IB psych paper 1 - extra biological (Annie) Flashcards
Evaluate the theory of localization of function in the brain.
Localization of function = specific behavioral and cognitive functions are localized in specific regions of the brain
HM: Scoville and Milner 1957
Aim: Study the hippocampus’ effect on memory in a longitudinal study.
Procedure: HM fell off his bike at an early age and cracked his skull, resulting in severe epileptic episodes. They got so bad that he had an experimental surgery conducted on him by scoville (neurosurgeon) that took out parts of his brain (temporal lobe - hippocampus). Milner proceeded to complete studies on the post-op HM, testing his IQ, observations, interviews, and cognitive tests, researching the changes in function (methodological triangulation). until his death after which she carried an autopsy to assess the damage done to his brain. An MRI was used.
Results: HM could not attain new episodic or semantic knowledge. The brain structures that were removed past the incident were essential for LTM. Carried normal conversations and motor skills were intact; so his working and procedural memory were functioning. MRI> damage to temporal lobe including hippocampus
Conclusion: damage explains the problem of transferring info from STM to LTM. Temporal lobe & hippocampus were areas that acetylcholine is believed to play an important role in forming explicit memories.
Evaluation: Insight for further research, case study (ethical considerations are given a pass), high ecological validity, difficult to ethically replicate and generalize. Identity Privacy?
Closing: the damage to the temporal lobe and hippocampus caused problems in the forming of new episodic memories, suggesting that that area is somewhat responsible for this function.
Maguire 2000 (Experiment)
MRI: uses strong magnetic fields, magnetic field gradients, and radio waves to generate images of the organs in the body.
Aim: investigate the difference in brain activity between experienced taxi drivers and non-taxi drivers in London.
Procedure (summarized): 16 right-handed male taxi drivers’ brains were compared with 50 other non-taxi drivers using data collected from MRI scans.
Results: pixel counting revealed that the posterior hippocampus of the taxi drivers was larger than that of the average non-taxi driver while the anterior was smaller. There has been a shift in brain matter.
Evaluation: No cause and effect relationship> not controlled. High ecological validity, Brain scans were coded so that the analysis was anonymous (avoiding researcher bias). The sample size is small and gender bias is present > hard to generalize.
Closing: The use of MRIs made the otherwise impossible data collectible. Without the use of the MRIs the researchers will not be able to ethically collect the data without causing damage.
Discuss the effects of neurotransmission on human behavior (inhibitory and excitatory).
Neurotransmission: occurs in neurons when an electrical impulse goes down the axon to terminal buttons where vesicles trigger the release of neurotransmitters. Neurotransmitters then cross the synaptic gap to nearby postsynaptic dendrites where the message continues (excitatory) or stops (inhibitory) depending on the type of neurotransmitter.
Sacks (1982)
Aim: Research encephalitis lethargica patients and their “awakenings” and relapses from L-Dopa (while trying to “cure” the patients or help them along the way)
Methods: Intrinsic case study, to study a unique occurrence for research purposes (can’t necessarily be transferable unless a case similar pops up in the future) - used method triangulation (observation and interview of patients), a convenience sample
Details: Encephalitis lethargica (sleepy sickness with symptoms similar to Parkinson’s with long-term apathy and paralysis) patients began to be treated by sacks with high amounts of L-Dopa. The drug caused “awakenings” where the patients would regain consciousness, however, a tolerance to the drug built as the patients received more and more (symptoms being dyskinesias (abnormal movements), gastrointestinal symptoms, insomnia, hallucinations, psychosis). By 1982, 17 of 20 patients had died
Findings: Dopamine deficiency probably plays an important role in encephalitis lethargica (like it does in Parkinson’s disease). There are 2 types of symptoms: 1) due to dopamine deficiency and are treated easily with L-Dopa, 2) result of neurological damage caused by the metabolites of dopamine.
supports that dopamine influences voluntary movement, pleasure, attention/focus
** l-dopa increased dopamine in the system (agonist), resulting in awakening of patients, could walk, talk, move eyes to sound. when tolerance was built up, they needed more dopamine in their system or else they would relapse back to paralysis or coma.
