Evolution of Parental Behavior

Unique to most mammals, primates are known to be extremely caring and warm to their offspring. Their parenting styles and child development processes are parallel to any hominid. The mother is the main benefactor of the care, but she is often supported by the father as well. One of the reasons primates are smarter than other mammals is because of the prolonged care the parents provide for fewer offspring. Since their dedication is more concentrated on fewer offspring they develop more socially complex manners. The development of their social complexity also calls for a longer development period. “By caring for their offspring, providing them with food, and teaching them about social roles and social behavior generally, primates increase the chances of their species’ survival.”

Primates also have relatively longer periods of birth because of the lengthier development processes and the attentiveness that goes into them by the parents. Primates also tend to live in groups which consist of several mothers but fewer fathers who usually have more mates than the females do. The mothers are supportive of each other in order to provide nutritional needs to the young. This is very similar to a human commune where everyone, whether they are blood related or not, take care of one another.

For the entire species, normally the sex with the greater rate of reproduction invests more into mating rather than parenting, while the sex with the worse rate of reproduction invests more into parental effort/child development than in the mating effort. This is because, according to Clutton-Brock, “following mating, members of the sex with the higher potential rate of reproduction can rejoin the mating pool more quickly than can members of the opposite sex, and it is often in their reproductive best interest to do so, particularly when biparental care is not necessary for the viability of offspring.”

Owen Lovejoy, an American anthropologist, was the one to suggest a correlation of female and male body sizes to their suggested behaviors. Because of Lovejoy’s hypothesis, researchers believed, for a long time, that the early male hominids were extremely competitive in terms of mating because they were highly dimorphic and that they did not participate in caring for the offspring. Nevertheless if they were not especially dimorphic then the male competition for mates was probably not part of the early hominid behavior.

Philip Reno, another American anthropologist, and his associates have studied early hominid bones and determined that “Relatively little sexual dimorphism in the body size suggests that males were cooperative, not competitive. This cooperative behavior could have included pair bonding –one female with one male-a behavior pattern necessary for the kind of provisioning for Lovejoy’s hypothesis.”

Our group agrees that cooperative behavior as opposed to competition seems to be the key that sets apart from the rest of the mammal kingdom when it comes to parenting and in all aspects of human behavior. With cooperation whole civilizations are built and ground-breaking discoveries are made. When it is disturbed, than less advancements are made. Cooperation is key especially when it comes to such a vital thing as a raising as raising a child.

For more reading see:

Flinn, Mark. "Evolution of Human Parental Behavior and the Human Family." PARENTING: SCIENCE AND PRACTICE. 1.1&2 (2001): 14-32. Print/Internet.

Larsen, Clark Spencer. Our Origins. Ed. Pete Lesser. New York: W.W. Norton & Company Inc. , 2008. Print.

New Approaches to the Evolution of Human Behavior

            Agustin Fuentes puts forth a new perspective on the evolution of human behavior in “A new synthesis: Resituating approaches to the evolution of human behavior,” which appears in Anthropology Today. Traditionally, evolution has been analyzed through basic neo-Darwinian theory. This theory places the importance on natural selection and sexual selection as forces for evolutionary change. Individuals are “fit” if they have a reproductive advantage as determined by the environment. Agustin believes that sexual selection and natural selection are not the only important evolutionary theories for anthropology. He says, “Anthropology, in a general sense, should be concerned with evolutionary theory, an incorporate relevant perspectives well beyond those that focus exclusively on the action of natural and sexual selection as the prime drivers of evolutionary change” (Fuentes).

            Fuentes introduces three additional evolutionary theories: multi-inheritance systems theory, development systems theory, and niche construction. The multi-inheritance systems theory states that the evolution of human behavior is brought about through genic, epigenetic, behavioral, and symbolic inheritance systems. Genetic inheritance follows the basic model. Epigenetic inheritance, or the physiological processes of the body above the level of the DNA, is present in all organisms. Behavioral inheritance, or social learning, is present in some animals. Symbolic inheritance is present only in humans, and comes along with language and the exchange of information. The developmental systems theory says that human behavior evolves through the constant construction and influence of demography, social interactions, cultural variations, and environmental manipulations. Niche construction uses the tri-inheritance vision model, which states human behavior results from information processing at three levels, population genetic, ontogenetic, and cultural.

