Instructions: Why do most of us shake salt and pepper over our food, frequently before we have tasted it?

Why do we bite into a chili pepper, knowing it will cause pain?

Why do we put heaping spoonfuls of sugar into iced tea, then add sour lemon juice?

Because eating merely for subsistence - eating to live, if you will - is not pleasing or even satisfying for very long.

Scientists recognize four taste sensations - sweet, salty, bitter and sour - and we crave them all in varying combinations and intensities.

Almost forever, cooks have factored flavor contrasts into their cooking. The most highly developed expression of this comes in Chinese cooking, with the philosophy of yin and yang. Great cooking, whatever the cooks nationality, begins with this search for complementary pairs. Or, as Barbara Tropp calls it in her landmark book, "The Modern Art of Chinese Cooking," "a purposeful pairing of opposites."

She cites, among other examples, sugar and vinegar (sweet and sour), soy sauce and rice wine, ginger and scallion ...

An easily prepared and timely experiment is to make Tropps salt and Szechwan pepper mix and use it to season buttered steamed corn.

The contrasts include salt and sweet, salt and bitter. At the same meal, consider making crisp fried shrimp with garlic from Nina Simonds "Classic Chinese Cuisine." Here you will contrast bitter and sweet, salt and sweet, crisp and soft.

If you would like to email yourself the recipe for later use, or share the recipe with your friends or family, enter the email addresses below and this recipe will be emailed to you and others as well.