Evaluation: methodological triangulation to ensure a thorough collection of dependable data was used to create the final conclusion and theories. bias of the interpretations was somewhat limited as well, due to the different perspectives the triangulation provided. It doesn’t state anywhere any other methods to heighten reflexivity. Ethicality is always iffy on case studies as the confidentiality of the patients was not kept and the whole study might have been to intrusive in the way that Sacks waked the patients up with a drug without known consent and caused the patients some physical harm (symptoms) and psychological harm (waking up years in the future with no memory of those years and studying them all of the time).
Crockett (2010) (SSRIs)
Aim: Investigate the effect of serotonin on prosocial behavior.
Procedure: participants were presented with the classic trolley problem where they had to choose between killing 1 or 5 people by personally or impersonally interfering. Half of the participants were given citalopram (SSRI) and both were presented with the personal and impersonal scenario.
Results: the group that received the citalopram was less likely to intervene in a personal scenario. No difference between the groups in the impersonal scenario.
Conclusion and closing: serotonin prevents the acceptance of causing harm promoting pro-social behavior.
Evaluation: internal validity, cause and effect. Might have put pps under stress. Low ecological validity
Explain the role of an agonist or antagonist.
Agonist = binds to receptors and acts as the neurotransmitter would (acts as a fake)
Sacks (1982)
Aim: Research encephalitis lethargica patients and their “awakenings” and relapses from L-Dopa (while trying to “cure” the patients or help them along the way)
Methods: Intrinsic case study, to study a unique occurrence for research purposes (can’t necessarily be transferable unless a case similar pops up in the future) - used method triangulation (observation and interview of patients), a convenience sample
Details: Encephalitis lethargica (sleepy sickness with symptoms similar to Parkinson’s with long-term apathy and paralysis) patients began to be treated by sacks with high amounts of L-Dopa. The drug caused “awakenings” where the patients would regain consciousness, however, a tolerance to the drug built as the patients received more and more (symptoms being dyskinesias (abnormal movements), gastrointestinal symptoms, insomnia, hallucinations, psychosis). By 1982, 17 of 20 patients had died
Findings: Dopamine deficiency probably plays an important role in encephalitis lethargica (like it does in Parkinson’s disease). There are 2 types of symptoms: 1) due to dopamine deficiency and are treated easily with L-Dopa, 2) result of neurological damage caused by the metabolites of dopamine.
supports that dopamine influences voluntary movement, pleasure, attention/focus
** l-dopa increased dopamine in the system (agonist), resulting in awakening of patients, could walk, talk, move eyes to sound. when tolerance was built up, they needed more dopamine in their system or else they would relapse back to paralysis or coma.
Evaluation: methodological triangulation to ensure a thorough collection of dependable data was used to create the final conclusion and theories. bias of the interpretations was somewhat limited as well, due to the different perspectives the triangulation provided. It doesn’t state anywhere any other methods to heighten reflexivity. Ethicality is always iffy on case studies as the confidentiality of the patients was not kept and the whole study might have been to intrusive in the way that Sacks waked the patients up with a drug without known consent and caused the patients some physical harm (symptoms) and psychological harm (waking up years in the future with no memory of those years and studying them all of the time).
Explain the formation of neural networks (dendritic branching).
Neuroplasticity = ability of our brains to adapt to the environment and experiences
Dendritic branching = changes in pathways and possible structure - biological process by which neurons form new dendritic trees and branches to create new synapses
Neural Pruning = “use it or lose it”, results from long-term potentiation (strengthening of patterns of synaptic activity that produce a long-lasting increase in signal transmission between 2 neurons), keep only what u regularly use
gray matter = a type of tissue in your brain and spinal cord (central nervous system) that plays a crucial role in allowing you to function normally from day to day. It consists of high concentrations of neuronal bodies, axon terminals (endings), and dendrites.
