To negate "at least one" change to "not at least one" = none.
So the negation is: *None of them was not a creative researcher*
Get rid of the double negative: *All of them were a creative researcher*
... completely neutral, because of the negation test. For example, if an ... economic attitudes of investors. The negation test would be voter's ... movies after dinner, the negation means a person sometimes does ... eats ice cream, the negation test would mean Jerry never ...