Beispiel 1

Beispiel 1
Lesen Sie den beiliegenden Text aus der New York Times vom 17. Februar 2005 und
beantworten Sie kurz folgende Fragen:
1. Was tut ein Champagnerkäufer in der beschriebenen Situation, wenn er nur dem
Eigeninteresse folgt?
2. Wie verhält sich ein Käufer, dem die "Champagner-Kultur" wichtiger ist als das
Eigeninteresse?
3. Was wurde bei einer experimentellen Studie über das Verhalten von Ökonomiestudenten
herausgefunden?
February 17, 2005
ECONOMIC SCENE
The Theory That Self-Interest Is the Sole Motivator Is Self-Fulfilling
By ROBERT H. FRANK
NEW YORKER cartoon depicts a well-heeled, elderly gentleman taking his grandson for a walk in the woods.
"It's good to know about trees," he tells the boy, before adding, "Just remember, nobody ever made big money
knowing about trees."
If the man's advice was not inspired directly by the economist's rational-actor model, it could have been. This model assumes
that people are selfish in the narrow sense. It may be nice to know about trees, it acknowledges, but it goes on to caution that
the world out there is bitterly competitive, and that those who do not pursue their own interests ruthlessly are likely to be swept
aside by others who do.
To be sure, self-interest is an important human motive, and the self-interest model has well-established explanatory power.
When energy prices rise, for example, people are more likely to buy hybrid vehicles and add extra insulation in their attics.
But some economists go so far as to say that self-interest explains virtually all behavior. As Gordon Tullock of the University of
Arizona has written, for example, "the average human being is about 95 percent selfish in the narrow sense of the term." Is he
right? Or do we often heed social and cultural norms that urge us to set aside self-interest in the name of some greater good?
If the search is for examples that contradict the predictions of standard economic models, a good rule of thumb is to start in
France. During my recent sabbatical in Paris, I encountered many such examples, but one in particular stands out. One midNovember afternoon, I asked my neighborhood wine merchant if he could recommend a good Champagne. It was the week
before Thanksgiving, and my wife and I had invited a few American friends to our apartment for a turkey dinner.
He just happened to have an excellent one on sale for only 18 euros. (Normal price, 24 euros.) Fine, I said, and then asked if
he could also recommend a bottle of cassis, since I knew some of our guests would want a kir royale - a cocktail of cassis and
Champagne. In that case, he said, I would have no need for the high-quality Champagne, because no one would be able to tell
the difference once it was mixed with cassis. Well, then, what should I buy? He brought back a bottle that he said would be just
right for the purpose.
That particular Champagne, however, was not on sale. When he told me it was 20 euros per bottle - 2 euros more than the
better one - an awkward pause ensued. Though I thought I knew the answer, I felt I had to ask whether a kir royale would taste
worse if made with the better Champagne. He assured me it would not. And because I knew that some of us would be drinking
our Champagne straight, I bought several bottles of the better one. He did not protest, but I could feel him reclassify me as yet
another American barbarian.
For many French, the logic of the self-interest model is trumped by an aesthetic principle about what Champagnes are right for
specific applications. This particular principle leads to a better outcome over all, because it directs the best Champagne to the
uses in which quality matters most. So even though I personally was better off for having ignored the merchant's advice
(because I got to drink a better Champagne and spent less), at least some of the better Champagne I bought was wasted.
France is, of course, not the only place in which the self-interest model's predictions fall short.
Most Americans, for example, leave tips even after dining in restaurants they will never visit again. We take the trouble to
vote in presidential elections, even though no single individual's vote has ever changed the outcome in any state. We
make anonymous donations to charity. From society's perspective, our willingness to forgo self-interest in such instances
leads to better outcomes than when we all act in a purely selfish manner.
Does what we believe about human motivation matter? In an experimental study of private contributions to a common
project, two sociologists from the University of Wisconsin, Gerald Marwell and Ruth Ames, found that first-year graduate
students in economics contributed an average of less than half the amount contributed by students from other disciplines.
