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what unites both behavioral ecology and developmental psychology?

Mortality and morbidity outcomes in offspring --> interest in how paternal care/ stress may influence offspring viability and condition


support that father absence influences well being of offspring

There are a number of large epidemiological studies in the West which find an association between parental divorce (usually synonymous with father absence in these data) and poorer adult health, shorter adult height, and shorter life expectancy in offspring (Sheppard et al. 2015).

In some samples, the associations between family structure and later offspring outcomes were mediated by stressors inherent in, or other sequelae of, the separation (e.g., Maier and Lachman 2000), which is consistent with other evidence suggesting relational stress in childhood may be associated with health outcomes in later years.


what is different to data on offspring health and wellbeing compared to reproductive data

these associations are not limited to WEIRD samples.


who studied offspring viability/ health in non-western sample

give background to study.

Flinn and England (1997) assessed the living conditions of children and adolescents living in a village in Dominica
took regular saliva samples (several times a day for multiple days) to assess their levels of cortisol (a stress-related hormone) and monitored children’s health.
The population they studied was matrilocal and the parenting conditions were very varied; approx half of children were living with their mother and their biological or stepfather, while a further 12 % lived alone with a single parent. The remainder of the children lived with mother and kin, grandparents, distant kin or nonrelatives.


who studied offspring viability/ health in non-western sample

what did they find?

Flinn and England (1997) assessed the living conditions of children and adolescents living in a village in Dominica

Found that children living without their biological father experienced significantly more days of illness and had significantly higher cortisol levels than those living with both parents (even if their father was often absent from the home, e.g., for work or after rows).

-children who were living in a single mother/ blended family/ distant relatives were ill more likely (in % days) than those who lived with nuclear family or mother with maternal kin


what do organisms have a limit on?

a limited energy supply


list what a reproductive bout takes energy away from

• Each reproductive bout takes energy away from:
o Growing
o Mate seeking
o Caring for previous offspring
o Future reproduction
o Self-repair (maintenance)


what is LHT ostensibly about?

LHT is ostensibly about variation across species


who proposed two selection types and what were these?

MacArthur (1962; MacArthur & Wislon, 1967)- r and K selection

• Two opposing ecological strategies, r and K
• r= rate of population growth (under optimal conditions)
• K= carrying capacity of the environment (how many individuals can the environment sustain)


what strategies did MacArthur propose?

) essentially had optimal conditions and the population was growing as fast as it could
2) constrained ecological conditions and when constrained the population can not grow in number meaning that the most successful individuals are the ones who produce the highest quality offspring who are going to be able to best compete for resources.


when should r selection be used?

Under R selection the most successful individuals are those that produce the most offspring as fast as they can.


when should K selection be used?

Under K selection it is those who invest their resources in high quality competitive offspring.


what do r selected species tend to have as features?

R selected species tend to
• Spend a short time growing
• Reproduce early
• Reproduce with multiple offspring per bout
• Die young
• Offspring likely to die of predation


what do K selected species tend to have as features?

K selected species tend to
• Spend a long time growing
• Less reproductive bouts with small amounts of offspring
• Spend long time rearing offspring before next bout of offspring
• Live long


are humans r or K and why?

• Humans are overwhelmingly K-selected- one of a small number of species that are at the end of the continuum (with e.g. elephants and whales)
o Small family size (c. 5 children per female)
o Long gestation
o Long lactation and pre-reproductive period
o Late reproduction
o Long lifespan
o Large brains


but what has been argued about humans on the r or K continuum? and why?

been argued that some are more K than others (more at the extreme end of the human extreme)
– We vary in family size (0-67 children/female highest documented to one female)‏
– We vary in lactation (0-c.48 months)‏ some don’t breast feed at all.
– We vary in pre-reproductive period (8-18 years)‏
– We vary in timing of reproduction (12-45 years)‏
– We vary in lifespan factors (smoking, diet, risky behaviours etc)‏


what does life history theory focus on rather than the genetic variation in individuals

Facultative variation


how can genes cause alternative morphs?

• Due to fluctuating selection pressures- selection pressures changing back and fourth a lot some genomes favoured some years and some other years thus both remain in the population.
• Frequency dependant selection- two morphs can co-exist in relative frequencies that balance out
• Alternative adaptive strategies- can both exist in the population as occupy different social niches
• (or lots of other reasons)


what does facultative variation suggest

that there is plasticity to the brain and that this plasticity results in different conditional strategies

• Differences in the environment produce differences in behaviour out of the same genotype


why would we potentially have facultative variation. who proposed two ideas?

