The results sought are pre-planned. The overwhelming majority of screamers are just stuck in a tantrum behavior pattern. As a child, they threw tantrums and got what they wanted. As an adolescent, they pressed the bounds of behavior. Whether the outrageous behavior is fake or real, we can deal with it without making serious compromises.
Silence is first.
Some negotiators simply want to be heard. Genuinely upset, some negotiators become quite compliant after they have vented. These responses do not help. We must avoid these taunts, secure in the knowledge that our objective of a negotiated agreement is primary. This technique has limited utility but when effective is best used as an out of character response.