Once you heard the verdict, we gave you a poll asking you to estimate the percentage
chance of Neil Fox being found guilty or not guilty.
Some of you viewed a video in which Neil Fox was found to be
guilty and the rest viewed a video in which he was found to be not guilty.
What we typically find in this situation is that the actual outcome that people are presented
with increases their estimate that that outcome would have occurred.
Bear in mind that everyone would have seen exactly the same depiction of the trial itself
– so in principle everyone had exactly the same basis on which to make their estimates
of the outcome likelihood. People tend to overestimate what they would have known if
they hadn’t heard what the outcome was.
So - knowing the actual outcome shouldn’t affect these estimates - but it does! This
is known as the hindsight bias – or the “knew it all along” effect.
This effect was first empirically demonstrated by a classic 1975 article by Baruch Fischhoff
of the Hebrew University of Jerusalem, in which he asked the participants to estimate
the likelihood of various outcomes to unfamiliar historical events.
He found that not only did knowing the actual outcome increase people’s beliefs about
the inevitability of that outcome, but people were largely unaware that their judgements
were being affected.
This bias has major implications for all sorts of things
– including the criminal justice system.
To give just one example, in situations where we’re trying to judge whether someone has
acted reasonably or negligently, then the hindsight bias may mean that, when there’s
a bad outcome as there presumably will be if it’s gone to court, the actions leading
up to that outcome are more likely to be seen as negligent.
Studies have shown hindsight bias effects both judges and jurors. That is, it looks
more inevitable that those actions would result in the bad outcome and hence the
actions can’t be justified.
One additional interesting finding is that visual reconstructions of the event – for
instance, computer animations of vehicle crashes – can increase hindsight bias. So, it could
be that hindsight bias in our crime drama might be enhanced by the very fact that we’ve
presented it as a video reconstruction of what happened.
Are there any techniques we can use to counter the hindsight bias? Erin Harley of the University
of California, Los Angeles, reviewed research into reducing the hindsight bias. She reported
that this is one bias that has proved resistant to interventions – where, typically, jurors
still show the bias even when the bias is explained to them, for example, by the judge,
before they make their judgement.
However, some bias-reduction success has been obtained by getting people to think through
what’s known as “counterfactuals” – that is, all the other ways that events
could have played out.
So, in principle, in our demonstration we might first ask you to imagine that Fox was
found guilty, and consider reasons why this might occur. Then we might ask you to imagine
that Fox was found not guilty, and consider reasons why this might occur. We’d predict
that this ought to reduce the hindsight bias.
In everyday life, you might find it generally useful to think through the “counterfactuals”
– the alternative hypotheses – whenever you need to make an important judgement.
The evidence suggests that this is likely to lead to better decisions.