A young colleague recently said he didn't want to end up like older folks he knew who didn't keep up with new music fashions.  Some of us older folks suggested he probably would become like us, and he would probably like it.  He was horrified.

People often wonder what it will be like for them to be old, or married, or with a successful career, etc.  They usually conclude they just can't know, and must wait and see.  Yet all around them are other folks who are old, married, etc. – why not just accept those experiences as a good predictions of such futures? 

People usually respond that they are too different from these other folks for their experiences to be a good guide.  A paper in the latest Science suggests otherwise: 

Two experiments revealed that (i) people can more accurately predict their affective reactions to a future event when they know how a neighbor in their social network reacted to the event than when they know about the event itself and (ii) people do not believe this.

We mistakenly prefer an "inside" view, imagining how we'd respond to particular details, but in fact the "outside" view of others' reactions is more reliable.  

This seems to me more than a simple cognitive error.  It seems folks feel that they would not be motivated enough to exercise, marry, work, etc. if they thought their future was going to be much like the futures of others around them.  Are they right?  More from that paper:

In two experiments, participants more accurately predicted their affective reactions to a future event when they knew how a neighbor in their social network had reacted to it than when they knew about the event itself. Women made more accurate predictions about how much they would enjoy a date with a man when they knew how much another woman in their social network enjoyed dating the man than when they read the man’s personal profile and saw his photograph. Men and women made more accurate predictions about how they would feel after being evaluated by a peer when they knew how another person in their social network had felt after being evaluated than when they previewed the evaluation itself. Although surrogation trumped simulation, both participants and independent judges had precisely the opposite intuition. By a wide margin, they believed that simulation was more likely than surrogation to produce accurate affective forecasts.