Screaming (barking / lunging / reacting) for no reason
As humans, we do not go around screaming for no reason.
There is almost always a reason - whether we feel that reason is justified or not is not the point. The person doing the "screaming" will have a reason.
Maybe they desperately need money for something so they attack an elderly gentleman and steal his wallet - THE REASON for this screaming (the attack) could be an overwhelming fear of not getting his next fix.
Maybe somebody is being followed as they walk down a dark alley so, in that moment, to protect themself, they scream & pick up a brick and hit it over the head of the person who was following them- THE REASON? Likely fear of being in danger.
Perhaps you've had a particularly stressful week. Just about everything has gone wrong and you are so incredibly stressed by the end of the week that you lash out at your partner and really lose your temper - THE REASON would likely be that you are just so stressed at the moment.
Maybe you're in pain and its been ongoing for weeks now. You're feeling so miserable and can't get on top of this annoying pain that it is making you snappy. A total stranger accidentally bumps into you whilst you're out walking around the shops and you lose your rag with them - THE REASON? The pain and the fear of getting hurt more. Plus the stress you are experiencing.
Perhaps there's a history of this particular thing hurting you before so now you are understandably cautious as you are predicting more pain - THE REASON? Well, the Dentist hurt you the past 5 times you went to see him so it's likely that visit Number 6 will hurt too.
Whatever the reason is, it is likely that the "screaming" would not have happened in the first place if that person had not been in that particular environment / feeling that particular emotion / at that particular time.
It's a combination of things that cause us to scream & lose our temper ..... If we are happy / stress free / pain free / not in a scary situation / not startled etc then we would likely go through our whole entire lives without ever screaming
.When we do scream our friends & family often have so much empathy for us .... "Oh, you poor thing, that must have been so scary. Here, have an extra glass of wine to help you relax" or "OUCH, I bet that is so sore, I'll run you a nice hot bath and you can relax for a bit" or "Oh, my goodness, what a rubbish week you've had. Lets cancel our plans for this weekend and just stay home & have a quiet one"
What our friends & family never do is: OH MY GOD, SHES SO AGGRESSIVE!!! WE'LL HAVE TO GET HER A MUZZLE BEFORE WE TAKE HER OUT AGAIN AND A STRAIGHT-JACKET.!! WE NEED TO BOOK A THERAPIST AND WE MIGHT EVEN HAVE TO FIND HER A NEW HOME. LET'S LOCK HER UP ON HER OWN FOR A FEW HOURS SO THAT SHE REALISES HOW NAUGHTY SHE HAS BEEN"
When our poor dogs "scream" due to the current environment they are in / the emotion they are feeling we instantly label them as "aggressive" but aggression is just a symptom of the bigger picture .... If the dog wasn't frightened of strangers (the emotion of FEAR) then he wouldn't be screaming at strangers so we don't fix the aggression because the aggression wouldn't happen if the emotion were different......
When our dogs "scream" when you try to take a bone off of them we'll use that "aggressive" label again but just like the elderly gentleman above who was afraid of being mugged your dog is just reacting to his environment at that time .... We don't teach humans "How to Accept Being Mugged on a Daily Basis by Reece Orse Guarding" just like we don't teach dogs how not to growl when a human tries to take the stolen sock off them. Instead, we need to change the emotion from "fear of being mugged" to "YAY! Good things happen when my humans come near me!!"
Aggression isn't a thing.
Aggression wouldn't exist if the exact same dog was in a different environment at different time and had a different emotional response.
We don't fix the aggression.
We fix the cause and change the way the dog feels so that the aggression doesn't need to occur.
Its an emotion, not a behaviour - fix the emotion