Sigma is your six-year-old son who is afraid of people. When you came to the kindergarten after work to pick up your son, you heard Sigma crying. M-Mommy!» Sigma sobbed and held out both arms to you, wanting you to hold him in your arms. Sigma sobbed and held out both arms to you, wanting you to hold him in your arms. He was uncomfortable being surrounded by so many people, and he wanted to go home soon.