Decision Making (Risky choice) Flashcards
What is a decision?
A choice between alternatives that is intended to produce a desired or favourable outcome
A choice between alternatives that is intended to produce a desired or favourable outcome
This is known as…?
A decision
What are the 4 types of choices/decision-making?
- Riskless Multiattribute Choice
- Intertemporal choice
- Decisions under uncertainty
- Decisions under risk
What is Riskless Multiattribute Choice?
Making decisions by evaluating and prioritising a limited set of alternatives based on multiple conflict attributes with no risks
Making decisions by evaluating and prioritising a limited set of alternatives based on multiple conflict attributes with no risks
This is known as…?
Riskless Multiattribute Choice
You go to a supermarket, you found some beans with different types of attributes.
You have to decide which can of beans to buy based on those attributes.
You can easily take it off the shelf and it is yours. There are no probabilities involved.
What type of decision is this…?
Riskless Multiattribute Choice
What is intertemporal choice?
Choosing between options available at different points in time
Simply = Deciding between smaller, sooner and larger, later rewards
Choosing between options available at different points in time
Simply = Deciding between smaller, sooner and larger, later rewards
This is known as…?
Intertemporal choice
When one of the attributes varies is time
a. Intertemporal choice
b. Riskless Multiattribute Choice
c. Decisions under uncertainty
d. Decisions under risk
a. Intertemporal choice
When there are no probabilities involved
a. Intertemporal choice
b. Riskless Multiattribute Choice
c. Decisions under uncertainty
d. Decisions under risk
b. Riskless Multiattribute Choice
What is the typical decision people make when they have to make a intertemporal choice?
People prefer immediate rewards over later rewards even if later rewards are greater
Would you rather receive £10 right now, or £25 one year from today?
This is an example of…?
a. Intertemporal choice
b. Riskless Multiattribute Choice
c. Decisions under uncertainty
d. Decisions under risk
a. Intertemporal choice
Making a decision whilst not knowing what your probabilities are
a. Intertemporal choice
b. Riskless Multiattribute Choice
c. Decisions under uncertainty
d. Decisions under risk
c. Decisions under uncertainty
What are decisions under uncertainty?
Making a decision whilst not knowing what your probabilities are
When one or more of the possible outcomes are probabilistic (i.e., they are not certain to occur)
Simply = Making a decision whilst knowing what your probabilities are
a. Intertemporal choice
b. Riskless Multiattribute Choice
c. Decisions under uncertainty
d. Decisions under risk
d. Decisions under risk
What are decisions under risk?
When one or more of the possible outcomes are probabilistic (i.e., they are not certain to occur)
Simply = Making a decision whilst knowing what your probabilities are
Sometimes the probabilities are not known precisely, in which case the decision may be referred to as …?
Under uncertainity
Sometimes risky choices are made from…?
“From description” (information about the options is explicitly presented – e.g., in writing)
Sometimes risky choices are made “from description” (information about the options is explicitly presented – e.g., in writing)
Other choices are made from…?
“From experience” (the decision-maker has to
learn the outcomes and their probabilities by repeatedly sampling the environment)
Decisions made when:
The decision-maker has to
learn the outcomes and their probabilities by repeatedly sampling the environment
This is known as…?
Decisions made from experience
Decisions made when:
Information about the options is explicitly presented
This is known as…?
Decisions made from description
What are decisions made from description?
Decisions made when:
Information about the options is explicitly presented
What are decisions made from experience?
Decisions made when:
The decision-maker has to
learn the outcomes and their probabilities by repeatedly sampling the environment
Choices made from description and from experience are made when faced with _____ choices
Risky
How do we make risky choices?
List 2 ways
- Choices from description
- Choices from experience
A. An 80% chance of £4000 (and a 20% chance of nothing)
B. £3000 for sure
Would you rather play A or B?
What type of choice is this?
Risky choice
What is a rational choice?
Choices people make if they sought to maximise their well-being and to behave consistently
Choices people make if they sought to maximise their well-being and to behave consistently
This is known as…?
Rational decisions
Name one way we could potentially make a rational decision
We could calculate the expected value
What is the expected value (EV)
The sum of each possible outcome weighted by its probability
The sum of each possible outcome weighted by its probability
This is known as…?
