3.4. The basis of epistemic exceptionalism: The overconfidence feedback loop

Let’s recap briefly. We aren’t especially good at detecting the properties

that covary with the target property we want to predict—especially when

we have strong background opinions and when the informational situation

is complex. We aren’t especially good at recalling or attending to lots

of different avenues of information. And often, the feedback we get about

the quality of our judgments or behavior is unrepresentative (and we don’t

know it) or incomplete (and we don’t see that this is a serious problem).

As a result, it is not surprising that we aren’t especially reliable in our

judgments about complex social phenomena.

Against this background, the sluggish reception SPRs have received in

the disciplines whose business it is to predict and diagnose is particularly

puzzling. (Resistance to the use of SPRs is particularly strong when it

comes to making social predictions. SPRs have found easier acceptance in

non-psychiatric medical diagnosis.) In the face of a half century of studies

showing the superiority of SPRs, many experts still base judgments on

subjective impressions and unmonitored evaluation of the evidence. Resistance

to the SPR findings runs deep and typically comes as a kind of

epistemic exceptionalism. Those who resist the SPR findings take their

reasoning powers to be exceptional, and so they defect from the judgments

of SPRs when they find what they take to be exceptions to it. They are

typically quite willing to admit that in the long run, SPRs will be right more

often than human experts. But their (over)confidence in their subjective

powers of reflection leads them to deny that we should believe the SPR’s

prediction in this particular case.

We suspect that epistemic exceptionalism, which we suggest has led

to the sluggish reception of SPRs, is the result of two facts about people.

When it comes to prediction, we find the success of SPRs hard to believe,

The Amazing Success of Statistical Prediction Rules 43

and we find our lack of success hard to believe. The reason we find our

own lack of success hard to believe is that most of the failures of our

predictive capacities are hidden from us. We don’t see what’s gone wrong.

We don’t detect the right covariations, but we think we do. We can’t attend

to the relevant complexities, but we think we have. We aren’t getting

representative feedback on our predictions, but we think we are. As a result,

we tend to be overconfident about the power of our subjective reasoning

faculties and about the reliability of our predictions (Trout 2002).

Our faith in the reliability of our subjective powers of reasoning bolsters

our (over)confidence in our judgments; and our (over)confident judgments

bolster our belief in the reliability of our subjective faculties (Arkes

1991; Sieck and Arkes [unpublished manuscript]). Let’s focus on each side

of this overconfidence feedback loop.

The first side of the overconfidence feedback loop consists in overconfidence

in our judgments. This overconfidence leads too often to defection

from a successful SPR. That we fall victim to an overconfidence

bias is one of the most robust findings in contemporary psychology:

[A] large majority of the general public thinks that they are more intelligent,

more fair-minded, less prejudiced, and more skilled behind the wheel of an

automobile than the average person. . . . A survey of one million high school

seniors found that 70% thought they were above average in leadership

ability, and only 2% thought they were below average. In terms of ability to

get along with others, all students thought they were above average, 60%

thought they were in the top 10%, and 25% thought they were in the top

1%! Lest one think that such inflated self-assessments occur only in the

minds of callow high-school students, it should be pointed out that a survey

of university professors found that 94% thought they were better at their

jobs than their average colleague. (Gilovich 1991, 77)

The overconfidence bias goes far beyond our inflated self-assessments. For

example, Fischhoff, Slovic, and Lichtenstein (1977) asked subjects to indicate

the most frequent cause of death in the U.S. and to estimate their

confidence that their choice was correct (in terms of ‘‘odds’’). When

subjects set the odds of their answer’s correctness at 100:1, they were

correct only 73% of the time. Remarkably, even when they were so certain

as to set the odds between 10,000:1 and 1,000,000:1, they were correct only

between 85% and 90% of the time. It is important to note that the overconfidence

effect is systematic (it is highly replicable and survives changes

in task and setting) and directional (the effect is in the direction of

over rather than underconfidence). But overconfidence is eliminated or

44 Epistemology and the Psychology of Human Judgment

reversed when the questions are very easy. This phenomenon is known as

the difficulty (or hard-easy) effect (Lichtenstein and Fischhoff 1977).

The second side of the overconfidence feedback loop consists of our

overconfidence in the reliability of our subjective reasoning faculties. We

are naturally disposed to exaggerate the powers of our subjective faculties.

A very prominent example that we have already discussed is the interview

effect. When gatekeepers avail themselves of unstructured interviews, they

actually degrade the reliability of their predictions. Although the interview

effect is one of the most robust findings in psychology, highly educated

people ignore its obvious practical implication. We suspect that this occurs

because of our confidence in our subjective ability to ‘‘read’’ people.

We suppose that our insight into human nature is so powerful that we

can plumb the depths of a human being in a 45-minute interview—unlike

the lesser lights who were hoodwinked in the SPR studies. As we have said,

a major reason our (over)confidence survives is because we typically don’t

get systematic feedback about the quality of our judgments (e.g., we can’t

compare the long-term outcomes of our actual decisions against the

decisions we would have made if we hadn’t interviewed the candidates).

To put this in practical terms, the process by which most working philosophers

were hired was seriously and, at the time, demonstrably flawed.

This will be of no comfort to our colleagues, employed or unemployed.