Draganski 2004
Aim: to see if learning a new skill would have an effect on the brains of PPs
Procedure: 3 MRI scannings were done on 24 volunteers, 3 of which were male. An MRI scan was done prior to the start of the experiment. The PPs were divided into jugglers and non jugglers. The Jugglers had to learn the new skill of juggling and were given an MRI scan after mastering the skill. They were told not to juggle anymore for 3 months and then another MRI scan was conducted.
Results: At the time of the second scan the jugglers showed larger amounts of grey matter in the mid temporal area in both hemispheres which is an area associated with visual memory. 3 months after the jugglers stopped juggling the amount of grey matter decreased but it was still more than the non-jugglers.
Evaluation: pretest and posttest design., cause and effect, the control group was present. Small sample size, problem with internal validity (participants were at home)
Closing: After practicing the new skill for 3 months the amount of grey matter that was presented had increased greatly, demonstrating the new neural connections
Explain neural pruning (synaptic pruning).
Neuroplasticity = ability of our brains to adapt to the environment and experiences
Dendritic branching = changes in pathways and possible structure - biological process by which neurons form new dendritic trees and branches to create new synapses
Neural Pruning = “use it or lose it”, results from long-term potentiation (strengthening of patterns of synaptic activity that produce a long-lasting increase in signal transmission between 2 neurons), keep only what u regularly use
gray matter = a type of tissue in your brain and spinal cord (central nervous system) that plays a crucial role in allowing you to function normally from day to day. It consists of high concentrations of neuronal bodies, axon terminals (endings), and dendrites.
Draganski 2004
Aim: to see if learning a new skill would have an effect on the brains of PPs
Procedure: 3 MRI scannings were done on 24 volunteers, 3 of which were male. An MRI scan was done prior to the start of the experiment. The PPs were divided into jugglers and non jugglers. The Jugglers had to learn the new skill of juggling and were given an MRI scan after mastering the skill. They were told not to juggle anymore for 3 months and then another MRI scan was conducted.
Results: At the time of the second scan the jugglers showed larger amounts of grey matter in the mid temporal area in both hemispheres which is an area associated with visual memory. 3 months after the jugglers stopped juggling the amount of grey matter decreased but it was still more than the non-jugglers.
Evaluation: pretest and posttest design., cause and effect, the control group was present. Small sample size, problem with internal validity (participants were at home)
Closing: After practicing the new skill for 3 months the amount of grey matter that was presented had increased greatly, demonstrating the new neural connections
**
Discuss the effect of the environment on physiological processes (neuroplasticity).
Neuroplasticity = ability of our brains to adapt to the environment and experiences
Dendritic branching = changes in pathways and possible structure - biological process by which neurons form new dendritic trees and branches to create new synapses
Neural Pruning = “use it or lose it”, results from long-term potentiation (strengthening of patterns of synaptic activity that produce a long-lasting increase in signal transmission between 2 neurons), keep only what u regularly use
gray matter = a type of tissue in your brain and spinal cord (central nervous system) that plays a crucial role in allowing you to function normally from day to day. It consists of high concentrations of neuronal bodies, axon terminals (endings), and dendrites.
Draganski 2004
Aim: to see if learning a new skill would have an effect on the brains of PPs
Procedure: 3 MRI scannings were done on 24 volunteers, 3 of which were male. An MRI scan was done prior to the start of the experiment. The PPs were divided into jugglers and non jugglers. The Jugglers had to learn the new skill of juggling and were given an MRI scan after mastering the skill. They were told not to juggle anymore for 3 months and then another MRI scan was conducted.
