NAIVE REALISM:

The Tease of Memory: Psychologists are dusting off 19th-century explanations of déjà vu. Have we been here before? (DAVID GLENN, 7/23/04, Chronicle Review)

In the summer of 1856, Nathaniel Hawthorne visited a decaying English manor house known as Stanton Harcourt, not far from Oxford. He was struck by the vast kitchen, which occupied the bottom of a 70-foot tower. "Here, no doubt, they were accustomed to roast oxen whole, with as little fuss and ado as a modern cook would roast a fowl," he wrote in an 1863 travelogue, Our Old Home.

Hawthorne wrote that as he stood in that kitchen, he was seized by an uncanny feeling: "I was haunted and perplexed by an idea that somewhere or other I had seen just this strange spectacle before. The height, the blackness, the dismal void, before my eyes, seemed as familiar as the decorous neatness of my grandmother's kitchen." He was certain that he had never actually seen this room or anything like it. And yet for a moment he was caught in what he described as "that odd state of mind wherein we fitfully and teasingly remember some previous scene or incident, of which the one now passing appears to be but the echo and reduplication."

When Hawthorne wrote that passage there was no common term for such an experience. But by the end of the 19th century, after discarding "false recognition," "paramnesia," and "promnesia," scholars had settled on a French candidate: "déjà vu," or "already seen."

The fleeting melancholy and euphoria associated with déjà vu have attracted the interest of poets, novelists, and occultists of many stripes. St. Augustine, Sir Walter Scott, Dickens, and Tolstoy all wrote detailed accounts of such experiences. (We will politely leave aside a certain woozy song by Crosby, Stills, Nash & Young.)

Most academic psychologists, however, have ignored the topic since around 1890, when there was a brief flurry of interest. The phenomenon seems at once too rare and too ephemeral to capture in a laboratory. And even if it were as common as sneezing, déjà vu would still be difficult to study because it produces no measurable external behaviors. Researchers must trust their subjects' personal descriptions of what is going on inside their minds, and few people are as eloquent as Hawthorne. Psychology has generally filed déjà vu away in a drawer marked "Interesting but Insoluble."

During the past two decades, however, a few hardy souls have reopened the scientific study of déjà vu. They hope to nail down a persuasive explanation of the phenomenon, as well as shed light on some fundamental elements of memory and cognition. In the new book The Déjà Vu Experience: Essays in Cognitive Psychology (Psychology Press), Alan S. Brown, a professor of psychology at Southern Methodist University, surveys the fledgling subfield. "What we can try to do is zero in on it from a variety of different angles," he says. "It won't be something like, 'Boom! The explanation is there.' But we can get gradual clarity through some hard work." [...]

Most of today's déjà vu scholars have chucked primal-preobject-libidinal representations in favor of brain scans and neuroimaging. Taking advantage of a recent explosion of experimental research on memory errors, Mr. Brown and a few like-minded colleagues have dusted off the theories of déjà vu proposed during the late Victorian era. At last, he hopes, such hypotheses can be subject to rigorous experimental tests. He warns, however, not to expect quick results: "A lot of science is geared at, How can I get tenure? How can I crank out a study in a year? The luxury of being able to attack difficult problems is often more risky. There's a little more investment of your personal resources, a little bit of gambling."

In Mr. Brown's account, scientific theories of déjà vu fall into four broad families. The first are theories of "dual processing." The late neuropsychiatrist Pierre Gloor conducted experiments in the 1990s strongly suggesting that memory involves distinct systems of "retrieval" and "familiarity." In a 1997 paper, he speculated that déjà vu occurs at rare moments when our familiarity system is activated but our retrieval system is not. Other scholars argue that the retrieval system is not shut off entirely but simply fires out of sync, evoking the fatigue theory of a century earlier.

In the second category are more purely neurological explanations. One such theory holds that déjà vu experiences are caused by small, brief seizures, akin to those caused by epilepsy. That idea is buttressed by the fact that people with epilepsy often report having déjà vu just before going into full-blown seizures. Researchers have also found that déjà vu can be elicited by electrically stimulating certain regions of the brain. In a 2002 paper, the Austrian physician Josef Spatt, who works with epilepsy patients, argued that déjà vu is caused by brief, inappropriate firing in the parahippocampal cortex, which is known to be associated with the ability to detect familiarity.

Mr. Brown's third category consists of memory theories. These propose that déjà vu is triggered by something we have actually seen or imagined before, either in waking life, in literature or film, or in a dream. Some of these theories hold that a single element, perhaps familiar from some other context, is enough to spark a déjà vu experience. (Suppose, for example, that the chairs in Stanton Harcourt's kitchen were identical in color and shape to Hawthorne's decorously neat grandmother's, but that he didn't recognize them in this new context.) At the other end of the scale are gestalt theories, which suggest that we sometimes falsely recognize a general visual or audio pattern. (Suppose that the Stanton Harcourt kitchen looked similar, in broad visual outline, to a long-forgotten church that Hawthorne had once attended.)

In the final box are "double perception" theories of déjà vu, which descend from Allin's 1896 suggestion that a brief interruption in our normal process of perception might make something appear falsely familiar. In 1989, in one of the first laboratory studies that tried to induce something like déjà vu, the cognitive psychologists Larry L. Jacoby and Kevin Whitehouse, of Washington University in St. Louis, showed their subjects a long list of words on a screen. The subjects then returned a day or a week later and were shown another long list of words, half of which had also been on the first list. They were asked to identify which words they had seen during the first round.

The experimenters found that if they flashed a word at extremely quick, subliminal speeds (20 milliseconds) shortly before its "official" appearance on the screen during the second round, their subjects were very likely to incorrectly say that it had appeared on the first list. Those results lent at least indirect support to the notion that if we attend to something half-consciously and then give it our full attention, it can appear falsely familiar.

The study is one of many that demonstrate the potential pitfalls of everyday memory and cognition, says Mr. Jacoby. "At our core, I think all of us are naïve realists. We believe the world is as it presents itself," he says. "All of these experiments are a little unsettling if you're a naïve realist."

But amusing if you think empiricism is bunk.

Posted by Orrin Judd at April 20, 2005 10:23 PM