Yet more reasons why people believe weird things

Research at Victoria University of Wellington is shedding light on the often irrational processes by which people assess new information. This article is based on presentations to the 2010 NZ Skeptics conference.

Jacqui Dean was alarmed. The Otago MP had received an email reporting the deaths of thousands of people – deaths caused by the compound dihydrogen monoxide. Dihydrogen monoxide is commonly used as an industrial solvent and coolant, it is fatal if inhaled, and is a major component of acid rain (see dhmo.org for more facts about dihydrogen monoxide). Only after she declared her plans to ban dihydrogen monoxide did she learn of its more common name: water (NZ Herald, 2007).

Ms Dean’s honest mistake may be amusing, but when large groups of people fail to correctly assess the veracity of information that failure can have tragic consequences. For example, a recent US survey found 25 percent of parents believe that vaccines can cause autism, a belief that may have contributed to the 11.5 percent of parents refusing at least one recommended vaccine for their child (Freed et al, 2010).

Evidence from experimental research also demonstrates the mistakes people can make when evaluating information. Over a number of studies researchers have found that people believe:

  • that brand name medication is more effective than generic medication;
  • that products that cost more are of higher quality;
  • and that currency in a familiar form – eg, the US dollar bill, is more valuable than currency in a less familiar form – eg, a dollar coin (Alter & Oppenheimer, 2008; for a review, see Rao & Monroe, 1989).

Why is it that people believe these weird things and make mistakes evaluating information?

Usually people can evaluate the veracity of information by relying on general knowledge. But when people have little relevant knowledge they often turn to feelings to inform their decisions (eg Unkelbach, 2007). Consider the following question: Are there more words in the English language that start with the letter K or have K in the third position? When Nobel prize winner Daniel Kahneman and his colleague Amos Tversky (1973) asked this question most people said there are more words that start with the letter K. And they were wrong. People make this error because words that start with the letter K, like kite, come to mind more easily than words that have a K in the third position, like acknowledge, so they judge which case is true based on a feeling – the experience of ease when generating K examples.

Generally speaking, information that is easy to recall, comprehend, visualise, and perceive brings about a feeling of fluent processing – the information feels easy on the mind, just like remembering words such as kite (Alter & Oppenheimer, 2009). We are sensitive to feelings of fluent processing (fluency), and we use it as a cue to evaluate information. For example, repeated information feels easy to bring to mind, and tends to be judged as more true than unrepeated information; trivia statements written in high colour contrast (Osorno is the capital of Chile) are easier to perceive and are judged as more true than statements written in low colour contrast (Osorno is the capital of Chile); and financial stocks with easy to pronounce ticker symbols (eg KAR) outperform those with difficult to pronounce ticker symbols such as RDO (Alter & Oppenheimer, 2006; Hasher et al, 1977; Reber & Schwarz, 1999).

Most of the time, fluently processed information is evaluated more positively – we say it is true, we think it is more valuable. And on the face of it, fluency can be a great mental shortcut: decisions based on fluency are quick and require little cognitive effort. But feelings of fluency can also lead people to make systematic errors. In our research, we examine how feelings of fluency affect beliefs, confidence, and evaluations of others. More specifically, we examine how photos affect people’s judgements about facts; how repeated statements affect mock- jurors’ confidence; and how the complexity of a name affects people’s evaluations of that person.

Can decorative photos influence your beliefs about information?

If we told you that the Barringer Crater is on the northern hemisphere of the moon, would that statement be more believable if we showed you a photo of the Barringer Crater? Because the photo is purely decorative – that is, it doesn’t actually tell you anything about the location of the Barringer Crater (which is in fact in Arizona) – you probably wouldn’t expect it to influence your beliefs about the statement.

Yet, evidence from fluency research suggests that in the absence of relevant knowledge, people rely on feelings to make decisions (eg Unkelbach, 2007). Thus, not knowing what the Barringer Crater is or what it looks like, you might turn to the photo when considering whether the statement is true. The photo might bring about feelings of fluency, and make the statement seem more credible by helping you easily picture the crater and bring to mind related information about craters – even though this would still give you no objective information about where the crater is located. In our research, we ask whether decorative photos can lead people to be more willing to believe information.

How did we answer our research question?