Results: At the time of the second scan the jugglers showed larger amounts of grey matter in the mid temporal area in both hemispheres which is an area associated with visual memory. 3 months after the jugglers stopped juggling the amount of grey matter decreased but it was still more than the non-jugglers.
Evaluation: pretest and posttest design., cause and effect, the control group was present. Small sample size, problem with internal validity (participants were at home)
Closing: After practicing the new skill for 3 months the amount of grey matter that was presented had increased greatly, demonstrating the new neural connections.
Rosenzweig and Bennet (1972)
Aim: investigate if animals raised in highly stimulating environments will demonstrate differences in brain growth and chemistry when compared to animals raised in a plain or dull environment.
Method: lab experiment
Details: 12 sets of 3 male rates, each from the same litter, were studied. There were 3 conditions: 1 rat remained in the lab cage with the rest of the colony, 1 rat went to the “enriched environment” cage, and the last rat went to the “impoverished” cage. 6-8 rats lived in the enriched cage with 25 new, random toys added per day. Rats lived in these environments for varying amounts of time, and then they were eventually killed. The rats then had their brains measured, weighed, and analyzed to determine the amount of cell growth and neurotransmitter activity. Acetylcholinesterase enzymes were also studied – allowing for more neurotransmission.
Findings: Enriched rats were very different from the impoverished rats. The cerebral cortex was heavier and thicker in enriched rats. Also, greater Acetylcholinesterase activity in the enriched rats. While there was not necessarily a difference in the number of brain cells, there were larger neurons noticed in the enriched rats. The ratio of RNA to DNA was larger in enriched rats too, implying more chemical activity. Synapses of enriched rats were 50% larger than impoverished rats. In only 1 trial were the results not statistically significant.
Evaluation:
-Many unethical things happening here!
-Difficult to generalize data to humans.
-The person performing the autopsy would not know the rat’s condition.
X
Evaluate the use of brain imaging technologies in investigating the relationship between the brain and behavior.
Draganski 2004
Aim: to see if learning a new skill would have an effect on the brains of PPs
Procedure: 3 MRI scannings were done on 24 volunteers, 3 of which were male. An MRI scan was done prior to the start of the experiment. The PPs were divided into jugglers and non jugglers. The Jugglers had to learn the new skill of juggling and were given an MRI scan after mastering the skill. They were told not to juggle anymore for 3 months and then another MRI scan was conducted.
Results: At the time of the second scan the jugglers showed larger amounts of grey matter in the mid temporal area in both hemispheres which is an area associated with visual memory. 3 months after the jugglers stopped juggling the amount of grey matter decreased but it was still more than the non-jugglers.
Evaluation: pretest and posttest design., cause and effect, the control group was present. Small sample size, problem with internal validity (participants were at home)
Rosenzweig and Bennet (1972)
Aim: investigate if animals raised in highly stimulating environments will demonstrate differences in brain growth and chemistry when compared to animals raised in a plain or dull environment.
Method: lab experiment
Details: 12 sets of 3 male rates, each from the same litter, were studied. There were 3 conditions: 1 rat remained in the lab cage with the rest of the colony, 1 rat went to the “enriched environment” cage, and the last rat went to the “impoverished” cage. 6-8 rats lived in the enriched cage with 25 new, random toys added per day. Rats lived in these environments for varying amounts of time, and then they were eventually killed. The rats then had their brains measured, weighed, and analyzed to determine the amount of cell growth and neurotransmitter activity. Acetylcholinesterase enzymes were also studied – allowing for more neurotransmission.
Findings: Enriched rats were very different from the impoverished rats. The cerebral cortex was heavier and thicker in enriched rats. Also, greater Acetylcholinesterase activity in the enriched rats. While there was not necessarily a difference in the number of brain cells, there were larger neurons noticed in the enriched rats. The ratio of RNA to DNA was larger in enriched rats too, implying more chemical activity. Synapses of enriched rats were 50% larger than impoverished rats. In only 1 trial were the results not statistically significant.
