diff --git a/macs2.wdl b/macs2.wdl
index ade425b64d2bfe292ed98416028bd259e9f424a5..612e5d18908f3d885596be949df92bb3ba43b96f 100644
--- a/macs2.wdl
+++ b/macs2.wdl
@@ -5,7 +5,7 @@ task PeakCalling {
     String sampleName
     Int? threads
     Int? memory
-    Boolean? nomodel = false
+    Boolean? nomodel
 
     command {
         set -e -o pipefail