Transcript Document
Introduction to Psychology Suzy Scherf Lecture 12: How Do We Know? Thinking Gone Wrong Stress and Health EEA versus Today 1. Longer life span today • People used to die primarily from infectious diseases • Now more illnesses of age - stroke, hypertension, Alzheimer’s disease • Also, more and more causes of death related to behavior EEA versus Today 2. Different living conditions: • Radically different diet - much more limited • Much less activity and exercise • Less proximity to biological relatives • Many more interactions with strangers • Sexual differentiation of labor EEA versus Today 2. Different living conditions: Modern hunter-Gatherers - Aborigines EEA versus Today 2. Different living conditions: Poison Poison Safe Poison Safe The variety in our ancestor’s food included 1000s of items - now we only consume about 50 animals and 600 plants! Mismatch Hypothesis • Many health problems result from differences between our current lifestyle and living conditions and that of the EEA. • Mismatches between our evolved characteristics and the present environment contribute to stress and health problems. Mismatch Hypothesis • Highlights the differences between proximate and ultimate causes. • Knowing the ultimate or “WHY” explanations behind our bodies’ reactions to our local environments can help us change or treat these reactions! Proximate vs. Ultimate Causes 1. Americans are getting fatter by the year Proximate Cause - we need more education on nutrition, exercise, and dieting Proximate vs. Ultimate Causes 1. Americans are getting fatter by the year Ultimate Cause 1. Our bodies have evolved to maintain a stable weight and our metabolisms facultatively respond to the availability of food. 2. Availability of food and decreased activity are a mismatch between evolved metabolic mechanisms and our local environment. Proximate vs. Ultimate Causes Typical American Diet Gov’t Recommended Diet Carbs Fat Protein 12% 12% 46% 30% 42% EEA Diet 41% 37% 22% 58% Proximate vs. Ultimate Causes 1. Americans are getting fatter by the year Why is it so hard for us to modify our diet and exercise? Because we are lazy? Because, in order to do so we have to curb some very strong evolved tendencies - liking food that is high in sugar and fat! Proximate vs. Ultimate Causes 2. Americans are more and more stressed and sleep deprived Proximate Cause - we work hard to acquire status as well as the things we need Proximate vs. Ultimate Causes 2. Americans are more and more stressed and sleep deprived Ultimate Cause 1. We evolved in small communities of our biological relatives and rarely encountered strangers. 2. Now we are constantly monitoring interactions with strangers, which requires lots of vigilance, and we spend the majority of our time with nonbiological relatives, which is a source of stress. Thinking Gone Wrong - Psychopathology How do we know when behavior is strange enough to require intervention? • Hallucinations are seen as visions in some cultures and are thought of as valuable not aberrant • Murder in war time is normal, but abnormal during peace time Thinking Gone Wrong - Psychopathology How do we know when behavior is strange enough to require intervention? • Speaking in tongues is thought of as a sign of spirit inhabitation by the Catholic church • Self-inflicted pain is revered in some religious sects Thinking Gone Wrong - Psychopathology Much of the world agrees that abnormal behavior has a biological basis and should be classified and treated according to a Medical Model Problem: Identifying a profile of abnormal behavior as a disease does not require an understanding of the causes or treatments for the “disease.” Thinking Gone Wrong - Psychopathology Our current system for identifying behavior disorders is the DSM-IV (Diagnostic and Statistical Manual of Mental Disorders - Version 4) The DSM-IV is: • Empirically derived • A-theoretical! Problem: There is little or no agreement among psychiatrists and psychologists on the causes of the disorders or treatments! Evolutionary Psychology and Psychopathology Possible evolutionary causes of behavioral disorders: 1. Some “disorders” may be adapted defenses, not dysfunctional behaviors, like a fever or a cough. 2. Some “disorders” may be side effects of genes with fitness benefits, like sickle-cell anemia. Evolutionary Psychology and Psychopathology Possible evolutionary causes of behavioral disorders: 3. Some “disorders” may be the result of frequencydependent selection that maintains more than one type of individual in the population. 4. Some disorders may reflect the malfunctioning of a mental module. Evolutionary Psychology and Psychopathology Possible evolutionary causes of behavioral disorders: 5. Some “disorders” may be the result of a mismatch between evolved mechanisms and the present environment. 