Nettle Bateson (2015)- came up with a model arguing two ways that this plasticity can work…

1) informational

2) somatic state based


what is the informational (standard psychosocial acceleration models) about?

a informational model when you are early in lifespan you can extract information from your environment. Detecting something in childhood environment that predicts something about what environment will be in adulthood. Then develop into an adult have a phenotype that is appropriately developed for the predicted environment.


what is an issue with the informational model?

- in order for this to work is medium turn environmental change- if environment is constant then childhood environment is fantastic predictor of adult environment but don’t need conditional adaptation because the information in the environment is always going to be the same so no benefit to evolving conditional adaptation.
Alternatively, if environmental change is very rapid and is changing lots within a life span. Means that info in childhood doesn’t actually bear resemblance to environment in adulthood- thus conditional adaptation isn’t any good- not helping you to develop right phenotype
In order for conditional, information adaptations to emerge what you need is an environmental change that is happening but that is slow enough that in a lifespan of an individual you are not likely to experience huge change


what is the somatic state based (internal prediction models)

juvenile environmental input is effecting you- not using it as info but has a direct effect on you- e.g. if environment is very detrimental it is essentially damaging long term somatic (physical body) condition. You develop and whatever damage you took in youth persists and when you become an adult you develop a behavioural phenotype that is appropriate to you given the physical state you are in post-childhood. Adult phenotype is all about responding to the damage or advantage you’re carrying from early environment. Early environment is effecting the outcome but doing this directly through you not through any information about predicted adult environment- thus a little more predictive power as not restricted to which situations it is applicable in.


what is less commonly considered compared to menarche

• Adrenarce- adrenal glands maturing- slowly from about age 6
• Thelarche- breast bud development
• Spermarche: first ejaculation
• All of these are hard to measure and require repeated questionaires or hormone measures


earlier menarche in father absence ALSPAC cohort but issues

Culpin et al. (2014)
• looked at ALSPAC cohort
• found that father absence in early childhood was predicting maternal depression and financial issues in mid childhood
• all of these, either directly or indirectly were all resulting in earlier menarche in females
• multiple direct influences.. fits into idea that what we’re looking at is holistic stress
issue though… meta-analyses if inputs you put in are rubbish then outputs out will be rubbish- Sohn (2017) argued that research is biased as less likely to get engagement from low SES participants. The ALSPAC cohort has tended to lose more of their low SES families certainly in the longitudinal studies. When this happens because being low SES is a form of stress we are losing a group of people who are really important in understanding this phenomenon.
Conditioning on a collider—your meta analytic soup is only as good as your ingredient studies – Boothroyd


best father absence and earlier onset puberty study and why

Ellis et al, 2003
 Prospective, longitudinal, SES-controlled studies in two cohorts…!
 Found that those who had been father absent in childhood were more likely to be sexually active in early- mid teens. In both US and NZ cohorts


what have some argued in terms of puberty and LHT and becoming an adult

 Ellis (2004; Tither & Ellis, 2008)
All well and good that evidence shows that father absence seems to be associated with 6 months or so earlier for menarche but why are we so convinced that this is all about reproducing- what about if instead this is not about becoming a reproductive adult but instead ending childhood.
– Is early menarche a means of ending childhood rather than commencing adulthood…?
o Argued always better to adapt strategy on the fly if you can because then can more readily adapt to changes in environment which is always going to be advantageous if possible.

– If you’re in a bad ecology the last thing you want to be is be vulnerable so is much better to finish childhood, finish growing and become an adult so more protected against problems in environment


what supports the idea that puberty is about ending childhood not starting adulthood

premature infants- they are very vulnerable, they engage in a period of catch up growth (initially plotted correct to gestational age for weight and length) but then plot them as normal age as they catch up. They are much more likely to reach puberty early and be short because stopped growing than infants born at term.
o Premature babies are particularly vulnerable so shove energy early on into growing and then stop and get on with being an adult.


impacts of father absence in preindustrial societies for health

The impacts of father absence on mortality in preindustrial populations, however, are rather more ambiguous. While there are notable examples of father absence or death of father being associated with slightly higher offspring mortality in both anthropological and historical records, Sear and Coall (2011) found that in more than half of small-scale societies for which data were published, father loss (by death or absence) had no significant link with offspring survival.


facial evidence for health in nuclear families

Boothroyd and Perrett (2006)
o Students at St. Andrews uni
o Parents separated pre puberty, parents had bad relationship, parents had good relationship
o People whose parents separated/ bad relationship looked less healthy than those whose parents were together and had a good relationship.