In one experiment, people responded true or false to trivia statements that varied in difficulty; some were easy to answer (eg, Neil Armstrong was the first person to walk on the moon), some were more difficult (eg, Turtles are deaf). Half of the time, statements were paired with a related photo (eg, a turtle). In a second study, people evaluated wine labels and guessed whether each of the wine labels had won a medal. We told people that the wine companies were all based in California. In fact, we created all of the wine names by pairing an adjective (eg, Clever) with a noun (eg, Clever Geese). Some of the wine labels contained familiar nouns (eg, Flower) and some contained unfamiliar nouns (eg, Quills). Half of the wine labels appeared with a photo of the noun.

What did we find?

Overall, when people saw trivia statements or wine names paired with photos, they were more likely to think that statements were true or that the wines had won a medal. However, photos only exerted these effects when information was difficult – that is, for those trivia statements that were difficult to answer and wine names that were relatively unfamiliar. Put more simply, decorative photos can lead you to believe claims about unfamiliar information.

Is one eyewitness repeating themselves as believable as three?

If you were a juror in a criminal case, you would probably be more willing to convict a man based on the testimony of multiple eyewitnesses, rather than the testimony of a single eyewitness. But why would you be more likely to believe multiple eyewitnesses? On the one hand, you might think that the converging evidence of multiple eyewitnesses is more accurate and more convincing than evidence from a single eyewitness, and indeed, multiple eyewitnesses are generally more accurate than a single eyewitness (Clark & Wells, 2008).

On the other hand, as some of the fluency research discussed earlier suggests, you may be more likely to believe multiple eyewitnesses simply because hearing from multiple eyewitnesses means hearing the testimony multiple times (Hasher et al, 1977). Put another way, it may be the repetition of the testimony, rather than the number of independent eyewitnesses, that makes you more likely to believe the testimony. In our research, we wanted to know whether it is the overlap of statements made by multiple eyewitnesses or the repetition of those statements that makes information more believable.

How did we answer our research question?

We asked subjects to read three eyewitness reports about a fictitious crime. We told half of the subjects that each report was written by a different eyewitness, and we told the other half that all three reports were written by the same eyewitness. In addition, half of these subjects read some specific claims about the crime (eg, The thief read a Newsweek magazine) in one of the eyewitness reports, while the other half read those same specific claims in all three reports. Later, we asked subjects to tell us how confident they were that certain claims made in the eyewitness reports really happened during the crime (eg, How confident are you that the thief read a Newsweek magazine?).

What did we find?

This study had two important findings. First, regardless of whether one or three different eyewitnesses ostensibly wrote the reports, subjects who read claims repeated across all three reports were more confident about the accuracy of the claims than subjects who read those claims in only one report. Second, when the claims were repeated, subjects were just as confident about the accuracy of a single eyewitness as the accuracy of multiple eyewitnesses. These findings tell us that repeated claims were relatively more fluent than unrepeated claims – making people more confident simply because the claims were repeated, not because multiple eyewitnesses made them.

Would a name influence your evaluations of a person?

Your immediate response might be that it shouldn’t – people’s names provide no objective information about their character. We hope that we make decisions about others by recalling information from memory and gathering evidence about a person’s attributes. Indeed, research shows that when we have knowledge about a topic, a person or a place, we do just that – use our knowledge to make a judgement- and we can be reasonably accurate in doing so (eg, Unkelbach, 2007).

But when we don’t know a person and we can’t draw on our knowledge, we might be influenced by their name. As we have described, when people cannot draw on memory to make a judgement, they unwittingly turn to tangential information to make their decisions. Therefore, when people evaluate an unfamiliar name, tangential information, like the complexity of that name, might influence their judgements. More specifically, we thought that unknown names that were phonologically simple – easier to pronounce – would be judged more positively on a variety of attributes than names that were difficult to pronounce.

How did we answer our research question?

We showed people 16 names gathered from international newspapers. Half of the names were easy to pronounce (eg, Lubov Ershova), and half were difficult to pronounce (eg, Czeslaw Ratynska). We matched the names on a number of factors to make sure any differences we found were not due to effects of culture or name length. So for example, people saw an easy and difficult name from each region of the world and names were matched on length. Across three experiments, we asked subjects to judge whether each name was familiar (Experiment 1), trustworthy (Experiment 2), or dangerous (Experiment 3).

What did we find?

Although the names were not objectively different from each other on levels of familiarity, trustworthiness, or danger, people systematically judged easy names more positively than difficult names. Put another way, people thought that easy-to-pronounce names were more familiar, more trustworthy, and less dangerous than difficult-to-pronounce names. So although we would like to think we would not evaluate a person based on their name, we may unwittingly use trivial information like the phonological complexity of a name in our judgements.

