Friday, November 10, 2006
Dance and Lectures On Sex and Spirituality
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Published: February 5, 1993
A conference on "The Union of Sex and Spirit," a daylong program of dance performances and lectures on the link between sexuality and spirituality in Eastern and Western myths and religions, is to take place tomorrow at St. Peter's Church, Lexington Avenue and 54th Street, from 8:30 A.M. to 6 P.M. The sponsor is Cauldron Productions, which presented similar events at the Asia Society. Tickets are $80; $60 for students and the elderly. Telephone: (212) 245-0445.
The lectures will deal with the ancient Near East, Medieval Europe, India, Tibet and the United States. The choreographers on the program will be Muna Tseng, Tamar Rogoff, Leela Raja and Ze'eva Cohen.
Save
Published: February 5, 1993
A conference on "The Union of Sex and Spirit," a daylong program of dance performances and lectures on the link between sexuality and spirituality in Eastern and Western myths and religions, is to take place tomorrow at St. Peter's Church, Lexington Avenue and 54th Street, from 8:30 A.M. to 6 P.M. The sponsor is Cauldron Productions, which presented similar events at the Asia Society. Tickets are $80; $60 for students and the elderly. Telephone: (212) 245-0445.
The lectures will deal with the ancient Near East, Medieval Europe, India, Tibet and the United States. The choreographers on the program will be Muna Tseng, Tamar Rogoff, Leela Raja and Ze'eva Cohen.
NEW HAVEN, Conn. – In a lecture hall on Yale's storied Old Campus, not long after an afternoon astronomy class has cleared out, a middle-aged sex toy saleswoman demonstrates her technique and hands out free products to an eager crowd.“I want you to close your eyes,” Patty Brisben playfully instructs a young man as she rubs scented lotion into his forearm and, to raucous laughter, reaches for an electric toy and a glove. “Fantasize about having an all-over body massage.” Welcome to Sex Week at Yale, a biennial celebration that has become one of the most provocative campus events in the country.
Organizers say Sex Week gets students talking about sex in a way that's more relevant than middle-school film strips, more honest than movies and television, and more fun than requisite college health lectures.
“To get people's attention, we do have to do things a little risque and a little different than other sex education programs,” said junior Dain Lewis, who was inspired to direct Sex Week 2006 after attending the 2004 event.
Yale's event, which ends today, includes lectures from dating specialists, a sex therapist and a discussion of homosexuality with a former Roman Catholic priest. More provocative sessions include a panel of porn stars and stripping lessons from a Playboy Channel hostess.
Critics say Sex Week is just the latest act of debauchery at colleges in recent years: Students started sex columns. Vassar and others created erotica journals. Harvard launched H-Bomb, a magazine featuring suggestive pictures of undergraduates. Washington University in St. Louis offered a sex-themed week with orgasm seminars and condom telegrams.
“I don't see how bringing a Playboy stripper to campus is helping anything,” said Travis Kavulla, editor of the Harvard Salient, which joined other conservative newspapers in giving Sex Week the Collegiate Network 2004 Outrage Award. “How are universities trying to educate students in sponsoring activities like this?”
Sex Week is a recognized student organization but Brisben's company, PureRomance.com, sponsors the events, not Yale. Advertising helps pay for marketing and for Sex Week at Yale: the Magazine.
The magazine contains sex advice for men, help for selecting the right condom and suggestions for women trying to satisfy themselves.
Editors say they're promoting sexual awareness, not sex. The magazine includes an article encouraging abstinence until marriage, a guide to healthy relationships and an essay on unrequited love.
The interview with the porn star, organizers said, was just for fun.
“It would seem like we were trying to intellectualize sex if we didn't have something on the other end of the spectrum,” said Whitney Seibel, a senior psychology major who posed for the cover wearing only red panties and a strategically placed arm.
About 25,000 copies were distributed at Yale and on other campuses nationwide. The editors are considering a second printing.
While Yale may be giving off a flirty vibe this week, Brisben said she was surprised at how reserved the students were at her seminar. And for all their good grades, Brisben said Yale students seemed less clued in about sex than students elsewhere.
“I have a lot of inhibitions and fears that I'm not sure where they come from,” said Kaja Wilmanska, a 20-year-old sophomore from Poland. “It opens up the ground to talk about issues people aren't comfortable talking about otherwise. Basically, I want to see what other people are saying.”