            Fuentes notes the disagreements between the three perspectives, but he sees the possibility of applying all three along with the neo-Darwinian point of view to the evolution of human behavior. Fuentes sets forth a framework for approaching the evolution of human behavior. Human behavior must be seen as an evolving system, with niche construction as a core factor for the evolution. Communication and the transfer of information are key to understanding human behavior. Natural selection may not always be the most prominent force of evolutionary change.

            Fuentes illustrates his theory with the bond between owner and pet. He says, “…it appears that humans can cast this physiological, social and symbolic bonding ‘net’ beyond biological kin, beyond reciprocal exchange arrangements, beyond mating investment and in particular, beyond our species…this is of anthropological interest” (Fuentes). The interactions between pet and human could be seen as reciprocal altruism. However, Fuentes posits the human-animal interactions are a complex system of physio-behavioral engagement and shared ecologies. Animal physiologies and human physiologies can affect each other with mutual interaction and modification within a shared social network and ecology.

            There is a definite biological effect of human-animal interactions, fitting with the neo-Darwinism perspective. Human interactions with pets also have a profound social effect. Fuentes uses the example of jumping of a bridge to save your dog instead of your brother, simply because you like your dog more.

            Fuentes’ example of human-pet relationships demonstrates the interaction of the various evolutionary perspectives. He says, “Using aspects of all of these lenses, we see that this human behaviour can be explained by a variety of complex approaches wherein no one ‘driver’ or ‘architect’ is privileged” (Fuentes). Neo-Darwinism can interact with the multi-inheritance systems theory, development systems theory, and niche construction.

            As a group, we agree with Fuentes’ analysis. Human social behavior cannot be explained simply by genetics. Our interactions with others are so complex, that genes cannot be the only source of behavioral change. Fuentes’ example of human-pet relationships is an excellent way of demonstrating the interaction of all of the theories. We would like to think that the bond and relationship between our pets and us is not simply good for passing on our genes, but also contributes to our happiness.
 
For more information about Agustin Fuentes and his work, see http://anthropology.nd.edu/faculty-staff/fuentes_agustin/index.shtml.

Works Cited

Fuentes, Agustin. “A new synthesis: Resituating approaches to the evolution of human behavior.” Anthropology Today. Vol. 25 (2009). W

Reciprocal Altruism

Reciprocal Altruism

            When discussing human behavior, altruism is always a topic that comes into questioning. Some people say that it is simply a human instinct, while others argue that it is imbedded into us genetically. Biology Professor Robert T. Trivers of Rutgers University states that altruistic behavior is, “behavior that benefits another organism, not closely related, while being apparently detrimental to the organism performing the behavior, benefit and detriment being defined in terms of contribution to inclusive fitness”  (39). Arguably, if a human runs into a building that is on fire to save a non-related human, it can be seen as an act of instinct, but if a human runs into that same fire to save one of his or her offspring, they are said to be saving there genes. Is there a genetic bond, or is it simply apart of human nature to risk a life to save a life?

            During Trivers study The Evolution of Reciprocal Altruism; he discusses three instances of altruistic behavior. The first is the behavior involved in cleaning symbioses, the second discusses the warning cries in birds, and the third and final instance discusses human reciprocal altruism. The focus of his study is to prove how kin selection, which is the altruistic behaviors that increase the donor’s inclusive fitness, that is, the fitness of the donor’s relatives, can be the reason for altruistic acts, but he also mentions how kin selection can be ruled out when people perform acts of altruism for those that they do not know. His model includes altruistic behavior of organisms of different groups, and he sheds light on how helping others will not only benefit the organism in need, but the organism performing the act as well.

            One concern that our group had was, scientist try to create an explanation for everything, why can’t altruism simply be an act that organisms commit because they genuinely care, rather than something that has to be for the benefit of their species? Evolutionary Biology Professor Richard Dawkins, formerly of Oxford University, provides somewhat of an answer to our question by explaining the idea of selfish genes and how they relate to reciprocal altruism in this short video.

http://www.youtube.com/watch?v=Wgh5ShwnMlU

He explains how genetically, organisms commit altruistic acts because of kin selection and the idea of survival of the fittest, which essentially means the survival of genes. But unlike Dawkins, Trivers gives an example on how organisms without kin selection work together in order to benefit one another. In his example of cleaning symbioses, the symbiotic relationship may be categorized as mutual, commensal, or parasitic in nature. In each instance, the relationship between the different organisms proves that a genetic bond between organisms is not needed in order to commit altruistic acts.