Other studies have found that repeated exposure to the self-interest model makes selfish behavior more likely. In one
experiment, for example, the cooperation rates of economics majors fell short of those of nonmajors, and the difference
grew the longer the students had been in their respective majors.
My point is not that my fellow economists are wrong to stress the importance of self-interest. But those who insist that it is
the only important human motive are missing something important. Even more troubling, the narrow self-interest model,
which encourages us to expect the worst in others, often brings out the worst in us as well.
Perhaps the theories of human behavior embraced by other disciplines influence their practitioners in similar ways. A core
principle of behavioral biology, for example, is that males are far more likely than females to engage in "extra-pair
copulations." Does teaching this model year after year make male biologists more likely to stray?
Several years ago, I attended a dinner with a group of biologists that included a married couple. After describing the
research about how economics training appears to inhibit cooperation, I asked whether anyone had ever done a study of
whether males in biology were more likely than scholars from other disciplines to be unfaithful to their partners. The
uncomfortable silence that greeted my question made me wonder whether I had stumbled onto a data point relevant for
such a study.
But if biologists are like economists in being influenced by their own theories, they are different from us in another
respect: Their most cherished hypothesis is much less likely than ours to be contradicted by the French.
Robert H. Frank is an economist at the Johnson School of Management at Cornell University and the author, most
recently, of "What Price the Moral High Ground?"
Beispiel 2
Betrachten Sie das Modell (Beispiel) auf den Folien II/8 - II/9 des Kurses.
Vergleichen Sie es mit einem Modell mit rein privaten Gütern, bei denen im
Unterschied zu kollektiven Gütern keine positiven externen Effekte auftreten.
D. h. wir nehmen nun an, die beiden Haushalte wohnen so weit auseinander,
dass jeder nur aus seiner eigenen Beleuchtung einen Vorteil (subjektive
Zahlungsbereitschaft von 800,--) zieht, aber keinen aus der des anderen.
Wie wird sich jeder Haushalt bezüglich der Errichtung der Beleuchtung
entscheiden, wenn die Kosten c = 1.000,-- betragen? Wie, wenn die Kosten c
= 600,-- betragen? Welcher Vergleich ist hier relevant? Erklären Sie kurz,
warum hier strategisches Verhalten (d. h. eine Überlegung, wie sich wohl der
andere Haushalt entscheidet) keine Rolle spielen wird.
Beispiel 3
Zwei Familien A und B wohnen jenseits eines Baches. Es gibt den Vorschlag, den
bestehenden Steg durch eine befahrbare Brücke zu ersetzen.
a) Handelt es sich dabei um ein kollektives Gut? Begründen Sie die Antwort.
Die Kosten der Brücke hängen von ihrer Breite ab. Nehmen Sie an, je Zentimeter
Breite entstehen konstante Grenzkosten von 500,-- Euro (die Fixkosten sind Null).
Die marginale Zahlungsbereitschaft p (inverse Nachfragekurve) der Familien A, B für die
Brücke ist gegeben durch (x = Breite in cm)
A: p = 1.000 - 2x
B: p = 1.600 - 4x
b) Angenommen, es lässt sich jede Familie ihre eigene Brücke bauen, welche Breiten
werden die beiden Brücken aufweisen? (Hinweis: verwenden Sie p = 500 als inverse
Angebotskurve)
c) Würde sich durch eine gemeinsame Brücke eine effizientere Lösung finden
lassen? Wenn weiterhin die obigen Angaben für die Grenzkosten und die marginalen
Zahlungsbereitschaften gelten, wie breit wäre dann die effiziente Brücke (Lindahl
Gleichgewicht)? Wie hoch sind die gesamten Kosten dieser Brücke (= Preis mal Breite
der Brücke)? Wer zahlt welchen Anteil des Preises bzw. der gesamten Kosten, wenn
jede Familie einen Preisanteil gemäß der eigenen marg. ZB für die effiziente
Brückenbreite übernimmt? Welche Schwierigkeiten stehen der Realisierung dieser
Lösung entgegen?
d) Zusatzfrage (Lösung nicht unbedingt erforderlich): Ist die gemeinsame Lösung
für jede Familie besser als eine eigene Brücke? Warum?