A REPORTER once asked Rose Nader what made her son tick. "What makes the others not tick?" she replied.In the Nader home, civic spirit was the norm. Her son Ralph is, of course, a household name, the man who took on General Motors and showed that one individual could still make a difference. Ralph's two sisters - Laura and Clair - and his late brother, Shafeek, pursued similar if less-publicized paths. Lots of ticking occurred in that family, and Mrs. Nader has received many letters over the years asking for her secrets. What did she feed them as children? What did they talk about at dinner? In response, Mrs. Nader has written a book, and it just may surprise those who have a stereotyped view of the man. Many on the right have portrayed Ralph Nader as leftist and even subversive. But it turns out that he was weaned on the same "traditional family values" that his critics so often espouse. He differed from them only in expecting the world of business to live up to these values too. "It Happened In the Kitchen," is the title of Mrs. Nader's book (available from Kitchen, Box 19367, Washington DC 20036, $9.) There are recipes for simple Middle Eastern dishes that were the family favorites, from stuffed eggplant to a pistachio pastry called Ma'mool. But what happened in the Nader kitchen was much more than lunch and dinner. "Food is more than sustenance," Mrs. Nader writes. "It is an expression of health, affection, cultural transmission, stimulation, teaching, transmission, and bondin g." The story began in Lebanon, where Mrs. Nader was raised under a sod roof, in a small town. There were eight daughters and four cousins, and many of her memories revolve around the kitchen - the storytelling and aphorisms, the brick oven in which they baked bread. Rose became a schoolteacher before sailing to America with her new husband, Nathra. They settled in Winsted, Conn., where Mrs. Nader turned the family kitchen into the kind she grew up in. She told stories at lunch time, long sagas that might last for weeks. She engaged the children in conversation about school and life, feeding them with aphorisms as well as hummus: "A person who practices telling the truth is likely to discover more of it." The Nader children didn't have a lot of games or toys; how can parents expect to "communicate" with their kids, she asks, if they don't talk with them? The kids did chores after meals, ate what they were given, weren't allowed to do things just because the other kids did. It was an old-fashioned upbringing, but with an Old World warmth and wisdom. Mrs. Nader quotes her mother: "Make your child cry a little now, rather than cry later over him." When the kids complained about a teacher, Mrs. Nader wouldn't let them off the hook. "Do not blame anyone but yourselves," she would say. "I believe it's you." It is not hard to see the beginnings of a man who took on the job of full-time citizen, and who expects corporations and government to be - his favorite word responsible." Mrs. Nader was active in civic affairs as well. Once she shook the hand of then-Sen. Prescott Bush, the president's father, and refused to let go until he agreed to do something about the local flooding. But the civic activist in the family was Nathra, whose life was a lover's quarrel with his adopted country. Nathra was a regular at town meetings, and turned his little restaurant on Main Street into a kind of forum - an extension of the family kitchen. The last section of "It Happened In the Kitchen" recalls Nathra Nader's observations. It is hard to capture in a few words the blend of idealism, irony, and wit. He told his customers they complained about government too much, and did too little. He deplored the decline in civic participation and debate. "Television has replaced the dictator's ban on three or more people gathering in public without a permit," he said. My favorite is the exchange at the restaurant with a doctor, back when coffee was 10 cents a cup. Dr.: Why are the auto workers' wages so high? N.N.: So they can afford to pay your bills. Why do you charge so much? Dr.: Because we often treat poor people for free. N.N.: Well, in that case [smiling] since we give free coffee to poor people, your coffee today is $1. Thank you.