Eyewitness testimony is a crucial part of many criminal trials even though research increasingly suggests that it may not be as accurate as we (and many lawyers) would like it to be. For example, if you witness a man in a blue sweater stealing something, then overhear people talking about a gray shirt, how likely are you to remember the real color of the thief's sweater? Studies have shown that when people are told false information about an event, they become less likely to remember what actually happened - it is easy to mix up the real facts with fake ones. However, there is evidence that when people are forced to recall what they witnessed (shortly after the event), they are more likely to remember details of what really happened.

Psychologists Jason Chan of Iowa State University, Ayanna Thomas from Tufts University and John Bulevich from Rhode Island College wanted to see how providing false information following a recall test would affect volunteers' memories of an event that they witnessed. A group of volunteers watched the first episode of "24" and then either took an immediate recall test about the show or played a game. Next, all of the subjects were told false information about the episode they had seen and then took a final memory test about the show.

The results, reported in the January issue of Psychological Science, a journal of the Association for Psychological Science, were surprising. The researchers found that the volunteers who took the test immediately after watching the show were almost twice as likely to recall false information compared to the volunteers who played the game following the episode.

The results of a follow-up experiment suggest that the first recall test may have improved subjects' ability to learn the false information - that is, the first test enhanced learning of new and erroneous information. These findings show that recently recalled information is prone to distortion. The authors conclude that "this study shows that even psychologists may have underestimated the malleability of eyewitness testimony."

Trials showing a positive treatment effect, or those with important or striking findings, were much more likely to be published in scientific journals than those with negative findings, a new review from The Cochrane Library has found.

"This publication bias has important implications for healthcare. Unless both positive and negative findings from clinical trials are made available, it is impossible to make a fair assessment of a drug's safety and efficacy," says lead researcher, Sally Hopewell of the UK Cochrane Centre in Oxford, UK.

The international team of researchers carried out a systematic review of all the existing research in this area. In addition to showing that negative results were published less often, they found that if these results were eventually published, they would take between one and four more years to appear in journals than studies showing positive results.

Results from one of the five studies in the review indicated that investigators and not editors might be to blame. The reasons most commonly given for not publishing were that investigators thought their findings were not interesting enough or did not have time. "The registration of all clinical trial protocols before they start should make it easier to identify where we are missing results," says Kay Dickersin from Johns Hopkins University in Baltimore, USA, another of the researchers on this project.

One of the other researchers, Kirsty Loudon, based in Scotland, adds, "Registration of trials and their results would help people conducting systematic reviews to look at both published and unpublished evidence, to reach reliable conclusions."

The researchers say their study also highlights the need for a worldwide commitment to the disclosure of the findings of clinical trials. Mike Clarke of Trinity College Dublin in Ireland, says, "The World Health Organisation recently found widespread support for the development of such a process."

Andy Oxman from the Norwegian Knowledge Centre for Health Services concludes, "Healthcare decisions need to be based on all the evidence, not just the most exciting results."

New research helps explain link between social rejection and aggressive behavior

People who feel socially rejected are more likely to see others' actions as hostile and are more likely to behave in hurtful ways toward people they have never even met, according to a new study. The findings may help explain why social exclusion is often linked to aggression – which sometimes boils over dramatically, as in the case of school shootings, for example.

"Prior case studies show the majority of school shooters have experienced chronic peer rejection," said the study's lead author, C. Nathan DeWall, Ph.D., from the University of Kentucky. "And while not everyone who feels rejected reacts violently, we found they tend to act out aggressively in other ways. We wanted to help explain psychologically why this happens." A full report of the study appears in the January issue of the Journal of Personality and Social Psychology, published by the American Psychological Association.

DeWall conducted four separate experiments with 190 participants, all college students.

In one experiment, 30 participants completed a personality test and were given bogus feedback about the results. A third of the participants, the excluded group, were told their personalities would mean they would probably end up alone later in life. The rest of the participants, the control group, were either told they would have many lasting and meaningful relationships or were given no feedback at all.

