About three years ago, Wisconsin's Senator William Proxmire discovered that the National Science Foundation in Washington had given Dr. Elaine Walster, a social psychologist who teaches both psychology and sociology at the University of Wisconsin, and one of her research partners, Dr. Ellen Berscheid of the University of Minnesota, an $84,000 grant to continue a study of passionate and companionate love. Ever the watch-dog of the public purse, the senator quickly fired off this protest:

"I object to this not only because no one - not even the National Science Foundation - can argue that falling in love is a science; not only because I'm sure that even if they spend $84 million or $84 billion they wouldn't get an answer that anyone would believe. I'm also against it because I don't want the answer.

"I believe that 200 million other Americans want to leave some things in life a mystery, and right at the top of things we don't want to know is why a man falls in love with a woman and vice versa . . .

"So National Science Foundation - get out of the love racket. Leave that to Elizabeth Barrett Browning and Irving Berlin. Here, if anywhere, Alexander Pope was right when he observed, 'If ignorance is bliss, 'tis folly to be wise.'"

Proxmire's criticism led the National Science Foundation to withdraw its grant, but Walster stayed in the love racket, and the result, published this week, is a New Look at Love, written with her husband G. William Walster, a statistician with an interest in the social sciences.

In his introduction to the book, T George Harris, former editor of Psychology Today, recalls that not everyone agreed with Proxmire. James Reston, of The New York Times, concluded that, although love will undoubtedly remain a mystery, ". . . if the sociologists and psychologists can get even a suggestion of the answer to our pattern of romantic love, marriage, disillusions, divorce - and the children left behind - it would be the best investment of federal money since Jefferson made the Louisiana Purchase."

Without destroying the mystery at all, A New Look At Love does manage to suggest some answers to the eternal question. Some of what was discovered confirms commonsense notions of love that have been passed down for generations; other findings challenge some of our traditional, and most cherished, assumptions. Here are some highlights of the Walsters' most interesting discoveries which should intrigue anyone who's ever been in love, or hopes to be. Perhaps even Senator Proxmire?

Susan Wood What is love anyway?

Love can appear in two very different forms: passionate love and companionate love. Passionate love is a wildly emotional state, a confusion of feelings: tenderness and sexuality, elation and pain, anxiety and relief, altruism and jealousy. Companionate love, on the other hand, is a lower-key emotion. It's friendly affection and deep attachment to someone. Almost all of us make a sharp distinction between our passionate feelings and our companionate ones. Which is "true love"? People disagree sharply on this question.

We asked a number of people to describe to us what passionate love feels like for them.Here's what two of them said:

When I'm in love, I think about the man I love constantly, I can twist any conversation around in my mind to lead to him. When I see him - POW! - my heart takes a leap, my cheeks flush, and I can't help smiling. At night before going to bed, I think of all the little things we said or did throughout the day - and smile. When I'm in love, I never look at any other guys with interest . . . I always seem to be in a good mood . . .

Bloomingdale's saleswoman, New York.

Love is a feeling of belonging, having someone to identify with. To feel overwhelming trust and jealousy at the same time. Everything you do and think about is shared with the other. When you touch one another, or just hear their voice, there is a desperate feeling of want and need, a feeling inside that actually hurts. When I first felt love it was the best feeling in the world.

Dry cleaner's assistant, Nebraska.

And here is what two others said about companionate love:

Being a romantic at heart I had very definite ideas about how "love" should be. Somehow, however, it didn't turn out the way I had imagined. The earth didn't move, as I imagined it would. I feel comfortable with this man. I can communicate with him on all levels. He understands me.

Ex-nun, New Jersey.

Love means wanting the best for another. Love is often expressed by letting the other person know you believe in him/her and that you support them in what they are doing. You help them to grow as a person. You allow yourself to need the other. You support them to the extent of letting them know you share the same fears and goals and dreams and hopes. You are willing to be vulnerable.

A Ford assembly-line worker, Detroit. What is the difference between liking all loving?

Liking and companionate love have quite a lot in common. Liking is simply the affection we feel for casual acquintances. Companionate love is the affection we feel for those with whom our lives are deeply intertwined. The only real difference between liking and loving is the depth of our feelings and the degree of our involvement with the other person.

Attraction theorists are generally agreed upon the genesis of liking and companionate love. In order to explain why we feel profoundly attracted to some people and why we can't stand others, theorists cite the principle of reinforcement: You're likely to feel some fondness for the person who makes you feel marvelous about yourself and the world around you, and you'll come to feel a distinct aversion toward someone who makes you feel rotten. We also come to like people who are merely assciated with good times and to dislike those who are merely associated with bad ones.

Psychologists have amassed considerable evidence for their contention that we all practice love - or guilt - by association. One psychologist tested the hypothesis that our reaction to people is colored by what we think of the environment they inhabit. He asked young people to get to know a stranger. Half of the men and women met in a cool, calm environment; the other half met in an uncomfortably hot room. The men and women who got to know each other in comfortable surroundings ended up liking each other a lot more than did the men and women who met under miserable conditions.

