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Biological Level of Analysis (LOA) The biological or physiological level of analysis explains behavior in terms of physiology meaning that it explains behavior in terms of the brain, genes, neurotransmitters and hormones. What are the Principles of the Biological LOA? 1. Behavior is biologically determined by physiological processes such as the nervous system (neurotransmitters e.g. serotonin) and the endocrine system (hormones e.g. testosterone) 2. The above principle was expressed as "all that is psychological is first physiological" 3. Patterns of behavior can be inherited through genetics 4. The study of animals can inform our understanding of human behavior Principles of the Biological Level Demonstrated in Theories and Research Localization of function (case study of Phineas Gage) Genetic predisposition of diseases using correlational twin research (Minnesota Twin Studies) Research Methods Experiments Observations Correlational Studies (Twin studies) Case studies (Phineas Gage) Ethical Concerns Describe the ethical concerns associated with the Biological LOA ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ Physiology and Behavior Localization of Function Broca's Area - Involved in speech production - Patients with Broca's aphasia lack fluency of speech Wernicke's Area - Involved in speech comprehension - Patients can produce speech but not comprehend it Phineas Gage (case study) Much of what psychologists know about the human brain has come from case studies of individuals who had brain surgery or brain damage in accidents. Phineas Gage is one such case study. He was a young railroad worker in 1848 who had an accident at work. He was forcing gun powder into a rock with a long iron rod when the gun powder exploded. The iron rod shot through his cheek and out the top of his head, resulting in substantial damage to his frontal lobe. Incredibly, he did not appear to be very hurt. His memory and mental abilities were intact, and he could speak and work. However, his personality totally changed. Before the accident, he had been nice to be around, but afterward he became ill-tempered and dishonest. He lost his job and ended up working as an exhibit at fairs. Phineas Gage’s injury served as a case study for the effects of frontal lobe damage. He did not lose a specific mental ability, such as the ability to speak or follow directions. However, his personality and moral sense were altered. Psychologists now know that parts of the cortex (called the association areas) are involved in general mental processes, and damage to those areas can greatly change a person. Describe at least two limitations of this case study. ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ Effects of Neurotransmission on Behavior Neurotransmitters 1. Serotonin Sleep Arousal Levels Emotion Happiness - Monks hallucinated after 48 hours of no food or water - linked to increased serotonin levels (Kasamatsu & Hirai, 1999) Study: An Electroencephalographic Study on the Zen Meditation. (Kasamatsu & Hirai, 1999) Aim: to determine how sensory deprivation affects the brain Method: studied Buddhist monks on a 72 hour pilgrimage to a holy mountain; took blood samples before the trip and after monks reported hallucinations Results: found increase in serotonin levels had activated the hypothalamus Serotonin plays diverse roles in various parts of the brain affecting our frame of mind, appetite, learning aptitude, memory, and arousal levels. A study carried out in 1999 at Tokyo’s University by two researches named Kasamatsu and Hairi sought to find out how sensory deprivation affects our brain. They followed monk’s on a pilgrimage to a holy mountain in Japan. The trip was intended to take 72 hours without any food, water, or dialogue. After 48 hours, the monk’s began to hallucinate and thought they saw ancient ancestors or felt their presence by their side. The researches had taken blood samples of the monk’s before the trip and after they began to hallucinate. The results were an increase in the serotonin level, which means that the thalamus and frontal cortex of the brain became active, causing them to hallucinate. Higher serotonin levels will activate parts of the brain that causes hallucinations. Find a second neurotransmitter and a psychological study using this neurotransmitter. Briefly describe the study, findings, and limitations. Be sure to include title of study, researcher, and year. ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ Functions of Two Hormones on Behavior 1. Testosterone – Aggression Study: Hormone Spikes After Handling Gun, Making Men More Aggressive (Klinesmith, 2006) The finding comes from a study by psychology student Jennifer Klinesmith and her professors at Knox College, Galesburg, Ill. (2006) Klinesmith designed the study, in which 18- to 22-year-old college men participated. Klinesmith told the men they'd be taking part in a study of the effect of attention to detail on taste sensitivity. She collected a saliva sample for testosterone testing. Then she led each man into a room where he sat at a table with an object on it. The man had to take apart the object and put it back together according to instructions. For half the men, the object was a pellet gun that mimicked a Desert Eagle automatic handgun. The other half of the men worked with a child's game called Mouse Trap. Fifteen minutes later, the men gave another saliva sample. Then they were asked to taste a lidded 3ounce cup of water with a drop of Frank's Red Hot Sauce in it. Hot-Sauce Trick Finally, the men were given a 3-ounce cup of water and a bottle of the hot sauce. They were told the water would be given to the next man in the study, and that they could — anonymously — put as much hot sauce in the water as they liked. This hot-sauce trick has been used before. The more aggressive a man is feeling, the more hot sauce he tends to put in the next man’s drink. Sure enough, testosterone went up about 100 times more in the men who handled the gun than in the men who handled the children's toy. And the gun handlers put three times more hot sauce in the water — on average, about a half ounce — than the toy handlers. The more a man's testosterone went up after gun handling, the more hot sauce he put in the water. "Such findings raise many of the usual questions about whether the presence of guns in modern society contributes to violent behavior," Klinesmith and colleagues conclude. "Although our study is clearly far from definitive, its results suggest that guns may indeed increase aggressiveness partially via changes in the hormone testosterone." The study appears in the July issue of Psychological Science. 2. Oxytocin - Trust Study: Oxytocin increases trust in humans. (Kosfeld et al, 2005) Biology of trust There is a simple hypothesis about what steers the human brain to trust another human: a hormone called oxytocin. Oxytocin is produced in the brain’s hypothalamus and stored in the posterior pituitary gland. We know that it helps smooth muscle contractions in childbirth and in breastfeeding mothers. But recently we’ve discovered that its applications go beyond the maternal. It turns out that oxytocin also reduces social anxiety and helps people meet and bond with each other. A man and woman involved in the mating dance are releasing oxytocin; so are friends having a good time at dinner. Forming relationships like these involves trust, but is there a direct connection between trust and oxytocin? To find out, my colleagues and I conducted an experiment in which participants took either oxytocin or a placebo. Fifty minutes later, participants played the trust game against four different anonymous partners. They played with real money, with each point worth almost half a Swiss franc. The results revealed that oxytocin does indeed seem to grease the wheels of trust. Of the 29 investors who had taken oxytocin, 45 percent transferred the maximum amount of 12 points in each interaction. By contrast, only 21 percent of the placebo-group investors did so. The average transfer made by the oxytocin-group investors was 9.6 points, compared with 8.1 points by the placebo group investors. Interestingly, the investors’ expectations about the back-transfer from the trustee did not differ between the oxytocin and placebo recipients. Oxytocin increased the participants’ willingness to trust others. The Trust Game This is a two player game with the following setup. One player, an investor, is given money at the start. The investor can take the money and end the game, or he can give all or part of it to the other player, the trustee. Whatever money is offered is tripled before the trustee gets it. In turn, the trustee can either take the money or send part or all of it back to the investor. Effects of Environment on Physiological Processes Brain plasticity - ability to rewire connections between neurons o Enriching environment leads to increased cortical thickness in rats compared to boring environment (Rosenzweig & Bennett, 1972) Environmental stressors at work can increase our susceptibility to disease (e.g. heart disease). Sleep deprivation in rats causes increased metabolism (210-270%) despite increased food intake and for most rats eventual death (Rechtschaffen & Bergman, 1995) Look up one of the above studies. Briefly describe the research method, findings (results), and list at least one limitation. ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ Interaction between Cognition and Physiology in Terms of Behavior Meditation produces gamma waves found using a PET scan with monks (Davidson, 2004) o Limitation - Did not account for confounding variable of practice since monks meditate a lot Brain Imaging Techniques EEG - records brain waves o Cannot show what is happening in deeper brain regions o Cannot show actual functioning of brain regions PET - monitors glucose metabolism in brain via injection of radioactive glucose o Can record ongoing activity like thinking fMRI - provides 3D image of brain o Easier to carry out compared to PET o Higher resolution than PET o Cannot record ongoing activity - just snapshots Evaluation of Brain Imaging Techniques MRI scanners are