🔬 Biological Approach Flashcards
London taxi drivers & hippocampus size
Maguire et al. (2000)
Aim: Investigate the brain structure of London taxi drivers and its association with navigational skills.
Procedure: MRI was used to identify structural differences in the brain.
Results: Increased grey matter in the hippocampus was found in taxi drivers, associated with their advanced navigational skills.
Conclusion: The hippocampus plays a role in spatial navigation and can change in response to environmental demands.
🏠 MRI (techniques to study the brain)
🧠 Neuroplasticity
📍 Localization of function (hippocampus & memory)
Serotonin depletion & amygdala reactivity
Passamonti et al. (2012)
Aim: Explore the impact of serotonin on the amygdala and prefrontal cortex (PFC) during the perception of social threats.
Procedure: fMRI was used to examine brain activity under different serotonin conditions.
Results: Serotonin levels influenced brain activity in the amygdala and PFC.
Conclusion: Serotonin plays a role in modulating brain activity during the perception of social threats.
🏠 fMRI (techniques to study the brain)
🎭 Neurotransmitters (serotonin & behavior)
Testosterone & amygdala response
Radke et al. (2015)
Aim: Examine the role of testosterone in amygdala activation when approaching threatening faces.
Procedure: fMRI was used to measure how testosterone influenced brain activity during this task.
Results: Increased testosterone led to heightened amygdala activation during the task.
Conclusion: Testosterone plays a role in amygdala activation when perceiving threats.
🏠 fMRI (techniques to study the brain)
💪 Hormones (testosterone & aggression)
PET scans in Parkinson’s disease patients
Freed et al. (2001)
Aim: Investigate the role of dopamine in alleviating symptoms of Parkinson’s disease.
Procedure: PET scans were used to observe the effects of dopamine on brain function and symptom improvement.
Results: Dopamine infusion improved brain function and symptoms, particularly in younger participants.
Conclusion: Dopamine plays a significant role in alleviating symptoms of Parkinson’s disease.
🏠 PET (techniques to study the brain)
🎭 Neurotransmitters (dopamine & Parkinson’s disease)
Brain structure changes in jugglers
Draganski et al. (2004)
Aim: Investigate whether learning a new skill (juggling) induces structural brain changes.
Procedure: Participants were divided into jugglers and non-jugglers. Jugglers practiced juggling for three months, followed by three months of non-practice. MRI scans were taken at baseline, after three months, and after six months.
Results: Increased grey matter in the mid-temporal cortex of jugglers after practice. Grey matter volume decreased after non-practice but remained higher than baseline.
Conclusion: Learning a new skill induces growth in brain areas associated with that skill, while lack of practice leads to partial regression, demonstrating neural pruning.
🔄 Neuroplasticity
Childhood poverty & hippocampal size
Luby et al. (2013)
Aim: Investigate the relationship between poverty, stress, parenting, and hippocampal development.
Procedure: MRIs measured hippocampal volume, and parent-child interactions were observed in a stress-inducing scenario. Correlations between socioeconomic status, stress, and brain development were analyzed.
Results: Positive parent-child interactions were associated with larger hippocampal volume, while stress and poverty negatively correlated with hippocampal development.
Conclusion: Childhood experiences, including stress and parenting, shape brain structure, highlighting neuroplasticity in response to environmental factors.
🔄 Neuroplasticity
🧬 Epigenetics (gene-environment interaction)
Split-brain research
Sperry (1968)
Aim: Investigate how brain functions are divided between the two hemispheres in split-brain patients.
Procedure: Visual stimuli were presented to one visual field at a time, and participants were asked to identify or manipulate unseen objects.
Results: Objects shown to the right visual field (left hemisphere) could be named, while objects shown to the left visual field (right hemisphere) could be physically identified but not named.
Conclusion: Language functions are primarily localized to the left hemisphere, with support from the right hemisphere for basic language tasks.
📍 Weak localization of function
Split-brain research
Gazzaniga (1967)
Aim: Investigate how brain functions are divided between the two hemispheres in split-brain patients.
Procedure: Visual stimuli were presented to one visual field at a time. Participants were asked to identify or manipulate unseen objects.
Results: Objects shown to the right visual field (left hemisphere) could be named. Objects shown to the left visual field (right hemisphere) could be physically identified but not named.
Conclusion: Language functions are weakly localized, with dominance in the left hemisphere but support from the right.
📍 Weak localization of function
Acetylcholine & spatial memory
Antonova et al. (2011)
Aim: See whether acetylcholine (ACh) aids spatial memory, and if it can be slowed down by scopolamine, which is an antagonist for acetylcholine.
Procedure: Participants were injected with scopolamine or a saline placebo and completed a virtual maze. After 3-4 weeks, they received the alternative injection and repeated the maze task using a randomized double-blind crossover design.
Results: Scopolamine led to more errors in the maze and reduced activity in the hippocampal area.
Conclusion: Scopolamine reduced hippocampal activity, demonstrating a correlation between acetylcholine and spatial memory.
🎭 Neurotransmitters (acetylcholine & memory)
Serotonin & moral decision-making
Crockett et al. (2010)
Aim: Investigate how serotonin influences moral decision-making and prosocial behavior.
