Well first off, morality is just something that can be learned as someone gets older. I think a lot of how we learn right from wrong is from consequence. What you can implement is something called Operational Conditioning.
You said brief so basically what that is, behavior that leads to something. Whatever that result is, if your behavior leads to a positive result it will be repeated. If your behavior results in punishment, you will avoid that. It's something that humans do.
You do your homework you get ice cream, you don't do it you get spanked. That's a good summary of it. I think a factor of telling right from wrong is from what actions leads to reward or punishment.
How does one's own body betray a person? Winston means involuntary movements a person might make from bottling up so much emotional and intellectual tension for so long. He once witnessed a man with a contorted face walking by. His expression was involuntary but Winston surely knew the man would be killed.