            When looking at warning calls in birds, this altruistic behavior is only used to protect one’s mate, offspring, or another bird very close in kin. This goes back to the idea of saving ones genes, and even though the two parent birds are not directly related, it is beneficial for both the mates to survive in order to produce more offspring. Trivers also explains that if a bird does not use a warning call for other non-related birds, it could be a disadvantage to that bird. If a predator eats a near by bird, it is more likely to eat him as well. There for altruistic behavior can be beneficial to both the organism performing the act, and the recipient receiving the help.

            With the example of altruism in other organisms, human reciprocal altruism provides an insight as to why some organisms might lower their chances of “fitness” in order to increase the “fitness” of another. Kin selection can be the answer as to why some people risk their lives in order to save family members, or their genes, but this is not the case for all acts of altruism. Some people commit these acts of kindness in order to gain favors from those of whom they help, it is kind of like the motto, “you scratch my back, and I will scratch yours.” According to Trivers, reciprocity is more expected from kin than non-kin due to the genetic bonds, but not all acts of altruism have to be for the benefit of a species. So is this act of human behavior simply done in order to increase the “fitness” of an organism, or can it be said that people commit these acts out of the kindness of their hearts?

Works Cited

Trivers, Robert L. "The Evolution of Reciprocal Altruism." Quarterly Review of Biology 46.1 (1971): 35-57. JSTOR. The University of Chicago Press, 7 Apr. 2008. Web. 27 Mar. 2011. <http://www.jstor.org/stable/2822435>.

Its Not All Sex And Violence

Kristin Otto, Kelsey Moore, Yuki Nakano, Sasha Neufeld, Jeffrey Perkins

 

Last week, we attended the lecture “It’s Not All Sex and Violence” given by Augustin Fuentes from the University of Notre Dame and author of “The Evolution of Human Behavior.”  In his talk he focused on an alternate view of how humans behave, offering that not all human tendencies and interactions are based on conflict and sex, the cliché and widely accepted view of human evolution. 

Why did the homo-erectus species take off, and the majority of the species at the time died off?  Fuentes argues that looking at broad trends that prioritize sex and violence make us miss important aspects of human evolutionary success, which is, we argue, is largely based on behavior.  All of our anthropological evidence shows that early human ancestors were organized into medium sized, multi adult male and female child societies.  The typical view of human behavior and social organization is problematic in that it severely limits our evolutionary perspectives by envisioning the pair as the base unit of behavior. 

By using the pair as the basal model, Fuentes argues that we focus too much on sex and violence and that this approach over simplifies human behavior by using a comparative animal approach.  As we see it, humans as compared to other animal species have radically different roles in reproductive systems.  Therefore, the comparative animal behavior approach that many evolutionary theorists take to explain the evolution of human behavior is misdirected.  There are fundamental differences between humans and some other animals when it comes to sexual reproduction and relationship structures. 

            Fuentes then talked about humans as social mammals that have “social minds” where relationships and kinship are important.  Increased social complexity and heightened cooperation, then, lead to more “human” like tendencies in prior mammals.  Fuentes highlighted the importance of symbolic sociality, extreme cooperation, and teach that lead to the characterization of human behavior as separate from previously identified “ape” like behaviors.  Characteristic human behaviors include extended allocare and the shift to more complex environmental manipulation and geographic expansion.  Environmental stimuli encountered during geographic expansion required changes in behavior in order that humans adapt to their surroundings.  Out of this trend, we see the inventions of tool and fire use, as well as a host of other trends that require cooperative teaching, learning, and transport of knowledge.  The development of trade and intergroup cooperation also led to increases in symbolic communication (language) between humans.  All of these trends require heightened cooperation and collaboration in order for survival. 

