IBM SPSS Statistics is an advanced statistics analysis application.
In SPSS, click “File” > “New” > “Syntax”. In the newly opened syntax editor, type
SET LOCALE = “en_US”
and click the green “Selection” arrow (or press Cmd + R on your keyboard).
This will change the decimal separator to a dot in SPSS.
Note: according to this website it should be possible to use the syntax “SET LOCALE = DOT” in SPSS version 20.0 (by IBM). At least in version 18.x this did not work.