Procedure: Participants were given either citalopram (an SSRI) or a placebo. They were presented with moral dilemmas, including impersonal and personal scenarios based on the “trolley problem.”
Results: In personal scenarios, participants under citalopram were less likely to choose harm, reflecting increased prosocial tendencies. Impersonal decisions were unaffected.
Conclusion: Serotonin enhances prosocial behavior by reducing the acceptability of causing direct harm to others.
🎭 Neurotransmitters (serotonin & prosocial behavior)
Romantic love & dopamine (fMRI)
Fisher, Aron, & Brown (2005)
Aim: Investigate the neural basis of romantic love and its association with dopamine activity.
Procedure: Participants viewed images of their romantic partner and neutral acquaintances while undergoing fMRI scans. Brain activity patterns were compared.
Results: Photos of romantic partners triggered increased activation in dopamine-rich brain regions linked to reward and motivation.
Conclusion: Romantic love is associated with dopamine activity, reinforcing its role in reward processing.
🎭 Neurotransmitters (dopamine & romantic attraction)
💞 Psychology of human relationships (love & attraction)
Testosterone & aggression in rats
Albert et al. (1986)
Aim: Investigate the causal relationship between testosterone levels and aggression in alpha male rats.
Procedure: Testosterone levels were manipulated through castration and subsequent hormone replacement. Alpha male rats were castrated, while others remained intact, and testosterone was reintroduced to observe behavioral changes.
Results: Castrated rats showed reduced aggression, and aggression returned to baseline when testosterone was reintroduced.
Conclusion: Testosterone directly influences aggressive behavior, establishing a cause-and-effect relationship in animal models.
💪 Hormones (testosterone & aggression)
🐀 Animal research
Oxytocin & social bonding
Scheele et al. (2012)
Aim: Explore how oxytocin influences fidelity in heterosexual males.
Procedure: Participants received either oxytocin or a placebo intranasally. They participated in a stop-distance paradigm and an approach/avoidance task involving images of attractive women.
Results: Oxytocin caused men in relationships to maintain a greater physical distance from attractive women, while single men showed no such effect. Oxytocin also influenced reactions to images of attractive women.
Conclusion: Oxytocin promotes fidelity by modulating social behaviors, particularly in pair-bonded males.
💞 Hormones (oxytocin & romantic relationships)
Pheromones & mate selection
Wedekind et al. (1995)
Aim: Investigate if women prefer the scent of men with different MHC genes.
Procedure: Men wore t-shirts for two days to capture their body odor. Women, during their fertile phase, smelled the shirts and rated them for intensity, pleasantness, and sexiness.
Results: Women preferred scents from men with dissimilar MHC genes, but this preference reversed for women on contraceptives.
Conclusion: Pheromones may play a role in signaling genetic compatibility, influencing mate selection.
👃 Pheromones & behavior (attraction)
💞 Psychology of human relationships (evolutionary attraction)
5-HTT gene & depression
Caspi et al. (2003)
Aim: Investigate how 5-HTT gene variants affect the likelihood of developing depression after stressful life events.
Procedure: Longitudinal study of 1,037 New Zealand individuals, with genetic mapping to classify participants by allele type. Stressful life events and depression symptoms were measured.
Results: Participants with one or two short alleles experienced more depressive symptoms after stress than those with two long alleles. The short allele amplified vulnerability to stress.
Conclusion: The short allele of the 5-HTT gene predisposes individuals to stress-related depression, demonstrating a gene-environment interaction.
🧬 Genes & behavior (gene-environment interaction & depression)
🏥 Abnormal psychology (biological explanations of depression)
Twin studies & intelligence
Bouchard & McGue (1981)
Aim: Estimate the heritability of intelligence using twin data.
Procedure: Meta-analysis of 111 twin studies calculating IQ correlations between MZ and DZ twins (both reared together and apart), siblings, and parents, applying the Falconer Model to estimate heritability.
Results: MZ twins reared together: IQ correlation = 0.85; MZ twins reared apart: IQ correlation = 0.67; DZ twins reared together: IQ correlation = 0.58. Heritability of intelligence: 54%.
Conclusion: Intelligence is significantly influenced by genetic factors but also shaped by environmental inputs.
🧬 Genetic similarity (twin studies)
Evolutionary disgust responses
Curtis, Aunger, & Rabie (2004)
Aim: Test the hypothesis that disgust is an evolutionary adaptation to avoid disease, serving as a biological mechanism to reduce the risk of infection.
Procedure: An online correlational survey with over 77,000 participants from 165 countries, where participants rated 20 images on a disgust scale and were asked about sharing a toothbrush with familiar and unfamiliar individuals.
Results: Disease-salient images received higher disgust ratings. Responses were consistent across cultures and stronger in females. Disgust responses declined with age. Participants were more likely to share a toothbrush with familiar individuals.
Conclusion: Disgust is a biologically ingrained response to disease-related stimuli, supporting the theory that it evolved to protect against infection and reduce disease risk.
🦠 Evolutionary explanation of behavior
