I think they've built a better mousetrap.  And I think cheese, the old school bait, the one they use in cartoons, does slightly more efficient work than peanut better.

8 traps set. 

4 cheese.  4 peanut butter.

4 old school style.  4 newfangled.  Peanut butter and cheese evenly distributed between types.

3 caught mice. 1 old school with cheese.  1 newfangled with cheese.  1 newfangled with peanut butter.

2 had their bait taken without snapping.  1 old school with peanut butter.  1 newfangled with peanut butter.

1 snapped but caught nothing.  An old school trap with cheese.

2 went untouched. 1 old school with peanut butter.  1 newfangled with cheese.  They were clearly placed on the wrong shelf and will relocate tonight.

I should have graphed or tabled that.  But that might have been a little overkill for a mouse catching experiment.  Oh well.  Maybe next time.