Hormones

What are hormones?

• Hormones are chemical messengers that are part of the endocrine system.

• Unlike neurotransmitters, hormones are secreted by glands and released into the bloodstream.

• Because they travel through the bloodstream, hormones act more slowly than neurotransmitters, but their effect last longer.

How do hormones work?

• hormones only affect target cells → cells that have the appropriate receptor sites for a specific hormone.

• When a hormone binds to its receptor, it increases or decreases cellular function.

• Some hormones can also act as neurotransmitters, like oxytocin or adrenaline.

What is the endocrine system and how does it relate to hormone release?

• The endocrine system is responsible for hormone secretion and regulation.

• Major glands in the system include:

  1. Adrenal glands → adrenaline / cortisol are released → for stress response (fight or flight).

  2. Pituitary gland → growth hormone, oxytocin are released → for regulation of other glands and for social bonding.

  3. Testes → testosterone is released → for aggression, competition and sexual behaviour.

  4. Ovaries → oestrogen and progesterone are released → for mood regulation and reproductive health.

What is the hormonal response to stress?

The Hypothalamic-Pituitary-Adrenal Axis (HPA Axis).

• When the body detects a threat, the hypothalamus triggers the pituitary gland, which activates the adrenal glands, releasing:

  1. Adrenaline → increases heart rate, blood pressure, and respiration.

  2. Cortisol → provides energy by increasing blood sugar but can impair memory if levels stay high for to long.

What is adrenaline?

• A fast acting hormone released during fight or flight response.

• Prepares the body for immediate action by increasing heart rate, blood flow, and energy availability.

• Works closely with the autonomic nervous system to trigger physiological changes.

What effects does it have on behaviour and cognition?

• Increases alertness and reaction speed.

• Enhances emotional memory consolidation (helps remember strong emotional experiences)

• Can contribute to anxiety and stress disorders if activated too often.

What is the role of adrenaline in memory?

• adrenaline is released during emotionally significant events, leading to the creation of flashbulb memories (highly detailed, vivd memories of shocking events).

• This happens because those emotions activate the amygdala, which help encode these memories more strognly in the hippocampus.

What is cortisol?

• A slow-acting stress hormone released in response to long-term stress.

• Increases glucose availability for energy.

• Suppresses non-essential functions (digestion, immune system)

• Helps the body maintain homeostasis under stress.

What is the effect of cortisol on behaviour and cognition?

• increases motivation and energy levels in short bursts.

• Chronic stress (high cortisol levels) impairs memory and learning.

• Prolonged cortisol exposure can shrink the hippocampus, affecting memory.

What is the role of cortisol in memory?

• It affects memory retrieval and formation, but its effects depend on stress levels and duration.

  • Short-term stress (low cortisol levels) → enhances memory consolidation.

  • Chronic stress (high cortisol levels) → impairs retrieval and can shrink the hippocampus, damaging memory.

What studies support hormones?

1. McGaugh & Cahill.

2. Newcomer et al.

When did McGaugh and Cahill take place?

1995 and 1996

What is the aim of the study of McGaugh and Cahill?

The role of emotion in the creation of memories.

What were the conditions of this study?

Participants were divided into two conditions. Each groups saw 12 slides which were accompanied by a different story.

1. 1st condition → a rather boring story about a woman and her son who paid a visit to the son’s father in a hospital where they witnessed the staff in a disaster preparation drill of a simulated accident victim.

2. 2nd condition → a boy was involved in a car accident where his feet were severed. He was quickly brought to a hospital where the surgeons reattached the injured limbs. Then he stayed in a hospital for some weeks and then went home with his mother.

What was the procedure of this study?

• The participants were asked how emotional they found the story on a scale of 1-10.

• Two weeks after participating the participants were asked to come back and their memory for specific details was tested.

• The test was a recognition task that consisted of a series of questions about the slides with three options for them to choose from.

• The researchers did a follow-up study the next year.

• The procedure was repeated, but this time the participants were injected either with propranolol or a placebo.

  • Propranolol → a drug used to treat heart disease because the beta-blockers block target cells for the hormone so that the heart will pump more slowly and efficiently.

  • In this study propranolol was used to prevent the activation of the amygdala.

What were the results of the study?

• first experiment →

  • The participants of the second condition demonstrated better recall of specific details of the story.

  • They could also recall more details from the slides.

• Second experiment →

  • The participants who received the beta-blocker did no better than the group that heard the “mundane” story.

What was the conclusion of te study?

Amygdala play an important in the creation of memories linked to emotional arousal.

Tell me about the study of McGaugh & Cahill.

Date: 1995

Aim: study the role of emotion in the creation of memories.

Conditions: participants were divided into two conditions. Each groups saw 12 slides which were accompanied by a different story.

1. 1st condition → a rather boring story about a woman and her son who paid a visit to the son’s father in a hospital where they witnessed the staff in a disaster preparation drill of a simulated accident victim.

2. 2nd condition → a boy was involved in a car accident where his feet were severed. He was quickly brought to a hospital where the surgeons reattached the injured limbs. Then he stayed in a hospital for some weeks and then went home with his mother.

Procedure:

• The participants were asked how emotional they found the story on a scale of 1-10.

• Two weeks after participating the participants were asked to come back and their memory for specific details was tested.

• The test was a recognition task that consisted of a series of questions about the slides with three options for them to choose from.

