James Bond preferred his vodka martinis “shaken, not stirred,” but is there any difference? Yes, according to a psychologist and a chemist who like their science with a twist.

In celebration of the centenary of the birth of Ian Fleming, creator of the world’s most famous secret agent, the psychologist Charles Spence and the chemist Andrea Sella will be unveiling the secrets of 007’s favorite drink and a range of other cocktails, at a lecture at the Cheltenham Science Festival in England next month.

To these aficionados, the creation and presentation of a cocktail is a true science: “Molecular mixologists” can create alcoholic alchemy, from Bond’s dry martini to daiquiris and beyond.

Take the all-important issue of shaking rather than stirring the martini. In 1999, a group of students at the University of Western Ontario in Canada decided to test Bond’s preference in a series of experiments on gin and vodka martinis. While the detailed chemistry is not fully understood, martinis were much more effective than their basic ingredients at deactivating hydrogen peroxide — a potent source of the free radicals linked to aging and disease — and about twice as effective when shaken.

Mr. Sella, a researcher at University College London, believes that shaken martinis are not only healthier, but also taste better. This is due to what experts call “mouthfeel” — the shaken martini has more microscopic shards of ice, making its texture more pleasing. He plans to test this hypothesis at the festival, where he is not expecting a shortage of volunteers.

Martinis pack quite an alcoholic punch — but how quickly would they have an effect on 007? Alcohol is alcohol, but it is taken up at different rates, depending on many factors. Drinks that are creamy or sugary will creep up on you more slowly, hence the idea that a glass of milk will line your stomach. But the absence of bubbles in a martini would slow the uptake of alcohol.

And the effect of cocktails is not just chemical, but also psychological. Mr. Spence explains that our perception of cocktails is affected by the shape of the glass — people do not enjoy drinks as much if they are served in a container they feel is inappropriate.

The appearance of a drink can also affect how happy we are with it: Our brains make a pleasant association between the colors of ripening fruit and increased sugar content. “Such colors, particularly bright reds, are especially powerful visual cues,” Mr. Spence said. “When incorporated into a drink, they can dramatically change the perceived flavor, as well as increasing the perceived sweetness by as much as 12%.”

French researchers tested this by using an odorless dye to color white wine red. The wine tasters who tried the result used typical red-wine descriptors, suggesting that its color played a significant role in how they thought of it.

Even the link with Bond will affect the way we perceive a martini. People are likely to pay more for a cocktail if it has a more elaborate name or — in this case — reputation.

There are differences in the extent to which people use their senses to rate drinks. About a quarter of the population are “supertasters” — those born sensitive to bitter flavors who ignore visual tricks such as dyeing white wine red.

Despite his excellent taste in shaking rather than stirring his martinis, Bond is probably not among their number: They would be likely to taste the vermouth and olives as bitter and unpleasant. Instead, like most of the population, his perception would more likely be dominated by his eyes. This neatly ties into other aspects of the Bond legend, Mr. Spence pointed out — in particular his liking for the best-looking women.