Parent-Offspring Conflict and Kinship Theory

Flashcards covering key concepts of parent-offspring conflict, asymmetry of kinship relationships, Trivers' graphical model of investment termination, and David Haig's maternal-fetal conflict.

Parental Investment

Any behaviour of a parent toward an offspring that contributes to the reproductive success of that offspring at the cost of the parent's ability to invest in other offspring.

Asymmetry of Kinship Relationships

The structural reality that family members are not related equally (e.g., parents are genetically unrelated to each other, and siblings are more related to themselves than to one another), resulting in differing evaluations of investment costs and benefits.

Sex Differences in Parental Investment Curve

A graphical representation demonstrating that females incur a steeper cost in future offspring given up ($P_i$) for each additional offspring produced compared to males.

$$P_i$$

The number of future offspring given up by a parent in order to provide care for present offspring.

Parent-Offspring Conflict Theory Predictions

Theoretical predictions stating that parents and children will conflict over the timing of weaning (parents favoring earlier termination), parents will encourage offspring to value siblings more than they naturally do, and parents will punish sibling conflict while rewarding cooperation.

Trivers' Parent-Offspring Conflict Model (1974)

A graphical model showing that conflict occurs over the termination of investment during the period between point $p$ (where $B/C = 1$) and point $o$ (where $B/C = 1/2$), based on the declining benefit to offspring ($B$) relative to the cost to parent's other offspring ($C$).

Intermediate Zone of Parental Investment

The developmental time interval during which the child continues to demand parental investment, but the parent's optimal fitness is achieved by terminating care to invest in another child.

Maternal-Fetal Conflict

An evolutionary framework described by David Haig where the fetus has evolved mechanisms to manipulate maternal physiology to extract more nutrition and resources than is in the mother's best genetic interest to provide.

Conflict Over Quality

A manifestation of maternal-fetal conflict where the mother attempts early spontaneous abortion of abnormal conceptuses ($78\%$ of fertilized eggs are abnormal), while the fetus secretes hCG into maternal blood to prevent menstruation and force implantation.

Human Chorionic Gonadotropin (hCG)

A hormone produced by the fetus and secreted into the mother's blood that prevents menstruation, secures continued implantation, and is released in higher amounts when fetal blood supply is restricted to drive up maternal blood pressure.

Conflict Over Food Supply

A maternal-fetal struggle in which the fetus releases physiological factors to raise maternal blood pressure and access higher blood flow, lowering spontaneous abortion rates but potentially causing dangerous maternal hypertension complications and pregnancy diabetes.

Kin-Specific Psychological Adaptations

Specialized psychological mechanisms expected to have evolved distinctly for each category of kin relationship, treating parenting as a specific subcategory of kinship investment.