• The researchers did a follow-up study the next year.

• The procedure was repeated, but this time the participants were injected either with propranolol or a placebo.

  • Propranolol → a drug used to treat heart disease because the beta-blockers block target cells for the hormone so that the heart will pump more slowly and efficiently.

  • In this study propranolol was used to prevent the activation of the amygdala.

Results:

• first experiment →

  • The participants of the second condition demonstrated better recall of specific details of the story.

  • They could also recall more details from the slides.

• Second experiment →

  • The participants who received the beta-blocker did no better than the group that heard the “mundane” story.

Conclusion: amygdala play an important in the creation of memories linked to emotional arousal.

How do you link this study to the theory?

Influence of hormones on memory by showing how adrenaline released during emotionally arousing events, enhances the consolidation of long-term memories, highlighting the crucial role of hormonal responses in memory formation.

Evaluate this study.

1. Cause-and-effect relationship between adrenaline and the activation of the amygdala → they could block adrenaline in an experimental design.

2. The study is artificial and highly controlled → low ecological validity, but high internal validity.

3. It is easily replicated because of the standardized procedure → allows to test reliability of the results.

When was Newcomer et al conducted?

1999

What was the aim of this study?

To investigate whether high levels of the stress hormone cortisol interfere with the verbal declarative memory.

Who were the participants of this study?

• All participants were employees or students of a university.

• They were given a clinical interview with a physician.

• Excluded from the sample if they:

  • Were pregnant.

  • Had a history of mental illness

  • Had suffered from trauma

  • Had suffered from an illness that had been treated with corticosteroids.

What were the conditions of this study?

• Double blind laboratory experiment.

• 3 conditions:

  1. Condition 1 → high level of cortisol.

     • they were given a tablet of cortisol(160mg) on each day of the 4-day experiment.

     • This dose of cortisol produces blood levels similar to those seen in people experiencing a major stress event.

  2. Condition 2 → low level of cortisol.

     • tablet containing smaller dosage of cortisol (40mg) per day.

     • This does of cortisol is similar to the amount of cortisol circulating in the bloodstream of people undergoing minor surgical procedures such as having stitches removed.

  3. Condition 3 → placebo group.

     • they were given placebo tablets → a tablet that looked like the other tablets but with no active ingredient.

     • It was done to have a control group.

What was the procedure of this study?

• All participants were asked to listen and recall a prose paragraph.

• Each day they were given a different piece of prose with the same level of difficulty.

• They were tested 3 times.

• The participants were tested before taking any kind of tablet → served as baseline of the experiment.

• The participants were tested again 1 day after taking the pill and then again 4 days later.

• There was a test again 6 days later to make sure that there were no long-term effects of the treatment on the participants.

What were the results of this study?

• High cortisol levels impaired performance in the memory task since the participants who received the highest level of cortisol also showed the worst performance in verbal declarative memory.

• The effect is not permanent.

• No statistical difference between the low-dose and the placebo group on any day of testing.

What was the conclusion of this srudy?

There is a link between levels of cortisol and remembering → high levels of cortisol interfered with the recall of the prose passage.

Tell me about the study of Newcomer et al.

Aim: to investigate whether high levels of the stress hormone cortisol interfere with the verbal declarative memory.

Participants:

• All participants were employees or students of a university.

• They were given a clinical interview with a physician.

• Excluded from the sample if they:

  • Were pregnant.

  • Had a history of mental illness

  • Had suffered from trauma

  • Had suffered from an illness that had been treated with corticosteroids.

Conditions:

• Double blind laboratory experiment.

• 3 conditions:

  1. Condition 1 → high level of cortisol.

     • they were given a tablet of cortisol(160mg) on each day of the 4-day experiment.

     • This dose of cortisol produces blood levels similar to those seen in people experiencing a major stress event.

  2. Condition 2 → low level of cortisol.

     • tablet containing smaller dosage of cortisol (40mg) per day.

     • This does of cortisol is similar to the amount of cortisol circulating in the bloodstream of people undergoing minor surgical procedures such as having stitches removed.

  3. Condition 3 → placebo group.

     • they were given placebo tablets → a tablet that looked like the other tablets but with no active ingredient.

     • It was done to have a control group.

Procedure:

• All participants were asked to listen and recall a prose paragraph.

• Each day they were given a different piece of prose with the same level of difficulty.

• They were tested 3 times.

• The participants were tested before taking any kind of tablet → served as baseline of the experiment.

• The participants were tested again 1 day after taking the pill and then again 4 days later.

• There was a test again 6 days later to make sure that there were no long-term effects of the treatment on the participants.

Results:

• High cortisol levels impaired performance in the memory task since the participants who received the highest level of cortisol also showed the worst performance in verbal declarative memory.

• The effect is not permanent.

• No statistical difference between the low-dose and the placebo group on any day of testing.

Conclusion: There is a link between levels of cortisol and remembering → high levels of cortisol interfered with the recall of the prose passage.

How do you link this study to the theory?

High levels of the hormone cortisol affect declarative memory.

Evaluate this study.

1. Cause-and-effect relationship → study was experimental.

2. Baseline test → eliminate possible confounding variables.

3. Since the experiment wasn’t all the time in the laboratory, the researchers couldn’t control all the confounding variables, like stressors in the lives of the participants.

4. Difficult to generalise → memorizing a piece of prose perhaps isn’t the most authentic memory experience.