Biological Approach

Techniques to study the brain // Maquire + Antonova Neuroplasticity // Diamond + Maquire Neurotransmitters // Antonova + Roger Localization // Maquire + Antonova Hormones // Cahill + Baumgartner Pheromones // Wedekin + Zhou Genes and Behaviour // Capsi et Al + Balley Pilliard

MRI

A technique that uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of soft tissue; allows us to see structures within the brain

MRI advantages

procedure is non-invasive
minimal potential harm to the participant.
gives researchers a good sense of the actual structure of the brain.

MRI disadvantages

Only indicates structure; it does not actually map what is happening in the brain.

fMRI

shows actual brain activity and indicates which areas of the brain are active when engaged in a behavior or cognitive process.

When a specific brain area is active, it uses more oxygen, and therefore the blood flow increases. This can be detected by the fMRI scanner.

fMRI advantages

fMRIs are non-invasive
quality of the image is also much better and rather than a static image it produces a film that demonstrates a change in the brain over the period of the scan.

fMRI disadvantages

fMRI scanner is not a natural environment for cognition. Therefore, research may lack ecological validity. There is a lot of noise in the tunnel and participants may experience anxiety due to the claustrophobic nature of the machine.

Highly correlational. Much of the activity of the brain is spontaneous and is not a reaction to stimuli.

Neuroplasticity

Plasticity refers to the brain's ability to alter its own neural structure following changes within the body or in the external environment. It's ability to rearrange the connections between its neurons.

The more an action is repeated, the more dendritic branching will occur over a set period of time.

Dendritic Branching

The neurons connect to create a new trace in the brain due to new stimuli, like knowledge.

Synapse Pruning

refers to the process by which extra neurons and synaptic connections are eliminated in order to increase the efficiency of neuronal transmissions. This happens when a pathway is not used for long periods of time.

Rosenzweig, Bennett, and Diamond (AIM)

How enviroment would affect the plasticity of the brain and measure the effect of either enrichment or deprivation on the development of neurons.

Rosenzweig, Bennett, and Diamond (PROCEDURE)

In the enriched environment, rats were placed in cages with other rats. There were stimulus objects for the rats to play with.

In the deprived environment, the rat was alone with no stimulation.

The rats spent several months in their respective environments and then they were killed in order to measure the effect of the environment on their brain structures.

Rosenzweig, Bennett, and Diamond (RESULTS)

Those that had been in the stimulating environment had increased thickness in the cortex. The frontal lobe, associated with thinking, planning, and decision-making, was also heavier.

Two theories;
"arousal response" by the excitement at the new enviroment. This leads to increased motor behavior which may lead to neurogenesis - the creation of new nerve cells.
The "learning and memory hypothesis" argues that dendritic branching are the result of learning from interacting with the environment.

Rosenzweig, Bennett, and Diamond (EVALUATION)

It was not clear whether the effect was due to the environment (the toys) or the social activity.

Highly controlled laboratory experiment so it was possible to establish a cause-and-effect relationship.

The experiment used animals, so it may be difficult to generalize to humans unless research with humans
provides the same results.

Ethical considerations in terms of rats, as they were subjected to stress and then killed.

Maquire (AIM)

To observe how repeated actions in taxi drivers could result in changes to their neural pathways (dendritic branching)

Maquire (PROCEDURE)

All participants were taxi drivers who have had their license for atleast 1.5 years and had plenty of knowledge on London. The taxi drivers were compared with the MRI scans of 50 right-handed males who did not drive taxis. The study is correlational as the IV is not manipulated by the researcher.

They used two pixel counting techiniques to measure the amount of grey matter in the brain.

Maquire (RESULTS)

There were two key findings of the study. The posterior hippocampi of taxi drivers were significantly larger relative and the anterior hippocampi were significantly
smaller.
The posterior hippocampus is involved when
previously learned spatial information is used, whereas the anterior hippocampal region is more involved
during the encoding of new environmental layouts.

Maquire (EVALUATION)

The study was a quasi-experiment, so no cause-and-effect relationship can be established. There was no manipulation of the IV, with low internal validity.

The reading of the brain scans was done blind, preventing researcher bias. You cannot argue that the MRI has low ecological validity because the participants were not asked to do anything while in the scanner was happening.