Conclusions

Why is it that people believe these weird things and make mistakes when evaluating information? Our research suggests that decorative photos, repetition of information, and a person’s name all influence the way people interpret information. More specifically, decorative photos lead people to think information is more credible; repetition leads mock-jurors to be more confident in eyewitness statements – regardless of how many eyewitnesses provided the statements; and an easy-to-pronounce name can lead people to evaluate a person more positively.

Relying on feelings of fluency can result in sensible, accurate decisions when we are evaluating credible facts, accurate eyewitness reports, and trustworthy people. But the same feelings can lead people into error when we are evaluating inaccurate facts, mistaken eyewitnesses, and unreliable people. More specifically, feelings of fluency might lead us to think false facts are true, be more confident in inaccurate eyewitness reports, and more positively evaluate an unreliable person.

A common finding across our studies is that the effect of fluency was specific to situations where people had limited general knowledge to draw on. In the real world, we might see these effects even when people have sufficient knowledge to draw on. That is because we juggle a lot of information at any one time and we do not have the cognitive resources to carefully evaluate every piece of information that reaches us – as a result we may turn to feelings to make some decisions. Therefore it is inevitable that we will make at least some mistakes. We can only hope that our mistakes are comical rather than tragic.

The authors thank Professor Maryanne Garry for her invaluable guidance and her inspiring mentorship on these and other projects.

References

Alter, A, Oppenheimer, D 2006: Proc. Nat. Acad. Sci. 103, 9369-9372.
Alter, A, Oppenheimer, D 2008: Psychonomic Bull. & Rev. 15, 985-990.
Alter, A; Oppenheimer, D 2009: Personality and Soc. Psych. Rev. 13, 219-236.
Clark, SE; Wells, GL 2008: Law & Human Behavior 32, 406-422.
Dihydrogen Monoxide – DHMO Homepage. (2010).dhmo.org
Freed, G; Clark, S; Butchart, A; Singer, D; Davis, M 2010: Pediatrics, 125, 653-659.
Hasher, L; Goldstein, D; Toppino, T 1977: J. Verbal Learning & Verbal Behavior 16, 107-112.
NZ Herald 2007:www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10463579
Rao, A; Monroe, K 1989: J. Marketing Research, 26, 351-357.
Reber, R; Schwarz, N 1999: Consciousness & Cognition 8, 338-342.
Tversky, A; Kahneman, D 1973: Cognitive Psych. 5, 207-232.
Unkelbach, C 2007: J. Exp. Psych.: Learning, Memory, & Cognition 33, 219-230.

The fallibility of eyewitness memory

Eyewitness testimony is commonly regarded as very high quality evidence. But recent research has shown there are many ways memories of events can become contaminated. This article is based on a presentation to the NZ Skeptics conference in Wellington, 27 September 2009.

In 2003, a woman was tragically attacked and raped after leaving a bar in Christchurch. She remembered her assailant as a man with “rat- like” features. Later, she chose the police suspect from a photographic lineup, indicating that she was “90 percent sure” that he was her assailant. This identification became the central piece of evidence that convicted Aaron Farmer. But, in June 2007, Mr Farmer was exonerated after DNA proved that he could not have been the rapist – he had spent almost three years in prison.

Unfortunately, Mr Farmer’s case is not an isolated incident. Decades of legal and psychological research have shown that eyewitness identification error is the leading cause of wrongful conviction. Recently the former High Court judge, Sir Thomas Thorp, published an extensive review of legal research on miscarriages of justice. In that paper, he estimated that there are at least 20 innocent people in New Zealand prisons, and he emphasised eyewitness error as a leading cause of convictions. This conclusion fits neatly with exoneration data from the Innocence Project, based in New York. Since 1992, the Innocence Project has exonerated over 250 wrongfully convicted people, over 75 percent of whom were identified by at least one eyewitness.

How can human memory be so fragile as to lead a witness to choose an innocent person from a lineup? Over 30 years of research has shed light on this question. Ultimately, this research has shown that memory can go wrong in several ways. The best way to understand these errors is to think of memory as a three-stage process:
[1] encoding,
[2] retention, and
[3] recall.

At the encoding stage, information is perceived and transferred from the environment, through our senses. These perceptual processes allow us to lay down memory traces. Next, those traces are retained for a period of time. Of course this retention stage can last for anywhere between seconds and years, until finally we recall that information from memory. It is important to know that any one of these three stages can go awry.

