# Lernkarten

Fabienne Keller
Karten 67 Karten 5 Lernende Deutsch Universität 21.02.2013 / 22.07.2020 Kein Urheberrechtsschutz (CC0)
0 Exakte Antworten 67 Text Antworten 0 Multiple Choice Antworten

When do we speakt of games of perfect information?

If all moves are observed and not forgotten

difference between:

a) move

b) strategy

a) a move is a single action to be taken by a player at a information set controlled by him

b) A strategy is a specification of moves at each information set of the game for a player. It is a complete plan of action, that tells what a player does at any information set in which he may be called to decide.

What is a complete plan of action?

A complete plan of action tells what a player does at any information set in which he may be called to decide

Ultimatum Game:

a proposer has 100CHF to split with the responder. He offers a division and the responder can either agree or both get nothing.

If players are rational and only care about the money, the responder will accept anything and 1 will offer the smallest possible amount.

--> Why is this not observed in experiments?

(offers below 10% are rare and offers below 20% are often rejected)

proposers:

are unable to do the correct backward reasoning,

are altruistic or care about fairness / may feel ashamed

or may fear rejection of low offers

responders:

emotion-driven response,

stakes are too low in the Lab (stakes= Einsätze)

or biological aspects

What's the difference between a game with

a) perfect information

b) complete information?

a) you know, what the other players did before

b) you know the payoffs

What means "describe the game formally" ?

(-->give examples)

describe:

- set of players (ex:  I = {S, T })

- order of moves (ex: simultaneously)

- information set (ex: HS = ({⊘},{S,n},{S,n,S,n}) )

- actions (ex: AS= {S,N} )

- strategies (ex: SS ={(NNN),(SNN),(NSN),(NNS),(SSN),(SNS),(NSS),(SSS)}  )

- complete equilibrium strategies (ex: S *: {S, S, N}   )

Two types of stategies in simultaneous-move games:

1.) pure stategies: one specific strategy is played for sure.

2.) mixed stategies: the player randomizes and chooses different pure stategies with positive probability. For instance tossing a coin and go to Tonhalle if Tails comes out and go to the Opera House if Heads comes out.

The set of stategies in simultaneous-move games can either be..... (2)

1.) discrete (e.g. go to Tonhalle, or to the Opera House)

2.) continuous (e.g. supply of electricity, a price)