(FORTUNE Magazine) – Karin Hamel, an industrial psychologist and consultant in Washington, D.C., tells of a shock sustained recently by one of her corporate clients. The company decided that it needed to get rid of hundreds of older managers to make room for younger blood. To this end, it designed an early-retirement package that management hoped would persuade maybe 500 of its graying types to head for the golf course. Surprise -- when the package was offered, 1,500 older managers applied to take it. First test question for all aspirants to the higher managerial wisdom: Should the top brass at Hamel's client be worried? No, no, you hopeless softies, not about the restlessness that would impel so many employees to want to go. The real issue, instantly apparent to all executive hardnoses, is whether this company would be missing anything by eliminating from its managerial ranks what in these hurried times passes for an entire generation. The same question confronts companies concerned that they may somehow have ended up without a cadre of, say, thirtyish execs. When they dip into their pools of managerial talent some time hence, is there any danger that they'll come up empty of skills critical to the company's success? The possibility gives new urgency to a larger question that might otherwise be left to philosophers and poets of management, or merely to professors of organizational behavior: Are there distinct ages in a manager's life? Or, to put it less grandly, are there characteristics, good and bad, that a manager manifests simply because of his age? Short-form crib sheet answer for those who didn't do too well on the first test question: Yes. While people working for corporations are almost universally loath to discuss the subject -- did somebody even breathe the phrase ''age discrimination?'' -- conversations with psychologists, consultants, headhunters, and business school teachers provide a fairly clear picture of how a manager in his 30s, say, differs from his older or younger counterparts. As the experts hasten to say at the outset, this is not simple if- you're-45-you-must-be-having-a-midlife-crisis stuff. Professor John Kotter of the Harvard Business School observes, for example, that any systematic differences are a function of at least three things: the human life cycle, that is, the normal developmental phases that most adults go through; experiences associated with a particular age cohort -- different for a person born in 1940, say, than for one born in 1960; and what might be termed the career life cycle -- the fact, for instance, that an older manager has had time to acquire skills useful to him in his job. Inevitably, too, there will be people who prove exceptions to any age-based generalization. Women managers, in particular, may find that their experiences differ; regrettably, almost all the research done so far in this area has focused on men.

Caveats in mind, the ages of a manager: -- The 20s. Proving oneself worthy. In his 20s, the future manager must demonstrate that he has what it takes to do the job. In their research on the careers of professionals -- engineers, scientists, accountants, MBAs, and the like -- Professors Gene W. Dalton and Paul H. Thompson of Brigham Young University found that a newly hired graduate's initial apprenticeship typically lasts three to five years. Besides showing that he can get the job done under pressure and on time, he must also demonstrate -- are you ready for this, MBAs? -- a willingness to accept direction from his so-called superiors. This requirement couldn't come at a worse time adult-development-wise. Says Stanley Rosenberg, a professor of psychiatry at Dartmouth Medical School: ''In his 20s the individual feels a need to define himself, to break away from parental influences. Counterpoised to that is what's expected of him in the corporation -- acquiescence.'' What makes the tension worse these days is the likelihood that Young Protomanager has a graduate degree and a grasp of emerging technologies -- he knows how to use a computer -- while his boss may well have neither. Not exactly a situation to encourage the young to learn patiently at the knee of corporate higher-ups. Professors John Slocum and William Cron of Southern Methodist University recently surveyed some 675 managers at seven big companies. High performers under 30 said that what they wanted most was to be promoted. Move 'em up, or lose 'em. -- The 30s. Making one's mark. The clock is running. As Dalton and Thompson observe, if you don't propel yourself into the ranks of management by the time you're 40, you're probably never going to. To get there, they say, you must negotiate an intermediate stage, becoming expert in a particular subject or discipline and working independently. Even those who make the managerial cut well before The Big Four-O often persist in a frenzied quest to establish a reputation. Slocum and Cron found, for example, that what high-performing managers from 31 to 44 wanted most was not promotion but visibility -- a chance to shine in the eyes of the company's senior executives. This can tend to make a young exec more than a tad competitive. Victor Heckler, a vice president of Rohrer Hibler & Replogle, one of the largest