Evaluation:
-Many unethical things happening here!
-Difficult to generalize data to humans.
-The person performing the autopsy would not know the rat’s condition.
Discuss the effects of hormones on human behavior
Oxytocin = hormone excreted from pituitary gland than influences attachment, trust, love, and empathy
Feldman 2007
Aim: links between oxytocin and bonding in mothers
Method: Correlational study, purposive sampling of mothers
Details: measuring plasma oxytocin from 62 pregnant women in 1st and 3rd trimester and 1 month after birth. Observed mother-child interaction regarding levels of attachment for gaze, touch, and vocalization. Survey and interview on bond thoughts, feelings, and behaviors.
Findings: 1st-trimester oxytocin links high prego hormones to more after-birth engagement. Oxytocin in the first trimester prepares mothers for bonding with the infant.
Evaluation: large sample, do no harm respected as only plasma was taken, observing mother-child after birth seems intrusive
Closing: Oxytocin was shown to increase bond and attachment which correlated with the idea that hormones affect psychological behavior.
Kirsch (2005)
Aim: investigate oxytocin’s effect on fear and trust. The effects of sniffing oxytocin on amygdala function.
Method: lab experiment
Details: 15 male participants had their brains scanned while looking at scary or angry faces or threatening scenes. In a control condition, they looked at simple shapes. Before scanning, 1/2 of the participants sniffed oxytocin and the other 1/2 sniffed placebo.
Findings: Placebo participants had a significant increase in amygdala activity, especially when compared to the oxytocin group. Oxytocin participants had significantly less brain activity while looking at scary images, suggesting oxytocin dampens social fears. No difference was found in the questionnaires participants filled out about how they felt.
Evaluation:
-Correlational
-Many researchers create more validity
- Lack of ecological validity
-Small participant pool
Discuss the effect of pheromones on behavior.
Miller et al (2007)
Aim: study lap dancers tips and fertility
Method: field, 18 dancers over 60 days (representing about 5,300 lap dances and 296 work shifts)
Details: Recorded tip earnings by dancers in a lap-dancing club. Dancers provided information on their menstrual cycle and use of hormonal contraception
Findings: before ovulation = $335, other parts of cycle = $260, menstruation=$185
Evaluation: not many dancers but over 60 days provide satisfactory data amounts
Closing: signals that pheromones of fertility may affect reactions from others when the dancer was more fertile = more tips/higher attraction.
Wedekind et al. (1994)
Aim: This study investigated women’s preference for t-shirt smells and whether there was a deter or attraction toward similar MDC types.
Method: Quasi Experiment
Details: 49 female students and 44 male students were types for their HLA class 1 antigen. Female students were then asked if they took birth control (control for confounding variables). The men wore t-shirts (100% cotton) for 2 days and were asked to abstain from odor-creating activities. On the following Tuesday, women were asked to rate the odor from 1-10 (on pleasantness and sexiness) of 6 t-shirts (3 dissimilar MHCs and 3 similar MHCs).
Findings: Women who are not taking oral contraceptives and have a dissimilar MHC type = perceived the man as more pleasant smelling than those with a similar MHC type. Indicates that MHC-dependent body odor may play a role in actual mate choice.
Evaluation:
-Well-controlled
-research triangulation
-ethical
X
Discuss with reference to relevant research studies, to what extent genetic inheritance influences behavior
Behavioral genetics is studied in many different ways in order to research the genetic similarities, differences, and their impact on behavior. One method of studying behavioral genetics is through kinship studies. Kinship studies (studies involving those who are familially tied and related to each other through birth) are commonly used as half of a person’s genes are taken from each parent, meaning that there is a significant amount of shared genes.
