Biological approach Flashcards
Brain scanning techniques: MRI scans
Structural Imaging: MRI scans
An MRI scanner uses magnetic field and radio waves to map the activity of hydrogen molecules, which are present in different brain tissue to different degrees.
The image can either be viewed as a slice of the brain from any angle, or it can be used to create a three-dimensional image of the brain
The human body is mostly water. Water molecules contain hydrogen protons, which become aligned in a magnetic field. An MRI scanner applies a strong magnetic field which aligns the proton ‘spins’.
The scanner also produces a radio frequency current that creates a varying magnetic field. The protons absorb the energy from the magnetic field and flip their spins. When the field is turned off, the protons gradually return to their normal spin, a process called precession. The return process produces a radio signal that can be measured by receivers in the scanners and made into an image.
The MRI is a composite image of several images of the brain.
Evaluation of structural imaging: MRI scans
Strengths:
- it is non-invasive, with minimal potential harm to the participant
- the image has a high spatial resolution; this gives the researchers a good sense of the actual structure of the brain.
Weaknesses:
- the MRI only indicates structure; it doesn’t actually map what is happening in the brain
- MRI research is correlational in research, not allowing researchers to establish a clear cause and effect relationship
Maguire
Aim:
Investigate if London taxi drivers’ brains show structural differences due to their spatial navigation skills.
Procedure:
16 right-handed male taxi drivers (licensed ≥1.5 years, passed “Knowledge” test).
Compared with 50 right-handed male non-taxi drivers (MRI database).
Used:
Voxel-based morphometry (VBM): Grey matter density.
Pixel counting: Hippocampal area in MRI scans.
Single-blind: Analyst didn’t know group identity of scans.
Findings:
Pixel Counting:
Taxi drivers: Larger posterior hippocampi, smaller anterior hippocampi vs. controls.
VBM:
Positive correlation: Right posterior hippocampal volume ↔ years as a taxi driver.
No differences in other brain areas.
Conclusion:
Hippocampus changes with spatial navigation demands.
Posterior hippocampus: Uses learned spatial info.
Anterior hippocampus: Encodes new layouts
Maguire link to use of MRI scans to investigate human behaviour
This study illustrates the utility of MRI technology in exploring the relationship between environmental demands and brain structure. MRI provides high-resolution images of the brain, enabling researchers to measure grey matter density and specific brain regions’ volumes, such as the hippocampus, with great accuracy. Through techniques like voxel-based morphometry and pixel counting, researchers can identify correlations between brain anatomy and behavioral variables, such as the extensive navigation experience of taxi drivers in this study. By revealing structural changes in the brain associated with specific experiences, MRI technology contributes significantly to our understanding of brain plasticity and the localization of function in human behaviour.
Localisation of brain function
Localisation of brain function refers to the theory that different parts of the brain are responsible for different aspects of human functioning, such as behaviours
This relates directly to the assumption of the biological approach that conditions, emotions and behaviours are products of the anatomy and physiology of our nervous and endocrine systems
Psychologists investigating localisation of brain function from the biological approach use brain-imaging techniques, brain surgeries and brain autopsies to investigate the correlation between brain processes and structures and human behaviour.
Maguire link to localisation of brain function
This study provides insight into the localization of brain function, specifically within the hippocampus. The findings suggest that different regions of the hippocampus have distinct roles: the posterior hippocampus is involved in retrieving and using previously learned spatial information, while the anterior hippocampus may be more crucial for encoding new spatial information. This distinction aligns with the theory of localized brain functions, where specific brain areas are responsible for particular cognitive processes. By demonstrating structural differences in the hippocampi of taxi drivers, who rely heavily on spatial navigation skills, the study underscores how environmental demands can shape and potentially localize brain function.
neuroplasticity
Neuroplasticity is the term used to describe the changes in neural pathways and synapses due to changes in behaviour, environment, thinking, emotions, as well as changing from bodily injury.
- It is fundamentally the ability of the brain to change through the making and breaking of synaptic connections between neurons. It occurs on different scales from synaptic plasticity to cortical remapping
- Synaptic plasticity is neuroplasticity occurring on the level of a separate neuron, construction of new synaptic connections (neural networks) and elimination of the ones that are not used (synaptic pruning)
- Cortical remapping is when neurons remap to new areas of the brain
Neuroplasticity is the brain’s ability to reorganise itself by forming new neural connections. It allows neurons in the brain to compensate for injury or to respond to changes in the environment.
