1. Exam Focus
Biological Rhythms

2. Connect
What questions do you think might come up on what we have studied so far?

3. Objectives Today you will So that you can
Consider types of exam questions
Consider material you could use to answer these questions
Consider requirements of these questions
So that you can
Plan and produce answers to cover the possible exam questions at least to your target grade standard

4. June 12 Outline one or more examples of ultradian rhythms. (4 marks)
(This should be about a 100 word answer – no AO2 needed)

5. January 11
Discuss the role of endogenous pacemakers in the control of one or more biological rhythms. (9 marks marks)
(This is just like the newer 24 mark essays. It should be around 200 words of AO1 – and 8 MRI points including at least 1 IDA)

6. What else could you get?
Outline one or more examples of infradian/circadian rhythms (4 marks)
Describe and evaluate research on circadian rhythms (8+16 marks)
Describe and evaluate research on infradian and ultradian rhythms (8+16 marks)
This question could be split into two lots of (4+8 marks)

7. The importance of IDA
If you look at the mark scheme for this unit, you will see that without using IDA at least once in your essays (12 or 24 markers) you cannot reach the top band for AO2.
This means that you would be losing at least 4 marks (This could be a whole grade!)
But what could you include?

8. A2 Psychology: IDA Superheroes ISSUES
The Animal Ace
Master Ethnocentric
Passionate that theories are prone to culture bias, The Master of Ethnocentrism would die to prove that theories which are Ethnocentric cannot be applied to all cultures.
Questioning the usefulness of animal research. Can animal behaviour be applied to humans?
Kitty says no!
Gender Bias Beauty
The Ethics Kid
Ironically, the Gender Bias Beauty wants equal application of theories to both Genders. Her pet hate is when theories or studies can only be generalised to one gender or only explain behaviour in just men or just women.
Can a theory or study be criticised on the grounds of ethics? Is it unethical? The Ethics Kid is here to find out!

9. A2 Psychology: IDA Superheroes DEBATES
Nature-Man
Doctor Determinism
Doctor Determinism knows that all behaviour is determined by forces beyond human control.
Fighting for all things natural. I believe that all behaviour is pre-determined by biological factors: hormones, genes & evolution.
Super-Nurture-al.
Determined to prove that behaviour is learned and influenced by social forces. I hunt down Nature-Man for the ultimate of battles: The Nature-Nurture Face Off.
Free Will-i-am
Fighting against the evil threat of Determinism, Free Will-i-am believes that we have the power to control our own behaviour. It’s all about the choice
Flying through the skies on a mission to show that psychologists reduce complex behaviour down to over-simplified factors. He believes that behaviour should be looked at holistically.
The Reductionist-er!

10. A2 Psychology: IDA Superheroes APPROACHES
Pavlov’s Power Puppy
The Freud-ster
In the name of Behaviourism, Pavlov’s Power Puppy is here to show that all behaviour can be learned. Just ring that bell and I’ll be there ready to help!
In the name of the Psychodynamic approach…
Motivated by his unconscious sexual desire, The Freud-ster wants to prove that our behaviour really is only the tip of the iceberg!
Tommy Testosterone
Darwin’s Double
In the name of Biology, Tommy Testosterone fights to prove that behaviour is underpinned by biological factors: brain structure, neurochemicals and genetics.
In the name of Evolution, this Double Act are here to show that humans really did evolve from Apes! It’s all about the genes!
The Memory Marvel
In the name of Cognitive Psychology, the Memory Marvel just goes to show that behaviour can be underpinned by cognitive processes. It’s all in the thinking!

11. What do you need to be able to do?
Write a description of circadian rhythms in about 100 words (4 marks) and 200 words (8 marks)
Identify 8 criticisms of this including one IDA topic (MRI – around 50 words each)
Write a description of ultradian and infradian rhythms in about 100 words each
Identify 4 criticisms of each of these including IDA (MRI)

12. Circadian Rhythms AO1 AO2 IDA
Sleep-wake Cycle
Circadian = 24 hours
Cycle persists despite isolation from light
Particpants not isolated from light in early research
Demonstrated by Siffre and Aschoff & Wever
External cues important too (Folkard at al)
Cycle length varies in individuals
Biological approach – suggests bodily rhythms can be explained by biological factors
Deterministic – ignores the element of choice/free will humans have over their behaviour
Core body temperature
Lowest at 04.30; highest at 18.00
Post-lunch dip, even without food
Linked to cognitive abilities (Folkard et al)
Evidence that change is caused by temp (Giesbrecht at al)
Other research suggests link is spurious
Hormones
Cortisol lowest at midnight
Melatonin and growth hormone highest at midnight.

