Examine one evolutionary explanation of behavior.

Evolutionary psychology states that human behavior is generated by psychological adaptations that evolved to solve recurrent problems in human ancestral environments. Darwin's theory of evolution is used to explain our behavior. All individuals, and therefore species, inherit characteristics from both biological parents. This is done by the passing on of DNA when genetic material in the alleles and chromosomes (24 pairs in the majority of cases for humans) from father and mother are combined, carried by the sperm and egg cells during reproduction (we inherit slightly different genetic material from all other individuals).

The environment of a species is very important for the survival of the species. Mutations and variance (and genetic drift) allow for physical chances in individuals. The characteristics of a species are therefore passed on over time in this way. The characteristics which are more useful for survival in any given environment are passed on because, as Freud says, the sex drive is the most important one of all species, and the individual with the most advantageous traits in terms of the potential success of survival. This process is called natural selection. The most "fit" will be most likely to produce healthy offspring because of their advantageous genes; and as these traits are passed on, traits which are harmful to the survival of the species will eventually become rarer.

EMOTION: A mental state that arises spontaneously rather than through conscious effort and is often accompanied by physiological changes; a feeling.

Emotions that may be innate:








· 'Cognitive' versus 'non-cognitive' emotions

· Instinctual emotions (from the amygdala), versus cognitive emotions (from the prefrontal cortex).

· Basic versus complex: where base emotions lead to more complex ones.

· Categorization based on duration: Some emotions occur over a period of seconds (e.g. surprise) where others can last years (e.g. love).


· Aids our decision making. Without emotion you cannot make reasonable decisions (E.g. Damasio explains this in "Descartes' Error". One of Damasio's key points is that rationality does not function without emotional input. Damasio explores in depth the famous case of Phineas Gage. While Gage's intelligence remained intact after his brain was damaged in an 1848 accident, Damasio believes that Gage's ability to reason and make rational decisions became severely handicapped because his emotions could no longer be engaged in the process. Damasio uses this and other brain-damage cases to develop his thesis on emotion and its relationship to human activity. He argues that rationality stems from our emotions, and that our emotions stem from our bodily senses. According to Simon we make a decision when we get the nearest to a satisfactory solution and "emotion-driven intuition" results in "irrational decisions".)

· Motivates behavior

· Aids communication within a group

Supporting studies

1) Observational learning of fear of snakes in primates (Mineka 1987)

Laboratory-bred infant rhesus monkeys viewed a video of an experienced demonstrator monkey behaving fearfully in the presence of a variety of fear-relevant (e.g. a toy snake) and fear-irrelevant stimuli (e.g. a flower).

The observer monkey was subsequently exposed to these stimuli and his reaction to them was analyzed for evidence of acquired fear.

The study indicated that monkeys who are not initially afraid of snakes will rapidly acquire an intense fear when they have watched a wild-reared monkey behaving fearfully in response to a toy snake.


Weaknesses: Generalization problem Strengths: Well-controlled study (e.g. cause and effect is clear)

Ethical considerations (captivity, stress) Replicable

2) Lorenz imprinting on newly-hatched geese

The sensory object (Lorenz) met by the newborn bird is stamped immediately and irreversibly into the nervous system (process called "imprinting", innate disposition to form attachments to with first moving thing they see)

Lorentz reared greylag geese from hatching,

The geese would treat him like a parental bird. The followed him about and when they were adults they courted him in preference to other greylag geese. The study points to the fact that goose offspring (and other species, by extension) follow their parents and copy behaviour automatically- innate impulse to imitate and become attached to mother for protection, survival techniques.


Weaknesses: Generalization Strengths: Provided insight into the combination of biological factors + experience for learning attachment


3) Bright and noisy water experiment (Garcia & Kolling 1966)

Condition 1: Two groups of rats were given sweetened water (saccharine flavored) followed by nausea (either by an emetic drug or radiation) or an electric shock

Condition 2: Two groups of rats were exposed to an audiovisual cue (a light and a clicking sound followed by either nausea or an electric shock

The results showed that the rats were more biologically prepared to form an association between sweetened water and nausea than an association between pain and sweetened water. The results also demonstrated that the rats were more biologically prepared to form an association between pain and an audiovisual cue than between nausea and an audiovisual cue.


Weaknesses: Generalization problem, Ethics of exposing rats to radiation

Strengths: well controlled, cause-effect could be established

Other studies

  • • Fessler (2006): Women in the first trimester of their pregnancy are more sensitive to disgusting scenarios involving food
  • • Curtis (2004): Disgust reactions are most strongly elicited for those which threaten one’s immune system and decreases with age
  • • Ekman (1973): Interviewed and tested participants from 22 countries, including the South Fore people in Papua Guinea, who have had no prior contact to western culture. People with different cultural background chose the same facial expression for their emotions. The conclusion was that our basic emotional life may be innate and has been formed by natural selection

Case Studies: Fessler (2006), Curtis et al. (2004)
BLOA #12 Sample Essay.docx