Check out XI 3.0 Security for Mere Mortals.
You can see the explicit list of rights that a particular access level has. Go to CMC -> Access Levels, right click on the one you want, and hit Included Rights.
In a nutshell:
Full Control Can perform all actions applicable to the object
Full Control (Owner) Like Full Control, but only for objects owned by the user
Schedule Like View, but also includes the ability to schedule the object
View Can view the object, but not perform any action that modifies or deletes it; or refresh data.
View On Demand Like Schedule, but also includes the ability to refresh reports interactively.
The above is very general. The actual meaning of an access level depends upon the type of object it’s applied to. For many (if not most) kinds of objects, Schedule and View on Demand are the same as View.
The default access levels are somewhat confusing in that their definition is somewhat self-explanatory for reports, but they make little sense for other types of objects.
Joe
joepeters 
(BOB member since 2002-08-29)