From the Enterprise Agility University's point of view, Psychological Safety means showing up and employing oneself without fear of negative consequences to self-image, status or prestige, or career.

In other words, psychological safety implies that members of an organization feel accepted and respected in their current roles. From the brain's perspective, this means that in companies where employees have a safe environment and a prominent level of psychological safety, cortisol levels in the brain are lower due to daily work.

High cortisol levels can affect employees' mental flexibility or Mental Agility. The first definitions of psychological safety emerged in organizational psychology in the 1960s and 1970s. Since then, several definitions and studies have been conducted by different people.

For more detailed information about them, check Enterprise Agility Fundamentals, Chapter 6, page 239.