Neural networks
- The process by which neural networks are formed is called neuroplasticity. This is known as synaptic plasticity
- When a neuron is stimulated, an action potential travels down the axon. Neural networks are created when a neuron, or set of neurons are repeatedly stimulated
- This repeated firing of the neurons, called long term potentiation, results in gene expression which causes the neurons to sprout new dendrites - known as dendritic branching
- This increases the number of synapses available for the behaviour
Synaptic pruning
Another way that our brain can change is through synaptic pruning- which is a decrease in the number of synapses as a result of removing dendritic branches
Synaptic pruning refers to the process by which extra neurons and synaptic connections are eliminated in order to increase the efficiency of neuronal transmissions
Synaptic pruning is a natural process that occurs in the brain between early childhood and adulthood. During synaptic pruning, the brain eliminates extra synapses. Synaptic pruning is our body’s way of maintaining more efficient brain function as we get older and learn new complex information.
- pruning can be the result of neuronal cell death, hormones such as cortisol or the lack of use of a neural pathway
- The exact mechanism of synaptic pruning is not yet fully understood.
Maguire link to neuroplasticity
This study illustrates the concept of neuroplasticity, the brain’s ability to reorganize itself by forming new neural connections in response to learning or environmental demands. The significant structural differences observed in the hippocampi of taxi drivers, specifically the enlargement of the posterior hippocampus and the reduction in the size of the anterior hippocampus, suggest that the brain can adapt to the cognitive demands of navigating complex environments. This adaptation is further supported by the positive correlation between the volume of the right posterior hippocampus and the number of years spent driving a taxi. These findings highlight how prolonged engagement in a specific cognitive activity, such as spatial navigation, can lead to measurable changes in brain structure, thereby demonstrating the brain’s capacity for neuroplasticity.
Draganski
Aim
The aim of the study was to investigate whether learning a new skill, specifically juggling, would have an impact on the brain structure of the participants.
Procedure
- Participants: 24 volunteers aged 20-24 (21 females, 3 males), all non-jugglers at the start.
- Baseline MRI: All participants underwent an initial MRI scan to measure grey matter and brain structure.
- Condition Assignment: Participants were divided into two groups - jugglers and non-jugglers (control group).
- Juggling Training: The juggling group learned a three-ball cascade routine and practiced until mastery. Upon mastering, they had a second MRI scan.
- Post-Juggling Phase: After the second scan, jugglers were instructed to stop juggling. A third MRI scan was conducted three months later.
- Control Group: The non-jugglers did not learn juggling and served as a control group throughout the study.
Findings
- Baseline Comparison: Initial MRI scans showed no significant differences in grey matter between jugglers and non-jugglers.
- Post-Learning: After mastering juggling, jugglers exhibited a significant increase in grey matter in the mid-temporal area of both hemispheres, linked to visual memory.
- After Cessation: Three months after stopping juggling, the jugglers showed a decrease in grey matter in the same brain regions.
- Control Group: There were no changes in grey matter in the control group throughout the study.
Conclusion
Learning to juggle led to an increase in grey matter in the mid-temporal areas of the brain, suggesting that juggling primarily enhances visual memory areas rather than procedural memory regions like the cerebellum or basal ganglia. This increase in grey matter diminished after participants stopped practicing juggling. The study demonstrates the brain’s plasticity in response to acquiring new skills and the reversibility of these changes upon discontinuation of the activity.
draganski link to neuroplasticity
The study highlights synaptic plasticity, the brain’s ability to adapt structurally through learning. Juggling practice led to an increase in grey matter in visual memory areas, likely due to long-term potentiation (LTP), where repeated practice strengthened neural connections. After participants stopped juggling, the reduction in grey matter reflects synaptic pruning, where unused connections are eliminated. This demonstrates the brain’s adaptability, with structural changes occurring in response to learning and reversing upon disuse.
Neurotransmitters
The Neuron is the basic unit in the nervous system. It is a specialised cell that receives and transmits electrochemical nerve impulses. Over three-quarters of all Neurons are found in the brain and there are three main types:
- sensory carrying information from the sense organs to the central nervous systems
- Motor carrying information from the central nervous system to the muscles and glands
- Relay- the most numerous and they connect neurons to other neurons and coordinate the activities of motor and sensory neurons
Neurotransmitters are chemicals that carry the electrical impulses between neurones in the brain and body. They act within the synapse.
