diff --git a/src/Socialbox/Objects/RpcRequest.php b/src/Socialbox/Objects/RpcRequest.php
index 7751907..a5a6013 100644
--- a/src/Socialbox/Objects/RpcRequest.php
+++ b/src/Socialbox/Objects/RpcRequest.php
@@ -71,7 +71,7 @@
          * @param bool $nullAllowed True if the parameter value can be null, False otherwise.
          * @return bool True if the parameter exists, False otherwise.
          */
-        public function containsParameter(string $parameter, bool $nullAllowed=true): bool
+        public function containsParameter(string $parameter, bool $nullAllowed=false): bool
         {
             if(!$nullAllowed)
             {