Chapter 7
BIOCULTURAL MODEL FOR HIGH MORTALITY RAPID KILLING EPIDEMICS
Anthropologists have a reputation for writing detailed ethnographic descriptions and the previous four chapters follow in this tradition in terms of providing details of how local people in Uganda and Congo reacted to deadly Ebola outbreaks. While maybe not particularly good at it, cultural anthropologists are also interested in explaining human behavior. Ethnographic descriptions are interesting but we also want to understand why people behave the way they do—in this case, how can we explain human behavior during high mortality, rapid killing epidemics like Ebola?
Chapter 2 introduced a few anthropological theories that influenced our selection of methods. The cultural models and clinical medical anthropological approaches indicate that how we think and feel dramatically influences our behavior. The structural violence approach suggests that global and local political-economic structures and institutions are prime factors that help explain human behavior. But while each theory explains part of the puzzle, each has limitations an cannot explain certain behaviors, such as the common feeling of fear and the desire to flee during an outbreak. This chapter develops a holistic and integrated biocultural model that we think helps to explain human responses to epidemics such as Ebola.
The biocultural model is presented and applied to data from the Congo and Uganda. The final part of the chapter examines how the biocultural model fits or does not fit other cross-cultural studies of epidemics.
A Biocultural Model
The previous chapters provide a starting point for understanding human responses to high mortality epidemics. A few commonalities emerge from the outbreaks, some of which are listed below.
1. fear and panic after observing the rapid death of several individuals
2. desire to flee infectious areas —individuals, villages, hospitals
3. sorcery cultural model used to explain early cases
4. epidemic concept and control measures as deaths continued
5. national or international political economic origin stories
6. fear of Euro-Americans
7. washing and touching the body as part of burial ritual
8. rapid spread of information, including rumors and misinformation
9. population density (e.g., urban versus rural) influences how many health workers are
infected
10. availability of resources influences transmission (e.g., in hospitals)
The aim of the model is to try to understand the relationships between some of these patterns.
The biocultural model is grounded in recent developments in evolutionary theory. We find evolutionary theory useful for several reasons. First, it focuses on individuals rather than groups. Natural selection is measured by the reproductive fitness of individuals not groups. This means individuals (men, women, children) are active agents in their cultural and natural environments. Cultural beliefs and practices exist, but they can be manipulated, added to or discarded by individuals given their particular political, economic, or natural environment. Second, contemporary evolutionary theory is biocultural. Most anthropologists are familiar with the biological (genetic) aspects of evolutionary theory, but few are familiar with evolutionary approaches to culture (described in more detail below). The culture concept described in Chapter 1 is alive and well in evolutionary theory. But more importantly, recent evolutionary approaches emphasize the interactions between biology and culture; rarely is human behavior the result of only genes or culture; behavior is mutually constituted. Third, evolutionary theory enables us to incorporate other contemporary theoretical approaches, such as cultural models and structural violence. These approaches are not inconsistent with an evolutionary approach, although their proponents may suggest otherwise.
The biocultural model, illustrated in Figure 7.1, is a heuristic, rather than a predictive model; this means the model is used to generate discussion and hypotheses rather than making specific predictions. The arrows going every which way are indicators of a heuristic model. According to the model, human responses to EHF can best be understood as the result of interactions between biology, culture and ecology.
Evolutionary psychology is the branch of evolutionary theory that has attracted the most attention and controversy, and why most anthropologists think evolutionary approaches are genetic. EP’s are interested in identifying biologically based (i.e., genetic) universals of the human mind that evolved during the environment(s) of evolutionary adaptation (EEA) and continue to shape human behavior. The EEA is the hunting-gathering period of human history; this way of life characterized over 90% of human history, farming is actually a relatively recent innovation. For instance, humans today desire foods with plenty of salt, sugar and fat because foods with these items were rare and important for survival in the EEA. They are biologically based desires that continue to influence dietary decisions. We do not have the desire for more fiber because this was common in the EEA. EP’s view the human mind as containing specific modules that evolved to solve re-occurring problems in the EEA. According to EP’s, some of the modules of the mind that evolved in the EEA and are biologically based include: sexual jealousy, language acquisition device for children, attachment in children and kin recognition. Current research emphasizes identification of the universal behavioral modules while their biological bases (i.e., specific genes or location in brain) are often assumed.
