Why, however, did he feel that he needed to cut corners at all? Certainly not because of Watson and Crick—he was barely aware of their endeavors—but because he did know that King’s and perhaps even the Cavendish had access to superior X-ray data. He must have assumed that it would not be too long before his old rivals Bragg, Perutz, Kendrew, or perhaps Wilkins would figure out the correct structure. He decided to gamble, and he lost.

But there is very little doubt that had Pauling significantly delayed publication of his model, some researchers from Cambridge or London would have published their correct model first. Even though Pauling did not think specifically about Watson and Crick, he did know that the competition had the better hand. Therefore, taking a calculated risk may not have been altogether crazy.

On a more speculative note, Pauling’s decision to rush publication may also have been related to a human cognitive bias known as the framing effect, which reflects a strong aversion to loss. Have you ever wondered why stores generally advertise ground beef as being “90 percent lean,” rather than “10 percent fat”? People are much more likely to buy it with the former label, even though the two labels are equivalent. Similarly, people are more likely to vote for an economic agenda that promises 90 percent employment than for one that emphasizes 10 percent unemployment. Numerous studies show that the degree to which we perceive loss as devastating is higher than the degree to which we perceive an equivalent gain as gratifying. Consequently, people tend to seek risks when presented with a negative frame. Pauling may have preferred to take the risk when faced with the possibility of a probable loss.

There is also the puzzling issue of Pauling’s forgetting the Chargaff rules and, more importantly, his own insights on the self-complementarity of the genetic system. I believe that the latter was a strong manifestation of the fact that even when he finally decided to work on DNA, Pauling was still not entirely convinced that this molecule truly represented the very secret of life—the mechanism of cell division and heredity. Four main clues lead me to this conclusion: (1) There is Peter’s testimony that to his father DNA was just another interesting chemical and nothing more. Pauling was, after all, a chemist and not a biologist. (2) In his letter to the president of the Guggenheim Foundation announcing his “discovery” of the structure of DNA, Pauling added this, rather lukewarm, sentence: “Biologists probably consider that the problem of the structure of nucleic acid is fully as important as the structure of proteins” (note the noncommittal flavor of the phrase “Biologists probably consider”). (3) We have the pointed question that Pauling’s wife, Ava Helen, asked him after all the hoopla surrounding the publication of the Watson and Crick model had subsided: “If that was such an important problem, why didn’t you work harder on it?” (4) The Pauling and Corey paper itself (on the triple helix) provides what is perhaps the most convincing piece of evidence for Pauling’s lack of confidence in DNA’s importance. Pauling and Corey discuss the biological implications of their model only obliquely. In the opening paragraph of their paper, they mention halfheartedly that evidence exists that the nucleic acids “are involved” in the processes of cell division and growth, and that they “participate” in the transmission of hereditary characters. Only in the last paragraph of the original manuscript do they vaguely address the topic of coding of information (but not of copying), noting, “The proposed structure accordingly permits the maximum number of nucleic acids to be constructed, providing the possibility of high specificity.” I believe that this lack of conviction on Pauling’s part about the crucial role of DNA was at the core of the reality that the topic of heredity—and Pauling’s important pronouncements on it—apparently remained largely disconnected in his mind from the problem of the structure of DNA.

Forgetting Chargaff’s rules is, in my opinion, less mysterious. First, Pauling’s personal dislike for Erwin Chargaff surely contributed somewhat to his lack of attention to Chargaff’s results. Second, recall that Pauling was continuously distracted during his work on DNA. Enmeshed in his attempts to complete the work on proteins and in his bitter political struggles with McCarthyism, he barely had any time left to concentrate. Actually, on March 27, 1953, just two months after Peter received the manuscript on DNA, Pauling wrote a letter to Peter in which he commented, “I am just putting the final touches on my paper on a new theory of ferromagnetism.” He was already thinking of something else! This hardly could have helped. Extensive studies by Swedish researchers showed that natural memory problems (known as benign senescent forgetting) occur much more frequently when attention is divided or has to be shifted rapidly. Therefore, Pauling’s not remembering Chargaff’s rules is not very surprising.