Expected value (EV)
What is the formula for expected value (EV)?
EV = p1a1 + p2a2 + p3a3….pNaN
EV = p1a1 + p2a2 + p3a3….pNaN
What is ‘a’ in this formula?
The value of the outcome
EV = p1a1 + p2a2 + p3a3….pNaN
What is ‘p’ in this formula?
The probability of the outcome
EV = p1a1 + p2a2 + p3a3….pNaN
What is ‘N’ in this formula?
The total number of outcomes
One potentially-rational way to choose between gambles would be to …?
Calculate the expected value (EV) of each option by weighting each outcome by its probability
Calculate the expected value (EV) for each option when:
Option A: An 80% chance of £4000
Option B: £3000 for sure
Option A:
EV = (0.80 x £4000) + (0.20 x £0) = £3200
Option B:
EV = 1.0 x £3000 = £3000
Option A: An 80% chance of £4000
EV = (0.80 x £4000) + (0.20 x £0) = £3200
Option B: £3000 for sure
EV = 1.0 x £3000 = £3000
Which choice is the more rational one?
Option A: An 80% chance of £4000
EV = (0.80 x £4000) + (0.20 x £0) = £3200
Option A: An 80% chance of £4000
EV = (0.80 x £4000) + (0.20 x £0) = £3200
Option B: £3000 for sure
EV = 1.0 x £3000 = £3000
Option A is the more rational choice but what % of people choose Option B? What does this mean?
80%
It means people are ‘risk averse’ for gains (they chose lower risk of not receiving any money)
Define risk averse
People choose the option with the lower risk of not receiving any reward
People choose the option with the lower risk of not receiving any reward
This is known as…?
Risk averse
80% chose the guaranteed 3000 rather than the risky option with higher expected returns
What does this mean?
They were risk averse for gains
Economists long ago replaced expected value with …?
Expected utility
What is utility?
The subjective value of an outcome, and is some transformation u(a) of the objective amount.
The subjective value of an outcome, and is some transformation u(a) of the objective amount
This is known as…?
Expected utility
What is the formula for expected utility (EU)?
EU = p1u(a1) + p2u(a2) + p3u(a3) …pNu(aN)
EU = p1u(a1) + p2u(a2) + p3u(a3) …pNu(aN)
What does ‘u’ mean in this formula?
The identity function
How does expected utility (EU) theory readily accommodate risk aversion?
Proposes that the utility function is concave
People have diminishing sensitivity to increasingly large gains so that the subjective value of (for example) £200 is not twice that of £100
True or False?
People have increased sensitivity to increasingly large gains
False
People have decreased sensitivity to increasingly large gains
True or False?
Decisions made according to expected utility are irrational
False
Decisions made according to expected utility are rational
Decisions made according to expected utility are rational
Why?
They conform to and follow from a set of axioms whose reasonableness it is hard to dispute
(for example, that if A is preferred to B and B is preferred to C then A is preferred to C)
Calculate the expected utility (EU) for each option when:
Option A: An 80% chance of £4000
Option B: £3000 for sure
Option A:
EU = 0.8 x u(£4000) + 0.2 x u(£0)
= 0.8 x 145 = 116
Option B:
EU = 1.0 x u(£3000)
= 1.0 x 122 = 122
Option A: An 80% chance of £4000
EU = 0.8 x u(£4000) + 0.2 x u(£0)
= 0.8 x 145 = 116
Option B: £3000 for sure
EU = 1.0 x u(£3000)
= 1.0 x 122 = 122
What do the results show?
The preference for B simply requires that the utility of £3000 is more than 80% of the utility of £4000, which we can see is the case
What is an advantage of making decisions based on the expected utility theory?
It is a rational, prescriptive account of choice
What is a disadvantage of making decisions based on the expected utility theory?
It is a poor description of reality
Simply = It does not provide an accurate description of how people actually behave
A rational, prescriptive account of choice but a poor description of reality
This applies to…?
Expected utility theory
The disadvantage of the expected utility theory led to the development of a major alternative known as…?
