Examine one evolutionary explanation of behavior.

“ Genetics is the key to the past. Every human gene must have an ancestor….each gene is a message from our forebears and together they contain the whole story of human evolution” ( Steve Jones, 1994, British Geneticist)

“Our modern skulls house a Stone Age mind “ (Cosmides & Tooby)  Evolutionary psychology is a combination of evolutionary biology and cognitive psychology. It sees the mind as a set of evolved mechanisms, or adaptations, that have promoted survival and reproduction.  Evolutionary Psychologists claim that all behavior is a result of these evolved mechanisms. Thus every behavior that we see today is the result of an evolved process.

 To understand evolutionary psychology it is necessary to have a basic understanding of genes, inheritance, and the principles of natural selection.

 Evolutionary psychology is inspired by the work of Charles Darwin and applies his ideas of natural selection to the mind.  Natural selection is the nonrandom process by which biological traits become more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution. A+ info on Darwin’s work ecies.pdf

 Darwin's theory argues that all living species, including humans, arrived at their current biological form through a historical process involving random inheritable changes (genetic mutations)  Some changes are adaptive, that is, they increase an individual's chances of surviving and reproducing.  Changes of this kind are more likely to be passed on to the next generation (natural selection), while changes that hinder survival are lost.

 Examples of adaptations which would have promoted survival and reproduction are behaviors such as aggression which might be understood as an adaptive necessity in the competition for limited resources.  Food preferences for sweet tastes might be understood as a adaptive urge to seek out scarce sweet, ripe fruits which provided energy.

 Even mental disorders might be explained from an evolutionary perspective.  Depression may be explained as an adaptive urge to strategic ally withdrawal to conserve energy and regroup after a setback of some kind.  Anorexia may have evolved from rationing tendencies. During human evolution it would not have been adaptive to always eat everything in site, but rather it would have important to effectively ration during lean times, as well as eating up during more abundant times. Thus, the capacity to "go without food" would have been important for survival.

 Attachment is a deep and enduring emotional bond that connects one person to another across time and space (Ainsworth, 1973; Bowlby, 1969).  Attachment does not have to be reciprocal. One person may have an attachment with an individual which is not shared.

 Attachment is characterized by specific behaviors in children, such as seeking proximity with the attachment figure when upset or threatened (Bowlby, 1969).  It appears to be a behavior that ALL living creatures have encoded in their genes.

 If the sole purpose of a gene is to ensure survival, having parents that have the gene that influences bonding would ensure the survival of the offspring.  Having children with an innate push to form attachments will also ensure the protection of the child (along with the gene).  This is suggesting that attachments are inherited from parents and expressed regardless of the environment.

 Attachment theory in psychology originates with the seminal work of John Bowlby (1958).  In the 1930’s John Bowlby worked as a psychiatrist in a Child Guidance Clinic in London, where he treated many emotionally disturbed children.

 This experience led Bowlby to consider the importance of the child’s relationship with their mother in terms of their social, emotional and cognitive development.  Specifically, it shaped his belief about the link between early infant separations with the mother and later maladjustment, and led Bowlby to formulate his attachment theory.

 Adaptive Behavior – According to Bowlby, infants have an innate desire to attach to their mothers as it increases their chances of survival.  If a mother does not care for her child, the child will die and therefore the mother’s genes will also die.  Due to this process, mothers now have a gene for looking after their babies.

 In 1935 Konrad Lorenz supported the evolutionary attachment thesis with young ducklings and goslings.  He observed that at a certain critical stage soon after hatching, they learn to follow real or foster parents.

 He divided goose eggs into two groups and marked each goose once hatched so he knew which geese were in which group.  One group was hatched with the mother goose and one group was hatched with Lorenz.  The geese that were hatched with Lorenz followed him and attached to him as if he were their mother and showed distress if they lost sight of him, none of the geese in this group became attached to their real mother goose.

 The process, which is called imprinting, involves visual and auditory stimuli from the parent object; these elicit a following response in the young that affects their subsequent adult behavior.  H-mUI&feature=related H-mUI&feature=related

 Harlow did a number of studies on an avolutionary theory of attachment in monkeys during the 1950's.  He stated that monkeys must form their attachments during the first year of life (critical period). His experiments took several forms:  1. Infant monkeys reared in isolation – some died, others were frightened and behaved in an abnormal manner. They could not interact with other monkeys even when they were older.

 Harlow did a number of studies on an evolutionary theory of attachment in monkeys during the 1950's.  He stated that monkeys must form their attachments during the first year of life (critical period). His experiments took several forms:

 This supports the evolutionary theory of attachment, in that the rhesus monkeys seem to innately seek out meaningful attachments.  Harlow concluded that for a monkey to develop normally s/he must have some interaction with an object to which they can cling during the first months of life (critical period).  Clinging, according to Bowlby and Harlow, is a natural response - in times of stress the monkey runs to the object to which it normally clings as if the clinging decreases the stress.

 Evaluate each study: ◦ Does the research exclude social and cultural factors that could also influence attachments? ◦ Are their ethical concerns that we must consider?

 Multiple research studies have supported a perceived innate drive for animals and humans to form attachments.  Cross-cultural research has shown the behavior to be present in nearly every culture (which suggest an innate drive to attach)

 Research into evolutionary explanations are ethically impossible to conduct in humans (this limits the research to computer models and animals)  The effect of evolution on behavior cannot be “proven” directly because we have little information on the behavior of our early ancestors

Questions?