diff --git a/doc/manual/source/the-model-file.rst b/doc/manual/source/the-model-file.rst
index d0704786d00b45920c140bd8f60c37e8403c0e98..2d60d43bde4789d0437badca6209f9f5d631f9af 100644
--- a/doc/manual/source/the-model-file.rst
+++ b/doc/manual/source/the-model-file.rst
@@ -6940,9 +6940,9 @@ observed variables.
 
     .. option:: prior_trunc = DOUBLE
 
-       Probability of extreme values of the prior density that is
+       Probability of extreme values of the prior density in each tail that is
        ignored when computing bounds for the parameters. Default:
-       ``1e-32``.
+       ``1e-10``.
 
     .. option:: huge_number = DOUBLE