 changing where they direct their attention, looking away, justifying themselves after the fact if they don't want to help or can't get involved. But it's really hard if you're forced to watch somebody in pain or get hurt. Now, you've also discussed things like the in-group and out-group effect, which is relevant to how much pain people experience for someone else. Could you pick that apart for us a little bit, the in-group, out-group effect?