diff --git a/reading_machine/src/Transition.cpp b/reading_machine/src/Transition.cpp
index cd652c5b7e08b728bbf99ecee3ae9b1804b1a546..856475f833acc56b50aeab0bd45300d0442dcf3b 100644
--- a/reading_machine/src/Transition.cpp
+++ b/reading_machine/src/Transition.cpp
@@ -209,7 +209,7 @@ void Transition::initReduce()
 
   cost = [](const Config & config)
   {
-    if (config.isToken(config.getWordIndex()))
+    if (!config.isToken(config.getWordIndex()))
       return 0;
 
     int cost = 0;