The Prospect Theory
The Prospect Theory is a theory developed to address the limitation in the________ theory
Expected utility
It does not provide an accurate description of how people actually behave
a. Prospect theory
b. Expected value theory
c. Expected utility theory
d. Rational decision theory
c. Expected utility theory
In addition to whatever you own you have been given:
£1000
Now choose:
A: 50% chance of £1000
B: £500 for sure
What % of people chose Option A?
16%
In addition to whatever you own you have been given:
£1000
Now choose:
A: 50% chance of £1000
B: £500 for sure
What % of people chose Option B?
84%
In addition to whatever you own you have been given:
£2000
Now choose:
C: 50% chance of -£1000
D: -£500 for sure
What % of people chose Option C?
69%
In addition to whatever you own you have been given:
£2000
Now choose:
C: 50% chance of -£1000
D: -£500 for sure
What % of people chose Option D?
31%
What contributes to the violation of decisions made based off of expected utility?
Framing
i.e. framing the options as a gain results in choosing the option that is certain
i.e. framing the options as a loss results in choosing the option that involves a probability/gambling
Framing the options as a gain results in choosing the option that is
a. certain
b. a probability
a. certain
Framing the options as a loss results in choosing the option that involves …?
a. certain
b. a probability
b. a probability
Assumes that losses and gains are valued differently, and thus individuals make decisions based on perceived gains instead of perceived losses
Which theory assumes this?
Prospect theory
What does the prospect theory assume?
Assumes that losses and gains are valued differently, and thus individuals make decisions based on perceived gains instead of perceived losses
Who thought of the prospect theory?
Kahneman and Tversky
What theory did Kahneman and Tversky propose?
Prospect theory
What is the fundamental problem with the expected utility theory?
It concerns the subjective value of final outcomes. But real decisions often violate this principle.
E.g. One’s ultimate state of wealth after playing a gamble
It concerns the subjective value of final outcomes. But real decisions often violate this principle.
E.g. One’s ultimate state of wealth after playing a gamble
This is a problem for…?
a. Expected utility theory
b. Expected value theory
c. Prospect theory
a. Expected utility theory
What is the reference point?
When outcomes can be considered as gains or losses with respect to a reference point.
Often the status quo
Simply = Outcomes can be framed to appear favourable if they are presented as an opportunity to gain something relative to a reference point, whereas they can also be framed to appear unfavorable, if they are presented as a loss relative to a given reference point
According to the prospect theory, outcomes can be framed to appear favourable if they are presented as ….?
An opportunity to gain something relative to a reference point
According to the prospect theory, outcomes can be framed to appear unfavourable if they are presented as ….?
A loss relative to a given reference point
What did Kahneman and Tversky (1979) do in their study on the prospect theory?
List 3 points
- Presented two decision tasks:
Task 1: In addition to whatever you own, you have been given £1000. You are now asked to choose between:
A. A 50% chance to gain £1000
B. Gaining £500 for sure
Task 2: In addition to whatever you own, you have been given £2000. You are now asked to choose between:
C. A 50% chance to lose £1000
D. Losing £500 for sure
Kahneman and Tversky (1979):
- Presented two decision tasks:
- Task 1: In addition to whatever you own, you have been given £1000. You are now asked to choose between:
A. A 50% chance to gain £1000
B. Gaining £500 for sure
- Task 2: In addition to whatever you own, you have been given £2000. You are now asked to choose between:
C. A 50% chance to lose £1000
D. Losing £500 for sure
Which option did the majority choose? and what % of people chose the option in Task 1?
84% chose Option B or sure gain
(Risk averse for (perceived) gains)
Kahneman and Tversky (1979):
- Presented two decision tasks:
- Task 1: In addition to whatever you own, you have been given £1000. You are now asked to choose between:
A. A 50% chance to gain £1000
B. Gaining £500 for sure
- Task 2: In addition to whatever you own, you have been given £2000. You are now asked to choose between:
C. A 50% chance to lose £1000
D. Losing £500 for sure
Which option did the majority choose? and what % of people chose the option in Task 2?
69% chose Option C or riskier option
(Risk seeking for (perceived) losses)
The preference reversal between the two versions of the task violates …?
