It started out as a typical class discussion of a recently published memory study. Wesleyan University psychology professor John Seamon, PhD, was describing its finding, that when people read lists of semantically similar words-"bed, rest, tired and dream" for example-they tend to falsely recall that similar words, such as "sleep," appeared on the list. The study by researchers Henry Roediger III, PhD, and Kathleen McDermott, PhD, in 1995-in the Journal of Experimental Psychology: Learning Memory and Cognition (Vol. 21, No. 4)-got student David Gallo thinking.
Until that point one of the quietest in class, he asked, "What if people were wise to that memory illusion before seeing the list? Would their false memory rate go down?"
Seamon paused, considering whether the question had already been investigated (it hadn't) and if it was testable (it was). "Let's find out," he said.
With Seamon's direction, Gallo tackled the memory illusion question for a course research project-he warned participants of the false-memory risk and advised them to strategize to avoid it. He found an interesting effect: The illusion was cut in half when people were warned. The experiment's results were so compelling that, with Seamon's help, Gallo and fellow undergraduate Meredith Roberts conducted a full-fledged version of the study, published in Psychonomic Bulletin & Review (Vol. 4, No. 2), with Gallo as first author.
That early success began Gallo's research career tracing the workings of memory. "I was fascinated that we can easily be made to remember events that didn't occur, often with a strong sense that they did occur," he explains.
That fascination led to his graduate and postdoc work with some of the top names in memory research, including Roediger, chair of Washington University's psychology department and president of the American Psychological Society, and Daniel Schacter, PhD, chair of Harvard University's psychology department. As part of Gallo's current postdoc, funded by a National Research Service Award, he and Schacter are using behavioral and neuropsychological approaches to study the effects of aging and Alzheimer's disease on memory.
Gallo, now a PhD, says Seamon's mentoring opened the door to his career path in memory research. When he entered Wesleyan, Gallo had planned to study political science, but then he discovered psychology's strong scientific underpinnings and changed his mind.
For an undergraduate, "David just jumped in" to doing research with unusual confidence and determination, says Seamon, who adds that he's never seen a student take to research so quickly.
Gallo's study was the first to show that warnings given before participants study word lists can reduce the associative memory illusion. More recently, Gallo, McDermott and Roediger have shown in Psychonomic Bulletin & Review (Vol. 8, No. 3) that warnings given after the lists are studied, but before people are tested on them, are ineffective. Collectively, such studies indicate how difficult it is to consciously control memory illusions.
During his undergraduate years, Gallo also co-authored two other published papers-another false-memory study with Seamon and an investigation of how readers access the meaning of words with Wesleyan psychologist Chun Luo, PhD. With three published studies under his belt, Gallo was primed for graduate school.
Deciding on a graduate program was simple. Gallo wanted to work with one of the researchers whose word-list study had triggered his own-Washington University's Roediger, who had accepted Gallo's first-author paper for publication in 1997.
"False-memory was a hot topic, and no one had more command of that literature than David," says Roediger of why he welcomed Gallo into Washington University's experimental psychology PhD program.
Among the topics Gallo studied with Roediger was implicit memory-the tendency for people's past experiences to influence their current thoughts and learning without consciously realizing it.
While that mechanism can give new learning something to build on, it can also interfere with learning and recollection when new information is only slightly-yet still distinctly-different from old information, says Gallo. For example, many Americans have had the frightening experience of driving on the wrong side of the road when vacationing in Europe.
"Our acquired habit of driving on the right interferes with our ability to temporarily switch over to driving on the left, and we may only become consciously aware of the tendency when other cars are honking at us," Gallo explains. He notes that such implicit-memory influences have been implicated in other types of memory errors, such as unintentional plagiarism, or cryptomnesia.
"Our general philosophy is that the mind takes shortcuts to help us understand the world," says Gallo. "Usually these shortcuts help us quickly and easily process necessary information, but sometimes they cause errors."
For Gallo, basic memory research can translate into early detection and, hopefully, early treatment of Alzheimer's disease. With that in mind, he's moved on to a three-year postdoc in Schacter's Harvard lab. There, he's examining the brain functioning of Alzheimer's patients and normal older people as it affects memory.
Gallo also says he hopes to keep a hand in basic cognitive research to gain the complete picture of how memory works. But that doesn't mean he'll risk becoming scattered. Because, in addition to good mentoring, Gallo says he owes his success to his determination to finish every project he starts.
"Especially early on, you have such great idealism and excitement about all sorts of research," he says. "But you need to cultivate one interest you can really call your own."