three minute review: motivation 1 what drives people to behave the way they do? regulatory drives...
TRANSCRIPT
Three Minute Review: Motivation 1
• what drives people to behave the way they do?• regulatory drives
– homeostasis– thermostat analogy
• non-regulatory drives• hypothalamus
– tiny area, important functions, links with limbic system, 4F’s• Hunger
– “hunger centre” (LH) vs. “satiation centre” (VMH) – how does the body maintain the correct level of food intake?– interplay between VMH and LH
• see also more detailed explanations, Gray Ch. 6, FQ10– feeling full– blood glucose levels– fat cells secrete leptin
– obesity• twin studies and adoption studies can be useful in nature vs. nurture questions• genetic factors play a large role in weight gain and weight distribution• “thrifty gene” in a Supersize culture?• set point theory
– changes to food intake may shift the set point making it harder to change your weight
– eating disorders• anorexia nervosa• bulimia nervosa• have our cultural ideals become unreasonable?
Sex• What determines sex drive?
– Hormones• androgens • estrogens
– Cultural influences and situations more important to women– Genetics
• Is there a “gay gene”?
• Sex Differences in Sex Drive– Women
• status, money, age, and concern for children
– Men • beauty, youth and sex
– Evolutionary theory• women: find a solid guy with good resources who’ll stick around• men: sow your seeds far and wide
• Pleasure centre– General motivational drive?– Dopamine is key neurotransmitter
• Many addictive drugs stimulate dopamine
Test YourselfWhich of the following could cause a rat to eat (true/false)?(From the lecture)• electrical stimulation to the ventromedial hypothalamus• a lesion (damage) to the ventromedial thalamus• electrical stimulation to the lateral hypothalamus• a lesion to the lateral hypothalamus• a decrease in blood glucose below the set point• a decrease in body fat below the set point
(From the book)• an injection of leptin• an injection of insulin• a water-filled balloon in the stomach• the presence of especially tasty rat chow even if the rat isn’t particularly
hungry• bell-ringing for a rat with a bell-food association (Pavlov’s rat?)
Why have emotions?1. Emotions communicate
– consistent across cultures and even species
2. Emotions aid in decision-making– gut feelings often right– people with damage to the
emotional system (orbitofrontal cortex) are poor at using past outcomes to regulate future behavior in a gambling task
3. Emotions capture attention and aid memory
4. Emotions strengthen interpersonal relations
– guilt, embarrassment , jealousy
What is this man from New Guinea feeling -- anger, happiness, disgust, sadness?
Video:Cavanagh:
Disk 3Emotion
Expression(2:10)
Arousal• Imagine you’re writing an exam of average
difficulty. How well would you do if you were– really mellow or drowsy – average– really stressed (or hooped on chocolate-covered
espresso beans)?
Low Medium High
LEVEL OF AROUSAL
QUALITY OF PERFORMANCE
Arousal• How much coffee would you want to
drink if you were:– driving?– writing an exam?– giving an important talk for the first time?
Yerkes & Dodson (1908)
Rats could avoid shock by going into brighter of two compartments
QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.
Experimenters varied the strength of the shocks given to the rat and measured their accuracy at picking the brighter compartment.
Yerkes-Dodson Curve
Yerkes & Dodson (1908)• rats did best if:
– the task was easy and they were highly aroused (by strong shocks)
– the task was moderately difficult and they were moderately aroused (by moderate shocks)
– the task was difficult and they were weakly aroused (by weak shocks)
Theories of Emotion2. James-Lange
“…we feel sorry because we cry, angry because we strike, afraid because we tremble, and not that we cry, strike or tremble because we are sorry, angry or fearful.”
-- William James
Schachter’s ExperimentSchachter & Singer (1962)• subjects were injected with adrenaline
(or a placebo)– adrenaline sweaty palms, increased
heart rate, shakes• some subjects were told they would
feel aroused; some were told nothing• left subjects in a waiting room with a
confederate– euphoria condition
• confederate played with a hula hoop and made paper airplanes
– angry condition• confederate asked obnoxious personal
questions (e.g., “With how many men other than your father has your mother had extramarital relations: (a) <5; (b) 5-9; (c) >9”Stanley Schachter
1922-1997
Theories of Emotion4. Schachter’s Attribution Theory
Degree of Arousal = INTENSITY of Emotion
Cognitive appraisal = TYPE of Emotion
This figure is simpler than Fig. 6.24 (which you can ignore) in your text
Misattribution of Emotion• emotions can be attributed to
the wrong source
(Dutton & Aron, 1974)• male subjects were asked to
meet the experimenter on a bridge across the Capilano River in B.C.– Group 1: Capilano suspension
bridge – Group 2: sturdy modern
bridge• attractive female research
assistant interviewed them in the middle of the bridge and gave her phone number
• Men interviewed on the scary bridge were more likely to call her
The Amygdala• part of the limbic system (with the
hippocampus and hypothalamus)• amygdala = “almond”• processes emotional significance
of stimuli and generates immediate reactions
• damage to amygdala – inability to recognize facial
emotions– absence of fear– absence of conditioned fear
response• abnormal activation of amygdala
– sudden violent rage
• in fMRI studies, the amygdala is activated by scary stimuli (even if you’re not aware of them)
Frontal Lobotomies• 1935: chimps who were neurotic before surgery
became more relaxed after it
• 1930s: Egaz Moniz begins frontal lobotomies in humans (and eventually wins Nobel Prize)
• 1950s: psychosurgery in vogue; 40,000 frontal lobotomies in North America
• The story of Agnes (Kolb & Whishaw)– no outward signs of emotion– no facial expression– no feelings toward other people (but still liked her
dog)– felt empty, zombie-like– Other patients lose prosody = emotional component
of speech
• orbitofrontal cortex – Patients with damage can remember info but don’t
have emotions associated with it
Lie Detectors
Polygraph tests are far from infallible• In one study (Klein-muntz & Szucko, 1984), polygraph tests identified guilty person 76% of time but falsely accused a truth-teller 37% of the time
Right hemisphere specialized for emotion
• Happy or sad?
• Why?– right hemisphere specialized for recognizing
emotions
Do the two hemispheres have different personalities?
• left hemisphere– activated by positive emotions– left frontal damage depressed
• sometimes overly catastrophic and weepy about injury
– diminished left hemisphere activation in depressed people
• right hemisphere– activated by negative emotions– right frontal damage fewer negative emotions
• often not appropriately upset or concerned about injury