Neurotransmitters are released from the terminal buttons. They fit into receptor sites on the post-synaptic membrane. Some stay in the synapse and many are eventually re-uptaken by the original neuron.
Synaptic Transmission
Action potential from presynaptic neuron stimulates fusion of vesicles with neurotransmitters to presynaptic membrane. Chemical neurotransmitters diffuse across the synaptic cleft and are detected by receptors in the postsynaptic neuron
Summation; the neurotransmitters are excited and increase the electric potential in the postsynaptic neuron. So that a threshold for new action potential forms
The chemical neurotransmitters are reabsorbed and placed into vesicles.
Excitatory and Inhibitory
Neurotransmission can either be excitatory or inhibitory- they can either instruct the receiving neuron to fire or not to fire. The effect of a synapse is determined by its neurotransmitter content and the properties of the receptors present in the postsynaptic membrane.
It is the action of the particular neurotransmitter in the terminal button which makes a synapse either excitatory or inhibitory.
- Excitatory neurotransmitters: Increase the likelihood of a neuron firing. excitatory neurotransmitters include acetylcholine
- Inhibitory neurotransmitters: Decrease the likelihood of a neuron firing. Inhibitory neurotransmitters include GABA
Acetylcholine is usually excitatory but can be inhibitory depending on the neuron receptor site; serotonin is both excitatory and inhibitory.
It is important to understand how neurotransmitters work in order to understand drug treatments. Drugs can replicate the shape of the neurotransmitter and then occupy the receptor site on the dendrites
Sometimes, the neurotransmitter or drug may be excitatory- that is, they activate the neuron- like stepping on a gas pedal. Sometimes the neurotransmitter or drug may be inhibitory- that is, it prevents a neuron from firing.
Antonova
Aim: Investigate how acetylcholine (agonist) affects encoding of spatial memories in humans using scopolamine (acetylcholine antagonist (blocker)).
Participants:
20 healthy males, avg. age 28.
Double-blind, repeated measures design.
Method:
Participants injected with scopolamine or placebo.
Played the Arena task (VR game testing spatial memory):
Navigate to a pole, rehearse location, start from a new position.
Brain activity tracked via fMRI during six trials.
Returned 3-4 weeks later for opposite treatment.
Findings:
Scopolamine group:
Lower hippocampal activation (fMRI).
Slightly higher error rate, but not significantly different from placebo.
Conclusion:
Acetylcholine is vital for encoding spatial memories.
Reduced hippocampal activity under scopolamine highlights its critical role.
Antonova link paragraph
This study highlights the critical role neurotransmitters play in human behavior, specifically in memory and learning. Acetylcholine, an important neurotransmitter involved in attention and memory, was shown to be essential for spatial memory encoding in the hippocampus. The reduction in hippocampal activation with scopolamine administration demonstrates how manipulating neurotransmitter systems can directly affect cognitive functions. This aligns with broader research indicating that neurotransmitters influence a range of behaviors and cognitive processes, including learning, memory, and attention. Understanding these mechanisms can provide insights into neuropsychiatric conditions and guide the development of targeted treatments.
Hormones
Endocrine system:
Works with CNS to control vital functions via sympathetic/parasympathetic systems
Slower and longer-lasting than nervous system
Regulates long-term processes (growth, metabolism, digestion, reproduction)
Interdependent with CNS
Uses hormones and glands as chemical messengers
Some chemicals (e.g., adrenaline) act as both hormones and neurotransmitters
Glands & Hormones
Glands produce hormones
Hormones travel through blood to influence physical and mental functions
Affect multiple organs, triggering powerful responses
Influence behavior by altering its probability, not directly causing it
How Hormones Work
Secreted by glands, not neurons
Adrenaline: hormone (adrenal glands), Norepinephrine: neurotransmitter (neurons)
Take longer to act but last longer than neurotransmitters
Act on target cells with specific receptors, altering their function
Hormones & Behavior
Influence a range of behaviors (50+ types)
Some act like neurotransmitters (target receptors in synapse)
Key Glands
Pituitary Gland: controls release of hormones from other glands
Thyroid: affects metabolism
Parathyroids: regulate calcium levels
Adrenal Glands: fight-or-flight response
Pancreas: regulates blood sugar
Testes/Ovaries: produce sex hormones
Key Hormones
Adrenaline: arousal, fight/flight, emotional memory
Cortisol: regulates blood sugar, metabolism, reduces inflammation, aids memory formation
Melatonin: relaxation, sleep
Neuropeptide Y: stimulates food intake, reduces anxiety, pain, stress
Oxytocin: mother-child bonding, social trust
Testosterone: linked to aggression (facilitates, doesn’t cause)
Hormones & Memory
Adrenaline: boosts senses, thought processes, energy (ATP)
Cortisol: increases glucose, metabolism (fight/flight), affects memory
High cortisol: impairs memory retrieval
Long-term: harms hippocampus, memory consolidation
Newcomer et al
Aim
Test if high cortisol levels mess with verbal declarative memory.