6. Some disorders may represent the extremes of the distribution of polygenetic traits. Adapted Defenses 1. Depression: • Non-clinical depression may actually be an adaptation that responds to a situation that does or would impair our fitness. • People who were sad and mildly depressed when an action was unlikely to succeed may have outproduced those who were not Adapted Defenses 1. Depression: • Frequent depression-inducing situations: • Postpartum depression • Death of a family member or partner • Loss of a job • Partner cheating or leaving relationship • Winter Adapted Defenses 1. Depression: • Frequent depression-inducing situations: • Feeling like a burden to family members • No productivity in life Adapted Defenses 1. Depression: • Expect that people have a “depression threshold” to ensure that they only get such feelings in response to detrimental situations or stimuli • People who have low “depression thresholds” may be more vulnerable to clinical depression Adapted Defenses 1. Depression: • Clinical depression may, in part, be a disorder of modern living situations • With industrialization comes more opportunities to encounter fitness-decreasing situation and stimuli without buffer from the social support of our biological relatives Adapted Defenses 1. Clinical Depression Today: • Many suburban women depressed - fairly isolated from social community - opposite of EEA • We have fewer opportunities for frequent, small successes that we can share with friends and relatives. Adapted Defenses 1. Clinical Depression Today: • Living in such large societies means that there are only a few visible folks at the top of the pecking order - unreasonable comparisons • We are forced to be vigilant about strangers all the time. • Older people more prone to feeling like a burden to their family members - decreasing their fitness Adapted Defenses 2. Post-Traumatic Stress Disorder (PTSD): • Difficulty sleeping, social withdrawal, emotional numbing, flashbacks, avoidance of traumatic event • Anxiety disorder that may be primarily a disease of modern life • Possibly a susceptibility to stress that overwhelms our evolved defenses Adapted Defenses 3. Anxiety Disorders: • Adaptive to have a healthy fear of certain stimuli and situations • Modern phobias to stimuli that were dangerous to our ancestors (snakes) not to stimuli that are dangerous to us today (cars) • Constant vigilance to monitor dangerous things in our local environments may help explain these disorders Frequency-Dependent Selection 1. Sociopathy: • Superficially charming and sociable, egocentric, impulsive, lack shame, guilt, remorse • A few consistent cheaters in the world get away with everything if the majority of people take a cooperative strategy of social interaction • Sociopaths make up a high percentage (20%) of prison inmates - their crimes tend to involve deception and manipulation Malfunctioning Mental Module 1. Autism (?): • Impaired a social interaction, don’t reason about minds well, severe language problems, cognitive delay, and over-sensitive sensory systems • Can explain some of symptoms as lack of fully functioning theory of mind module Side Effect of Genes with Fitness Benefits 1. Bipolar: • Mood disorder with manic episodes and depressive episodes • 1% of world’s population (1 of every 100 people) in every culture • If one twin has bipolar, there is a 70% chance that the identical twin will have it as well - runs in families - genetic predisposition Side Effect of Genes with Fitness Benefits 1. Bipolar: • Initial episode usually occurs in late adolescence or early adulthood • Manic episodes include very grandiose thoughts, delusions, often times psychosis • Extravagant with financial resources • Often hypersexual Bipolar: Depressive vs. Manic Brain Activity Side Effect of Genes with Fitness Benefits 1. Bipolar: • Seems to be a relationship between bipolar and intelligence and creativity (Van Gogh, Edgar Allen Poe, Walt Whitman, Virginia Woolf, Sylvia Plath, Kay Jamison, Georgia O’Keefe, Carrie Fisher, Robert Downey, Jr.) Side Effect of Genes with Fitness Benefits 1. Bipolar: • Appears to be a combination of genes that provide a fitness benefit for creativity - may facilitate lots of problem-solving strategies • Relatives of bipolar individuals also seem to be more intelligent and creative • In the EEA, the fitness benefit of creativity may have outweighed the cost of episodic depression Side Effect of Genes with Fitness Benefits 2. Schizophrenia: • Positive Symptoms: hallucinations, paranoia, strange motor movements, strange affect, disorganized thoughts • Negative symptoms: catatonia, no affect, poverty of speech, loss of volition, social withdrawal • Very strong genetic component Genein Quadruplets all Suffer from Schizophrenia Side Effect of Genes with Fitness Benefits 2. Schizophrenia: • Relatives of schizophrenics also tend to be more creative and intelligent • Schizophrenics have very low reproductive fitness - disease is very debilitating • Also 1% of world’s population across all cultures Side Effect of Genes with Fitness Benefits 2. Schizophrenia: • Having the genes for schizophrenia may convey some advantage on individuals who carry them, but not to the individuals who acquire the disorder • Positive symptoms may reflect the potential benefit conveyed to those who do not get the disease • Negative symptoms incredibly similar to symptoms in autism!