13. Ultradian and Infradian Rhythms
AO1
AO2
IDA
Ultradian
Less than one day
Sleep stages = 1st 4 – NREM, 5th – REM
BRAC = 90 mins within 24 hour rhythm
REM does not equal dreaming
BRAC important because it ensures biological processes work in unison
Determinist (e.g. PM) but can change through willpower (Born et al)
Real-world application - phototherapy
Infradian
Female menstrual cycle regulates ovulation
Male shave 20 day cycle of body temp and alertness
SAD caused by melatonin during winter months
Menstrual cycle also subject to exogenous cues
Some women suffer PMS
SAD could also be consequence of disrupted circadian rhythms

14. Preparation – working together
In our next lesson, you will be writing two essays.
Describe and Evaluate research on circadian rhythms (8+16)
Describe and evaluate research on ultradian and infradian rhythms. (8+16)

15. ESSAY writing

16. Questions for today (25 mins each!)
Describe and Evaluate research on circadian rhythms (8+16)
Describe and evaluate research on ultradian and infradian rhythms. (8+16)

17. Endogenous Pacemakers / Exogenous Zeitgebers

18. Connect What might influence our natural rhythms?
Make a list of as many things you can think of and try to categorise them into internal (endogenous) and external (exogenous)

19. Objectives Today you will So that you can
Learn about endogenous pacemakers
Learn about exogenous zeitgebers
Consider the implications of research done in this area
So that you can
Describe the role of endogenous pacemakers in biological rhythms
Describe the role of exogenous zeitgebers in biological rhythms
Evaluate the role of Eps/Ez’s in biological rhythms

20. Where is the body clock?
Light travels from retina (back of the eye) along the optic nerve, and is picked up by the SCN

21. The ticking of the biological clock
The basis of circadian rhythm lies in interactions between certain proteins creating the ‘tick’ of the biological clock
It is an ingenious negative feedback loop
Darlington et al (1998) first discovered it in fruit flies but actual proteins vary from species to species
The protein mechanism is present in SCN (central oscillator) and other cells throughout the body (peripheral oscillators)
This explains why different functions have different rhythms

22. Body clock negative feedback loop
In the morning two proteins bind
As CLK and BMAL1 decrease, production of PER and CRY decreases also
CLK + BMAL1
CRY
PER
PER + CRY
First two decrease
This makes second two decrease also
This stimulates production two new proteins
24 hour period
CLOCK and BMAL1 begin to decrease
These new proteins deactivate the first two

23. Eps: The suprachiasmatic nucleus (SCN)
Tiny cluster of cells, in the
hypothalamus, just above optic chiasm
Obtains info about light via optic nerve
If the sun rises earlier than day before, light resets the clock
There is one in each hemisphere, divided into two parts, dorsal and ventral.
Ventral is reset much more quickly, dorsal more resistant to being reset as it is less affected by light (Albus et al, 2005)

24. Eps: Pineal gland and melatonin
SCN sends signals to pineal gland telling it to increase melatonin at night
Melatonin induces sleep by inhibiting brain mechanisms responsible for alertness
In birds and reptiles this is just below the thin skull bone and so directly affected by light – light inhibts melatonin production.
Some lizards have a third ‘eye’ which sticks out of a small opening in the skull and receives info about light

25. Pineal eye of a Green Anole Lizard

26. Activity
Read over and complete the exercises on endogenous pacemakers in your booklet

27. Ezs: Resetting the biological clock
This process of resetting the biological clock is known as ENTRAINMENT.
The opposite of this is FREE-RUNNING
This is where the biological
clock runs without any
exogenous cues.

28. Ezs: Light Dominant zeitgeber in humans
Light can reset the main pacemaker (SCN)
It can also reset other oscillators because the protein CRY (chryoptochrome) is light sensitive
This may explain why Campbell and Murphy (1998) found that if you shine a light on the back of participants knees, it shifts their circadian rhythms

29. Ezs: Social cues Until recently it was thought these were the
main EZ’s – we eat, go to bed, get up etc
at socially determined times
It seemed our bodily rhythms were entrained by social convention, not internal biology.
Today we know light is the dominant EZ, and we also know that all parts of the body produce their own oscillating rhythms.
E.G. zeitgebers for heart and liver appear to be reset by eating, so light is not their primary zeitgeber. (Davidson, 2006)

30. Ezs: Temperature
Cold blooded animals have their circadian rhythms modified by external temperature
Buhr et al (2010)
Humans and other warm blooded animals’ body temperature cycle is governed by the circadian clock, and these temperature changes entrain other circadian rhythms.

31. Activity
Read over and complete the activities in your booklet on exogenous zeitgebers

32. Review Showdown Where is the SCN? What is its function?
Describe how the body clock works?
What other examples are there of endogenous pacemakers?
What three examples of exogenous zeitgebers have you learned?
One study that supports the influence of zeitgebers
One study that supports the influence of pacemakers
One IDA issue that can be applied to this topic

33. Homework For next week (TUESDAY!)
Discuss the role of endogenous pacemakers and exogenous zeitgebers in circadian rhythms (8+16)
There are some documents on Moodle to help you with this.

34. Endogenous Pacemakers and Exogenous Zeitgebers
AO1
AO2
IDA
Endogenous Pacemakers
SCN – main EP
SCN contains protein mechanism
Pineal gland controls melatonin secretion
SCN evidence – ‘mutant’ hamsters
Desynchronisation leads to symptoms similar to jet lag
Evolutionary approach – SCN lesions in chipmunks (deCoursey et al)
Non-human animal studies evaluated in terms of ethics and relevance.
Exogenous Zeitgebers
Light is dominant zeitgeber
Social cues also important
Biological rhythms can be entrained by temperature
Artifical lighting may also reset biological clock
Failure of biological clock leads to sleep-phase disorders
Biological clock is really a blend of endogenous and exogenous factors
You could also use studies from rhythms topics to add to your AO2:
You just need to make sure you say why they are relevant!