Lecturer to discuss sex harassment, same-sex marriage
Janet E. Halley, professor of law at Harvard University, will deliver three Messenger Lectures at Cornell this fall. The theme of the lectures will be "Sexuality Harassment/Same-Sex Marriage."
All of the lectures are free and open to the public; they are:
Monday, Oct. 15, "Sexuality Harassment I," 4:30 p.m., 165 McGraw Hall;
Tuesday, Oct. 16, "Sexuality Harassment II," 4:30 p.m., 165 McGraw Hall; and
Wednesday, Oct. 17, "Same-Sex Marriage: What is the Right Question?" 4:30 p.m., 165 McGraw Hall.
Halley, who joined the faculty of Harvard Law School in 2000 and teaches courses on family law, is a leading scholar on the law, politics and theory of sexual orientation and group identity. Says Harvard Law School Dean Robert C. Clark: "She is renowned for her work in family law, the theory of social movements and law and culture. She is both an experienced attorney and a bridge between the worlds of law and literary criticism."
Previously, Halley was on the faculty at Stanford Law School, where she was named the Robert E. Paradise Faculty Scholar for Excellence in Teaching and Research in 1996. At Stanford, she taught civil procedure, family law and a course titled Races, Communities and Nations: Identity in Law and Culture.
Halley is the author of Don't: A Reader's Guide to the Military's Anti-Gay Policy (Duke University Press, 1999) and a series of law review articles on equal protection for sexual minorities. She also has published widely on heresy and orthodoxy in early modern England and on 17th-century English literature. She has four books in progress, including Suspect Class(ifications): Rights and the Problem of Sexual Orientation Identity and Sexuality Harassment: A Critique of Sex Harassment Law.
The Messenger Lectures were established in 1924 by a gift from Cornell graduate Hiram Messenger 1880, with the intent of raising the moral standards of political, business and social life.
Janet E. Halley, professor of law at Harvard University, will deliver three Messenger Lectures at Cornell this fall. The theme of the lectures will be "Sexuality Harassment/Same-Sex Marriage."
All of the lectures are free and open to the public; they are:
Monday, Oct. 15, "Sexuality Harassment I," 4:30 p.m., 165 McGraw Hall;
Tuesday, Oct. 16, "Sexuality Harassment II," 4:30 p.m., 165 McGraw Hall; and
Wednesday, Oct. 17, "Same-Sex Marriage: What is the Right Question?" 4:30 p.m., 165 McGraw Hall.
Halley, who joined the faculty of Harvard Law School in 2000 and teaches courses on family law, is a leading scholar on the law, politics and theory of sexual orientation and group identity. Says Harvard Law School Dean Robert C. Clark: "She is renowned for her work in family law, the theory of social movements and law and culture. She is both an experienced attorney and a bridge between the worlds of law and literary criticism."
Previously, Halley was on the faculty at Stanford Law School, where she was named the Robert E. Paradise Faculty Scholar for Excellence in Teaching and Research in 1996. At Stanford, she taught civil procedure, family law and a course titled Races, Communities and Nations: Identity in Law and Culture.
Halley is the author of Don't: A Reader's Guide to the Military's Anti-Gay Policy (Duke University Press, 1999) and a series of law review articles on equal protection for sexual minorities. She also has published widely on heresy and orthodoxy in early modern England and on 17th-century English literature. She has four books in progress, including Suspect Class(ifications): Rights and the Problem of Sexual Orientation Identity and Sexuality Harassment: A Critique of Sex Harassment Law.
The Messenger Lectures were established in 1924 by a gift from Cornell graduate Hiram Messenger 1880, with the intent of raising the moral standards of political, business and social life.
Sunday, November 05, 2006
Syndromes, illness and disease
Medical usage sometimes distinguishes a disease, which has a known specific cause or causes (called its etiology), from a syndrome, which is a collection of signs or symptoms that occur together. However, many conditions have been identified, yet continue to be referred to as "syndromes". Furthermore, numerous conditions of unknown etiology are referred to as "diseases" in many contexts.
Illness, although often used to mean disease, can also refer to a person's perception of their health, regardless of whether they in fact have a disease. A person without any disease may feel unhealthy and believe he has an illness. Another person may feel healthy and believe he does not have an illness even though he may have a disease such as dangerously high blood pressure which may lead to a fatal heart attack or stroke.
