Hot and Cool Mothers

“Hot and Cool Mothers” moves toward a media theory of mothering and parental “fitness.” The article begins with an investigation into midcentury pediatric psychological studies on Bad Mothers and their impacts on their children. The most famous, if not persistent, of these diagnoses is that of the so-called refrigerator mother. The refrigerator mother is not the only bad model of maternality that midcentury psychiatry discovered, however; overstimulating mothers, called in this study “hot mothers,” were identified as equally problematic. From the mid-1940s until the 1960s and beyond, class, race, and maternal function were linked in metaphors of temperature. Whereas autism and autistic states have been extensively elaborated in their relationship to digital media, this article attends to attributed maternal causes of “emotionally disturbed,” queer, and neurodivergent children. The author argues that these newly codified diagnoses were inseparable from midcentury conceptions of stimulation, mediation, domesticity, and race, including Marshall McLuhan’s theory of hot and cool media, as well as maternal absence and (over)presence, echoes of which continue in the present in terms like “helicopter parent.”

Number and Size of Offspring

Offspring number and size are two of the most variable life-history traits. Among species, much of this variability can be attributed to genetic, developmental, physiological, or structural constraints. Some trait combinations are not possible because of differences associated with a species’ evolutionary history. Substantial variation in propagule number and size can exist among populations of the same species, generating questions concerning the adaptive significance of this variability. The most influential models are those attributed to Lack on clutch size and to Smith and Fretwell on offspring size. Fundamental to both sets of models is a trade-off between offspring number and parental investment per offspring. When offspring survival or fitness continuously varies with offspring size, the fitness of the parent depends on both offspring size and the number of offspring of that size that the parent can produce. If offspring survival is independent of offspring size, parental fitness is maximized when individuals maximize the production of minimally sized propagules.

Fitness Functions Determine Optimal Parental Allocation: Redefining Trivers–Willard Theory

According to Trivers-Willard theory1, females in a good condition should carry more male offspring to maximize their fitness while should carry more females in a poor condition. Diverse theoretical and empirical studies has been performed to verify the validity of this claim2,3. Some portion of the empirical observations, however, exhibited contrary outcome to Trivers-Willard theory4. To resolve this problem, we computationally and mathematically show in here that reversed Trivers-Willard theory actually could be the outcome of the parental fitness optimization. In our models with identical fitness functions, we found that selective equitable care is optimal, and the number of the cared offspring should monotonically increase with maternal condition (or expendable parental investment). In some of our models with two distinguished male and female fitness functions, optimizations results were congruent with the conventional Trivers-Willard theory. In other models of ours, contrary to Trivers-Willard theory, it was optimal to invest in males when maternal condition was low. The results along with our hypothesis can explain the empirical observations that were previously thought to be the counterexample of Trivers-Willard theory. We propose that Trivers-Willard theory should be interpreted in multidimensional way, and more elaborate empirical data need to be collected to verify such propositions.

Alloparenting

Who helped you develop into the person you are today? Most of us may think about a parent or parents, but many of us would also recognise the important role of other people. Perhaps it’s a teacher, a grandparent, or a neighbourhood friend. The fact that we are supported by many people in our childhood is, in fact, very unusual: In non-human mammals, support –or investments- for juveniles are typically and solely provided by the biological mother. Only 9-10% of mammals display parental care, where biological fathers are additionally involved in raising offspring, without the support of other helpers (Kleiman & Malcolm, 1981). In humans, we see a notably different system of facultative fathering, where biological fathers may or may not provide investments into their children, combined with a range of additional caregivers beyond the biological parents. These additional caregivers, or alloparents, can include siblings, grandparents and extended kin, as well as non-relatives such as step-parents, friends and neighbours.Support from alloparents, meaning “other parents,” is arguably an obligate human characteristic. This is because, compared to other primates, humans have an extended childhood and adolescence: while the conceptualisation and timing of adulthood does somewhat vary between cultures, broadly speaking, humans do not become “mature” and self-sustaining until their mid-teens to early 20s. During childhood and adolescence, we experience a prolonged period of physical growth and skills development, making us depended on sustained support from parents and alloparents to survive, develop and successfully reach adulthood. Non-parental caregivers are therefore necessary for successful reproduction and childrearing in humans- although who supports parents and how varies cross-culturally. But how did alloparenting evolve? Why do alloparents help in childrearing, and how do they influence parental fitness? This chapter provides an overview of alloparenting in humans, outlining different types of alloparenting, broadly addressing the evolution of alloparenting, and providing a brief review of key alloparents in humans across cultures.

