Unit 2: Biological Level of Analysis Session 9 ‘All that is psychological is first physiological’
Feb 22, 2016
Unit 2:Biological Level of
AnalysisSession 9
‘All that is psychological is first physiological’
A Quick Recap
What are hormones?
Hormones are chemicals that affect behaviour.
They are produced by the glands that make up the endocrine system
Hormones are a contributing factor to behavior.
Hormones and Neurotransmitters
Neurotransmitter: A chemical in the synapse that transmits signals between neurons
Hormone: A chemical secreted by an endocrine gland. Travels through the bloodstream. Usually involved in longterm functioning of the body.
Similarities & Differences between neurotransmitters and hormones
Similarities DifferencesChemicals are stored and released Neurons communicate with adjacent
neurons; hormones messages are sent long distances
Release of chemicals is due to stimulation
Neural messages induce rapid response compared to hormones which have slower messages which tend to be long term
Many different hormones & neurotransmitters
Neural messages can be directed as observed in behaviour; hormonal messages are primarily involuntary (cannot be directed)
Outline the similarities and differences between neurotransmitters and hormones
Last session’s Journal Entry
Today’s learning outcome
Explain, using examples, functions of two hormones in human behaviour
Explain, using examples, functions of two hormones in human behaviour
1.Oxytocin2.Melatonin3.Cortisol
Examples of hormones
Produced by the hypothalamus & released into bloodstream by pituitary gland
Plays role in inducing labour & lactation Released with touches & hugs Associated with bonding between mother &
child
Oxytocin
Also associated with bonding between lovers
Has been called the “love hormone” as it seems to be such an effective mediator of human social behaviour
Oxytocin
Watch the video on Oxytocin the “love hormone”
Take notes
Oxytocin
Oxytocin has been linked to trusting other people
Experimental manipulation of oxytocin levels has shown increase in trust
According to evolutionary psychologists, trust is an important social tool in the relationship between humans
Research is being carried out to see whether people suffering from social anxiety may benefit from doses of oxytocin
Oxytocin & Trust
Trust is an adaptive mechanism as is helps humans to form meaningful relationships at a personal and professional level
Betrayal disrupts bonds of trust and may result in avoidance of person who has betrayed you
Learning who to trust and who to avoid is important for survival and well-being
Humans should be able to move on after betrayal if mental well-being are to be preserved
Oxytocin could play a role in reducing fear reactions via the amygdala that may arise as a consequence of betrayal
Oxytocin & Trust: an evolutionary perspective
Aim To investigate role of oxytocin after breaches of trust
in a trust gameProcedure: Participants played a trust game used by economists
and psychologists to study social interaction The “investor” (player 1) receives a sum of money
and must decide whether to keep it or share it with a “trustee” (player 2)
If sum is shared sum is tripled Then player 2 (trustee) must decide if this sum
should be shared (trust) or kept (violation of trust)
Oxytocin & Trust: Baumgartner et al. (2008)
Procedure fMRI scans were carried out of 49 participants They recieved either oxytocin or placebo via a
nasal spray Participants played against different trustees
in the trust game and against a computer in a risk game
In 50% of games trust was broken They received feedback on this from
experimenters during the games
Oxytocin & Trust: Baumgartner et al. (2008)
Results
Oxytocin & Trust: Baumgartner et al. (2008)
Placebo Group Oxytocin GroupLess likely to show trust after feedback on betrayal. They invested less.
Continued to invest at similar rates even after recieving feedback on a breach of trust
fMRI scans showed decreases in responses in amygdala and caudate nucleus in Oxytocin group.Amygdala involved in emotional processing & has many oxytocin receptorsCaudate nucleus associated with learning & memory and plays a role in learning to trust
Oxytocin could explain why people are able to restore trust and forgive in long term relationships
Scanner research merely maping brain activity but nothing definite can be said about what it really means with current technology
Giving oxytocin like this in an experiment may not reflect natural physiological processes. Function of oxytocin very complex and it’s too simplistic to say it’s the “trust hormone”
Evaluation: Baumgartner et al. (2008)
Journal Entry
Summarise Baumgartner et al (2008)
You must include:1. Procedure2. Findings 3. Evaluation of study
Production of melatonin by pineal gland is stimulated by darkness and inhibited by light
Melatonin levels in bloodstream peak in middle of night and gradually decrease towards morning
Melatonin
In temperate climates when the days get shorter and winter approaches, the earlier onset of darkness means we become tired earlier
Until recent history, humans in temperate climates had up to 18 hours of darkness in winter months
The use of artificial lighting has increased awake time dramatically
Melatonin
Melatonin release correlates with the circadian rhythm (the biological clock that is based on a 24 hour day/night cycle)
It is suggested that taking melatonin in the early evening may improve one’s ability to fall asleep
Through study of melatonin researchers hope to find a solution for those who suffer from insomnia and jet lag
Melatonin
Melatonin & Circadian Rhythm
Rosenthal (1987)
Evidence to suggest that higher levels of melatonin contribute to seasonal affective disorder (SAD)
SAD= a subcategory of depression that is characterised by sleepiness, cravings for carbohyodrates & lethargy
Reduced levels of sunlight in autumn and winter believed to disrupt circadian rhythm is certain people leading to this depression
Perhaps why we see higher levels of SAD in Scandinavia
Melatonin & SAD
As increased sunlight improves the symptoms, phototherapy (prolonged exposure to bright light) often main treatment for people with SAD
Despite some claims success, there is lack of definitive evidence of its effectiveness One has to be careful about seeking quick solutions to complex questions
Melatonin & SAD
Watch the video on SAD
Melatonin & SAD
Journal Entry
What is melatonin?
What is its link with SAD?
How might SAD be treated?
More on hormones and behaviour
Cortisol
Next session...