I highly recommend reading this from the brilliant people at Metric Lab.
Yes, it's a bit long and covers a variety of topics but it is well worth reading for both law enforcement and non-law enforcement personnel.
Behavior Patterns of the Taker-Negotiator Relationship
In addition to the creation of the Crisis Communication Rating Scale, McClain’s research team applied this system to archived transcripts of hostage negotiations and obtained preliminary results. These findings have identified certain communication patterns that are associated with a peaceful resolution.
First, the research indicated that increased communication between hostage taker and negotiator led to a greater chance of peaceful resolution…
Second, it was found that as more personal information about the hostage taker was disclosed, the negotiator-taker relationship deepened, leading to feelings of trust and willingness to cooperate…
Finally, it was found that the hostage taker tends to follow the lead of the hostage negotiator.
Read the full article from Metric Lab [HERE].