Blog 3

Who Keeps Children Alive? A review of the effects of kin on child survival 

Rebecca Sear, Ruth Mace

     Human children are different than many other species. Some species are born ready to move and fend from themselves right from birth. Others are in need their parents guidance and support to reach an age where they can survive alone. Some have a few years where they are dependant on their mother's milk. Human children are born completely helpless dependent and remain so for many years. Even after they are weaned, they still need an adult to provide them with food and protection. Furthermore, human females have additional offspring before their previously born children have reached an age of independence. This study shows that mothers may be getting support from various people to differing degrees and depending on the culture and ecological conditions present.

      This study was an overview of all other kin-helper studies done over various cultures, eras and environments. They first examined whether the presence of a mother increases or decreases the probability of child survival and, unsurprisingly, the result was a positive increase in survival of the child. When it came to other relatives, the results became more varied. Fathers, though generally held as important in child survival, frequently are shown to make no difference. In cases where the loss of the father resulted in the death of the child, it is unclear whether this is directly caused by the death of the father and his loss of provision for the child or other factors. The calories found in food from foraging exceeds the calories in meat. It may be more that the father provides protection from other rival males. But of course, the father data is very varied and may be due to the fact that in 10 of 22 studies only children under five were looked at, and father would play a very small role at this stage of a child's life and a larger one later in life. A grandmother of one kind or another helps to aid survival, in statistically significant cases the maternal grandmother helps 64% of the time and the paternal grandmother helps 60% of the time. However, in two of the studies the paternal grandmother had a detrimental effect and other studies clumped both grandmothers into one category meaning that it's impossible to find out in some cases what percentage the maternal or paternal grandmother helps or hinders child. The authors also suggest that paternal and maternal grandmothers may help in different ways: the maternal with direct care and the paternal with affecting the condition of the mother, for better or worse. Grandfathers are less important, in 10 of 12 cases examined, the maternal grandfather had no effect and the paternal grandfather had a combination of all possibilities: no effect in the majority, and a positive and negative effect was found in three studies each. The more distantly related relatives have an even more convoluted and less documented role. Uncles help seems more dependent on how the family is structured. Aunts are also dependent on structure. When females control the wealth, the survival rate is lowered. When males control the wealth, the aunts help protect against child mortality. Stepfathers have been shown to increase a child's risk of dying while stepmothers have been shown to increase the child's survival.

      It's hard to be critical of this article as it is it's own harshest critic. They acknowledge the limitations of the studies that they used, no constant parameters were used, different definitions of family members were used (all grandmothers vs maternal and paternal grandmothers separately), the effect of different cultures and ecological constraints, etc. The sudden shift into an evaluation of current family policy was fairly unexpected. The critique of the nuclear family from an evolutionary perspective says “the nuclear family system may not be the normative solution to the problem of raising children in all circumstances”. They're definitely right to qualify this statement with “in all circumstances”. The fact of the matter is, as this paper itself points out, there is a large body of research supporting that a child raised with two parents results in the best option of the child. The requirements for child-rearing vary from culture to culture and environment to environment, in modern times child death may be less common but the support of two parents both financially and emotionally is preferable for a child. The needs of the child in the most basic sense of the word are food, shelter and protection. But the “needs” include medical bills to ensure good health, toys for an enriched environment, college funds, etc. Modern critiques of family structure focus more on how well adjusted the child is rather than survival which is more definite in this age.

      This review of all research done in the field of child survival due to kin relations is as comprehensive as its results are varied. It aids the field of evolutionary psychology by compiling all the research in an easy to understand area while suggesting where future research should focus its efforts to make the data more definitive. It definitely questions the view of kin such as fathers (who one would expect to be helpful) and step-mothers (who are generally stereotyped as detrimental to children from the first mother). This study is an aid to its field due it's objectivity and cautious, self-critiquing of the research used and the results found.

References:

Sear, R. & Mace, R. (2008). Who keeps children alive? A review of the effects of kin on child survival. Evolution & Human Behavior, 29: 1-18.

 

Blog 2

Fertility and race perception predict voter preference for Barack Obama

Carlos David Navarrete, Melissa M. McDonald, Michael L. Mott,

Joseph Cesario, Robert Sapolsky

      After the monumental 2008 American presidential election, scientists were given an unique opportunity to study the effects that a relatively young, black American candidate would cause on the American consciousness, both during and after the election he subsequently won. The purpose of this particular study was threefold. First, to study the effects of the menstrual cycle on a woman's willingness to vote for Obama under the assumption he would perceived as an attractive, powerful man. In other words, an desirable mate and father for her children. Second, to explore whether as these cycling women would see Obama as more of a “dangerous agent” due to “extending [the] logic” that because black men are stereotyped as dangerous they would be negatively appraised as women approached ovulation, thus decreasing a woman's willingness to vote for him. Finally, the third purpose was to see how these two factors (race perception and the mate desirability during the menstrual cycle) would work when introduced to the third factor: political beliefs.

      They studied two groups of women, a sample of exclusively white women aged 18-22 for the first study and 186 white women and 38 black women for the second. The first study had the women meet many eligibility requirements (did not use oral contraceptives, willing to state voting preference, etc) and they then completed an online survey to measure social attitudes, personality, and who they wished to vote for. Their menstrual cycles were then inferred and their voting preference was then studied from September to election date. The second study was done online by survey, participants were asked questions about social attitudes, image, demographic items, and who they would be voting for in the election. In this study there was also a skin colour perception facet where participants were given a range of colours and asked which one was closest to Obama's skin colour, ranging from dark (1) to light (10). 