Explain neurotransmission

The process in which neurons pass messages and communicate with each other is done with the use of neurotransmitters. The pre-synaptic neuron releases neurotransmitters to cross the gap between the neurons; called the synapse. The neurotransmitters reach the receptor site of the post-synaptic neuron, which creates an action potential.

Neurotransmitters

chemical messengers that cross the synaptic gaps between neurons. they pass messages from one neuron to another and bind to receptors in the synapse.

Antagonists

Inhibitory neurotransmitters --> Decrease the likelihood of a neuron firing by hyperpolarizing the neuron. They 'take over' the receptors and don't allow the neurotransmitters to work.

Agonists

Exitatory neurotransmitters --> Increases the likelihood of a neuron firing by hypopolarizing the neuron.

Acetylcholine

A neurotransmitter that enables learning and memory, specifically the encoding of spatial memories.

Scopilamine

Antagonist. an acetylcholine inhibitor which prevents the neurotransmitter from firing an action potential (message)

Antonova et Al (AIM)

To investigate whether acetylcholine played a role in the encoding of spatial memories.

address the question of how
neurotransmitters play a role in behavior.

Antonova et Al (PROCEDURE)

The participants were either injected with scopolamine or a placebo saline solution. The participants were then put into an fMRI where they were scanned while playing the "Arena task."

This is a VR game in which the participants had to find a pole in the arena in the shortest amount of time using their memory of what the arena was like. The study was also a repeated measure's experiment.

Antonova et Al (RESULTS)

The researchers found that when participants were injected with scopolamine, they demonstrated a significant
reduction in the activation of the hippocampus compared to when they received a placebo. Acetylcholine could play a key role in the encoding of spatial memories in humans, as well as in rats. There was no significant difference between their results in the maze, however.

Antonova et Al (EVALUATION)

The study was a repeated measures design - eliminating the effect of participant variability. In addition, the
study was counter-balanced. Some of the participants did the scopolamine condition first, and others
did the placebo condition first. This controlled for practice effect.

The sample size was small and many participants reported that they had felt stressed out, affecting the internal validity of the experiment.

Roger and Kesner (AIM)

Study of the role of acetylcholine on memory and encoding spatial memories.
In the hippocampus there is a high concentration of acetylcholine receptors, making scientists question their role in the formation of spatial memory.

Roger and Kesner (PROCEDURE)

They had a group of rats acclimate to a maze. They then injected the rats directly in the hippocampus with a saline solution or with scopolamine. This was to make sure the act of getting an injection would not affect memory.

Encoding was assessed by the AVG number of mistakes made on the first 5 trials of Day 1. Retrieval was seen in the mistakes made in Day 2.

Roger and Kesner (RESULTS)

The scopolamine group took longer and made more mistakes in the learning of the maze (day 1), meaning that the scopolamine had affected the encoding of memories. It did not affect the retrieval of memories, however.

Roger and Kesner (EVALUATION)

Highly controlled with a placebo condition to avoid extrenaeous variables. It can create a cause-and-effect relationship.

It has a reductionist approach to memory.

Although animals can be used as models for humans, the question lies in how much one is able to generalize their findings to them.

Localization of Function

The theory that specific parts of the brain carry out various functions, being responsible for cognitive functions and behaviours.

For example, the hippocampus is assosiated with the transfer of short-term memory to long-term memory and the encoding of spatial memory.

Hormones

Chemical messengers that are produced by glands and released into the blood stream. They activate target cells at a distance and produce an effect, causing a slow change in behaviour.

Adrenaline

A hormone released into the bloodstream in response to physical or mental stress. It activates a response called 'flight or fight'. When there is a threat, the pituitary gland secretes a chemical which activates the adrenal gland.

Amygdala

Part of the brain related to emotional memory, in particular memories related to fear and agression.

Propanolol

A beta-blocker which prevents the release of adrenaline, preventing the activation of the amygdala.

Cahil and Mcaugh (AIM)

To investigate the role of adrenaline and the amygdala on emotional memory.

Cahil and Mcaugh (PROCEDURE)

Two conditions in which each participant saw a story through a set of slides. In the first condition, the participants read a boring story about a boy visiting a hospital. In the second condition, however, the story was incredibly traumatic and about a young boy had his feet severed.