List 2 things
- Rationality
- The Expected Utility account of decision-making
People are risk _____ for (perceived) gains
a. Seeking
b. Averse
c. Neutral
b. Averse
People are risk ______ for (perceived) losses
a. Seeking
b. Averse
c. Neutral
a. Seeking
Risk averse for (perceived) _______
a. Neither gains nor losses
b. Losses
c. Both gains nor losses
d. Gains
d. Gains
Risk seeking for (perceived) losses
a. Neither gains nor losses
b. Losses
c. Both gains nor losses
d. Gains
b. Losses
According to the prospect theory, rather than basing decisions on the expected utility of end-states, people seem to focus on …?
Changes in wealth with respect to a reference point
According to the prospect theory, rather than basing decisions on the expected utility of end-states, people seem to focus on changes in wealth with respect to a reference point
What is the reference point?
This reference point is usually the status quo, but may also be an aspiration level or some other salient value
Kahneman and Tversky’s (1979) Prospect Theory posits an ______ value function
a. T-shaped
b. S-shaped
c. V-shaped
d. U-shaped
b. S-shaped
Kahneman and Tversky’s (1979) Prospect Theory posits an S-shaped value function which is _______ for gains
a. Concave
b. Convex
a. Concave
Kahneman and Tversky’s (1979) Prospect Theory posits an S-shaped value function which is ______ for losses
a. Concave
b. Convex
b. Convex
Kahneman and Tversky’s (1979) Prospect Theory posits an S-shaped value function which is concave for gains and convex for losses, where gains and losses are defined with respect to the …?
Current reference point
According to Kahneman and Tversky’s (1979) Prospect Theory, people show diminishing sensitivity to …?
List 2 things
- Progressively larger increases from the reference point
- Progressively larger decreases from the reference point
According to Kahneman and Tversky’s (1979) Prospect Theory, people show diminishing sensitivity to progressively _____ increases from the reference point, and diminishing sensitivity to progressively ______ decreases from the reference point
a. Smaller, Smaller
b. Smaller, Larger
c. Larger, Smaller
d. Larger, Larger
d. Larger, Larger
What does diminishing sensitivity mean when given options framed as gains?
The small but guaranteed gain has more than half the subjective value of a larger gain, so people take the safe option.
The small but guaranteed gain has more than half the subjective value of a larger gain, so people take the safe option.
Does this increase or decrease sensitivity?
Decrease
What does diminishing sensitivity mean when given options framed as losses?
The small but sure loss seems worse than the chance of losing something much larger, so people are prepared to take the risk
The small but sure loss seems worse than the chance of losing something much larger, so people are prepared to take the risk
Does this increase or decrease sensitivity?
Decrease
True or False?
The framing effect is only seen with money
False
This framing effect is not just seen with money
Describe Tversky and Kahneman’s (1981) experiment involving a humanitarian problem phrased as a gain/save to investigate the framing effect
List 2 points
- Presented Ps with the following problem:
“Imagine that the US is preparing for an outbreak of an unusual disease, which is expected to kill 600 people. Two alternative programs to combat the disease have been proposed…
If program A is adopted, 200 people will be saved
If program B is adopted, there is 1/3 probability that 600 people will be saved and 2/3 probability that no people will be saved”
- Ps had to choose one option
Tversky and Kahneman (1981):
- Presented Ps with the following problem:
“Imagine that the US is preparing for an outbreak of an unusual disease, which is expected to kill 600 people. Two alternative programs to combat the disease have been proposed…
If program A is adopted, 200 people will be saved
If program B is adopted, there is 1/3 probability that 600 people will be saved and 2/3 probability that no people will be saved”
- Ps had to choose one option
Which option did the majority choose? and what % of people choose that option?
72% chose program A, the “safe” program
Describe Tversky and Kahneman’s (1981) experiment involving a humanitarian problem rephrased as a loss to investigate the framing effect
List 2 points
- Presented Ps with the following problem:
If program A is adopted, 400 people will die
If program B is adopted, there is 1/3 probability that nobody will die and 2/3 probability that 600 people will die
- Ps had to choose one option