The Potters ended a run of three straight defeats as they beat Queens Park Rangers on Saturday to earn the vital three points in their quest to avoid relegation.
Pulis told reporters: "Ryan's grown up this year in an awful lot of respects, which is great to see.
"I had a chat with him the other day because Robert is not a great talker, so it's got to come from Ryan.
"I think he's waiting on Rob sometimes but he's got to take the lead and that's why he's captain."
Stoke are 15th in the Premier League, six points clear of the drop zone.