Procedure
Participants: Employees/students at Washington University Med Center.
Screening: Clinical interviews to exclude certain conditions.
Groups (matched for age/gender):
High cortisol: 160 mg/day (major stress levels).
Low cortisol: 40 mg/day (minor stress levels).
Placebo: No active ingredients.
Task: Recall different prose passages.
Testing: Before tablets, Day 1, Day 4, Day 6 (after stopping).
Findings
High cortisol: Worst memory performance.
Low cortisol & placebo: No big difference.
After stopping tablets: High cortisol group returned to normal.
Conclusion
High cortisol impairs verbal memory.
Effects are temporary (reversible after cortisol stops).
Shows how stress impacts cognitive function.
Newcomer link to hormones
This study illustrates how hormones, specifically cortisol, can significantly influence human behavior by affecting cognitive functions like memory. Cortisol, a stress hormone, was shown to impair verbal declarative memory when present in high levels, simulating a major stress event. This finding highlights the broader impact of hormonal responses to stress on human cognition, demonstrating that elevated cortisol levels can disrupt memory processes. The study also underscores the temporary nature of this effect, as memory performance normalized after cortisol levels returned to baseline, suggesting that the influence of hormones on behavior can be dynamic and reversible.
Pheromones
Pheromones
Chemical messengers → trigger responses in others of the same species.
Discovery: 1959 by Karlson & Luscher.
Animal studies: Bombykol in butterflies, Bruce effect (1959) → male mouse pheromones cause miscarriages.
Humans & Pheromones
Existence debated:
Possible sources: Apocrine glands (armpits), vaginal secretions (copulins).
Androstenes: Found in males, active after puberty.
Wyatt’s take: Humans likely lack functional pheromones due to no evolutionary need.
Vomeronasal Organ (VNO)
Detects pheromones in animals.
Grammer et al.: Says it’s functional in humans.
Wyatt: Thinks it’s non-functional.
Key Studies
Wedekind & Füri (1997):
People prefer scents of others with different MHC genes → mate choice link.
Key Pheromones & Scents
Androstadienone (AND): In male sweat/semen, affects human behavior.
Estratraenol: In pregnant women’s urine, pheromone-like effects.
MHC: Immune system genes → scent-based mate selection.
Wedekind
Aim:
The aim of the study was to determine whether one’s major histocompatibility complex (MHC) affects mate choice.
Procedure:
The study involved 49 female and 44 male students from the University of Bern, Switzerland. Participants were typed for their MHC, ensuring a wide variance. Men were asked to wear a T-shirt for two nights, using perfume-free detergent and soap, avoiding deodorants, perfumes, tobacco, alcohol, spicy foods, and sexual activity. Women, tested during their second week of menstruation, ranked the smell of seven T-shirts (three from MHC-similar men, three from MHC-dissimilar men, and one control) for intensity, pleasantness, and sexiness. Women using oral contraceptives were noted. The design was double-blind.
Findings:
Women rated the body odors of MHC-dissimilar men as more pleasant and sexy compared to MHC-similar men, suggesting MHC influences mate choice. This preference was reversed for women on oral contraceptives.
Conclusion:
The study supports the evolutionary argument that MHC affects human mate selection, as individuals may be subconsciously attracted to those with dissimilar MHC, enhancing offspring immune function. The influence of oral contraceptives indicates hormonal modulation of this preference.
