Joel Spolsky has an interesting take on this kind of cognitive bias WRT software planning, where his company uses software to attempt to quantify the amount of individual bias by tracking task estimates vs. actual times and developing an individualized factor for padding subsequent planning. See e.g. http://www.joelonsoftware.com/items/2007/10/26.html
Interestingly enough, this approach emphasizes tracking more granular inside view-type tasks over the large-scale outside view perspective mentioned in the original post. I'm curious whether generating estimate velocities in an outside view manner (i.e. for larger-scale tasks) would further improve the realism of this estimation method.