All participants were then instructed to read a personal essay supposedly written by another participant, whom they did not know. The essay was about an event in which the author's actions could be perceived as either assertive or hostile and the participants rated their impression of the author's actions. They were also told that the author was up for a research assistant position and were asked whether they thought the author would be a good candidate, based on what they had read.

Participants who were told they were going to have a lonely life perceived the author's actions as significantly more hostile and gave a much more negative evaluation than those in the control groups. The authors also note that the participants' moods did not seem to differ among the different groups, which led them to conclude that the participants' emotional response to their personality results did not play a role in how they performed in the experiments.

In another experiment, 32 students underwent the same bogus personality evaluation and rated the same essay from the previous experiment. Again, some were told they would lead a lonely life while others were assigned to the control groups. This time, participants were led to believe they were playing a reaction-time computer game with another person in the lab whom they could not see and had never met. During the game, the loser of each trial was forced to listen to a blast of white noise through headphones. The participants could set the noise's intensity level and duration.

Those who were told they were going to have a lonely life blasted a higher level of the painful noise than those in the control groups. "Across all experiments, the participants who experienced some form of social rejection acted in similar ways," said DeWall. "This suggests these people feel betrayed by others. In turn, they see otherwise neutral actions as hostile and behave badly towards others."

Prior research has examined whether emotions play a role in this type of aggression, but this study's researchers say their findings do not support this idea. "Excluded people see the world through blood-colored glasses and it is our hope that this research can lead to a better understanding of why rejection causes aggression and what we can do to prevent such unwanted and harmful behavior," said DeWall.

The Persistence of Racism

Recent research concludes that while people predict they will react negatively to racial slurs, their behavior proves otherwise.

60-Second Psych from Scientific American podcasts
13 January 2009

No such gender disparity exists for younger women

Younger women have equivalent access to kidney transplants compared with their male counterparts, but older women receive transplants much less frequently than older men, according to a study appearing in the March 2009 issue of the Journal of the American Society Nephrology (JASN). The results suggest that steps are needed to ensure that women are provided with equal opportunities to receive kidney transplants as they age.

Researchers have reported that women have less access to kidney transplants than men, but this recent study indicates that this disparity does not affect all women. Dorry Segev, MD, of the Johns Hopkins Medical Institutions in Baltimore, MD, and his colleagues discovered this by studying the United States Renal Data System, which collects, analyzes, and distributes information about end-stage kidney disease in this country. Their analysis included 563,197 patients with end-stage kidney disease diagnosed between 2000 and 2005.

The investigators found that while young women in this group had equivalent access to transplantation when compared with their male counterparts, access for older women decreased significantly. Specifically, women aged 18 to 45 years had access to transplantation that was equivalent to men, women aged 46 to 55 years had 3% less access, women aged 56 to 65 years had 15% less access, women aged 66 to 75 had 29% less access, and women over 75 years had 59% less access.

These disparities existed for both access to the deceased donor waiting list as well as access to live donations. However, the gender disparities were limited to referral to the waiting list—once a woman was on the transplant list, her chances of receiving a transplant were equivalent to a man's. This is very different from other disparities in transplantation such as race disparities, in which African Americans are less likely to be referred to the waiting list and are also less likely to receive a transplant once on the list.

Dr. Segev and his team also found that for every age group analyzed in this study, women had a similar or slightly higher survival benefit from transplantation compared with men, indicating that there is no reason to deny women transplants as they age.

These findings could help researchers develop ways to reduce disparities in kidney allocation. "Knowing that the gender disparity is limited to older women indicates that efforts should be made to identify specific differences between older men and older women—rather than general differences between all men and women—in an effort to minimize the gender disparity in access to transplantation," said Dr. Segev.

The Art of Diagnosis (~ 18 min. podcast)

Does very severe PMS constitute a mental disorder? That's one of many questions facing psychiatrists as they work to revise the Diagnostic and Statistical Manual of Mental Disorders or DSM, the definitive compendium of our psychic maladies. Because the DSM influences not just doctors and patients but medical research, insurance companies, the pharmaceutical industry, advertising and the culture at large, controversy surrounding its new edition abounds. Brooke looks at this powerful book

On the Media: This Week from NPR
December 26, 2008