Casey Mulligan has a book out that looks hard at the Panic of 2008 and explores its causes.  The book is called The Redistribution Recession, and I strongly recommend it.  Here are some highlights.

In this way, the simple supply and demand model…explains 81 percent of the labor market contraction from 2007-Q4 and 2009-Q4, as long as it incorporates the labor supply effects of the expanding social safety net.  The remaining 19 percent of the contraction is “explained” by unmeasured market distortions—that is, still unexplained by the measured factors present in the model.

And

The (theoretical) effects of the reward to working can also be seen from the perspective of wages.  The more that the safety net pays for not working, the less reason people in low-wage jobs have to keep their job and the less reason unemployed people have to accept a low-wage job.  In this way, the safety net raises wages, to which employers respond by hiring less.”

And

When food stamp or unemployment programs pay more, the sacrifices that jobs require do not disappear.  The commuting hassle is still there, the possibility for injury on the job is still there, and jobs still take time away from family, hobbies, sleep, etc.  But the reward to working declines, because some of the money earned on the job is now available even when not working.

Note that, as long as the government involves itself in the economy through its penchant for social engineering/safety nets, this creates a feedback loop.  The safety net (the parts of which Mulligan enumerates, but which I use here expansively to include the entire suite of components) reduces the incentive to work by replacing monies lost from not working, thus driving up costs to employers of attracting workers he otherwise would be interesting in hiring, reducing employers’ hire rates, leading the government to try to further expand the safety net, further reducing work-seeking incentive, driving up labor costs,….

And

…studies: Hoynes and Schanzenbach (2012) show how potential participants stopped working or reduced their work hours when the food stamp program was introduced.  Studies of unemployment insurance find that program rules have a statistically significant effect on how many people are employed, and how long unemployment lasts.  Yelowitz’s research (2000) shows how a number of young single mothers found employment exactly when, and where, state-level Medicaid reforms increased their reward from working.

And so on.  Note that none of this is to disparage people who make use of the safety net; they’re behaving entirely rationally in an economic sense.  Mulligan’s purpose is only to show how incentives of safety nets work.