Weissman (2005)
Aim: the role of inheritance of behavior in a family (genetic nature of Major Depressive Disorder-mood disorder characterized by persistent sadness and other symptoms and can be carried down through generations)
Method: Correlational, 161 families studied longitudinally for 20 years (3 generations), interviews 4 times by 2 clinicians
Details: Depression is genetically passed down most commonly when it has been passed down for 2 generations prior, as shown by correlations of grandparent/parent depression and grandchild depression/mental state
Findings: The inheritance of genes shown to increase the probability of an inherited mental illness. Based on the findings, if MDD has a pattern of showing up in your family, your susceptibility increases, compared to when there is no history of MDD.
Conclusion: Association between parental MDD and child diagnosis in moderated grandparental MDD status.
Kendler et al (2006)
Aim: identify a correlation between twins and depression to study potential genetic vulnerability.
Method: Correlational
Details: 42,000 twins from the Swedish national twin registry were studied to measure the heritability of depression (concordance rate of depression) between Monozygotic and Dizygotic twins.
Findings: Average concordance rate of MZ males was 31% and for DZ males was 11%. For women, MZ twins were 44% and 16%. This indicates that depression may be caused by a genetic predisposition.
Evaluation:
-large sampling group
-correlational
-low internal validity
**
Discuss two evolutionary explanations for behavior
The behavior we have now can be explained through our ancestral past.
Current behaviors appear to be dysfunctional but evolution argues that they can be understood as having been adaptive and functional in the past.
Anorexia may have been functional
Surbey 1987
Aim: study of the reproductive suppression hypothesis (evolutionary)- anorexia nervosa
Details: Ancestral girls delayed onset of sexual maturation- this is adaptive as it enables females to avoid giving birth at a time when conditions aren’t good for offspring’s survival
Findings: Supported by the observation that onset of puberty is delayed in girls with anorexia nervosa and the absence of menstruation is a characteristic of AN- so reproduction is effectively suppressed
Evaluation: Hypothosis cannot be falsified.
It’s impossible to scientifically test these hypothosis so there is little empirical research.
The past cannot be researched. We have no way of establishing the validity.
Closing: Girls with AN then push back menstruation and the ability to give birth in order to avoid giving birth at a bad time
Guisinger 2003
Aim: Adapted to flee famine’ hypothesis (AFFH)
Details: Suggests that anorexia is a reflection of behaviors that were adaptive for our ancestors. When our ancestors were hunter-gatherers they needed to move on regularly as food supplies in the local area were exhausted. Women with anorexia are more active and deny being hungry. These characteristics would have been adaptive when survival depended on migration in response to famine.
Evaluation: Hypothesis cannot be falsified.
It’s impossible to scientifically test these hypothosis so there is little empirical research.
The past cannot be researched. We have no way of establishing the validity.
Closing: Due to the characteristics of AN including denial of hunger and excessive movement, this may have been useful in the past as one had to move constantly in order to find food in a famine.
X
Discuss ethical considerations in research into genetic influences on behavior
Behavioral genetics is studied in many different ways to research the genetic similarities, differences, and their impact on behavior. One method of studying behavioral genetics is through kinship studies. Kinship studies (studies involving those who are familially tied and related to each other through birth) are commonly used as half of a person’s genes are taken from each parent, meaning that there is a significant amount of shared genes.
Weissman 2005
Aim: the role of inheritance of behavior in a family (genetic nature of Major Depressive Disorder-mood disorder characterized by persistent sadness and other symptoms and can be carried down through generations)
Method: Correlational, 161 families studied longitudinally for 20 years (3 generations), interviews 4 times by 2 clinicians
Details: Depression is genetically passed down most commonly when it has been passed down for 2 generations prior, as shown by correlations of grandparent/parent depression and grandchild depression/mental state
Findings: The inheritance of genes shows to increase the probability of an inherited mental illness. Based on the findings, if MDD has a pattern of showing up in your family, your susceptibility increases, compared to when there is no history of MDD.
Conclusion: Association between parental MDD and child diagnosis in moderated grandparental MDD status.