Wedekind link paragraph
Pheromones, chemical messengers emitted by individuals, can influence human behaviour by affecting physiological and psychological responses in others. For example, research suggests that pheromones play a role in mate selection. Studies, such as those by Wedekind and Füri, have shown that individuals can subconsciously prefer the body odors of potential partners with dissimilar major histocompatibility complex (MHC) genes, which may enhance the immune system of offspring. Additionally, experiments have indicated that exposure to male pheromones can affect female perceptions of male attractiveness, further suggesting that pheromones can influence sexual attraction and mate choice. While the existence and role of human pheromones remain debated, evidence indicates that they may contribute to the complex process of human social and sexual behaviour.
Genes
Genes: Segments of DNA that provide the blueprint for structure and function, including behavior.
Alleles: Different versions of a gene; humans inherit two alleles, one from each parent.
Human Genome: About 20,000-25,000 genes across 23 chromosome pairs.
Genes influence behavior indirectly (e.g., sensitivity to stress, neurotransmitter effects).
Behavioural Genetics
Investigates how genes and environment interact to shape behavior.
No genes for specific behaviors (e.g., depression, alcoholism).
Genetic predispositions require environmental stimuli to express behaviors.
Focus is on gene-environment interactions, not just genetic determinism.
Key Terms
Genotype: Genetic code.
Phenotype: Genetic code + environment (expression of traits).
Monozygotic Twins: Identical twins, one fertilized egg splits.
Dizygotic Twins: Fraternal twins, two separate eggs.
Behavioural Epigenetics
Focuses on gene expression and gene-environment interactions.
A gene linked to a condition (e.g., schizophrenia) may not be expressed without environmental triggers.
Explains why MZ twin concordance rates aren’t always identical.
Key Studies
Caspi et al. (2003)
Kendler et al. (2006)
Holistic Evaluation
Nature-Nurture: Not a debate, but a relationship. Behavior is shaped by both heredity and environment.
Mapping genomes and epigenomes has deepened understanding of environmental influences on behavior (through gene regulation).
Need clearer knowledge on how environmental and genetic factors interact in shaping behavior.
Research Limitations
Genetics research: Correlational, not causal.
Caspi et al.
Aim:
The aim of this study was to investigate the relationship between a genetic predisposition (specifically the 5-HTT serotonin transporter gene) and the development of depression in response to stressful life events. The research sought to determine whether there was a gene-environment interaction (G x E) involving the 5-HTT gene mutation, which could explain individual differences in the susceptibility to depression when exposed to stressors.
Procedure:
Caspi and his team studied a cohort of 847 New Zealanders, all 26 years old, who had been assessed for mental health regularly until age 21. The participants were divided into three groups based on their 5-HTT alleles:
- Group 1 had two short alleles (mutation of the gene).
- Group 2 had one short and one long allele.
- Group 3 had two long alleles.
The participants completed a “Stressful life events” questionnaire covering 14 stressors, such as financial, employment, health, and relationship issues, experienced between ages 21 and 26. They were also assessed for symptoms of depression and suicidal ideation.
Findings:
The study found that individuals with one or more short versions of the 5-HTT gene demonstrated more symptoms of depression and suicidal ideation when exposed to stressful life events, compared to those with two long alleles. The effect was particularly strong among individuals who experienced more stressful events. However, simply having the gene did not guarantee the onset of depression—it was the combination of stressful life events and the gene that significantly increased the likelihood of depression.
Conclusion:
The study concluded that the 5-HTT gene’s interaction with environmental stressors plays a significant role in the development of depression. The research provides evidence of gene-environment interaction, where genetic vulnerability (short alleles of the 5-HTT gene) combined with life stressors increases the risk of depression. However, inheriting the gene alone does not directly lead to depression; environmental factors play a crucial role.
Caspi link to genetics and behaviour
Genetic factors, such as mutations in the serotonin transporter gene (5-HTT), can significantly influence behavior by interacting with environmental stressors. For example, individuals with one or more short alleles of the 5-HTT gene are more prone to developing depression when exposed to stressful life events. However, genetics do not act in isolation. The diathesis-stress model proposes that while certain genes may predispose individuals to certain behaviors or mental health conditions, the environment plays a critical role in triggering these genetic tendencies. This explains why not everyone with a genetic predisposition, such as a short allele of 5-HTT, will develop depression—only those who also experience significant stress.
Genetic similarities
We have already looked at the concept of heritability of behaviour and gene-environment interactions and shown how difficult, if not impossible, it is to quantify how much of our behaviour is inherited from our parents and how much is the result of our environment. By looking at individuals it becomes clear that we all start with a different genetic code. If, we start with individuals who have identical genes, then we control for the confounding variable of a possible polymorphism or different genetic code and may be able to get nearer to deciding how much of human behaviour is genetically inherited and how much is down to the environment.