Disease can be thought of as the presence of pathology, which can occur with or without subjective feelings of being unwell or social recognition of that state; Illness as the subjective state of "unwellness", which can occur independently of, or in conjunction with disease or sickness; and sickness as the social classification of someone deemed diseased, which can also occur independently of the presence or absence of disease or illness (c.f. subjective medical conditions). So someone with undetected high blood pressure who feels well would be diseased, but not ill or sick. Someone with a diagnosis of late-stage cancer would be diseased, probably feeling quite ill, and recognized by others as sick. A person incarcerated in a totalitarian psychiatric hospital for political purposes could arguably be then said to not be diseased, nor ill, but only classified as sick by the rulers of a society with which the person did not agree. Having had a bad day after a night of excess, one might feel ill, but you would not be diseased, nor is it likely you could convince your boss to recognize you as sick.
Sickness confers the social legitimization of certain benefits, such as illness benefit, work avoidance and being looked after by others. In return, there is an obligation on the sick person to seek treatment and work to become well once more.
Medical usage sometimes distinguishes a disease, which has a known specific cause or causes (called its etiology), from a syndrome, which is a collection of signs or symptoms that occur together. However, many conditions have been identified, yet continue to be referred to as "syndromes". Furthermore, numerous conditions of unknown etiology are referred to as "diseases" in many contexts.
Illness, although often used to mean disease, can also refer to a person's perception of their health, regardless of whether they in fact have a disease. A person without any disease may feel unhealthy and believe he has an illness. Another person may feel healthy and believe he does not have an illness even though he may have a disease such as dangerously high blood pressure which may lead to a fatal heart attack or stroke.
Disease can be thought of as the presence of pathology, which can occur with or without subjective feelings of being unwell or social recognition of that state; Illness as the subjective state of "unwellness", which can occur independently of, or in conjunction with disease or sickness; and sickness as the social classification of someone deemed diseased, which can also occur independently of the presence or absence of disease or illness (c.f. subjective medical conditions). So someone with undetected high blood pressure who feels well would be diseased, but not ill or sick. Someone with a diagnosis of late-stage cancer would be diseased, probably feeling quite ill, and recognized by others as sick. A person incarcerated in a totalitarian psychiatric hospital for political purposes could arguably be then said to not be diseased, nor ill, but only classified as sick by the rulers of a society with which the person did not agree. Having had a bad day after a night of excess, one might feel ill, but you would not be diseased, nor is it likely you could convince your boss to recognize you as sick.
Sickness confers the social legitimization of certain benefits, such as illness benefit, work avoidance and being looked after by others. In return, there is an obligation on the sick person to seek treatment and work to become well once more.
Some basic assumptions of EDP
All evolutionarily-influenced characteristics develop, and this requires examining not only the functioning of these characteristics in adults but also their ontogeny.
All evolved characteristics develop via continuous and bidirectional gene-environment interactions that emerge dynamically over time.
Development is constrained by genetic, environmental, and cultural factors.
An extended childhood is needed in which to learn the complexities of human social communities and economies.
Many aspects of childhood serve as preparations for adulthood and were selected over the course of evolution (deferred adaptations).
Some characteristics of infants and children were selected to serve an adaptive function at specific times in development and not as preparations for adulthood (ontogenetic adaptations).
Children show a high degree of plasticity, or flexibility, and the ability to adapt to different contexts
All evolutionarily-influenced characteristics develop, and this requires examining not only the functioning of these characteristics in adults but also their ontogeny.
All evolved characteristics develop via continuous and bidirectional gene-environment interactions that emerge dynamically over time.
Development is constrained by genetic, environmental, and cultural factors.
An extended childhood is needed in which to learn the complexities of human social communities and economies.
Many aspects of childhood serve as preparations for adulthood and were selected over the course of evolution (deferred adaptations).
Some characteristics of infants and children were selected to serve an adaptive function at specific times in development and not as preparations for adulthood (ontogenetic adaptations).
