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The Affect Heuristic

Pachur et al 2012, table 1

VSL : ‘we asked people to indicate for each risk the value of a statistical life (VSL), which refers to the cost of reducing the number of deaths in a specific class of risk by one.’
dread score: how much participants would dread dying from that cancer. ‘The dread score for each risk was calculated as the mean rating on the 12 characteristics assessed in the risk questionnaire, coded such that a higher value indicates higher dread. ... In a risk questionnaire, people were asked to rate the 24 types of cancer on the 12 risk characteristics that Slovic, Fischhoff, and Lichtenstein (1980) found to contribute to the dread factor: voluntariness of risk, preventive control, control of severity, chronic-catastrophic, common-dread, certain to be fatal, equity of risks and benefits, threat to future generations, personal exposure, potential of global catastrophe, changes in risk, and ease of reduction.’
availability: how many people did each participant have in their social networks that were affected by the kind of cancer in question?

24 types of cancer

Three measures of risk:

perceived frequency (which cause of death has a higher annual mortality rate?)

Value of a Statistical Life, VSL (how much money should be spent to avoid one fatality due to this cause of death?)

perceived risk (which cause of death represents a higher risk of dying from it?)

How are people to answer these questions? They do not have access to the table, so they need some way to make guesses?
Frequency and risk should be the same (in most situations) but that is not how people think of these.

Inaccessible properties:

- frequency

- risk of dying from it

These should be the same, but that is not how people think.

Accessible properties:

- how easily can I bring to mind a case of this?

- how does imagining it makes me feel?

Insofar as the accessible property is a guide to the inaccessible property, it would make sense to use one as a substitute for the other.

Two heuristics

Availability Heuristic

The easier it is to bring a case of this cancer to mind, the more frequent or risky it is.

Is this really a heuristic?

It’s not a heuristic unless there’s a link between accessible and inaccessible attributes such that the presence of the accessible attribute reliably indicates, at least in a useful range of cases, the presence of the inaccessible attribute.
Pause over why this is a really heuristic: ease of bringing to mind is presumably in part a consequence of how frequently you have encountered it which may be correlated with its actual frequency.

Affect Heuristic

The more dread you feel when imagining it, the more frequent or risky it is.

Is this really a heuristic?

Dread is presumably related to how terrible the consequences would be and also how likely it seems to you. (Imagining being hit by an asteriod doesn’t cause me to feel much dread ...).
So although the accessible attribute involves factors other than frequency or risk of dying from it, it still appears that the two are linked in such a way that the presence of the accessible attribute reliably indicates, at least in a useful range of cases, the presence of the inaccessible attribute.

Hypothesis:
The Availablity Heuristic dominates frequency judgements ,
whereas the Affect Heuristic dominates risk and VSL judgements.

Prediction:
Number of cases in a subject’s social network will better predict frequency judgements,
whereas feelings of dread will better predict risk and VSL judgements.

Findings:
both predictions broadly confirmed.

Findings: ‘availability-by-recall offered a substantially better descriptive account than the affect heuristic when people judged deindividualized, statistical mortality rates. Affect, however, was at least on par with availability when people were asked to put a price tag on a single life saved from a risk, or when they were asked to indicate the perceived risk of dying’ \citep[p.~324]{pachur:2012_how}.

Pachur et al, 2012

Pachur et al, 2012 table 1

Summary

The Affect Heuristic:

The more dread you feel when imagining it, the more frequent or risky it is.

In general, heuristics

involve subsituting inaccessible for accessible properties;

and hypotheses about them generate testable predictions.

To find evidence for the operation of a heuristic, test a prediction about the correlates or causes of judgements.

How is this relevant?

In two ways ...
First respect in which it’s relevant.

1

Humans use an affect heuristic in some cases;

so the idea they use it in making unreflective ethical judgements

is at least worth considering.

Second respect in which it’s relevant.

2

We can use Pachur et al (2012) as a model

for what would count as evidence

that humans use an affect heuristic

in making unreflective ethical judgements ...

What do adult humans compute that enables their unreflective judgements to track frequency, VSL and risk?

What do adult humans compute that enables their unreflective judgements to track moral attributes (such as wrongness)?

affect (and availability) heuristics

Evidence

Affect and availability predict risk and frequency judgements, respectively

Evidence

???