This is from Ekman’s work on lie detection. He thinks that this comes from dealing with crowds—the SS spends much more time looking at different faces trying to detect emotions / intent to harm, and thus actually has practice at distinguishing faces, rather than considering one person for extended periods of time (like normal interrogations). It isn’t a commentary on how they respond to reports.
This is from Ekman’s work on lie detection. He thinks that this comes from dealing with crowds—the SS spends much more time looking at different faces trying to detect emotions / intent to harm, and thus actually has practice at distinguishing faces, rather than considering one person for extended periods of time (like normal interrogations). It isn’t a commentary on how they respond to reports.