So, one tip: of you and your lover want to establish a fledgling relationship - or keep the relationship you've got going strong - you should both be careful to do two things: (1) try to be rewarding partners in your own right, and (2) try to make sure that your times together continue to be good times. Maybe both of you do want to spend all your vacation time painting your apartment, repairing screens and cleaning out your gutter and downspouts. Or maybe you do want to devote all of your energy to your job - working nights and weekends - and are willing to settle for a middling sex life, because you're "too tired" for anything else. Whatever your inclination, just remember: unless you're sharing some pretty good times now, you might not have a future together. Who says men aren't romantics?

A group of sex researchers, interviewed 700 young lovers. They asked the men and women to tell them a little bit about the person they were in love with right now. (If they weren't in love with anybody right now, the scientists asked them to talk about the last time they were in love.) "How early," they asked, "did you become aware that you loved the other?" The scientists found that while 20 percent of the men fell in love before the fourth date, only 15 percent of the women fell in love that early. At the other extreme, only 30 percent of the men, but a full 43 percent of the women, were not sure if they were in love or not by the twentieth date.

A group of Harvard scientists got acquainted with 231 Boston couples and charted the course of their affairs for two years. They found that, usually, the women decided whether and when an affair should end; the men seemed to stick it out to the bitter end. When things finally did die down, it was the men who suffered the most. The men felt most depressed, most lonely, least happy, and least free after a breakup. They found it extremely hard to accept the fact they were no longer loved; that the affair was over and there was nothing they could do. They were plagued with the hope that if only they said the right thing . . . did the right thing . . . things would be as they were. Women were far more resigned and, thus, were better able to pick up the pieces of their lives and move on.

Interestingly enough, the researchers' contention that it is the men who suffer most when an affair flickers out is consistent with the fact that three times as many men as women commit suicide after a disastrous affair. But aren't women the real romantics?

The evidence from various studies makes it clear that there is no simple answer to the question. Men tend to fall in love more quickly and cling to a faltering love more tensciously than do women. However, while the relationship is at its most intense, women experience the euphoria and the agony of love more intensely than do men.

Feminist Arlie Hochschild contends that men and women differ markedly in their willingness to attend to feelings of various kinds, in how they prefer to label their feelings, and - most importantly - in how hard they try to manage their thoughts and feelings. She finds that women spend a great deal of time trying to feel what they "ought" to feel and trying not to feel what they think they ought not to feel.

Consider, for example, one woman's description of an attempt to make herself love another.

Since we both were somewhat in need of a close man-woman relationship and since we were thrown together so often (we lived next door to each other and it was summertime), I think that we convinced ourselves that we loved each other. I had to try to convince myself that I loved him in order to justify or somehow "make right" sleeping with him (which I never really wanted to do). We ended up living together supposedly because we "loved" each other but I would say instead that we did it for other reasons which neither or us wanted to admit. What pretending I loved him when I really didn't means to me was having a "secret" nervous breakdown.

Or consider this example:

Last summer I was going out with a guy often and began to feel very strongly about him. I knew though that he had just broken up with a girl a year ago because she had gotten too serious about him. So I was afraid to show any emotion. I also was afraid of being hurt, so I attempted to change my feelings. I talked myself into not caring about Mike . . . but I must admit it didn't work for too long. To sustain this feeling I had to almost invent bad things about him and concentrate on them or continue to tell myself he didn't care. It was a hardening of emotions I'd say. It took a lot of work and was upleasant, because I had to concentrate on anything I could find that was irritating about him. (The story does have a happy ending - I finally, after three months, let down my wall and admitted how I felt, and to my surprise and joy, he felt the same way. Things are now going very well.)

Men are far less likely to become so absorbed in monitoring and controlling their emotions; they simply feel what they feel. Women, however, try at least to temper their feelings according to the situation. Question: How can I tell if I'm really in love . . . or just infatuated?

College students at three universities were asked what one thing they most wished they knew about romantic love. A surprisingly frequent question was: "What is the difference between love and infatuation?"

The solution to the love-versus-infatuation riddle seems to be quite simply, that there is no difference. Psychologists have become increasingly skeptical that passionate love and infatuation differ in any way - at the time one is experiencing them. Two sex counselors concluded that the difference between passionate love and infatuation is merely semantic. Lovers use the term "romantic love" to describe loving relationships that are still in progress. They use the term "infatuation" to describe once-loving relationships that, for a variety of reasons, were terminated.

It appears, then, that it may be possible to tell infatuation from romantic love only in retrospect. If a relationship flowers, we continue to believe we are experiencing true love; if a relationship dies, we conclude that we were merely infatuated. We need not assume, then, that, at the time we are experiencing the feeling, true love differs in any way from the supposed counterfeit.

As Judith Viorst has written: "Infatuation is when you think that he's as sexy as Robert Redford, as smart as Henry Kissinger, as noble as Ralph Nader, as funny as Woody Allen and as athletic as Jimmy Connors. Love is when you realize that he's as sexy as Woody Allen, as smart as Jimmy Connors, as funny as Ralph Nader, as athletic as Henry Kissinger and nothing like Robert Redford in any category - but you'll take him anyway."