Children show a high degree of plasticity, or flexibility, and the ability to adapt to different contexts
[edit] Evolutionary stable strategies
Another driving force in the evolution of animal behavior is the concept of an evolutionary stable strategy (or ESS), a term derived from economic game theory which became prominent after John Maynard Smith's 1982 book, Evolution and the Theory of Games. However, the concept can be traced back (as with most evolutionary ideas) to W.D. Hamilton, R.A. Fisher and Charles Darwin. In short, evolutionary game theory asserts that only strategies that cannot be "invaded" by another strategy will be maintained in the population. Therefore, animal behavior can be said to be governed not only by what is optimal, but also by what other strategies are found in the population. Furthermore, the relative frequencies of each strategy can influence the fitness of the other strategies in the population (frequency dependence). It is important to consider that evolution is not only driven by the physical environment, but also the interactions between other individuals.
Another driving force in the evolution of animal behavior is the concept of an evolutionary stable strategy (or ESS), a term derived from economic game theory which became prominent after John Maynard Smith's 1982 book, Evolution and the Theory of Games. However, the concept can be traced back (as with most evolutionary ideas) to W.D. Hamilton, R.A. Fisher and Charles Darwin. In short, evolutionary game theory asserts that only strategies that cannot be "invaded" by another strategy will be maintained in the population. Therefore, animal behavior can be said to be governed not only by what is optimal, but also by what other strategies are found in the population. Furthermore, the relative frequencies of each strategy can influence the fitness of the other strategies in the population (frequency dependence). It is important to consider that evolution is not only driven by the physical environment, but also the interactions between other individuals.
Differential reproductive success
Ultimately, all behavior is subject to natural selection as with any other trait of an animal. Therefore animals that employ optimal behavioral strategies specific to their environment will generally leave greater numbers of offspring than their suboptimal conspecifics. Animals that leave a greater number of offspring than others of their own species are said to have greater fitness than their suboptimal cousins. However, over time environments change meaning that what might be good behavior today might not be the best behavior in 10,000 years time or even 10 years time. Recent glaciation and future global warming mean that one thing will be certain. The behavior of animals has and will continue to change in response to the environment. Behavioral ecology is one of the best ways to study these changes. As the great geneticist Theodosius Dobzhansky famously wrote, "nothing in biology makes sense except in the light of evolution".
Ultimately, all behavior is subject to natural selection as with any other trait of an animal. Therefore animals that employ optimal behavioral strategies specific to their environment will generally leave greater numbers of offspring than their suboptimal conspecifics. Animals that leave a greater number of offspring than others of their own species are said to have greater fitness than their suboptimal cousins. However, over time environments change meaning that what might be good behavior today might not be the best behavior in 10,000 years time or even 10 years time. Recent glaciation and future global warming mean that one thing will be certain. The behavior of animals has and will continue to change in response to the environment. Behavioral ecology is one of the best ways to study these changes. As the great geneticist Theodosius Dobzhansky famously wrote, "nothing in biology makes sense except in the light of evolution".
Optimization theory
Behavioral ecology, along with other areas of evolutionary biology, has incorporated a number of techniques which have been borrowed from optimization theory. Optimization is a concept that stipulates strategies that offer the highest return to an animal given all the different factors and constraints facing the animal. One of the simplest ways to arrive at an optimal solution is to do a cost/benefit analysis. By considering the advantages of a behavior and the costs of a behavior, it can be seen that if the costs outweigh the benefits then a behavior will not evolve and vice versa. This is also where the concept of the trade-off becomes important. This is because it rarely pays an animal to invest maximally in any one behavior. For example, the amount of time an ectothermic animal such as a lizard spends foraging is constrained by its body temperature. The digestive efficiency of the lizard also increases with increases in body temperature. Lizards increase their body temperature by basking in the sun. However, the time spent basking decreases the amount of time available for foraging. Basking also increases the risk of being discovered by a predator. Therefore, the optimal basking time is the outcome of the time necessary to sufficiently warm itself to carry out its activities such as foraging. This example shows how foraging is constrained by the need to bask (intrinsic constraint) and predation pressure (extrinsic constraint).
