Evolutionary personality Psychology

November 1, 2017
Slide 1
The theory of evolutionary psychology has generated much debate among both psychologists and philosophers. Therefore it is imperative that evolutionary psychology be evaluated in detail. In doing so, one is forced to examine its forerunner, sociobiology, and also question the concept of a good theory. Metatheory dictates that a good theory should be simple, accurate, fruitful, consistent, etc. Sociobiology, although strong in its Darwinian foundations, is highly criticized as being limited in scope and difficult to falsify. Evolutionary psychology is also criticized as being difficult to falsify, but scientists commend this theory for its fruitfulness and its ability to encompass many different fields of psychology while connecting psychology to the more hardcore sciences. The field of psychology in general has been criticized by the scientific community as being unscientific, because disorganization and bickering among theorists minimizes the strengths of each individual theory. One theory, evolutionary psychology, claims to unify the various branches of psychology. Buss (1995) explains, "Because all behavior depends on complex psychological mechanisms and all psychological mechanisms at some basic level of description are the result of evolution by selection, then all psychological theories are implicitly evolutionary psychological theories" (p. 2). However, among psychologists, this claim is heavily debated and the field readily criticized. Therefore, it is imperative to examine evolutionary psychology's forerunner, sociobiology, and to dissect the field of evolutionary psychology itself. In doing this one must decide if both sociobiology and evolutionary psychology fit the various metatheory criteria. Metatheory dictates that all theories should be applicable, progressive, consistent, broad in scope, simple, and accurate.


Sociobiology is the study of the biological determinants of social behavior, based on the theory that such behavior is often genetically transmitted and subject to evolutionary processes. It stresses the importance of behavior and is committed to the theories of the adaptationist program. The adaptationist program assumes that certain creatures or groups of creatures currently exist because their past relatives possessed certain phenotypic traits that they were able to pass on to future generations.

According to Lewontin (1979), sociobiologists work under the assumption that "evolution of a species and community does in fact lead to high adaptation, high fitness, maximum intrinsic rate of increase, or some other attribute of the population related to reproductive success of individuals." Therefore it is the task of the individual theorist to decide what characteristics of the organism would be optimal given the state of the environment (p. 5). Note, that by using the term "nature" one is often referring to environment. Take for example the selection for black moths during the Industrial Revolution. When normally white trees became covered with soot due to factory pollution, the white moths became sparse, for they were easily sighted and eaten by birds. But the previously black moth minority population quickly increased as they were easily camouflaged by the soot. This exemplifies the theory of natural selection. The theory of natural selection is well established in scientific circles and rarely questioned.

In 1975, Wilson published Sociobiology, which was highly debated among theorists of the time. However, one no longer hears that psychology will be encompassed by sociobiology; rather psychology has incorporated some sociobiological theses while rejecting the more extreme assertions (Anker, 1987, p. 426). This is evident to those who have taken courses in various fields of psychology. Since 1975, evidence of genetic influence on behavior and acceptance of the theory has increased steadily. However, because of the general form of sociobiological argument, many remain skeptical.

Methods of Sociobiology

Sociobiologists begin like many psychologists. They describe the behavioral phenotype of a species. A phenotype is the type of behavior one can see clearly. But like genetic phenotypes, one must realize that what is seen is sometimes superficial and often lacks the deeper, less obvious perspective. Once they do this, they must design an adaptationist story to explain that the circumstances that would cause individuals to act in a certain way would actually benefit the individual's or group of individuals' reproductive success. Kitcher (1987) states, "Another common indictment of sociobiology is that it pursues an illegitimate adaptationist program, in which the evolutionary process is regarded as generating optimal phenotypes" (p. 66). However, it must be noted that sometimes there is no optimal phenotype available. Other times the optimal phenotype or genotype is hidden within a heterozygous pair. One example of this would be the protection from malaria due to a combination of the dominant and recessive genes for sickle cell anemia. Sickle cell anemia is present only when two recessive genes are present. Therefore, genetic protection from sickle cell anemia is hidden within a heterozygous pair. However, they then must prove this behavior to be genetically transmittable. But this is highly problematic, and sociobiology suffers from a number of serious methodological and epistemological problems (Lewontin, 1979, p. 6). For example, how does one prove that circumstances once existed when it is impossible to determine specific environments of the past?