We expect, however, that the unemployed will find it considerably less

surprising.

Let’s recap briefly. We aren’t especially good at detecting the properties

that covary with the target property we want to predict—especially when

we have strong background opinions and when the informational situation

is complex. We aren’t especially good at recalling or attending to lots

of different avenues of information. And often, the feedback we get about

the quality of our judgments or behavior is unrepresentative (and we don’t

know it) or incomplete (and we don’t see that this is a serious problem).

As a result, it is not surprising that we aren’t especially reliable in our

judgments about complex social phenomena.

Against this background, the sluggish reception SPRs have received in

the disciplines whose business it is to predict and diagnose is particularly

puzzling. (Resistance to the use of SPRs is particularly strong when it

comes to making social predictions. SPRs have found easier acceptance in

non-psychiatric medical diagnosis.) In the face of a half century of studies

showing the superiority of SPRs, many experts still base judgments on

subjective impressions and unmonitored evaluation of the evidence. Resistance

to the SPR findings runs deep and typically comes as a kind of

epistemic exceptionalism. Those who resist the SPR findings take their

reasoning powers to be exceptional, and so they defect from the judgments

of SPRs when they find what they take to be exceptions to it. They are

typically quite willing to admit that in the long run, SPRs will be right more

often than human experts. But their (over)confidence in their subjective

powers of reflection leads them to deny that we should believe the SPR’s

prediction in this particular case.

We suspect that epistemic exceptionalism, which we suggest has led

to the sluggish reception of SPRs, is the result of two facts about people.

When it comes to prediction, we find the success of SPRs hard to believe,

The Amazing Success of Statistical Prediction Rules 43

and we find our lack of success hard to believe. The reason we find our

own lack of success hard to believe is that most of the failures of our

predictive capacities are hidden from us. We don’t see what’s gone wrong.

We don’t detect the right covariations, but we think we do. We can’t attend

to the relevant complexities, but we think we have. We aren’t getting

representative feedback on our predictions, but we think we are. As a result,

we tend to be overconfident about the power of our subjective reasoning

faculties and about the reliability of our predictions (Trout 2002).

Our faith in the reliability of our subjective powers of reasoning bolsters

our (over)confidence in our judgments; and our (over)confident judgments

bolster our belief in the reliability of our subjective faculties (Arkes

1991; Sieck and Arkes [unpublished manuscript]). Let’s focus on each side

of this overconfidence feedback loop.

The first side of the overconfidence feedback loop consists in overconfidence

in our judgments. This overconfidence leads too often to defection

from a successful SPR. That we fall victim to an overconfidence

bias is one of the most robust findings in contemporary psychology:

[A] large majority of the general public thinks that they are more intelligent,

more fair-minded, less prejudiced, and more skilled behind the wheel of an

automobile than the average person. . . . A survey of one million high school

seniors found that 70% thought they were above average in leadership

ability, and only 2% thought they were below average. In terms of ability to

get along with others, all students thought they were above average, 60%

thought they were in the top 10%, and 25% thought they were in the top

1%! Lest one think that such inflated self-assessments occur only in the

minds of callow high-school students, it should be pointed out that a survey

of university professors found that 94% thought they were better at their

jobs than their average colleague. (Gilovich 1991, 77)

The overconfidence bias goes far beyond our inflated self-assessments. For

example, Fischhoff, Slovic, and Lichtenstein (1977) asked subjects to indicate

the most frequent cause of death in the U.S. and to estimate their

confidence that their choice was correct (in terms of ‘‘odds’’). When

subjects set the odds of their answer’s correctness at 100:1, they were

correct only 73% of the time. Remarkably, even when they were so certain

as to set the odds between 10,000:1 and 1,000,000:1, they were correct only

between 85% and 90% of the time. It is important to note that the overconfidence

effect is systematic (it is highly replicable and survives changes

in task and setting) and directional (the effect is in the direction of

over rather than underconfidence). But overconfidence is eliminated or

44 Epistemology and the Psychology of Human Judgment

reversed when the questions are very easy. This phenomenon is known as

the difficulty (or hard-easy) effect (Lichtenstein and Fischhoff 1977).

The second side of the overconfidence feedback loop consists of our

overconfidence in the reliability of our subjective reasoning faculties. We

are naturally disposed to exaggerate the powers of our subjective faculties.

A very prominent example that we have already discussed is the interview

effect. When gatekeepers avail themselves of unstructured interviews, they

actually degrade the reliability of their predictions. Although the interview

effect is one of the most robust findings in psychology, highly educated

people ignore its obvious practical implication. We suspect that this occurs

because of our confidence in our subjective ability to ‘‘read’’ people.

We suppose that our insight into human nature is so powerful that we

can plumb the depths of a human being in a 45-minute interview—unlike

the lesser lights who were hoodwinked in the SPR studies. As we have said,

a major reason our (over)confidence survives is because we typically don’t

get systematic feedback about the quality of our judgments (e.g., we can’t

compare the long-term outcomes of our actual decisions against the

decisions we would have made if we hadn’t interviewed the candidates).

To put this in practical terms, the process by which most working philosophers

were hired was seriously and, at the time, demonstrably flawed.

This will be of no comfort to our colleagues, employed or unemployed.

We expect, however, that the unemployed will find it considerably less

surprising.