Kendler et al.
Aim:
- To investigate whether the heritability of major depression, which past studies estimate to be between 35-45%, holds true in a large Swedish sample.
- To explore potential gender differences in the heritability of major depression.
- To determine if genetic and environmental factors in major depression change over time.
Procedure:
The study utilized 15,493 complete twin pairs from the Swedish Twin Registry, born between 1886 and 1958, whose zygosity was confirmed. Telephone interviews were conducted between 1998 and 2003 by trained interviewers using modified DSM-IV criteria to assess lifetime major depression. Questions covered both “shared environment” and “individual-specific environment” to understand environmental factors affecting the twins’ likelihood of developing depression.
Findings:
- The heritability of major depression was found to be higher in women than men, with a significant difference in correlations between monozygotic and dizygotic twins. The overall heritability of major depression was estimated at 0.38.
- No evidence was found of changing genetic or environmental factors over time, either across birth cohorts from 1900 to 1958 or when split into pre-and post-World War II groups.
- The study confirmed previous findings on the heritability of major depression and revealed potential sex-specific genetic risk factors.
Conclusion:
This study demonstrates that the heritability of major depression is higher in women than in men and that genetic factors play a significant role in the disorder’s development, aligning with previous research. It also shows that genetic and environmental influences on depression appear stable over time, without significant differences across cohorts.
Kendler link to genetic similarities
Kendler et al. (2007) explored the genetic influence on human behavior, focusing on mental health.
Monozygotic (identical) twins, sharing 100% of their genes, had higher concordance rates for major depression than dizygotic (fraternal) twins, who share 50%.
Findings highlight the significant role of genetic similarity in the likelihood of developing depression.
Genetic influences on depression were found to be stable over time.
Heritability of depression was stronger in women, linking genetics and gender to mental health outcomes.
Evolutionary explanations
Evolutionary Explanations of Behaviour
Core idea: Natural selection shapes human behavior to maximize reproductive success, just as it does biology.
Adaptive behaviours: Traits/behaviours that increase survival or reproduction are passed down through generations.
Examples studied: Mating strategies, parenting styles, kinship bonds, cooperation, conflict resolution, and disgust.
Stress: Evolved to help humans handle life-threatening scenarios.
Gender cognition: Differences in male/female thinking tied to distinct reproductive roles.
Criticism: Arguments are often circular:
Start with current behaviour → infer past adaptations → claim those adaptations caused current behaviour.
Lack of falsifiable evidence undermines scientific rigor.
Evolutionary Explanations of Mate Selection
Females: Seek mates with maturity and resources (better support for offspring).
Males: Prioritize youth and health (indicators of fertility).
Ultimate goal: Choose mates who maximize offspring quality and survival.
Ronay and von hippel
Aim:
Investigate if men take greater risks in the presence of an attractive female compared to a male, and if testosterone plays a role in this behavior.
Explore intrasexual selection: males competing to impress potential mates.
Procedure:
Sample: 96 male skateboarders (avg. age 21.58) from skateboard parks.
Conditions: Male researcher (43) vs. female researcher (53).
Task: Perform an “easy” and a “difficult” trick (10 attempts each).
Test: After a break, repeat tricks in front of the same researcher or an attractive 18-year-old female.
Measures: Performance (success, crash landing, aborted), testosterone levels (saliva samples), heart rate (sports watch).
Findings:
Risk-Taking: More risk-taking in front of the attractive female (fewer aborted attempts).
Testosterone: Higher levels in the female researcher condition.
Heart Rate: No significant difference between conditions.
Conclusion:
Men take more risks when an attractive woman is present, possibly linked to increased testosterone levels.
Behavior suggests intrasexual competition—showing physical prowess to impress potential mates.
Ronay and von hippel link to evolutionary explanations
This study aligns with evolutionary theories of behavior, particularly intrasexual selection, where males compete with one another to gain the attention of females. Increased risk-taking in the presence of an attractive female can be seen as a signal of health, strength, and dominance—traits that are evolutionarily advantageous in attracting a mate. According to evolutionary psychology, behaviors that increase reproductive success tend to persist over time, and this study provides evidence that men’s risk-taking behavior may be part of a mating strategy to signal their fitness to potential partners.