unnatural environments for cognition - ecological validity Define: Ecological validity ________________________________________________________ ________________________________________________________ Colors in images may exaggerate activity in brain regions Equipment may not be sophisticated enough to detect subtle brain activity Brain areas activate for various reasons because the brain is highly interconnected so you cannot conclude that just because the amygdala is activated the patient is experiencing fear All of these imaging techniques are indirect measures of neural activity o They measure indicators that suggest neural activity is occurring o Other measures like single unit recording directly measure neural activity by implanting electrodes into the brain o Ethical issues with using single unit recording on humans Genetics and Behavior Extent of Genetic Inheritance on Behavior Huntington's - Only neurodegenerative disease with a 100% genetic cause o Use Minnesota Twin Studies to relate genetics and behavior Intelligence Both genetics and environment play crucial role o Poverty tends to correlate with low IQ Meta-analysis of 111 studies found highest correlation for IQ was kinship (Bouchard & McGue, 1981) Minnesota Twin Study (Bouchard et al., 1990) o MZ twins raised together compared to MZ twins raised apart longitudinal study o Estimate that heritability accounts for about 70% of intelligence o Criticism (limitations) Media coverage to recruit participants - possible sample bias Ethical concerns about how he reunited the twins who were reared apart No control over how often the twins reared apart visited each other prior to study Equal environment assumption - cannot assume twins raised together experience same environments (e.g. treatment from parents, experience with friends and peers in school and at home) Ethical Considerations for Research into Genetic Influences Undue stress on patients being tested for Neurodegenerative diseases (Alzheimer's, Parkinson's…) Parents can feel responsible for fate of the child Patient may feel less responsible for their disease and make less of an effort to recover, instead relying on medications to do the psychological work Evolutionary Explanation of Behavior (Evolutionary Psychology) Disgust Promotes survival (Fessler et al., 2004) Confirmed by online survey that found participants had the strongest disgust reaction to stimuli which threatened the immune system (Curtis et al., 2004) Has also been related to biological preparedness and phobias because animals that elicit a disgust response can be poisonous and avoiding these creatures because they evoke disgust further promotes survival Study: Elevated disgust sensitivity in the first trimester of pregnancy (Kessler at al., 2004) Imagine a thick, juicy steak...swarming with maggots. Disgusted? Congratulations, you're evolved! Disgust is a survival skill, says Dan Fessler, associate professor of anthropology and director of UCLA's Center for Behavior, Evolution, and Culture: "We experience disgust today [because] the response protected our ancestors, [allowing them] to survive long enough to produce offspring." Fessler and colleagues asked 496 healthy pregnant women to consider scenarios that included the maggots-on-meat, fish hooks through fingers, and contact with feces or urine. During the first trimester of pregnancy, increased levels of the hormone progesterone lowers a woman's immune system to keep it from fighting the "foreign" genetic material taking shape in the womb, making both the woman and her fetus extremely vulnerable. First-trimester women scored much higher in disgust sensitivity than counterparts in subsequent trimesters when it came to scenarios involving food — perhaps, Fessler reasons, a disgust response to protect against food-borne illness. "A lot of the diseases that are most dangerous are food-borne, but our ancestors could not afford to be picky all the time about what they ate," Fessler said. "Natural selection may have helped compensate for the greater susceptibility to disease during this risky point in pregnancy by increasing the urge to be picky about food, however much additional foraging that required. That the sensitivity seems to lift as the risk of disease and infection diminish is consistent with the view of disgust as protection against pathogens." Evaluation of Evolutionary Arguments Testing evolutionary theories of behavior is empirically difficult so researchers may be led astray by confirmation bias Define: Confirmation Bias ________________________________________________________ ________________________________________________________ ________________________________________________________ We know little, if anything, about Homo sapiens’ behavior - it is purely speculative Disregard the role of culture in shaping behavior Look up the Minnesota Twin Study. Briefly describe the study, including method and findings. Discuss how the study specifically links genetics to a particular disease. ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________ ________________________________________________________