Sunday, August 15, 2010

APA Dispatch I: Science and public policy

I had intended to limit my dispatches from the American Psychological Association convention in San Diego to forensic highlights. But I would be remiss if I didn't touch on the big news from psychological science and public policy. Anyway, it's all related to forensics.

Conference theme: Ending marriage discrimination

A public policy highlight of the convention was its theme of opposing marriage laws that discriminate against gay men and lesbians. Walking into the futuristic convention hall, one was greeted by a life-sized hologram of the APA's CEO, Norman B. Anderson, speaking of the scientific advocacy role in this area of the APA, which at 152,000 members is the world's largest psychological organization and devotes a good share of its $115 million annual budget to advocacy. Kiosks gave attendees a chance to don large lapel pins supporting marriage equality, or send a message to their legislator calling for an end to the federal ban on same-sex marriage.

The theme, planned months ago, could not have been more timely, especially given the conference's location. Just as the convention got underway yesterday, Judge Vaughan Walker lifted the stay on gay marriages in California following his earlier ruling that marriage discrimination was unconstitutional. Many of the key expert witnesses who presented scientific evidence at that trial were featured speakers at the convention: Gregory Herek of UC Davis on sexual orientation and stigma (introduced by APA President Carol Goodheart), Anne Peplau of UCLA on same-sex relationships, and Charlotte Patterson of the University of Virginia summarizing the empirical research regarding the emotional health of children raised in lesbian and gay families.

The APA leadership seems delighted to be on the correct side of history this time, especially after the lengthy debacle over psychologists' role in the torture of detainees at Guantanamo.

Memory: How the brain reconstructs reality

Meanwhile, memory research was on the cutting edge of the psychological science presented at the convention. I had the great fortune to hear preeminent scholar Daniel Schacter present some of the very latest findings.

We already know that retrieving a memory is nothing like opening a file on your computer. In calling up a memory, the brain -- specifically the hippocampus -- grabs a bunch of bits and pieces stored here and there around the brain, and reintegrates them to suit the current situational demand. This is adaptive. It allows us to use our accumulated experience to respond flexibly to an ever-changing environment. But it comes at a cost of errors and distortions, which Schacter has summarized beautifully in The Seven Sins of Memory (which all forensic practitioners should read).

In his talk, Schacter illustrated with the case of "John Doe 2," the composite creation of a faulty memory who was the subject of a massive FBI manhunt after the Oklahoma City bombing. As it turned out, John Doe 2 (despite lingering conspiracy theories to the controversy) was most probably an Army private who had nothing whatsoever to do with McVeigh; he happened to have been at the auto body shop where McVeigh rented his van, but a full day later.

The advent of neuroimaging technology has enabled this memory research to advance at a rapid pace. (The hippocampus even has its own journal now, named after itself!) In their most recent work, Schacter and his colleagues are localizing the precise hippocampal sites that activate when various tasks are being performed. Distinct patterns of hippocampal activity are visible on fMRI when someone is storing initial memories, retrieving those memories, and imagining future possibilities.

Intriguingly, it turns out that the brain tasks involved in remembering are not so different from those involved in imagining the future, or imagining a fictional version of the past, for that matter. Which makes sense: Like recalling real events, imagining fictional scenarios first requires us to think about our past experiences, and then tweak them (consciously or unconsciously).

Australian study: Sharing distorts eyewitness memory

The fact that the very act of retrieving a memory causes it to be distorted (also the topic of a rather dry convention presentation by researcher Joseph LeDoux, author of The Emotional Brain) explains a new finding by forensic psychology lecturer Helen Paterson of the University of Sydney in Australia. She found that sharing memories leads to contamination that cannot be reversed through providing corrective information.

Paterson's team showed participants one of two different versions of a video of a crime. After discussing the crime with each other, most participants reported seeing specific details that were not in the version they had watched. The researchers believe that discussions among co-witnesses are more likely to damage accurate recall for a crime than are other avenues of distorted information such as reading a news account or being asked leading questions by investigators.

Like the broader memory research of Schacter and others, Paterson's study, published in the journal Applied Cognitive Psychology, has direct implications for witness reliability. Once a memory is distorted, the inaccuracies remain even when witnesses are told that the new information is wrong, as witnesses " find it difficult, if not impossible, to distinguish between genuine memories and false memories of an event," Paterson said.

The forensic implications of this line of memory research are rather mind-boggling, when you stop and think about it. Not only do we need to be extremely cautious about putting too much weight on someone's memory for an event but, as the accumulating research shows, we must be skeptical even if multiple people agree on the "facts."

Coming up in Part II: Whither juvenile forensics

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