Caspi (2003)
Aim: investigate the relationship between genetic type (5-HTT - 2 short alleles, 1 short and long, and 2 long alleles) and depression symptoms.
Method: Quasi-experiment
Details: 847 caucasian New Zealand (all in their 20s) participants were split into 3 groups, based on allele type. Participants were then told to fill out life history surveys. No difference was found in life stressors among the 3 groups. Then, the researchers measured depression levels using the Diagnostic Interview Schedule. The researchers also gathered informant data to control for lying.
Findings: 17% of the total subjects qualified for a major depressive disorder diagnosis (58% female and 43% male). Data was analyzed with a correlation between depression symptoms and genotype. Researchers correlated having a short allele with greater self-reports of depression. Greater depression rates occurred with short alleled people ages 21-26.
Evaluation:
-Possible long-term harm of knowing about this gene
-Only looked at 20-year-olds in New Zealand.
-Research triangulation
-states that future research is needed, increasing validity.
-Supports diathesis-stress theory
-Isolates gene, increasing reliability.
Discuss how and why particular research methods are used with the biological approach to understanding human behavior.
Draganski 2004
Aim: to see if learning a new skill would have an effect on the brains of PPs
Procedure: 3 MRI scannings were done on 24 volunteers, 3 of which were male. An MRI scan was done prior to the start of the experiment. The PPs were divided into jugglers and non jugglers. The Jugglers had to learn the new skill of juggling and were given an MRI scan after mastering the skill. They were told not to juggle anymore for 3 months and then another MRI scan was conducted.
Results: At the time of the second scan the jugglers showed larger amounts of grey matter in the mid temporal area in both hemispheres which is an area associated with visual memory. 3 months after the jugglers stopped juggling the amount of grey matter decreased but it was still more than the non-jugglers.
Evaluation: pretest and posttest design., cause and effect, the control group was present. Small sample size, problem with internal validity (participants were at home)
Closing: After practicing the new skill for 3 months the amount of grey matter that was presented had increased greatly, demonstrating the new neural connections.
Rosenzweig and Bennet (1972)
Aim: investigate if animals raised in highly stimulating environments will demonstrate differences in brain growth and chemistry when compared to animals raised in a plain or dull environment.
Method: lab experiment
Details: 12 sets of 3 male rates, each from the same litter, were studied. There were 3 conditions: 1 rat remained in the lab cage with the rest of the colony, 1 rat went to the “enriched environment” cage, and the last rat went to the “impoverished” cage. 6-8 rats lived in the enriched cage with 25 new, random toys added per day. Rats lived in these environments for varying amounts of time, and then they were eventually killed. The rats then had their brains measured, weighed, and analyzed to determine the amount of cell growth and neurotransmitter activity. Acetylcholinesterase enzymes were also studied – allowing for more neurotransmission.
Findings: Enriched rats were very different from the impoverished rats. The cerebral cortex was heavier and thicker in enriched rats. Also, greater Acetylcholinesterase activity in the enriched rats. While there was not necessarily a difference in the number of brain cells, there were larger neurons noticed in the enriched rats. The ratio of RNA to DNA was larger in enriched rats too, implying more chemical activity. Synapses of enriched rats were 50% larger than impoverished rats. In only 1 trial were the results not statistically significant.
Evaluation:
-Many unethical things happening here!
-Difficult to generalize data to humans.
-The person performing the autopsy would not know the rat’s condition.
Discuss how theories and concepts relating to the biological approach to understanding human behavior have been demonstrated through research.
Draganski 2004
Aim: to see if learning a new skill would have an effect on the brains of PPs
Procedure: 3 MRI scannings were done on 24 volunteers, 3 of which were male. An MRI scan was done prior to the start of the experiment. The PPs were divided into jugglers and non jugglers. The Jugglers had to learn the new skill of juggling and were given an MRI scan after mastering the skill. They were told not to juggle anymore for 3 months and then another MRI scan was conducted.