Two weeks after this, the participants were brought back in and their memory on the story was tested with a set of questions.

In a follow up study, participants in the 'non boring' story were injected with propanolol.

Cahil and Mcaugh (RESULTS)

The participants who heard the traumatic story were more likely to remember it than those who heard the boring story, answering the questions to a higher degree of detail.

In the follow-up study, they found that those that had received the beta-blocker performed the same as the people in the 'boring' story group.

This suggests that adrenaline might have an effect in emotional memory formation and the activation of the amygdala.

Cahil and Mcaugh (EVALUATION)

The fact that the researchers could block adrenaline in an experimental design gives rise to a cause-and-effect
relationship between adrenaline and activation of the amygdala to create emotional significance of the story.

The study is artificial and highly controlled. Therefore, there is a concern about ecological validity.

The study can be easily replicated because of its standardized procedure, allowing other researchers to test the
reliability of the results.

Oxytocin

Produced by the hypothalamus and secreted by the pituitary gland. Plays a role in mother-child attachment; believed to play a role in social bonding and trust between people.

Baumgartner et al (AIM)

Investigate the role the hormone oxytocin in trust and social bonding.

Baumgartner et al (PROCEDURE)

Participants were either given a placebo or oxytocyn through a nasal spray. They were told to act as investors in a trust game while being inside an fMRI. In the game, player 1 (the participant) would recieve a certain amount of money. If they share it with a second player, the money is tripled. The second player would then choose whether they also shared the money, or if they would keep it all.

The participants were told that their trust had been broken on the first trial of the game, and were given the chose to trust again or take the money.

Baumgartner et al (RESULTS)

Placebo participants were less likely to trust again after being cheated, while participants who were given oxytocyn where much more likely to keep trusting and doing investments.

Participants in the oxytocin group showed decreases in responses in the amygdala. Oxytocin may have a role in decreasing fear reactions (via the amygdala) due to betrayal.

Baumgartner et al (EVALUATION)

Highly controlled. The use of the placebo allows for a control over extreneous variables and infer a cause and effect relationship.
fMRI is an artificial enviroment, causing low ecological validity.

Using a nasal spray to increase oxytocin does not reflect natural relationships.

Pheromones

chemical messengers that are emitted into the environment from the body where they can then activate specific behavioural responses in other individuals of the same species. unlike hormones, who target our own organs, pheromones target outside individuals and help with signalling amongst members of the same species.

It is highly debated whether humans have pheromones or not.

MHC

MHC is a group of genes that play an important role in the immune system.
MHC genes are expressed co-dominantly - that is, we inherit the MHC from both of our parents and they are expressed equally.
It would be beneficial, therefore, to have evolved systems of recognizing individuals with different MHC genes.

Wedekin (AIM)

The aim of the study was to determine whether one's MHC would affect mate choice and also see if there is a human pheromone present in sweat.

Wedekin (PROCEDURE)

Each participant was "typed" for their MHC.

It was noted if the women were taking oral contraceptives. The men were asked to wear a T-shirt for two nights. They were told to not do anything that might affect their natural smell, like wear deodorant or perfume.

Then, the women were asked to rank the smell of 7 t-shirts. The women were tested in the second week after the beginning of menstruation, as women are odor-sensitive at this time. They had also used a nasal spray beforehand.

Three of the seven boxes contained T-shirts from men with MHC similar to the woman's own; three contained T-shirts from MHC dissimilar men; and one contained an unworn T-shirt as a control. Every woman scored the odors of the T-shirts for intensity and for pleasantness.

Wedekin (RESULTS)

Women scored male body odors as more pleasant when they differed from their own MHC than when they were similar. This difference in odor assessment was reversed when the women rating the odors were taking oralcontraceptives. This suggests that the MHC may influence human mate choice and that human sweat contains some sort of pheromone.

Wedekin (EVALUATION)

The study has been succesfully replicated, giving it ecological validity.
It was a double-blind expertiment, preventing both participant and researcher bias.

Despite all the evidence, some argue that the theory is too reductionist - that is, it over-simplifies the behavior of
human mate selection by bringing it down to the MHC - ignoring cognitive and sociocultural factors.