Behavioral ecology, along with other areas of evolutionary biology, has incorporated a number of techniques which have been borrowed from optimization theory. Optimization is a concept that stipulates strategies that offer the highest return to an animal given all the different factors and constraints facing the animal. One of the simplest ways to arrive at an optimal solution is to do a cost/benefit analysis. By considering the advantages of a behavior and the costs of a behavior, it can be seen that if the costs outweigh the benefits then a behavior will not evolve and vice versa. This is also where the concept of the trade-off becomes important. This is because it rarely pays an animal to invest maximally in any one behavior. For example, the amount of time an ectothermic animal such as a lizard spends foraging is constrained by its body temperature. The digestive efficiency of the lizard also increases with increases in body temperature. Lizards increase their body temperature by basking in the sun. However, the time spent basking decreases the amount of time available for foraging. Basking also increases the risk of being discovered by a predator. Therefore, the optimal basking time is the outcome of the time necessary to sufficiently warm itself to carry out its activities such as foraging. This example shows how foraging is constrained by the need to bask (intrinsic constraint) and predation pressure (extrinsic constraint).
Optimization theory
Behavioral ecology, along with other areas of evolutionary biology, has incorporated a number of techniques which have been borrowed from optimization theory. Optimization is a concept that stipulates strategies that offer the highest return to an animal given all the different factors and constraints facing the animal. One of the simplest ways to arrive at an optimal solution is to do a cost/benefit analysis. By considering the advantages of a behavior and the costs of a behavior, it can be seen that if the costs outweigh the benefits then a behavior will not evolve and vice versa. This is also where the concept of the trade-off becomes important. This is because it rarely pays an animal to invest maximally in any one behavior. For example, the amount of time an ectothermic animal such as a lizard spends foraging is constrained by its body temperature. The digestive efficiency of the lizard also increases with increases in body temperature. Lizards increase their body temperature by basking in the sun. However, the time spent basking decreases the amount of time available for foraging. Basking also increases the risk of being discovered by a predator. Therefore, the optimal basking time is the outcome of the time necessary to sufficiently warm itself to carry out its activities such as foraging. This example shows how foraging is constrained by the need to bask (intrinsic constraint) and predation pressure (extrinsic constraint).
Behavioral ecology, along with other areas of evolutionary biology, has incorporated a number of techniques which have been borrowed from optimization theory. Optimization is a concept that stipulates strategies that offer the highest return to an animal given all the different factors and constraints facing the animal. One of the simplest ways to arrive at an optimal solution is to do a cost/benefit analysis. By considering the advantages of a behavior and the costs of a behavior, it can be seen that if the costs outweigh the benefits then a behavior will not evolve and vice versa. This is also where the concept of the trade-off becomes important. This is because it rarely pays an animal to invest maximally in any one behavior. For example, the amount of time an ectothermic animal such as a lizard spends foraging is constrained by its body temperature. The digestive efficiency of the lizard also increases with increases in body temperature. Lizards increase their body temperature by basking in the sun. However, the time spent basking decreases the amount of time available for foraging. Basking also increases the risk of being discovered by a predator. Therefore, the optimal basking time is the outcome of the time necessary to sufficiently warm itself to carry out its activities such as foraging. This example shows how foraging is constrained by the need to bask (intrinsic constraint) and predation pressure (extrinsic constraint).
Proximate causation
Proximate causation is also divided into two factors which are ontogenetic factors and mechanistic factors. Ontogenetic factors are the entire sum of experience throughout the lifetime of an individual from embryo to death. Hence, factors included are learning the genetic factors giving rise to behavior in individuals. Mechanistic factors, as the name implies, are the processes of the body that give rise to behavior such as the effects of hormones on behavior and neuronal basis of behavior
Proximate causation is also divided into two factors which are ontogenetic factors and mechanistic factors. Ontogenetic factors are the entire sum of experience throughout the lifetime of an individual from embryo to death. Hence, factors included are learning the genetic factors giving rise to behavior in individuals. Mechanistic factors, as the name implies, are the processes of the body that give rise to behavior such as the effects of hormones on behavior and neuronal basis of behavior
Ultimate causation
The two causes that contribute to ultimate causation are phylogenetic contingencies that contribute to the development of behavior and the second is adaptive significance. Phylogenetic constraints are generally factors that might stop certain lineages developing certain behavioral or morphological traits. Hence, it is no coincidence that generally birds are able to fly and mammals cannot. The evolutionary history of these lineages have made it profitable for birds to fly and for mammalian feet to remain planted on the ground. Adaptive significance is akin to asking what a trait is good for in an evolutionary context. Therefore, the adaptive significance of flight in birds might have enabled avian ancestors to escape from predators. However, it is not sufficient to apply these explanations where they seem convenient. These have been labeled Just So Stories by some biologists after Rudyard Kipling's tales for children about how animals came to be the way they are. To be rigorous, one must suppose a hypothesis and then test it scientifically. Hence, for avian flight, one can suppose that when birds are not at risk of being eaten, they might lose the ability to fly. This has been observed in bird faunas on oceanic islands such as New Zealand. Historically these land masses had no mammalian predators and so had a higher proportion of flightless bird species compared with avifaunas exposed to mammalian predation.
