Individual Differences

Question 1

What are the individual differences

Answer 1

Age, gender, circadian rhythms, genetics

Question 2

Describe Carskadon & Rechtschaffen 2005 study

Answer 2

• Sleep latency: how long it takes to get to sleep
• Wake after sleep onset: amount of time spent awake after initially falling asleep: age 45+ increases e.g. weak bladder
• SWS: decreases with age, young children spend a lot of time here
• REM: aged 0 - 5 spend a lot of time here
• Stage 1&2: not much of a difference between children and adults

Question 3

What study describes a general overview of the lifespan of sleep?

Answer 3

Carskadon & Rechtschaffen 2005

Question 4

Describe newborn sleep: AGE

Answer 4

16-18 hours a day
No external cues
Hasn’t developed circadian rhythms yet because brain is still developing
Has shorter cycles of 50-60 mins
Episodes last 2.5 to 4 hours
Fall asleep in REM which is different to adults as this is the last stage
Spend time in SWS throughout night but adults start later
More time in REM throughout night but adults start 2nd half of night
Can sleep through day and night

Question 5

Describe first year: AGE

Answer 5

14-15 hours a day
Rhythms arise around 2-3 months, respond to environmental cues
Longer periods of sleep in night
Greater wakefulness in day
Sleep onset begins with NREM
REM throughout night
Spend lot of time in SWS
Each cycle 50-60 mins
6 months - total sleep reduced & continuous sleep increases to 6 hours
12 months - majority of sleep consolidated at night with 1 or 2 naps during day

Question 6

Which studies describe sleep in young children

Answer 6

Jenni & Carskadon , Davis et al 2004

Question 7

Describe young children: AGE

Answer 7

Sleep decreases with age: physiological & social factors influence

REM decreases: occurs throughout night

Cycles: 90 mins & more typical to adults

Nap but consolidate sleep through night, stops from 3 to 5 (because of social factors: attend school and there is a routine)

Question 8

Describe Ferber & Kruger 1995 study

Answer 8

Day time sleep decreases with age and spend more time asleep at night

Question 9

What study explicitly describes sleep in young children?

Answer 9

Ferber & Kruger 1995

Question 10

Describe teenagers: AGE

Answer 10

9-10 hours sleep (Carskadon et al 2003) but lots of changes in sleep patterns

Tendency to go to bed late & weekends later, so wake up late. This reinforces circadian delay and cumulative sleep debt

Delayed body clock means hormone changes

Genuine biological predisposition to sleep later when teens

Other factors: video games, texting, tv

Question 11

What study explicitly describes sleep in teenagers?

Answer 11

Kelley et al 2015

Question 12

Describe Kelley et al 2015

Answer 12

Students aged 13-14
Tested students on paired activity task at 10 am then 2pm
Better when tested later in day

Question 13

Describe adults: AGE

Answer 13

Longer sleep cycles

NREM & REM

Question 14

What study describes sleep in adults and elderly?

Answer 14

Neurbauer 1999

Question 15

Describe elderly: AGE

Answer 15

Increased waking: WASO
Decreased SWS: struggle to initiate
Delayed sleep onset
Struggle to initiate REM: have shorter bouts

Question 16

Describe Campbell, Murphy & Stauble 2005

Answer 16

Poor thermoregulation & cognitive function present, but naps increase performance

Question 17

What study promotes naps for the elderly?

Answer 17

Campbell, Murphy & Stauble 2005

Question 18

How does chronotype play a part in individual differences?

Answer 18

Chronotype preference has a genetic basis: clock genes

Chronotype changes with age

Decides whether you are morning or evening person

Teens likely to be more evening

Adults more likely to be morning people

Question 19

Describe process of clock genes

Answer 19

Genes turned on 
Produce message 
Produce clock proteins 
Clock proteins work
Go into nucleus 
Turn off own genes 
See no message, so no protein, protein degraded 
Cycle repeats

Question 20

What are clock genes?

Answer 20

To some extent, determine whether you are a morning or evening person: specific gene of period 3 has been linked to this

Identified in 1994

18 genes critically important

Different in each person

Operate on molecular feedback loop: determine circadian drive

Question 21

What is period 3

Answer 21

Estimated to be 50% heritable
Drops in adulthood, but increases in elderly
PER 3 5/5, PER 3 4/4

Question 22

What did Horne & Ostberg 2003 create

Answer 22

MEQ questionnaire

Question 23

Describe Roenberg et al 2007

Answer 23

Normal distribution of morning & evening people

Difference between males and females

Men tend to go to bed later, but evens out with age

Question 24

Describe Kehkhof & Dongen 1996

Answer 24

Body temperature: directed by circadian drive
So a morning person: temp decreased by 10pm and increases early morning

An evening person: temp decreases after 10pm and increases late morning

Alertness
Morning: alert but decreases and drops at 10pm

Evening: low during day but alert in evening

Question 25

What studies observe morning and eveningness?

Answer 25

Roenberg et al 2007, Kehkhof & Dongen 1996, Maire et al 2014, Moore 2007

Question 26

Describe Maire et al 2014

Answer 26

Morning: higher unintentional sleep episodes, which map onto melatonin levels which peak at same time Morning people seem to have greater sensitivity to melatonin, so likely to have quicker sleep onset Evening: unintentional sleep doesn't increase

Question 27

Describe Moore 2007

Answer 27

During day, sleep pressure increases due to adenosine (bi product of ATP) Brain is active during day and uses up ATP. This decreases during metabolism and is converted in adenosine Adenosine increases in prefrontal cortex which increases sleep pressure & drive to sleep Sleep duration related to response to build up of adenosine Some are more sensitive to adenosine

Question 28

Describe Karasek & Winczyk 2006

Answer 28

Melatonin levels Important for sleep Young children have high levels, adults have low levels May explain why elderly cant maintain sleep throughout night