Have you ever noticed how much easier it is to do a newspaper crossword puzzle later in the day? Me neither. But according to Rupert Sheldrake, it is because the collective successes of the morning resonate through the cultural morphic field.

In Sheldrake's theory of morphic resonance, similar forms (morphs, or "fields of information") reverberate and exchange information within a universal life force. "Natural systems, such as termite colonies, or pigeons, or orchid plants, or insulin molecules, inherit a collective memory from all previous things of their kind, however far away they were and however long ago they existed," Sheldrake writes in his 1988 book, Presence of the Past (Park Street Press). "Things are as they are because they were as they were." In this book and subsequent ones, Sheldrake, a botanist trained at the University of Cambridge, details the theory.

Morphic resonance, Sheldrake says, is "the idea of mysterious telepathy-type interconnections between organisms and of collective memories within species" and accounts for phantom limbs, how dogs know when their owners are coming home, and how people know when someone is staring at them. "Vision may involve a two-way process, an inward movement of light and an outward projection of mental images," Sheldrake explains. Thousands of trials conducted by anyone who downloaded the experimental protocol from Sheldrake's Web page "have given positive, repeatable, and highly significant results, implying that there is indeed a widespread sensitivity to being stared at from behind."

Let us examine this claim more closely. First, science is not normally conducted by strangers who happen on a Web page protocol, so we have no way of knowing if these amateurs controlled for intervening variables and experimenter biases.

Second, psychologists dismiss anecdotal accounts of this sense to a reverse self-fulfilling effect: a person suspects being stared at and turns to check; such head movement catches the eyes of would-be starers, who then turn to look at the staree, who thereby confirms the feeling of being stared at.

Skepticism is the default position.

Third, in 2000 John Colwell of Middlesex University in London conducted a formal test using Sheldrake's experimental protocol. Twelve volunteers participated in 12 sequences of 20 stare or no-stare trials each and received accuracy feedback for the final nine sessions. Results: subjects could detect being stared at only when accuracy feedback was provided, which Colwell attributed to the subjects learning what was, in fact, a nonrandom presentation of the trials. When University of Hertfordshire psychologist Richard Wiseman also attempted to replicate Sheldrake's research, he found that subjects detected stares at rates no better than chance.

Fourth, confirmation bias (where we look for and find confirmatory evidence for what we already believe) may be at work here. In a special issue in June of the Journal of Consciousness Studies devoted to a fierce debate between "Sheldrake and His Critics," I rated the 14 open peer commentaries on Sheldrake's target article (on the sense of being stared at) on a scale of 1 to 5 (critical, mildly critical, neutral, mildly supportive, supportive). Without exception, the 1's, 2's and 3's were all traditional scientists with mainstream affiliations, whereas the 4's and 5's were all affiliated with fringe and pro-paranormal institutions. (For complete results, see Table 1 in the online version of this column at www.sciam.com)

Fifth, there is an experimenter bias problem. Institute of Noetic Sciences researcher Marilyn Schlitz--a believer in psychic phenomena--collaborated with Wiseman (a skeptic of psi) in replicating Sheldrake's research and discovered that when they did the staring Schlitz found statistically significant results, whereas Wiseman found chance results.

Sheldrake responds that skeptics dampen the morphic field, whereas believers enhance it. Of Wiseman, he remarked: "Perhaps his negative expectations consciously or unconsciously influenced the way he looked at the subjects."

Perhaps, but wouldn't that mean that this claim is ultimately nonfalsifiable? If both positive and negative results are interpreted as supporting a theory, how can we test its validity? Skepticism is the default position because the burden of proof is on the believer, not the skeptic.