diff --git a/lib/mocha/mock.rb b/lib/mocha/mock.rb
index f82121e41..8276ecdbe 100644
--- a/lib/mocha/mock.rb
+++ b/lib/mocha/mock.rb
@@ -324,11 +324,7 @@ def method_missing(symbol, *arguments, &block) # rubocop:disable Style/MethodMis
     # @private
     def respond_to_missing?(symbol, include_private = false)
       if @responder
-        if @responder.method(:respond_to?).arity > 1
-          @responder.respond_to?(symbol, include_private)
-        else
-          @responder.respond_to?(symbol)
-        end
+        @responder.respond_to?(symbol, include_private)
       else
         @everything_stubbed || all_expectations.matches_method?(symbol)
       end