Which responses in EHF outbreaks might be explained by EP’s? Aspects of outbreaks that are common to outbreaks in any culture or country, and responses that one might attribute to “human nature” are most likely to fall under this evolutionary branch. The EP approach suggests that regardless of whether you are in Nebraska or central Africa, that once you hear about or see an epidemic it should evoke similar feelings and responses. If epidemics are a re-occurring problem in the EEA, which is likely (bacterial ones more likely than viral ones due to lower population density), behaviors that led to greater survival and reproductive advantages over others would have be selected for and become part of our evolved psychology or human nature. A few considerations from our study:
1. fear, anxiety and panic after observing the rapid death of several individuals
2. desire to flee infected areas—individuals, villages, hospitals
3. special efforts to protect children during an epidemic
4. care for biological family members more than neighbors or unrelated people
5. ability to identify sick from healthy individuals
An individual who became fearful and attentive after watching a few people die relatively rapidly is more likely to leave more descendents than others who were not afraid or not concerned. Observing a few rapid deaths of individuals over time evokes fear. The desire to flee may also be part of our evolved psychology. Those in the EEA who moved away from infected individuals and camps were more likely to leave more kin behind than those who stayed close to the infected.
In Congo and Uganda, explicit protocols provided special attention to children. They were viewed as particularly vulnerable especially as the deaths continued. EPs and other evolutionists emphasize the importance of inclusive fitness, which is an unconscious preference to assist biologically related individuals. Protecting your own children from potential risk of death is a clear example of inclusive fitness. It is also not unusual in outbreak situations that primarily immediate family members take care of the sick. Families in Gabon that were trying to take sick family members down river to the hospital did not receive any help from friends or others passing by. Those who share genes with a sick individual have more to loose and are more likely to take the risks of caregiving infected individuals. Another example of inclusive fitness influencing behavior is when Ugandan survivors where more likely to be accepted by their families than by neighbors. Family members are more likely to take the risk that their biological relative is cured. But it is important to remember that spouses and in-laws are not biological kin; the EP approach predicts more conflicts between spouses and in-laws than among biologically related individuals, such as brothers and sisters. As mentioned in Chapter 6, several Ebola survivors were abandoned by their spouses. In-law conflicts are also predicted to increase in outbreaks. For instance, in Congo, the older brother of two young girls died. When his in-laws came to help prepare for his funeral, the girls proclaimed to the in-laws that, “this is not Ebola” and suggested it was sorcery. The in-laws responded “then you wash the body!” The two frightened young girls ran off. Their mother washed her son’s body, became infected with Ebola and died. Families are not stigmatized if they are accused of sorcery, but stigmatization occurs if a family member(s) becomes infected with EHF.
Finally, many of the proposed features of human nature listed above assume humans have the ability to distinguish sick from healthy individuals and evaluate levels of severity of disease. It makes reproductive sense that individuals in the EEA who were able to distinguish sick from healthy individuals and keep some distance from those that were sick, especially those who were very sick, were more likely to survive and leave more descendents than individuals without these abilities. Sickness was a re-occuring problem in the EEA, as it is today, and those who were able to intuitively identify sick from healthy were more likely to survive. Certainly, cultural knowledge contributes substantially to this ability, but our experiences with children suggest that an understanding of contamination comes early and easily in life.
Several of the biologically-based behaviors mentioned above may be not be unique to humans. Inclusive fitness is a concern of any species and fleeing infected areas, protecting offspring and identifying sick from healthy probably have higher primate ancestry. Chimpanzees reportedly treat themselves with medicinal plants when they are fill, and primatologists at Lossi indicated gorilla mothers kept their babies away from gorillas that had died from Ebola and that the group fled their traditional foraging area after several gorillas died. The adaptive problems continued in the EEA but humans probably build upon an existing phylogenetic biology.
Evolutionary ecologists (EE), more precisely known as human behavioral ecologists, are quite different than EPs. They view the mind as more flexible and designed in a general way to enhance reproductive fitness and are interested in explaining human behavioral diversity rather than human universals. From this perspective, humans evaluate cost-benefit trade-offs in making decisions to optimize or maximize their reproductive fitness in a particular social, demographic, or political environment. For instance, a mother’s decision to care for her child suffering from EHF will be influenced by the mother’s age, her child’s age, how many other children she has, their ages, and a variety of other factors in her current environment. Questions an EE researcher might ask to help to understand human responses during an outbreak would include:
1. Is the disease localized or widespread?
2. Is the outbreak in a rural or urban area?
3. How many people are available to help out?
4. What are the resources available (money, gloves, isolation supplies, medications)?
5. What ecological factors trigger shifts in the cultural models?
The nature of the disease will influence whether or not it makes sense to try and flee the village. Urban verus rural settings tend to impact how many health workers are infected and die in outbreaks. As mentioned in Chapters 4 and 5 Uganda was an urban outbreak and Congo was a rural outbreak. Individuals who get sick in rural areas stay in the village because the hospital is far away. They infect other family members and individuals from other villagers who attend funerals. In urban areas, one sick person brought to the hospital can infect the healthcare personnel and other patients in the hospital; nosocomial transmission such as this, is often exacerbated by the severe lack of such basic resources as soap, bleach, clean water and proper training for those involved in the care of Ebola patients
The national and global political-economic setting influences the availability of a wide variety of resources essential for control efforts. Finally, they would be interested in what ecological conditions contribute to a shift in the cultural models. How many deaths does it take for a shift to occur? What is the role of past experience? From an EE perspective culture is simply one way humans adapt to diverse environments. Culture does not have any special properties of its own.
The final evolutionary approach illustrated in Figure 7.1, is evolutionary cultural anthropology (ECA). ECA researchers use the definition and concept of culture (as presented in Chapter 1) to point out that culture exhibits the characteristics required for natural selection: 1) production of variation, 2) competition and fitness effects of cultural variants, 3) inheritance (i.e., transmission) of cultural variants, 4) accumulation of modifications. For instance, during EHF outbreaks, individuals within a culture can have several ideas (e.g., herbal, biomedicine, sorcery), or cultural variants, individuals select and utilize one or more of the ideas (i.e., some of the ideas are acted upon and become the “phenotype” where selection takes place) which leads to individual variability in survival. Those who survive transmit this knowledge to future generations and new knowledge about EHF is added to existing knowledge about epidemics in general. Although cultural transmission differs in significant ways from genetic transmission it should be possible to understand some of the evolutionary features of culture. Most studies to date try to identify and describe the nature of cultural transmission mechanisms. Some ECA researchers are population geneticists who point out that genetic mechanisms can produce genetic maladaptation. For instance, if parents in West Africa are heterozygous for the sickle-cell trait (i.e., carry genes for both normal and sickle-shaped red blood cells), they have a 25% chance of producing a child who inherits only their sickle-cell genes, which usually leads to the death of child before age 15. If genetic mechanisms produce maladaptation, it seems reasonable to hypothesize that cultural mechanisms could produce maladaptive patterns as well. The suggestion that culture has its own features and can lead to maladaptive behaviors does not sit well with the EEs and EPs.
The mechanisms identified by ECA research are briefly described in Figure 7.2. Humans have different mechanisms to learn because it does not make sense to learn everything by trail and error; it is more efficient and leads to greater reproductive fitness to learn from parents (vertical), friends (horizontal), leaders (one-many) or from all of those around you (group). If everyone else is doing it, it is likely to be adaptive. Some mechanisms lead to the conservation of culture while other mechanisms lead to rapid culture change. Vertical transmission and group effect are most likely to be important in stable environments while horizontal and one-many transmission are likely in rapidly changing environments where individuals need regular updating. Vertical transmission was common for most of human history, but horizontal transmission is more important today in our rapidly changing world.
Researchers have demonstrated that many aspects of kinship and family organization are a result of demic diffusion (movement of people with their beliefs), vertical cultural transmission and group effect rather than adaptations to natural or social environments, or cultural diffusion (Hewlett et al. 2002). These researchers would hypothesize that cultural models for illness are linked to spread of particular groups of people and the people’s conserving those beliefs as they moved. For instance, beliefs in sorcery and epidemics spreading with the “wind” are common in sub-Saharan Africa, and are probably linked to the expansion of Bantu-speaking peoples about 2000 years ago. ECA researchers would focus on these features of the EHF outbreaks:
1. cultural models; sorcery, epidemic, biomedical
2. fear of Euro-Americans
3. washing and touching the body as part of burial ritual
4. rapid spread of information, including rumors and misinformation
5. national or international political economic origin stories
All of the above elements are socially transmitted and learned. The first three are likely to be transmitted via vertical and conformist or group mechanisms. This means they are highly conserved, slow to change, and individuals are likely to have strong emotions attached to them. Obviously, individuals can modify and adapt in unusual circumstances influencing survival, but people will have strong feelings about them. Africans have a long history with whites and local people have cultural models or schemas developed as a result of these repeated interactions. In a similar way, local people have developed epidemic control measures due to repeated occurrences of epidemics. Both types of information are socially learned, often via vertical and group transmission.