Results: At the time of the second scan the jugglers showed larger amounts of grey matter in the mid temporal area in both hemispheres which is an area associated with visual memory. 3 months after the jugglers stopped juggling the amount of grey matter decreased but it was still more than the non-jugglers.
Evaluation: pretest and posttest design., cause and effect, the control group was present. Small sample size, problem with internal validity (participants were at home)
Closing: After practicing the new skill for 3 months the amount of grey matter that was presented had increased greatly, demonstrating the new neural connections
Rosenzweig and Bennet (1972)
Aim: investigate if animals raised in highly stimulating environments will demonstrate differences in brain growth and chemistry when compared to animals raised in a plain or dull environment.
Method: lab experiment
Details: 12 sets of 3 male rates, each from the same litter, were studied. There were 3 conditions: 1 rat remained in the lab cage with the rest of the colony, 1 rat went to the “enriched environment” cage, and the last rat went to the “impoverished” cage. 6-8 rats lived in the enriched cage with 25 new, random toys added per day. Rats lived in these environments for varying amounts of time, and then they were eventually killed. The rats then had their brains measured, weighed, and analyzed to determine the amount of cell growth and neurotransmitter activity. Acetylcholinesterase enzymes were also studied – allowing for more neurotransmission.
Findings: Enriched rats were very different from the impoverished rats. The cerebral cortex was heavier and thicker in enriched rats. Also, greater Acetylcholinesterase activity in the enriched rats. While there was not necessarily a difference in the number of brain cells, there were larger neurons noticed in the enriched rats. The ratio of RNA to DNA was larger in enriched rats too, implying more chemical activity. Synapses of enriched rats were 50% larger than impoverished rats. In only 1 trial were the results not statistically significant.
Evaluation:
-Many unethical things happening here!
-Difficult to generalize data to humans.
-The person performing the autopsy would not know the rat’s condition.
Discuss ethical considerations related to research studies using the biological approach to understanding human behavior.
Weissman 2005
Aim: the role of inheritance of behavior in a family (genetic nature of Major Depressive Disorder-mood disorder characterized by persistent sadness and other symptoms and can be carried down through generations)
Method: Correlational, 161 families studied longitudinally for 20 years (3 generations), interviews 4 times by 2 clinicians
Details: Depression is genetically passed down most commonly when it has been passed down for 2 generations prior, as shown by correlations of grandparent/parent depression and grandchild depression/mental state
Findings: The inheritance of genes shows to increase the probability of an inherited mental illness. Based on the findings, if MDD has a pattern of showing up in your family, your susceptibility increases, compared to when there is no history of MDD.
Conclusion: when being aware one might have a predisposition to depression, there is a chance this might cause stress or a self-fulfilling prophecy (the process through which an originally false expectation leads to its confirmation) as the individual is being labeled with “MDD prone.”
Caspi (2003)
Aim: investigate the relationship between genetic type (5-HTT - 2 short alleles, 1 short and long, and 2 long alleles) and depression symptoms.
Method: Quasi-experiment
Details: 847 caucasian New Zealand (all in their 20s) participants were split into 3 groups, based on allele type. Participants were then told to fill out life history surveys. No difference was found in life stressors among the 3 groups. Then, the researchers measured depression levels using the Diagnostic Interview Schedule. The researchers also gathered informant data to control for lying.
Findings: 17% of the total subjects qualified for a major depressive disorder diagnosis (58% female and 43% male). Data was analyzed with a correlation between depression symptoms and genotype. Researchers correlated having a short allele with greater self-reports of depression. Greater depression rates occurred with short alleled people ages 21-26.
Evaluation:
-Possible long-term harm of knowing about this gene
-Only looked at 20-year-olds in New Zealand.
-Research triangulation
-states that future research is needed, increasing validity.
-Supports diathesis-stress theory
-Isolates gene, increasing reliability.