The two causes that contribute to ultimate causation are phylogenetic contingencies that contribute to the development of behavior and the second is adaptive significance. Phylogenetic constraints are generally factors that might stop certain lineages developing certain behavioral or morphological traits. Hence, it is no coincidence that generally birds are able to fly and mammals cannot. The evolutionary history of these lineages have made it profitable for birds to fly and for mammalian feet to remain planted on the ground. Adaptive significance is akin to asking what a trait is good for in an evolutionary context. Therefore, the adaptive significance of flight in birds might have enabled avian ancestors to escape from predators. However, it is not sufficient to apply these explanations where they seem convenient. These have been labeled Just So Stories by some biologists after Rudyard Kipling's tales for children about how animals came to be the way they are. To be rigorous, one must suppose a hypothesis and then test it scientifically. Hence, for avian flight, one can suppose that when birds are not at risk of being eaten, they might lose the ability to fly. This has been observed in bird faunas on oceanic islands such as New Zealand. Historically these land masses had no mammalian predators and so had a higher proportion of flightless bird species compared with avifaunas exposed to mammalian predation.
Life history theory is an analytical framework widely used in animal and human biology, psychology, and evolutionary anthropology which postulates that many of the physiological traits and behaviors of individuals may be best understood in terms of the key maturational and reproductive characteristics that define the life course.
Examples of these characteristics include:
Age at weaning
Age of sexual maturity or puberty
Adult body size
Age specific mortality schedules
Age specific fecundity
Time to first sexual activity or mating
Time to first reproduction
Duration of gestation
Litter size
Interbirth interval
Variations in these characteristics reflect differing allocations of an individual's resources (i.e., time, effort, and energy expenditure) to competing life functions, especially growth, body maintenance, and reproduction. For any given individual, available resources in any particular environment are finite. Time, effort, and energy used for one purpose diminishes the time effort, and energy available for another. For example, resources spent growing to a larger body size cannot be spent increasing the number of offspring. In general terms the costs of reproduction may be paid in terms of energy being diverted away from body repair and maintenance and by reducing investment in immunological competence.
Thus the allocation of resources involves trade-offs. These trade-offs and strategies can be compared between species. Two of the most well-known trade-offs involve number of offspring (few or many) and timing of reproduction (accelerated maturation and reproduction versus delayed, allowing for larger size and more complex social supports). The extremes at the species level of these fundamental dimensions of reproduction were recognized long before life history theory, and are traditionally termed r/K selection theory. An r-selection strategy is the production of a large number of offspring (of whom only a minority may survive) as early in life as possible. The K-selection strategy is to produce a smaller number of "fitter" offspring with higher survival chances.
According to life history theory the individuals of a species are able to make limited shifts in reproductive strategies in response to the prevailing environments. Depending on abundance of resources and probable individual longevity, individuals consciously or unconsciously shift their reproductive strategy in one direction or the other to take advantage of available resources or to compensate for resource shortage or uncertainty.
Initially life history theory postulated that life history characteristics were essentially 'extrinsic' (Charnov, 1993, Kozlowski & Wiegert, 1986) and not subject to endogenous processes. However this approach has more recently been found to be theoretically unsatisfying, as there is evidence that higher organisms exert control over virtually all causes of mortality (e.g., by altering patterns of travel to avoid predators, by investing in immune function etc) and these endogenous processes can also be seen at work in the varyiance in ages of menarché and menopause (Kaplan and Robson, 2002, Kaplan et al, 2003). This argument has some resonance with more recent economic approaches, notably Robert Fogel and Dora Costa’s idea of technophysio evolution (Fogel, 2004).
The traditional life history framework has also been thought to be analytically limited, in that it does not allow for a full understanding of how mortality rates evolve. In reality what varies as a function of ecological factors are not set mortality rates, but rather functional relationships between mortality and efforts allocated to reducing it. Exogenous variation can be thought of in terms of varying 'assault' types and rates (Kaplan et al, 2003).
