What are the signs of separation anxiety, and how do I train my dog to be alone (the 5-second rule)?

Quick answer

If your dog howls, scratches at the door, drools, or trashes the house when you leave, separation anxiety is likely. Don't make a big emotional goodbye before leaving. Instead, practice stepping outside as if leaving, then coming back in after 5 seconds with a treat (gradually extending to 10 seconds, 1 minute, 5 minutes) to build the trust that 'Mom and Dad always come back.'