diff --git a/transition_machine/src/Oracle.cpp b/transition_machine/src/Oracle.cpp
index 2ca022dbca69fce22ce2b78a2be24d608ef6665a..b27b2e2a15638c9c71ece036e48cb70741664c1a 100644
--- a/transition_machine/src/Oracle.cpp
+++ b/transition_machine/src/Oracle.cpp
@@ -321,8 +321,8 @@ void Oracle::createDatabase()
   },
   [](Config & c, Oracle * oracle)
   {
-    const std::string & form = c.getTape("FORM")[c.getHead()];
-    const std::string & pos = c.getTape("POS")[c.getHead()];
+    const std::string & form = c.getTape("FORM")[0];
+    const std::string & pos = c.getTape("POS")[0];
     std::string & lemma = oracle->data[form + "_" + pos];
 
     if(lemma.empty())