More recently researchers working in the life history tradition have drawn attention to way the functional relationships described may also be understood in terms of the the fetal programming hypothesis. This hypothesis holds that early growth retardation results in adjustments or impairments in fetal development which have permanent consequences for function and health risk. Programming is thought to occur through "induction, deletion or impaired development of a permanent somatic structure as a result of a stimulus or insult" (Davies and Norman, 2002:386). An accompanying mechanism has also been advanced in an attempt to explain the operation of the programming: the thrifty phenotype hypothesis. The thrifty phenotype process is thought to operate via altered glucose-insulin metabolism (Hales and Barker, 1992, 2001). Although evidence of fetal programming in humans has been questioned on the basis of weaknesses in retrospective epidemiological studies (Huxley et al, 2002), there is very strong evidence from studies of animals to show that poor nutrition in fetal life can have profound effects on metabolic and cardiovascular disease risk in adulthood (Langley-Evans, 2006).
The fetal origins hypothesis has subsequently been developed to include the idea of an 'appropriateness of fit' between the phenotype and its environment. This has resulted in increased attention being drawn to the problems which may occur if there is a mismatch between physiologic capacities established in early development and the environments in which they later function.
In life history terms, fetal programming works to 'configure' our somatic system so that in conditions of good maternal health, low juvenile morbidity rates, and sustained normal nutrition the 'settings' work just so as to increase overall productivity and reduce the relative cost of maintenance (the meaning of 'good health', 'low juvenile morbity' and 'normal nutrition' should be understood in terms of the pre-historic foraging environment where our biology effectively evolved). From this initial 'setting' any sustained increase in nutritional energy input (or reduction in the disease load on the immune system) tends towards increased growth and accelerated maturation (this incidentally may help understand those puzzling long-term fluctuations in population sizes and final heights which characterised the pre-industrial period). Such improved environmental circumstances are also know to operate indirectly on age at maturity since they act as a signal that resource availability is reliably good and that mortality risk is low. Hence it has been found that the norm of reaction for timing of maturation in humans is large, and documented population median ages at menarche range from 12.3–18 years (Eveleth and Tanner, 1990), and the mean age at menarche has been falling steadily in modern growth environments (Weil, 2005).
Thus the trade-offs identified by life history can be interpreted as implying that the present health consequences of differential fetal outcomes represent the resurfacing of costs deferred in early trade-offs. According to the fetal programming hypothesis permanent alterations in metabolic regulation under early conditions of adversity could be seen as adaptive in virtue the overarching need to produce an energy-sparing phenotype (Hales and Barker, 2001). The resulting conceptual problem has been to clarify why such permanent changes should be adaptive if they yield little in the way of future benefits, yet do exact a future cost.
Life history theory has provided new perspectives in understanding many aspects of human reproductive behavior, such as the relationship between poverty and fertility. A number of statistical predictions have been confirmed by social data, though not always reproducibly. The implications for social policy have been hotly debated because statistical associations are not always causal, and a preferred interpretation may be a more minor factor than another unpalatable relationship.
Examples of these characteristics include:
Age at weaning
Age of sexual maturity or puberty
Adult body size
Age specific mortality schedules
Age specific fecundity
Time to first sexual activity or mating
Time to first reproduction
Duration of gestation
Litter size
Interbirth interval
Variations in these characteristics reflect differing allocations of an individual's resources (i.e., time, effort, and energy expenditure) to competing life functions, especially growth, body maintenance, and reproduction. For any given individual, available resources in any particular environment are finite. Time, effort, and energy used for one purpose diminishes the time effort, and energy available for another. For example, resources spent growing to a larger body size cannot be spent increasing the number of offspring. In general terms the costs of reproduction may be paid in terms of energy being diverted away from body repair and maintenance and by reducing investment in immunological competence.
Thus the allocation of resources involves trade-offs. These trade-offs and strategies can be compared between species. Two of the most well-known trade-offs involve number of offspring (few or many) and timing of reproduction (accelerated maturation and reproduction versus delayed, allowing for larger size and more complex social supports). The extremes at the species level of these fundamental dimensions of reproduction were recognized long before life history theory, and are traditionally termed r/K selection theory. An r-selection strategy is the production of a large number of offspring (of whom only a minority may survive) as early in life as possible. The K-selection strategy is to produce a smaller number of "fitter" offspring with higher survival chances.
