http://lesswrong.com/lw/2y2/willpower_not_a_limited_resource...
http://lesswrong.com/lw/1fe/antiakrasia_technique_structured...
See also
http://lesswrong.com/lw/1yn/what_would_you_do_if_blood_gluco... (and all the studies in the comments especially)
http://lesswrong.com/lw/h3/superstimuli_and_the_collapse_of_...
http://lesswrong.com/lw/2y2/willpower_not_a_limited_resource...
http://lesswrong.com/lw/1fe/antiakrasia_technique_structured...
See also
http://lesswrong.com/lw/1fe/antiakrasia_technique_structured...
http://lesswrong.com/lw/1yn/what_would_you_do_if_blood_gluco... (and all the studies in the comments especially)
http://lesswrong.com/lw/h3/superstimuli_and_the_collapse_of_...