Androstadienone (AND) and Estratetraenol (EST)

Two potential human pheromones are Androstadienone (AND) - found in male semen and sweat - and Estratetraenol (EST), which is found in female urine.

Zhou (AIM)

See if Androstadienone (AND) or Estratetraenol (EST) influences human mating behavior.

Zhou (PROCEDURE)

The participants were asked to smell cloves, there were 3 different conditions for the cloves
- Condition 1: cloves mixed with androstadienone
- Condition 2: cloves mixed with estratetraenol
- Condition 3: regular cloves (control group)
Participants were then asked to watch an animation of a stick figure walking and identify its gender

Zhou (RESULTS)

Smelling androstadienone biased heterosexual females and gay males, but not heterosexual males or lesbian women, toward perceiving the walkers as more masculine.

Smelling estratetraenol systematically biases heterosexual males and, to some extent, lesbian women toward perceiving the walkers as more feminine.

The researchers concluded that pheromones influence the communication of gender information in a sex-specific manner.

Zhou (EVALUATION)

The participants were exposed to very high levels of pheromones; it is unclear if this response would happen in a naturalistic setting.
Although they identified the figure as masculine or feminine, this is not a clear study of sexual attraction.
Reductionist view on sexual attraction

Gene

A segment of DNA on a chromosome that codes for a specific trait.

Genetic Predisposition

An inherited genetic pattern that makes one susceptible to a certain disease or condition

Genetic Similarities

A quantitive measure of the relative contribution of genetic factors into a trait/behaviour. Methods include twin studies, family studies, and adoption studies.

Diathesis-stress theories of depression

an individuals reaction to stressful events is dependent on their genetic makeup. If an individual has a specific genetic predisposition towards a disorder (genotype), then interaction with stressors can cause these genes to be expressed.

Capsi et al (AIM)

To determine whether there is evidence for a gene-environment interaction. For a mutation of the serotonin transporter gene -5HTT

Capsi et al (PROCEDURE)

The participants were divided into three groups based on -5HTT alleles
1 --> Two short alleles
2 --> One long , one short
3 --> Two long alleles

The mutilation of the 5-HTT has shorter alleles

The participants were then assessed in a "Stressful life event" and assessed for depression.

Capsi et al (RESULTS)

People with short versions of the allele demonstrated more symptoms of depression and suicidal ideation in response to stressful life events. Simply inheriting the gene was not enough to cause depression but the gene interacting with the stressors increased the likelihood of developing depression.

Capsi et al (EVALUATION)

The study is correlational, so no cause-and-effect relationship can be determined.

Information about life events was self-reported.
It may be the salience of the negative life events which
plays a role in depression - that is, those that recalled them more easily may tend towards depression.

The theory acknowledges the interaction between both biological and environmental factors in depression.
This is a more holistic approach, not reductionist.

Twin studies

A research design in which hereditary influence is assessed by comparing the resemblance of identical twins and fraternal twins with respect to a trait.

Balley Pilliard (AIM)

Role of genetics in the study of sexuality using a twin study.

Balley Pilliard (PROCEDURE)

The researchers recruited monozygotic and dizygotic twins as well as adopted brothers. All twins were raised together.

The sexual orientation of relatives was assessed by asking them directly or asking the gay participant who volunteered.
In addition, the researchers used questionnaires to assess the participants' level of Childhood Gender Non Conformity

Balley Pilliard (RESULTS)

52% of MZ twins were both self-identified gay, 22% of DZ twins were so and 11% of non-related adopted brothers were so.

The closer genetically a pair is, the more likely they both are to exhibit gay tendencies.

Balley Pilliard (EVALUATION)

The study relies on self-reported data.
The construct of homosexuality is difficult to standardize. It is difficult to know what exactly it means to be
"homosexual" and whether it would be interpreted equally by all who answer the questionnaires.
The sample sizes of such studies tend to be very small

Evolutionary Psychology

the study of the evolution of behavior and the mind, using principles of natural selection. It is a theory which argues that behaviour which work best with survival are more readily past down that those that don't.