According to life history theory the individuals of a species are able to make limited shifts in reproductive strategies in response to the prevailing environments. Depending on abundance of resources and probable individual longevity, individuals consciously or unconsciously shift their reproductive strategy in one direction or the other to take advantage of available resources or to compensate for resource shortage or uncertainty.
Initially life history theory postulated that life history characteristics were essentially 'extrinsic' (Charnov, 1993, Kozlowski & Wiegert, 1986) and not subject to endogenous processes. However this approach has more recently been found to be theoretically unsatisfying, as there is evidence that higher organisms exert control over virtually all causes of mortality (e.g., by altering patterns of travel to avoid predators, by investing in immune function etc) and these endogenous processes can also be seen at work in the varyiance in ages of menarché and menopause (Kaplan and Robson, 2002, Kaplan et al, 2003). This argument has some resonance with more recent economic approaches, notably Robert Fogel and Dora Costa’s idea of technophysio evolution (Fogel, 2004).
The traditional life history framework has also been thought to be analytically limited, in that it does not allow for a full understanding of how mortality rates evolve. In reality what varies as a function of ecological factors are not set mortality rates, but rather functional relationships between mortality and efforts allocated to reducing it. Exogenous variation can be thought of in terms of varying 'assault' types and rates (Kaplan et al, 2003).
More recently researchers working in the life history tradition have drawn attention to way the functional relationships described may also be understood in terms of the the fetal programming hypothesis. This hypothesis holds that early growth retardation results in adjustments or impairments in fetal development which have permanent consequences for function and health risk. Programming is thought to occur through "induction, deletion or impaired development of a permanent somatic structure as a result of a stimulus or insult" (Davies and Norman, 2002:386). An accompanying mechanism has also been advanced in an attempt to explain the operation of the programming: the thrifty phenotype hypothesis. The thrifty phenotype process is thought to operate via altered glucose-insulin metabolism (Hales and Barker, 1992, 2001). Although evidence of fetal programming in humans has been questioned on the basis of weaknesses in retrospective epidemiological studies (Huxley et al, 2002), there is very strong evidence from studies of animals to show that poor nutrition in fetal life can have profound effects on metabolic and cardiovascular disease risk in adulthood (Langley-Evans, 2006).
The fetal origins hypothesis has subsequently been developed to include the idea of an 'appropriateness of fit' between the phenotype and its environment. This has resulted in increased attention being drawn to the problems which may occur if there is a mismatch between physiologic capacities established in early development and the environments in which they later function.
In life history terms, fetal programming works to 'configure' our somatic system so that in conditions of good maternal health, low juvenile morbidity rates, and sustained normal nutrition the 'settings' work just so as to increase overall productivity and reduce the relative cost of maintenance (the meaning of 'good health', 'low juvenile morbity' and 'normal nutrition' should be understood in terms of the pre-historic foraging environment where our biology effectively evolved). From this initial 'setting' any sustained increase in nutritional energy input (or reduction in the disease load on the immune system) tends towards increased growth and accelerated maturation (this incidentally may help understand those puzzling long-term fluctuations in population sizes and final heights which characterised the pre-industrial period). Such improved environmental circumstances are also know to operate indirectly on age at maturity since they act as a signal that resource availability is reliably good and that mortality risk is low. Hence it has been found that the norm of reaction for timing of maturation in humans is large, and documented population median ages at menarche range from 12.3–18 years (Eveleth and Tanner, 1990), and the mean age at menarche has been falling steadily in modern growth environments (Weil, 2005).
Thus the trade-offs identified by life history can be interpreted as implying that the present health consequences of differential fetal outcomes represent the resurfacing of costs deferred in early trade-offs. According to the fetal programming hypothesis permanent alterations in metabolic regulation under early conditions of adversity could be seen as adaptive in virtue the overarching need to produce an energy-sparing phenotype (Hales and Barker, 2001). The resulting conceptual problem has been to clarify why such permanent changes should be adaptive if they yield little in the way of future benefits, yet do exact a future cost.
Life history theory has provided new perspectives in understanding many aspects of human reproductive behavior, such as the relationship between poverty and fertility. A number of statistical predictions have been confirmed by social data, though not always reproducibly. The implications for social policy have been hotly debated because statistical associations are not always causal, and a preferred interpretation may be a more minor factor than another unpalatable relationship.
