Or

Everything you’ve ever wanted to know about sexual selection but were afraid to

ask

Definitions of interactions:

The whole is greater than the sum of its parts

The relationship between the variables is multiplicative instead of additive

The effectiveness of one intervention is contingent upon another intervention

Yes

Yes

No

No

0

5

3

-20

Yes

Yes

No

No

0

5

10

100

Valium

Alcohol

Ya Ya Sisterhood

Female

Scorpion King

Male

10

-10

-10

10

Gender

Movie

Survival of the fittest

Finding/Harvesting Resources

Avoiding Predators

Avoiding Illness

REPRODUCING!!!

If other organs such as the stomach and spleen were evolutionarily advantageous, why not the brain?

Mate Selection

Men – Looking to “spread their seed”

Women – Looking for a mate who will care for children

Post Hoc Theorizing Game

He who hesitates is lost

Look before you leap

Birds of a feather flock together

Opposites attract

Nature NurtureVs.

Identical Twins100%

Fraternal Twins50%

Adopted Child

Adopted Family

Genetic Family

Shared environment

Shared Genetics

Heritability Estimates – The proportion of the total variance in a trait that is attributable to genetic variation within a group.

Heritability Estimates

Intelligence: .70Neuroticism: .55Depression: .44Doing Crosswords: .55Liking Sweets: .65Playing Chess: .62

Assertiveness: .72Smoking: .48Ambition: .54Humility: .42Leadership: .59Time Reading: .43

However, it is generally accepted that behavior is determined by a nature x nurture interaction

e.g. A person with a genetic predisposition towards alcoholism won’t become an alcoholic if he never takes a sip of liquor

Heart RateBlood Pressure

Skin ConductanceElectromyography

Cortisol LevelsBreathing RatesTone of Voice

Polygraphs

Liars feel:

1) Nervous that they’ll get caught

2) Guilty about lying

Polygraphs

How it works:

1) Tell the truth, get a baseline measure

2) Tell a lie, get a measure of deception

3) Compute the difference between the two

4) Ask real questions, if subject looks more like a liar than a truth-teller, then the subject is lying

Polygraphs

Problems:1) Questions may be anxiety provoking2) Knowing that if the machine says that

you’re lying you’ll go to jail causes anxiety

3) Not all liars exhibit psychophysiological responses.

How to trick a polygraph:

Time

Arou sal

Difference

How to trick a polygraph:

Time

Arou sal Difference

How polygraphs REALLY work

Criminals get scared by the prospect of being detected, and they confess their crimes!

Other areas that psychophys can study

EmotionAttitudes

Unconscious Processes

The Sleep-Wake CycleFree of all time cues, the human day

averages about 25 hoursBody temperature, and hormone levels

follow this cycleRegulated by the hormone melatoninSince we have a ~24 hour cycle, the longer

we stay awake, the less we sleep!

Giant Sloth: 20 hoursBrown Bat: 19 hoursHouse Cat: 14 hoursJaguar: 10 hoursHuman: 8 hoursElephant: 3 hoursHorse: 2 hours

Average Hours Sleeping per Day

The Randy Gardner CaseMood Disturbance commonComplex Cognitive tasks unaffectedDull cognitive tasks are difficultLongitudinal partial sleep deprivation

causes more difficulty than short term total sleep deprivation

Microsleeps

Experimental rats die after several days. Yoked Rats not affected.

Increasing sleep efficiency after deprivation

Da Vinci’s sleep strategy15 minute nap every 4 hours

Total of 1.5 hours of sleep per dayReplicated by Stampi, (1992) in a lab.

Takes 2 weeks to adjust, during which time...

1) Evolution may have impacted our behavior, but be wary of post-hoc analysis

2) The nature vs. nurture debate should be viewed as an interaction

3) Psychophysiology can tell us a great deal, but polygraphs are useless.

4) Sleep is good.

Example for class:

Spanking Children