According to evolutionary theory, increased risk-taking is a sign to potential mates that the male is healthy, strong, and dominant - that is, would be able to intimidate any potential rival.

Ronay and Von Hipple (AIM)

Investigate the potential role of evolutionary factors in male skateboarding behavior. determine if men would take greater risks in the presence of an attractive female, than in the presence of a male.

Ronay and Von Hipple (PROCEDURE)

Skateboarders were asked to do one "easy trick" and one difficult trick. They were told to practice both tricks. After a break, they were asked to make more attempts of each trick but this time in front of the same male researcher or an attractive 18-year-old female researcher.

The skateboarders' attempts were coded for one of three outcomes: success, crash landing, or aborted attempt.
High levels of aborted attempts would be seen as an indicator of low-risk taking.

Ronay and Von Hipple (RESULTS)

Participants took greater risks on the difficult tricks in the presence of the female researcher. The study showed that young men take great physical risks when in the presence of an attractive woman and that testosterone may account for this behavior.

According to evolutionary theory, this makes sense. The increased risk-taking is a sign to potential mates that the male is healthy, strong, and dominant - that is, would be able to

Ronay and Von Hipple (EVALUATION)

The experiment is well-controlled. The attractiveness of the female researcher, the time of day, and the heart
rate were all controlled for in this experiment.

The experiment was also conducted under highly naturalistic conditions, leading to high ecological validity.

The design was a repeated measures design. Order effects - such as fatigue - could have influenced the
findings.

Animal Models

The use of non-human models to study a psychological process similar to human condition. They can be used to gain insight into human psysiology and behaviour.

Why are animals used?

There are some experiments which cannot ethically be done in humans, like isolation and surgery.
Lifespan of animals is shorter so the effects of a variable can be studied over several generations.

Arguments for the use of animal models (5)

1. Animal testing contributes to many life-saving treatments.
2. In order to test a drug for side effects, we need a "whole body system.". Cells are not enough in most cases.
3. Many animals and humans share much of their DNA.
4. Shorter life expectancy
5. Experiments that cannot ethically be done in humans

Arguments against animal testing in humans (4)

1. Although we share DNA, there are a lot of anatomical, metabolical and cellular differences which make results less reliable.
2. A large number of drugs that are effective in animals are not in humans.
3. Behavioural effects in animals are not the same that in humans.
4. Many key symptoms for disorders cannot be modelled in animals. . For example, in depression - we cannot model depressed mood, feelings of worthlessness, and recurring thoughts of death or suicide. However, we can model learned helplessness, chronic mild stress, and social withdrawal.

Criticisms of ANIMAL MODELS

external validity - What is observed in animals does not predict what will happen in humans.
Low ecological validity - Highly controlled environment and the way that variables are operationalized.
It cannot be generalized to humans!!
Quality of the data. - Animals cannot readily communicate their responses

Animal experimentation is Invasive?

Animal experimentation is often invasive - it involves injecting drugs, removing part of the brain, or causing other permanent harm to the animal . An example of this is Rosenzweig, Bennet & Diamond, where they had to kill the rats.

Brady (AIM)

Study the effects of stress in business men

Brady (PROCEDURE)

monkeys were allocated to one of two conditions:
"executive monkey" and "yoked monkey."

Both monkeys received an electric shock every 20 seconds for six hours at a time over a three-week period.

The executive monkey could pull a lever to stop the shock, but the yoked monkey could not.

Brady (RESULTS)

The executive monkeys developed ulcers and eventually died.
The yoked monkeys showed no negative health effects.

Brady concluded that high levels of stomach acid as the result of stress led to ulcers and the eventual death of the animal. seemed to explain why some high-stress positions have problems with ulcers.

Brady (EVALUATION)

the monkeys were not randomly allocated to conditions.
The monkey that learned to pull the level faster was then given the position of the "executive."
the study is highly unethical.
The study lacks external validity

Animal Research Directive

Replace the use of animals with alternative techniques, or avoid the use of animals altogether.
Reduce the number of animals used to a minimum.
Refine the way experiments are carried out, to make sure animals suffer as little as possible.

What should researchers consider in terms of animal models?

The number of human beings who would benefit from the study
the effect on humans if the study is not conducted
The number of animals suffering in the experiment
The harm done to animals