Sociobiologists must first decide how the evolution of an organism is to be divided. Should it be divided according to function or physiological location? Lewontin (1979) argues that evolution cannot select for mental processes, only physical traits. As we will see later, evolutionary psychologists have objections to this assumption. It is argued that although mental constructs are not real objects, they can alter the future course of evolution. But Lewontin is quick to say that this happens more in the evolution of plants than in humans.

Criticisms of Sociobiology

Others have argued that sociobiology can be considered racist. Take for example the controversial book The Bell Curve, which attempts to correlate race and intelligence. Some philosophers and critical scientists say that sociobiology lacks predictive qualities. Others say that it is too limited to animals and has little value in reference to human beings. There remain, however, philosophers and other theorists who see sociobiology as a rationalization for the misbehaviors of both individuals, in the case of rape for example, and of society, for instance, the exploitation of women and children (Anker, 1987, p. 426). This was, however, never the intent of sociobiologists. Buss describes some of the errors of sociobiology, and how it differs from evolutionary psychology.

Sociobiology Versus Evolutionary Psychology

Buss (1995) begins by saying, "Although sociobiologists and evolutionary psychologists do share the same basic evolutionary theory in its modern instantiation as inclusive fitness theory, they depart in ways that are crucial for psychology" (p. 9). Specifically, sociobiologists believe that the main goal of humans is to increase reproductive success, to be "fitness maximizers." However, evolutionary psychologists believe humans to be "adaptation executors" or "mechanism activators." They believe the main goal of human beings is to solve the problems of survival that aid in reproduction and improve fitness. Notice this is very different from Buss (1991) who emphasizes that it is the sociobiologist who argues that humanity's main goal is reproduction. Evolutionary psychology is best regarded as a theory about origins, rather than the content of human nature (p. 463). Evolutionary psychologists specifically examine the causal processes that create specific mechanisms and not the mechanisms themselves.

Why can humans not be fitness maximizers? Buss (1995) answers this by saying that psychologists can not track fitness within a lifetime, much less action by action. Fitness is too nondescript, and contributors to fitness vary across species, sexes, ages, ecologies, and adaptive domains (p. 10). There are too many variable factors to specify what exactly contributes to fitness. He also describes the "sociobiological fallacy" by stating that many sociobiologists have skipped or neglected the 'psychological level' of analysis (p. 10). Simply, they have concentrated too much on the end product of behavior, and have failed to question why humans developed the behaviors in the first place. For example, why are people social animals? How do humans choose mates? Why do people behave in altruistic ways?

Evolutionary Psychology

The first aspect of evolutionary psychology refers to its reliance upon natural selection. This specific theory is rarely debated and is so widely accepted that the very domain of biology is reliant upon it. Buss (1991) states that evolutionary psychology also stresses that there is no such thing as a "purely environmental or situational cause of behavior" (p. 461). This aspect refers to hormonal and other physical causes or mechanisms of behavior. It is hypothesized that such mechanisms have evolved because they have behavioral consequences. One example of this would be the fight-or-flight response to danger. When a person encounters a dangerous situation, the sympathetic nervous system releases hormones that enable humans to react quickly to the stimuli: increased breathing, heart rate, etc. This is evolutionarily adaptive as it aids people in escaping dangerous situations.

Biological Foundations

It must be noted, however, that some biological phenonema arise through processes other than natural selection. An example of this would be genetic drift, pleiotropy, or chance. Genetic drift occurs in cases where random changes take place within large populations of organisms. Pleiotropy involves the expression of multiple phenotypic traits as the result of one gene. For example, albino organisms, who lack pigment, are light in coloring and pink eyed. Buss (1991) also specifies that other mutations may be neutral with respect to natural selection, and thus endure without being adaptive (p. 466). For example, some physical characteristics in humans such as height or hair color are currently neutrally adaptive. Such characteristics do not maximize fitness or reproduction and do not improve our chance of survival. Therefore, natural selection cannot account for all biological phenomena, and differentiating among such phenomena is extremely difficult for evolutionary psychologists.
Source: www.personalityresearch.org
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