Free Foundation Fear by Gregory Benford

'generational styles,' Dors calls it. I can
     take the Zones that consciously increased human lifespan. I time-step the equations
     forward, great -- but then I run out of data. How come? I mine the history some, and it
     turns out those societies didn't last long.”
    Hari shook his head. “You're sure? I'd imagine increasing the average age would bring a
     little wisdom into the picture.”
    “Not so! I looked deeper and found that when the lifespan reached the social cycle time,
     usually about a hundred and ten Standard Years, instability rose. Whole planets had wars,
     depressions, general social illnesses.”
    Hari frowned. “That effect -- is it known?”
    “Don't think so.”
    “This is why humans reached a barrier in improving their longevity? Society breaks down,
     ending the progress?”
    “Yeah.”
    Yugo wore a small, tight smile, by which Hari knew that he was rather proud of this
     result. “Growing irregularities, building to -- chaos.”
    This was the deep problem they had not mastered. “Damn!” Hari had a gut dislike of
     unpredictability.
    Yugo gave Hari a crooked smile. “On that one, boss, I got no news.”
    “Don't worry,” Hari said cheerfully, though he didn't feel it. “You've made good progress.
     Remember the adage -- the Imperium wasn't built in a day.”
    “Yeah, but it seems to be fallin' apart plenty fast.”
    They seldom mentioned the deep-seated motivation for psychohistory: the pervasive anxiety
     that the Empire was declining, for reasons no one knew. There were theories aplenty, but
     none had predictive power. Hari hoped to supply that. Progress was infuriatingly slow.
    Yugo was looking morose. Hari got up, came around the big desk, and gave Yugo a gentle
     slap on the back. “Cheer up! Publish this result.”
    “Can I? We've got to keep psychohistory quiet.”
    “Just group the data, then publish in a journal devoted to analytical history. Talk to
     Dors about selecting the journal.”
    Yugo brightened. “I'll write it up, show you -- ”
    “No, leave me out of it. It's your work.”
    “Hey, you showed me how to set up the analysis, where -- ”
    “It's yours. Publish.”
    “Well ... ”
    Hari did not mention the fact that, now, anything published under his name would attract
     attention. A few might guess at the immensely larger theory lurking behind the simple
     lifespan-resonance effect. Best to keep a low profile.
    When Yugo had gone back to work, Hari sat for a while and watched the squalls work through
     the data-fluids, still time-stepping in the air above his desk. Then he glanced at a
     favorite quotation of his. Pointed out to him by Dors, given to him on a small, elegant
     ceramo-plaque:
    Minimum force, applied at a cusp moment at the historical fulcrum, paves the path to a
     distant vision. Pursue only those immediate goals which serve the longest perspectives.
    -- Emperor Kamble's 9th Oracle, Verse 17
    “But suppose you can't afford long perspectives?” he muttered, then went back to work.
    7.
    The next day he got an education in the realities of Imperial politics.
    “You didn't know the 3D scope was on you?” Yugo asked.
    Hari watched the conversation with Lamurk replay on his office holo. He had fled to the
     University when the Imperial Specials started having trouble batting the media mob away
     from his apartment. They had called in reinforcements when they caught a tarn drilling an
     acoustic tap into the apartment from three layers above. Hari and Dors had gotten out with
     an escort through a maintenance grav drop.
    “No, I didn't. There was a lot going on.” He remembered his bodyguards accosting someone,
     checking and letting it pass. The 3D camera and acoustic tracker were so small that a
     media deputy could walk around with them under formal wear. Assassins used the same artful
     concealment. Bodyguards knew how to distinguish between the two.
    Yugo said with Dahlite savvy, “Gotta watch 'em, you gonna play