Encoding

Encoding depends heavily on our ability to pay attention to information in the environment. However, our attentional systems are limited. We can only pay attention to a few things at once. Anything that does not receive the requisite amount of attention does not have the chance to make it through the encoding phase of memory.

Furthermore, many variables, such as stress, can limit our attentional processes even more. As a result, witnesses will often not pay attention to details that could be forensically relevant. For example, a witness under stress may pay particular attention to the weapon being brandished by the offender, rather than paying attention to his facial details. If this is the case, those facial details may never be stored in memory, and if information is not stored, it cannot be recalled later.

Retention

The information that makes it into memory can be distorted easily. Perhaps the best known psychological science research in this field is the misinformation effect pioneered by Elizabeth Loftus. This research shows that a simple suggestion can change witnesses’ memories. In a typical misinformation experiment, there are three stages.

First, participants watch a simulated crime, such as a man stealing a maths book from a bookstore. After a delay, participants are exposed to post- event information (PEI), which is usually a narrative describing the simulated crime. For some participants, the PEI is accurate but generic (eg, “the man stole a book”), and for others the details are misleading (eg, “the man stole a science book”).

Finally, participants are questioned to determine their memory’s accuracy for the event. These participants are often specifically told to ignore everything they read in the narrative and only rely on what they saw during the event. Typically, those participants who read misleading details during the PEI have less accurate memories than those who read generic information.

This research shows the ease with which a person’s memory can be changed. Decades of research have shown that people can come to remember having seen a crime when in fact they have seen an innocuous event. Using this paradigm people can even come to remember having seen an innocuous event, when in fact they have seen a crime. Witnesses can often be exposed to misleading details from co- witnesses, suggestive interviewing techniques or sometimes, media reports of the crime. Any of these sources can lead witnesses to remember details that did not happen.

Recall

Psychological science has also shown that the way we test witnesses can also affect their memories for what they have seen. Some of the most prolific research in this field has examined the way that we test witnesses’ memories for offenders’ faces using the lineup technique. Photographic lineups are the most common method of testing eyewitness recall for offenders.

Usually, a lineup depicts a police suspect surrounded by known innocent people – known as distracters. A witness chooses a person from a lineup in the same way that a person chooses an option from multiple- choice question. When people choose the correct answer from a multiple- choice question it is considered evidence that they recognised the correct answer by relying on memory; and when witnesses choose the suspect from a montage, it is considered evidence that they recognised the suspect from the crime scene.

However, people do not always rely on their memory in either multiple- choice questions or lineups. A multiple-choice question can be biased towards the correct answer, as in this example:

What is the capital of Burundi?

Most people cannot rely solely on their memory to answer this question. Now consider these choices:

(a) Paris;
(b) Sydney;
(c) Wellington;
(d) Bujumbura.

You probably chose the correct answer (d), not because you had a memory for Burundi’s capital, but because you used a process of elimination to choose that answer. Similarly, a lineup is sometimes constructed so that witnesses do not need to rely on their memory for the offender; instead, they use a process of elimination – the suspect becomes the Bujumbura of the lineup.

Lineup bias

The danger arises when the wrong person is suspected of a crime and then included in a biased lineup. Research shows that witnesses will often choose from a lineup, even when the actual offender is not present. If the lineup has been constructed in a biased way (like the multiple choice question above), witnesses are even more likely to choose from the lineup. It is misidentifications like these that often lead to wrongful convictions.

Taken together, this research shows that witnesses’ memories are susceptible to several sources of error. As such, we need to ensure that we collect and test witnesses’ memories with scientifically valid interview and lineup techniques. Scientific recommendations regarding best practice procedures for witness evidence have been available for several decades, but few jurisdictions worldwide have taken them up. This lack of recognition for scientific validation is surprising given the relatively fast uptake of forensic science methods, such as DNA testing.

As a result, the best way to think of witness memory evidence is like biological evidence at a crime scene. If we were unlucky enough to stumble across a bloody crime scene, most people would be careful not to contaminate the scene by trampling through the blood spatter patterns, or handling any evidence. Similarly, we should treat witness memory with the same caution. When a witness has been exposed to a crime, we should not contaminate their memories with suggestive questioning and biased lineups. Instead, we should collect and preserve their memories with scenically valid techniques. Only then can we hope to reduce the increasing number of wrongful convictions caused by erroneous witness evidence.