Caffeine Can Make Hard Workers Slack Off?

  That's the reported results of a new study in the journal Nature.  There are however a couple things you should consider when reading this study.  They tested the effects of stimulants, and they first categorized the subjects on their base levels.  Some people are natural hard works, and others are natural slackers.  In this sense, slacker may not be the best term.  The test involved giving out food pellets for completing a task, and giving out more food pellets for completing a harder task.  The "slackers" did not do the extra work for more food, and the "hard workers" did.  It's a test of cost-benefit analysis.  Being a slacker meant that you didn't see the extra work as being worth the reward.
  The test showed that when administered amphetamines and caffeine, the slackers opted to do the extra work. When the hard workers were given both, they stayed hard workers, but when they were only given caffeine, they tended to become slackers.
  Does this mean that caffeine can make hard workers slack off?  No.  The basic take away from this study is that when a doctor prescribes a stimulant, it would be beneficial to consider the base-line state of the individual.
  Another way to look at it, perhaps caffeine takes away hunger?  I'm not an expert, but in this study if a subject  was less hungry, would that sway the cost-benefit analysis?  I believe this study was more about decision making than the physical effects of stimulants, or more appropriately, the effects of stimulants on decision making.
  We know caffeine can help keep you alert, so the question becomes, how does it effect the decisions you make every day?