You are right. What I should have said is: "the lack of sigils to indicate type of a variable". In perl this noise is everywhere, while in Ruby its is a lot less common.
Specially if you use accessor methods. In ruby, unlike smalltalk, this instance variable sigils are pretty much impossible to get rid off. This is because in Smalltalk local variables have to be declared, and if you don't, the Language will try to use the instance variables. In Ruby it would default to being a local variable, if already assigned, or invoking a method with no arguments.