Unfit by Accident: Third-Party Perception of Parental Fitness Based on Childbearing Intention

Prior research has examined the impact of unintended birth on parent and child welfare. The present studies examine another potential consequence: namely, how third-party observers react to information about parenthood intention. We examine whether the act of having intended (or not) to become a parent affects people’s impressions of (1) what type of caregiver the (un)intended parent will be, (2) the type of relationship the (un)intended parent will have with the child, and (3) potential outcomes for that family. Studies 1 and 2 demonstrate that people award less custody to accidental mothers and fathers because lack of intention during birth is perceived as decreasing parental quality and closeness between parent and child. Study 3 tests potential moderators of this effect including parenthood status and controllability, highlighting the potential negative consequences of this phenomenon for families in child custody disputes where third-party judgments are especially likely to bear weight.

The development of individual differences in cooperative behaviour: maternal glucocorticoid hormones alter helping behaviour of offspring in wild meerkats

The phenotype of parents can have long-lasting effects on the development of offspring as well as on their behaviour, physiology and morphology as adults. In some cases, these changes may increase offspring fitness but, in others, they can elevate parental fitness at a cost to the fitness of their offspring. We show that in Kalahari meerkats ( Suricata suricatta ), the circulating glucocorticoid (GC) hormones of pregnant females affect the growth and cooperative behaviour of their offspring. We performed a 3-year experiment in wild meerkats to test the hypothesis that GC-mediated maternal effects reduce the potential for offspring to reproduce directly and therefore cause them to exhibit more cooperative behaviour. Daughters (but not sons) born to mothers treated with cortisol during pregnancy grew more slowly early in life and exhibited significantly more of two types of cooperative behaviour (pup rearing and feeding) once they were adults compared to offspring from control mothers. They also had lower measures of GCs as they aged, which could explain the observed increases in cooperative behaviour. Because early life growth is a crucial determinant of fitness in female meerkats, our results indicate that GC-mediated maternal effects may reduce the fitness of offspring, but may elevate parental fitness as a consequence of increasing the cooperative behaviour of their daughters. This article is part of the theme issue ‘Developing differences: early-life effects and evolutionary medicine’.

The development of individual differences in cooperative behaviour: maternal glucocorticoid hormones alter helping behaviour of offspring in wild meerkats

The phenotype of parents can have long-lasting effects on the development of offspring as well as on their behaviour, physiology, and morphology as adults. In some cases, these changes may increase offspring fitness but, in others, they can elevate parental fitness at a cost to the fitness of their offspring. We show that in Kalahari meerkats (Suricata suricatta), the circulating glucocorticoid (GC) hormones of pregnant females affect the growth and cooperative behaviour of their offspring. We performed a 3-year experiment in wild meerkats to test the hypothesis that GC-mediated maternal effects reduce the potential for offspring to reproduce directly and therefore cause them to exhibit more cooperative behaviour. Daughters (but not sons) born to mothers treated with cortisol during pregnancy grew more slowly early in life and exhibited significantly more of two types of cooperative behaviour (pup rearing and feeding) once they were adults compared to offspring from control mothers. They also had lower measures of GCs as they aged, which could explain the observed increases in cooperative behaviour. Because early life growth is a crucial determinant of fitness in female meerkats, our results indicate that GC-mediated maternal effects may reduce the fitness of offspring, but may elevate parental fitness as a consequence of increasing the cooperative behaviour of their daughters.