both physical and cognitive skills. In fact making love is sexually operating on a body that -in heterosexual preferences- differs from one’s own sexual body and sexuality. Making love asks for (sexual) empathy, understanding the sexual needs of others and -in addition- ‘good’ sexual intentions. Mates are supposed to not hurt each other and not to leave them with physical harm or injuries. In the Sexual and Social Intelligence Hypothesis sex is considered as free will driven, based on mutual consensus. Rape is considered to be the exception to the rule; an anomaly. Making love is not a solely altruistic deed. In fact both mates want to experience an orgasm during sex. Its a mixture of egoistic and altruistic behaviour of two partners in the same sexual process.

The clitoris position in Pan is in the vagina. The clitoris position in Homo is hidden in the labia outside the vagina. The SSIH offers an explanation for these anatomically different positions through sexual selection and repeated mate choice. Besides explaining these anatomical facts the Sexual and Social Intelligence Hypothesis points orgasms (male and female alike) as selection pressure for the evolutionary split of Pan and Homo. 

Orgasm as selection pressure can be characterised within the (neuro)biological argumentation of emotions and needs. It can also be characterised within the (neuro)psychological arguing of striving and motivation. And within the biosemiotic discourse of signification and awareness. In case of neurobiology and – psychology learning by doing -or imitating- is important to be capable and fit to live everyday life and to survive in unexpected situations. The same applies to becoming a sexual competent adult by trial and error. Sexuality -making love in case of humans-  can be learned, and partners will be judging one another after the fact. From the biosemiotic perspective the question is what signs and tokens are relevant for sexual selection, mate recognition, sexual resistance, sexual rejection and sexual attraction.