I came across this section of  Boxes and Arrows blog post

What design researchers can learn from hostage negotiators

By Bryan McClain, Demetrius Madrigal on Learning From Others

with the same name as this blog. Let's see what we can learn from hostage negotiators:

 Building Rapport

Rapport is established through trust, open communication and empathy. Negotiators know that rapport is essential in their job. They use rapport to influence the hostage taker and gather information. If you can effectively build rapport with the participant, there is a higher likelihood he or she will trust you and disclose more information.
The following techniques used by hostage negotiators can help you build rapport with research participants:

1. Go slow – Engage in small talk at first. If you dive right into business, the situation can become uncomfortable.
2. Communicate openly – While you can’t disclose everything, it’s important to encourage an atmosphere of open communication. Tell the participant that there are certain aspects of the study that you can’t reveal, but he or she shouldn’t feel that you’re hiding something.
3. Actively listen – When you are listening to a participant’s story, listen for the emotions behind the words. Ask open-ended questions that dig for the source of those emotions.
4. Discuss personal topics – In a hostage situation, some of the most valuable topics that lead to a peaceful resolution are personal ones. The more a person feels that you accept them, the more comfortable they will feel with you.
5. Share your experiences – Building rapport is as much about sharing your experiences as it is about listening to the other person’s. Negotiators know that the more you reveal about yourself, the more the participant feels like he or she knows you and therefore trusts you.
6. Show you care – Hostage negotiators build rapport through empathy. Empathy is extremely important because it shows that you care about the other person and that you have their best interests in mind. As a researcher, you should do this also. If you show that you care, the participant will appreciate it and respond with more openness.