Here’s a candy-related science paper that I’ll never actually read in its entirety. Via Discover Magazine’s Discoblog, here’s an article called, “Oil migration in chocolate-peanut butter confectionary as a function of chocolate formulation.”
As best as I can tell from the abstract, scientists used MRI to measure the spatial and temporal changes in peanut oil in chocolate + peanut butter cups when different formulations of chocolate were used and at two different temperatures. At 20 degrees Celsius (68 Fahrenheit), everything stays put. At 30 degrees Celsius (86 degrees Fahrenheit), the peanut oil starts moving around.
It seems kind of, “Well duh” that high temperatures are worse for keeping peanut butter cups consistent. I’d guess, however, that their tests of the different chocolate formulations may help candy makers choose their optimal “chocolate particle size, milk fat content, and emulsifier level,” which is less obvious. Your tax dollars at work, folks!
Varsha 
sophia cook 
Vishal