Gossip, IQ tests, self-checkout: how much do you know about this week's psychology news?

Six questions on fresh psychology research: doomsday messaging, intelligence tests, gossip, queueing, teen sleep and deep brain stimulation. Not medical advice, just curiosity.

1. What can shocking doomsday messages trigger in people instead of action?
2. What does a new analysis of 109,000 workers show about how well general intelligence tests predict job performance?
3. Which Dark Tetrad trait showed the strongest link to frequent, malicious gossip?
4. According to psychology research, why is waiting in a self-checkout queue more nerve-racking?
5. When should school start for teenagers, given their different biological rhythm, according to the sleep researcher?
6. What did Mount Sinai researchers find about deep brain stimulation for severe, treatment-resistant depression?