consulting firms on matters of workplace psychology, notes: ''A manager moving into a line post in his 30s often develops very provincial views. He'll be extremely dedicated to the people for whom he's responsible, but if others aren't on his team, he'll give them short shrift.'' Senior managers typically take a broader view than just my-department- right- or-wrong. Heckler sees the need to act more cooperatively as part of the larger challenge confronting a 35-year-old: It's that old devil from the 20s, getting along with authority. ''Those who can accept a good relationship with authority will thrive,'' says Heckler. -- The 40s. Wrestling with limitations. The race is over sooner than you might expect. Okay, so you made it into management. The research of Dalton and Thompson indicates that if you're going on to top management, you'll probably know by the time you're 45. Most people don't make it. They are not going to be promoted again. The agenda for the 40s consists of learning to live with this and other limitations. Gee, and just when you were finally ready to be a pretty good boss. Probably more important, by your mid-40s you have likely gone through two passages identified by Yale psychologist Daniel Levinson, author of the much- admired book The Seasons of a Man's Life: first, what he calls ''becoming one's own man'' -- making that mark of yours in your late 30s; second, the fabled midlife transition. You have wrestled with ghostly authority figures from your past, with crazy expectations that others had of you (and that you may have had of yourself), perhaps even with the fact that someday you must die. You have learned from it all, and you're ready for new challenges. And there you sit, stuck in the same job six years, seven? Facing how many more years of the same? IT'S A DILEMMA that more people than ever will soon confront. The oldest of the baby-boomers turns 41 this year. Yale's Levinson puts the problem in a way that suggests its true dimensions: ''If it's simply not possible for 80% or 90% of people in their 40s to get promoted into work that will be more challenging to them, how do we deal with that? How do we create opportunities for work that will stimulate their future development?'' No one knows the answers yet, but companies had better be looking. They face the danger of fortyish execs dropping out intellectually and emotionally. -- The 50s and early 60s. Avoiding insularity. For the manager who has achieved authority enough to keep himself from brain death, the challenge now becomes learning to wield power wisely. Is he conscious of his effects on others? Does he work to bring subordinates along? Much is made in the higher business literature of the importance of mentoring; it dovetails nicely with the idea from psychology that at about this stage in an adult's development, he should achieve some ''generativity,'' passing along to younger people what he knows and cares about. But in the real world? Says Douglas Bray, who has studied AT&T managers for over 30 years: ''You see sponsorship, putting somebody up for a promotion or standing behind him. But coaching? Acting like an uncle? No.'' JUST ABOUT EVERY student of the human life cycle has detected in fiftyish men a propensity to insulate themselves. Friends fall away and are not replaced. The equivalent in the office, as observed by consultant Heckler, is for older managers to draw back a bit from the competitive fray, to lose touch with customers and, indeed, with markets. What the senior managers are relying on is their experience, sometimes interpreted as their intuition. But to do that these days may be dangerous. Burke Stinson, a public relations manager for AT&T, explains why this is so, at least at his company: ''In the days of a regulated monopoly, there was probably a better chance that a five-year-old solution might, with a little cutting and trimming, be made to fit a problem you come up against tomorrow. In our new, unpredictable environment, what worked five years ago might be just awful today.'' Early-retirement packages all around, then? No, not necessarily. The seniors have a few other things going for them. Having achieved some degree of peace with themselves, they just may be the most cooperative managers in the company, able to help different units work together for the common weal. A company without them may quickly come to resemble a loose confederation of warring tribes. The graybeards also serve as a repository for what the experts call institutional memory. They will stand around the water cooler and spin tales for the new hires about the founder and his high standards. If there's anything at all worth preserving in your corporate culture, these are the guys to keep it alive. ONE FINAL BONUS point for the elders: Elliott Jaques, an eminent psychiatrist and consultant, has done research indicating that, as managers grow older, they can envision, and plan for, increasingly long time spans. A true visionary, the kind you want running your giant companies, may be able to see decades ahead. But he probably won't be able to do it until he's in his 50s or maybe even his 60s. To retire a corporate asset like that at age 53 would be, truly, to give new meaning to the term shortsighted.