Raises are ticking upward this year, with the average salary bump expected to come in at roughly 3 percent in 2015. That marks the highest increase since 2009, according to one forecast. Workers should be grateful, right?

But a fair number of people who get merit increases don't feel more valued after receiving one — and even those who do at first quickly forget that feeling. An online poll released Wednesday that was conducted on behalf of The Workforce Institute, the research arm of software company Kronos, found that nearly a quarter of people who said they had gotten a pay raise reported it had no effect on them feeling appreciated at work. Among those who did feel a positive effect, 40 percent said that psychic benefit faded within six months.

After years of coping with a struggling economy and little in the way of pay boosts, why aren't employees happier about getting a raise? Kronos says its results, which come from an online survey of 2,030 adults, aren't based on a probability sample. So perhaps it turned up particularly ungrateful folks.

Still, the finding does fit with prior studies: Academic research has shown that small raises make very small differences. Boosts below 7 or 8 percent fail to "evoke positive perceptual and attitudinal reactions among employees," according to one study. Today's average raise is less than half that high.

Meanwhile, many people have also said they value other benefits like flexible work arrangements over a few extra bucks in the paycheck. And plenty of research has called into question whether simple financial rewards are really that effective at incentivizing people who do creative work.

For employers, though, the whole point of handing out raises is to make people feel appreciated. If that's not happening, it may be that the boss is relying too much on raises alone to keep people engaged. "Expressing gratitude is a form of communication that's often overlooked," says Joyce Maroney, director of the Workforce Institute. Saying thank you and offering positive feedback can have a strong impact on employees.

Though, let's not forget, so can pay bumps if they're of any real size.

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