1. Love and Marriage

2. Pheromones: An Introduction
Topic 5.2: Pheromones and Behaviour
Pheromones: An Introduction
Chapter 5: Love and Marriage

3. Hot Seat: Group Edition
A group review task
Groups of three
Review previous lessons
Get ready to present your summary to the class
5 minutes or less
One group will be randomly chosen to present
Make sure you cover:
Important topics
Terminology
Key studies
Some critical thinking aspects

4. Consolidate: Face Preference Studies
Watch this clip from the Discovery Channel’s “documentary”: The Science of Sex Appeal Link (3 mins).
This link can take you to some composite images made on flickr.

5. The “Sweaty t-shirt study”
Watch this replication of the sweaty t-shirt experiment from BBC’s documentary “Human Instincts” (link) (5 mins)
What do the results of this study suggest?

6. Pheromones: An Introduction
There will be a quiz on this after I finish explaining
Pheromones are a type of hormone
Transmitted from one individual to another
Transmitted through the air, water or ground
E.g. stags (male deer) rub themselves on trees and grass to spread their scent

7. Pheromones: An Introduction continued…
Detected by the sense of smell
The vomeronasal organ (a.k.a Jacobson’s organ) has sensory neurons to detect pheromones
The presence of VNOs in humans is debatable, with evidence on both sides
Even if we have one, whether or not they still function is also debatable
Image credit: Fred the Oytser on Wikicommons (That’s the real name given for attribution credit, I promise!)

8. Pheromones: An Introduction continued…evidence
Studies on pigs (starting in the 1960s)
Boars (male pigs) release androstenone through their saliva
If female pigs are presented androstenone, they get in a “mating stance” (which means they’re ready to “receive” the male)
If you block the vomeronasal organ, this same behaviour is still observed
This suggests maybe our lack of a functioning vomeronasal organ doesn’t matter after all
A boar (male pig)

9. Pheromones Quiz: In your workbooks
A pheromone is a type of …
What is the difference between a regular hormone and a pheromone?
What sense do animals use to detect most pheromones?
What organ detects pheromones?
What is one reason why there is debate over the existence of human pheromones?
How did studies in the 1960s on pigs show that pheromones can affect animal behaviour?
What is one piece of evidence that suggests there could be human pheromones?
Extension:
Does Wedekind’s sweaty t-shirt study provide evidence for pheromones?

10. Pheromones Quiz: Answers
A pheromone is a type of … hormone
What is the difference between a regular hormone and a pheromone? Pheromones transmit signals from one animal to another
What sense do animals use to detect most pheromones? Smell
What organ detects pheromones? Vomeronasal (Jacobson’s)
What is one reason why there is debate over the existence of human pheromones? Our VMO might not work – evidence to suggest it doesn’t or we don’t have one
How did studies in the 1960s on pigs show that pheromones can affect animal behaviour? Present pheromone and pig gets ready to mate
What is one piece of evidence that suggests there could be human pheromones? Block the VMO in a pig and effect is still observed (pheromone causes mating stance)
Extension:
Does Wedekind’s sweaty t-shirt study provide evidence for pheromones?

11. Reminder
Get ahead by reading ahead!

12. Topic 5.2: Pheromones and Behaviour Chapter 5: Love and Marriage
Androstadienone
Chapter 5: Love and Marriage

13. Pictionary
Write a key term on a piece of paper (an important one but not an obvious one)
We’ll split into groups
You have to draw the term
Your team has to guess what you’re drawing

14. SciShow’s “Do pheromones influence behaviour?”
Watch this video about pheromones (10 mins).
Focus questions in the workbook.
You’ll be quizzed on these after the video.

15. SciShow’s “Do pheromones influence behaviour?”
There are no identified human pheromones. True or false?
True
How do pheromones send messages?
Through the air, water, or on the ground.
How do male pigs (boars) secrete androstenone?
Saliva
What are the two types of pheromones?
Releasers and primers
How have humans used animal pheromones?
To control animal populations and to stop the spread of disease
What are two limitations of studies on human pheromones?
Small sample sizes, poor experimental design, poor replication (lack of test-retest reliability)
What is the VNO?
Vomeronasal organ
What important thing do human VNOs not have?
Sensory neurons
Why are pheromones less likely to influence human attraction as much as they influence other animal sexual behaviours?
Because our behaviour is influenced by other factors, like how we think

16. Speed dating You have one piece of information
It is needed to solve today’s guiding question
You are going to be partnered up randomly and you have 20 seconds each to share your key detail
You’ll then find a new partner
After you’ve heard from everyone, you need to figure out the answer.
You have to remember your piece of information – you can’t carry the paper around with you.

17. Speed dating summary
Methods and results of Saxton et al.

18. How does Saxton et al.’s study suggest that pheromones may influence human behaviour?
Use the textbook to help if you need it.
Critical Thinking Extension:
Why might we have evolved for smell to play a key role in attraction?

19. Androstadienone and Attraction
Topic 5.2: Pheromones and Behaviour
Androstadienone and Attraction
Chapter 5: Love and Marriage

20. First team to answer all questions wins!
Race to the Front Quiz
What organ detects pheromones and is inactive in humans?
What is one reason why high testosterone is healthy?
What do we call physical traits that distinguish males from females, but aren’t directly involved in procreation?
What time of the cycle are females most likely to get pregnant?
What were two results from Buss’s study?
Name one pheromone.
What could be the biological factor within females affecting what they find attractive?
Where can androstadienone be found?

21. Race to the Front Quiz - Answers
What organ detects pheromones and is inactive in humans?
Vomeronasal organ
What is one reason why high testosterone is healthy?
Strong immune system
What do we call physical traits that distinguish males from females, but aren’t directly involved in procreation?
Secondary sex characteristics
What time of the cycle are females most likely to get pregnant?
Ovulation
What were two results from Buss’s study?
Males prefer younger, females older / males prefer attraction and chastity / females prefer financial prospects
Name one pheromone.
Androstadienone or androstenone (these are also describe as being “putative” pheromones by some researchers)
What could be the biological factor within females affecting what they find attractive?
Hormone levels
Where can androstadienone be found?
Male sweat

22. Recap: Johnston et al.’s experiment
Studied what types of faces females find attractive
42 female participants took part at different times in their menstrual cycle
They could manipulate the faces to make more masculine or feminine
Results showed females are most attracted to masculine faces during ovulation
Masculine faces = strong jawline and a low brow
Suggest high testosterone
High testosterone is desirable as it suggests healthy genes that can produce a strong immune system in offspring
Conclusion: face structure gives a sign of high testosterone, which means healthy genes and this is attractive when females are looking to procreate
There are many images from the internet that could be found and added to these slides – I can’t add them for copyright reasons.

23. Centre Stage: Dramatic Re-Enactment
You need to assign each group member a “character” (or characters).
You have to work together to construct the story of “Cornwell et al.’s study on androstadienone and attraction.”
We’re doing this to understand how androstadienone affects attraction.
Characters:
Female participant #1
Female participant #2
Feminine face
Masculine face
Pheromones and control substances

24. Analyzing the Evidence

25. How might androstadienone influence behaviour?
Use the textbook to help if you need it.
Critical Thinking Extension:
What are the ethical considerations associated with this study?

26. Exit Ticket: Rate and Reflect
How well could you answer today’s guiding question?
1 (lowest) to 10 (highest)
This is the only time pheromones is covered in the course, so it’s essential you master it now.
What are two things you can do tonight to boost the score you just gave yourself?

27. Next Topic = Culture and Attraction
End of Topic 5.2
Next Topic = Culture and Attraction