Though some behavior is genetically inherited, a lot of it is learned based on environmental adaptation, which could in turn lead to niche construction, another point of focus in Fuentes view of human behavioral evolution.  For a definition and explanation of niche construction, see http://www.semioticon.com/seo/N/niche.html.  Fuentes claims that increased brain size and cooperation lead to increases in communicative complexity, increased effectiveness in avoiding predation, and expansion of types and patterns of habitats exploited.  As humans became predators and organized into hunter societies, other predatory animals shifted away from humans and toward other prey, thereby reducing the selective pressures of predation.  The creation of this niche allowed for an increase in social interaction and exploration which formed feedback for higher cognitive capabilities.  The heritable components of niche construction include social traditions, tool use and manufacture, and increased infant survivorship.  Fire use, increased habitat exploration, and increased information via complex communication patters are other examples of niche construction that are highly dependent on human cooperation. 

Our group was in agreement with Fuentes’ position on the evolution of human behavior.  While sex and violence are certainly aspects of human behavior, a disproportionate amount of focus is placed on such actions.  By limiting ourselves to these behaviors and limiting the social model to simple pair analysis, we miss the incredible evolutionary influences of human cooperation.  On any given day and in any given time period, the majority of human interactions are cooperative and collaborative.  Evolution happens in large-scale time frames, if the majority of behavior was centered on violence, the human population would not have survived or evolved with the success that it has. 

Investigating Male-Female Behavior Differences Using Evolutionary Biology

The Evolution of Human Behavior

Kristin Otto, Kelsey Moore, Yuki Nakano, Sasha Neufeld, Jeffrey Perkins

Investigating Male-Female Behavior Differences Using Evolutionary Biology

            Gary Cziko provides a thorough explanation of the evolution of human behavior in his book The Things We Do: Using the Lessons of Bernard and Darwin to Understand the What, How, and Why of Our Behavior. The phrase Darwinian evolution normally conjures up images of single-celled organisms, primates, humans. Cziko states that if human beings evolve due to natural selection, so must human behavior. “The Darwinian conclusion that human beings are also a product of biological evolution is scientifically inescapable, meaning that our behavior must also be compatible with and explainable by natural selection,” Cziko says (Cziko 148). In order for the evolution of human behavior to be possible, a few assumptions must be made. First, natural selection caused the human species to evolve over time into what it is today from more simple life forms. Second, human behaviors are adaptations that promote human survival and success in reproduction. Finally, there is an inherited, genetic basis for human behavior. These assumptions are consistent with research and biological theory

            There are many obvious differences between men and women which contribute to each gender’s has a distinct role in society. One of the less apparent difference is reproductive capacity. Women only produce a limited number of eggs in their lifetime, and invest quite a bit of time and energy into producing children. In contrast, a man has a seemingly endless supply of sperm, and is not as invested in the development of a child before birth. Thus, males have a higher reproductive capacity than females. The only limiting factor for male reproduction is the availability of fertile women. This should lead to competition among males for mates, which we see all human societies. Additionally, males are more interested in having sex with multiple women because of the possibility of a child without any involvement. This is shown in human behavior through adultery, the pornographic industry, and men paying women for sex. Although both genders participate in these activities, it is far more common among men. Men and women also differ in their choice of mate. Men prefer younger women because they have more reproductive years, thus maximizing their chances of passing on their genes. Women prefer men who can provide for them and their children, which leads to a preference of older men. In simple and rather blunt terms, men are looking for sex and women are looking for resources.

            Cziko presents a convincing argument for the evolution of human behavior. I can see how certain behaviors, such as competition for mates and attraction to certain age groups, results from a desire for reproductive success. However, I believe certain areas of Cziko’s analysis are debatable. For example, in this day and age, I am more inclined to believe that if a male has sex with multiple women, it is because he is not very invested in the relationship, not that he is trying to increase his chances of reproduction. Most males are not looking to have children when they are cheating; they are just looking for sex. I understand that animals exhibit this behavior in order to increase reproductive success. However, humans have to consider the stigma associated with cheating. If a man has sex with multiple partners, and it is “exposed,” many other women would not want to have a relationship with him because they do not trust him, thereby limiting his sexual encounters and lowering his reproductive success. I believe Cziko is correct that this behavior evolved as a useful way to increase reproductive success, but in today’s culture the behavior has a completely different connotation.

Works Cited

Cziko, Gary. “The Evolution of Human Behavior: The Darwinian Revolution Continued.” The Things We Do: Using the Lessons of Bernard and Darwin to Understand the What, How, and Why of Our Behavior. By Cziko. The MIT Press, 200. 147-75. www.faculty.ed.uiuc.edu/g-cziko/twd/pdf/twd08.pdf Web. 14 Feb. 2011.