The crustacean principle
When you shut down emotionally we stop learning. For development you need vulnerability which comes from the latin word vulnus which means the wound. Vulnerability is our capacity to be wounded, nothing grows when it is not vulnerable. Crabs (and other crustaceans) cannot grow in a linear fashion like most animals. Because they have a hard outer shell (the exoskeleton) which does not grow, they must shed their shells, a process called molting. So a crab cannot grow encased in a hard-shell, it has to make itself soft and vulnerable.
In the same way when we shut down emotionally we have difficulty learning. especially from negative experience. For learning you need curiosity, but curiosity is vulnerable, for when you are curious you care about something. You also need trial and error, and of course you need vulnerability, just in the case something doesn’t work. In order to release people from their hard shells of fear we need to prioritise their emotional security if people are to grow in their relationship with God. Invite someone to take a closer look at Christ and his church.