      Their results showed that woman’s preference for Obama was consistent with which stage of the menstrual cycle they were in. In both studies, as the risk of conception rose, so did support for Obama. The second studied also showed that this support was also connected to how participants viewed his skin colour. The lighter they believed his skin to be, the greater the increase in support with conception risk increase. When they perceived him as darker, the opposite results were found. These results were amplified when women were conservatives, which was what was expected due to the fact that liberal women would vote for Obama no matter what.

      There are several methodological flaws in this survey, the most obvious being the number of people who participated in these studies. Drawing conclusions for an entire species based on results found from 62 white women from Michigan State University is not only poor science, it's dangerous. Furthermore, there is only one study that is used to justify that ovulating women find black men a threat, and that study was carried out by the author of this paper, Navarrete (Navarrete et al., 2009). Once again this paper draws its conclusions based on the results found from 77 white women from Michigan State University, a very specific slice of the female population. The two papers were also published around the same time, the supporting paper was published in June of 2009 and this paper's initial receipt being submitted October 7^th, 2009. With the close publications of these two papers and the probable difficulty of finding women who were willing to participate in such a personal survey, it's possible that the same women who participated in the first study, which found that women have a race bias across the menstrual cycle, also participated in the study with Obama, thus making the results even more questionable. Furthermore, they were not controlling for extraneous variables. All of these studies were done at the same time, perhaps these sways were due to the news, statistics they had heard, or speeches by himself or McCain.

     Finally, one statement that is particularly troubling is that “...our findings raise the question of whether Barack Obama's success as a politician may in part be due to the possibility that, at a nonconscious yet operative level of cognitive processing, most American voters may not consider him to be black.” Obama is black. He considers himself black. The election and media focused on how important and historical this election was because he was black. American voters consider him to be black. I think what these authors were trying to say is that Obama is not a stereotype, “A dangerous agent”. To attribute Obama's success to him not being perceived as black is ridiculous and even insulting. Even if these results do hold up under more extensive and larger testing, I don't think it's fair to assume that these biases or preferences would actually affect actual voting behaviour.

      This research attempts to contribute to our knowledge about female preferences with respect to ovulation. They find support for all of their hypotheses which were constructed with respect to the theory that females avoid men they perceive of risks at times they are likely to conceive. However, with such small research numbers it's hard to draw any definite conclusions. There are some interesting aspects to this paper, but it is hardly anything new and the attempted application to the election seems shaky and tenuous.

References:

Navarrete, C. D., Fessler, D. M. T., Santos Fleischman, D., & Geyer, J. (2009). Race bias tracks conception risk across the menstrual cycle. Psychological Science, 20(6), 661–665.

Navarrete, C. D., McDonald, M.M.., Mott, M.L., Cesario, J., Sapolsky, R. (2010). Fertility and race  perception predict voter preference for Barack Obama. Evolution and Human Behaviour, 31(6), 394-399.

Blog 1

Adaptive memory: Ancestral priorities and the mnemonic value of survival processing

James S. Nairne, Josefa N.S. Pandeirada

       The purpose of Nairne and Pandeirada's research was to test the “stone-age brains” theory that has been proposed by many evolutionary psychologists. This theory asserts that because the human brain's evolution occurred during the stone age that our brains will be better adapted to accessing information given in an ancient context. Evolutionary psychology stresses that genes alone do not cause behaviour and cognition directly, rather it is an interaction between the environment and these genes. However, there is a standard set of psychological mechanisms that all mankind shares and these mechanisms were decided by natural selection to help give humans an advantage. By studying these mechanisms, such as memory processing in terms of fitness value seen in this article, in the context of their ancestral environment and the modern environment we can see if our mind has caught up with the dangers of modern day or if it is still dwelling in the savannahs of the Pleistocene era.

      Nairne and Pandeirada asked participants to evaluate several situations in an ancient and modern context, such as avoiding a predator in the ancient situation and an attacker in the modern or finding food for yourself by gathering plants in the ancient and simply going to the grocery store in the modern. After being presented with either the modern or the ancient scenario, they were given a list of words to rate in terms of their usefulness to them. Several other controls and rating tasks were employed for comparison and ruling out purposes.

      The central idea to this research is that humans remember things in terms of the ancestral condition better because our brains were evolved and groomed for this purpose. However, as seen in the rating tasks, where participants were asked to rate both the modern and ancient scenario in terms of how familiar or how interesting it was to them, the modern condition was seen as more familiar, and the details of everyday things are allowed to slip through the cracks of our minds. Going to the grocery story is familiar and commonplace, we don't remember the details of a real trip to the store anymore than one would assume we'd remember the details of an imagined one. But a trip to grasslands of a foreign land? How often does our modern day mind find itself there? Even a modern condition that is less common, like being stalked by an attacker will leave less of an impression, either due the fact we're overrun with television programming about this topic that has desensitized us or that a modern day human can easily think of the numerous modern day advances used to protect themselves (i.e. A gun, the police). At least to myself, the modern condition is something we deal with everyday, real or imaginary, so we already have the answers, why remember the details? The ancient condition is something further from our modern day world, how to make a spear, how to figure out what plants to eat. It's possible the ancient condition is more easily recalled because it's more foreign to our modern mind rather than the modern condition is forgotten due to our ancient mind.

      This research supports the theory that our mind has a stone-age component which will cause our memory to recall more when placed in the context in which it was originally evolved in. This article supports the current theory of fitness value assessment and supports the theory that our minds are still primed to survive in the ancient world, rather than the modern. However, as mentioned previously , it's possible the ancient world is just more interesting and different to the modern mind and therefore more easily remembered.