It is about siblings, not sex: Oedipus complex as an expression of parent-offspring conflict

Being Freud’s most famous contribution to psychoanalysis, the Oedipus complex is still a topic of heated interest. It has been disputed in many different disciplines ranging from anthropology to biology. This review was aimed to explain the phenomenon of the Oedipus complex in terms of parent-offspring conflict, sibling competition, and infanticide. All of these evolutionary biological concepts or their combination could conceive specific relational settings that may be mistakenly regarded as comprising the Freudian Oedipus complex by external observers. Furthermore, the propositions regarding the adaptive function of the Oedipus complex in terms of sexual imprinting and mate modeling are not robust and convincing. In this article, the author asserts while the Freudian Oedipus complex covers only the sex-contingent representations of parent-offspring conflict, the parent-offspring conflict may account for both sex-contingent and non-sex-contingent conflicts between the parents and the offspring. In light of these hypotheses, related literature and suggestions for further studies were discussed.

Imprinting as Social Learning

Imprinting is a form of rapid, supposedly irreversible learning that results from exposure to an object during a specific period (a critical or sensitive period) during early life and produces a preference for the imprinted object. The word “imprinting” is an English translation of the German Prägung (“stamping in”), coined by Konrad Lorenz in 1935 to refer to the process that he studied in geese. Two types of imprinting have traditionally been distinguished: filial imprinting, involving the formation of an immediate social attachment to the mother or a mother-substitute, and sexual imprinting, involving the formation of a sexual preference that is manifested later in life. Both types of imprinting were subject to extensive experimental study beginning around 1950. Originally described in precocial birds (ducks, geese, and domestic chickens), imprinting has also been used to explain the formation of early social attachments in other species, including human infants. Imprinting has served as a useful model for studying the neural processes involved in learning and behavioral development and has provided a framework for thinking about other developmental processes.

Sexual imprinting overrides order effects

ABSTRACTMate choice is a complex decision that requires the integration of cues from potential mates with individual preferences. Choosers’ preferences are shaped by recent events, early life experience and by the evolutionary history of its own species. To better understand the interaction between these factors, we studied mate choice in the female house mouse, Mus musculus. Females of one of the musculus subspecies, Mus musculus musculus, show preference for males of their own subspecies compared to males of the sibling subspecies, Mus musculus domesticus. Such an assortative preference is ecologically relevant at contact zones, where it contributes to the reproductive isolation of sympatric populations and can be reproduced in controlled laboratory conditions, but its origins are still under debate. Here, we show that female mouse mate choice depends on both early postnatal life experience and the order of prospective mates encountered as an adult and that these effects interact asymmetrically. Whereas females raised in their normal M. m. musculus environment display a robust assortative preference, females fostered in a M. m. domesticus family prefer the first male encountered, regardless of subspecies. Thus, early life experience of M. m. musculus females, when concordant with genetic self-identity, overrides sampling order effects, ensuring robust assortative choice. In the absence of this match between phylogeny and early life experience, first impression effects dominate mate choice.

Adult sex ratio influences mate choice in Darwin’s finches

The adult sex ratio (ASR) is an important property of populations. Comparative phylogenetic analyses have shown that unequal sex ratios are associated with the frequency of changing mates, extrapair mating (EPM), mating system and parental care, sex-specific survival, and population dynamics. Comparative demographic analyses are needed to validate the inferences, and to identify the causes and consequences of sex ratio inequalities in changing environments. We tested expected consequences of biased sex ratios in two species of Darwin’s finches in the Galápagos, where annual variation in rainfall, food supply, and survival is pronounced. Environmental perturbations cause sex ratios to become strongly male-biased, and when this happens, females have increased opportunities to choose high-quality males. The choice of a mate is influenced by early experience of parental morphology (sexual imprinting), and since morphological traits are highly heritable, mate choice is expressed as a positive correlation between mates. The expected assortative mating was demonstrated when theGeospiza scandenspopulation was strongly male-biased, and not present in the contemporaryGeospiza fortispopulation with an equal sex ratio. Initial effects of parental imprinting were subsequently overridden by other factors when females changed mates, some repeatedly. Females of both species were more frequently polyandrous in male-biased populations, and fledged more offspring by changing mates. The ASR ratio indirectly affected the frequency of EPM (and hybridization), but this did not lead to social mate choice. The study provides a strong demonstration of how mating patterns change when environmental fluctuations lead to altered sex ratios through differential mortality.