Mind Hacks

The APS Observer magazine has a fantastic article on the power of false confessions to warp our perception of other evidence in a criminal case to the point where expert witnesses will change their judgements of unrelated evidence to make it fit the false admission of guilt.

We tend to think that no-one would confess to a crime that they didn’t commit but there are numerous high profile cases where this has happened and the article notes that “because of advances in DNA evidence, the Innocence Project has been able to exonerate more than 200 people who had been wrongly convicted, 49 of whom had confessed to the crime we now know they didn’t commit.”

As a result of some of the early discoveries of false confessions, there is now a growing amount of research on what personal and situational factors trigger false confessions.

The classic book on the topic is forensic psychologist Gisli Gudjonsson’s The Psychology Of Interrogations And Confessions. It reviews the scientific evidence but also covers numerous legal cases where false confessions have played a part.

It turns out, people falsely confess to crimes for a wide array of reasons. Some are voluntary confessions where the person might want to gain notoriety, annoy the police or might genuinely believe they’ve committed the crime due to a delusion in the context of a psychotic mental illness like schizophrenia.

In other cases, a false confession can be triggered by pressure from the police or investigators. Sometimes this happens even when the person doesn’t genuinely believe their confession, because they just want to escape the high-pressure situation. In other cases, the psychological pressure leads the person to start doubting their own memories and they come to believe they have committed the crime.

There is now a great deal of research showing that highly suggestible people and people with learning disabilities or mental illnes are much more likely to make a false confession under pressure and police interview guidelines are being changed as a result.

However, the APS article takes a different tack. It looks at the psychology of how other people involved in deciding whether the person is guilty or not are influenced by confessions.

Imagine if an accused but innocent person falsely confesses and the other evidence doesn’t suggest that they have committed the crime. In this situation, it turns out that both lay people and experts tend to change their evaluation of the other evidence and perceive it as being stronger evidence against the accused.

Some of the studies cited in the article just blew me away:

In a 1997 study, Kassin and colleague Katherine Neumann gave subjects case files with weak circumstantial evidence plus either a confession, an eyewitness account, a character witness, or no other evidence. Across the board, prospective jurors were more likely to vote guilty if a confession was included in the trial, even when they were told that the defendant was incoherent at the time of the confession and immediately recanted what he said… Other studies have shown that conviction rates rise even when jurors see confessions as coerced and even when they say that the confession played no role in their judgment…

Kassin recently teamed up with psychologist Lisa Hasel to test the effect of confessions on eyewitnesses. They brought subjects in for what was supposed to be a study about persuasion techniques. The experimenter briefly left the room and, during that time, someone came in and stole a laptop off the desk. The subjects were then shown a lineup of six suspects, none of whom was the actual criminal, and they were asked to pick out which member of the lineup, if any, committed the crime. Two days later, the witnesses were brought back for more questioning… Of the people who had identified a subject from the original lineup, 60 percent changed their identification when told that someone else had confessed. Plus, 44 percent of the people who originally determined that none of the suspects in the lineup committed the crime changed their mind when told that someone had confessed (and 50 percent changed when told that a specific person had confessed). When asked about their decision, ‚Äúabout half of the people seemed to say, “Well, the investigator told me there was a confession, so that must be true.”…

In 2006, University College London psychologist Itiel Dror took a group of six fingerprint experts and showed them samples that they themselves had, years before, determined either to be matches or non-matches (though they weren’t told they had already seen these fingerprints). The experts were now given some context: either that the fingerprints came from a suspect who confessed or that they came from a suspect who was known to be in police custody at the time the crime was committed. In 17 percent of the non-control tests, experimenters changed assessments that they had previously made correctly.

The APS Observer has plenty more examples and demonstrates that false confessions are psychological sink holes that pull in both the accused and the legal process.

Link to ‘The Psychology and Power of False Confessions’.

An article in the latest edition of Current Directions in Psychological Science reviews studies on the best starting points to increase the final price in either negotiations or auctions. In general, start high in negotiations, start low in auctions.

It turns out that negotiations, where several parties are invited to discuss a price, and auctions, where people can include themselves by jumping in when they want, are quite different psychologically.

The article, by business psychologist Adam Gilinsky and colleagues, notes that starting prices are a form of ‘anchor‘ – a piece of information which is known to affect subsequent decisions. As the authors note, anchoring has a powerful influence on our reasoning:

An anchor is a numeric value that influences subsequent numeric estimates and outcomes. When people make judgments, their final estimates are often assimilated to—that is, become more similar to—the initial anchor value (Tversky & Kahneman, 1974).

For example, in one of the best-known anchoring studies (Tversky & Kahneman, 1974), participants were exposed to an arbitrary number between 0 and 100 from the spin of a roulette wheel and then asked to estimate the percentage of African nations in the United Nations: Participants whose roulette wheel landed on a relatively high number gave higher absolute estimates than did participants whose wheel landed on a lower number.

Even outside of trivia questions, few psychological phenomena are as robust as the anchoring effect; it influences public policy assessments, judicial verdicts, economic transactions, and a variety of psychological phenomena.

The evidence suggests that in negotiations, a high starting price most often leads to a high final price, as the anchoring effect seems to work in a relatively undiluted way (with the caveat that completely ridiculous starting prices could prevent any deal being reached).

There’s an interesting aside in the article, mentioning that you can protect yourself from high anchor points from other people by focusing on your own ideal price or your opponents weaknesses, as found by a 2001 study, or by considering why the suggested price might be inaccurate, as found by another study published in the same year.

It also turns out that, contrary to conventional wisdom, making the first offer is also a good strategy:

Many negotiation books recommend waiting for the other side to offer first. However, existing empirical research contradicts this conventional wisdom: The final outcome in single and multi-issue negotiations, both in the United States and Thailand, often depends on whether the buyer or the seller makes the first offer. Indeed, the final price tends to be higher when a seller (who wants a higher price and thus sets a high first offer) makes the first offer than when the buyer (who offers a low first offer to achieve a low final price) goes first.

In contrast, for auctions, starting with a low price is generally more likely to lead to a higher final price. The researchers note this is likely due to three factors: price rise in auctions seems to be driven by social competition and so starting with a low entry point encourages more people to join in; once someone has bid, they have made a commitment which is likely to encourage them to continue; and finally, more bids leads us to infer that the item has a higher value.

It’s not a huge article so is worth reading in full if you’re interested in economic reasoning. Luckily, the full text is available as a pdf pre-print if you don’t have access to the journal.

Link to DOI entry for study.
pdf of full text.