Abstract: The mental neural circuit activity and a series of the subsequent response in mental and behavioral under an alert situation constitute a broader alarm system. In fact, under both threatening and uncertain conditions, the way people form their judgments is more complicated than that has been explained in traditional equity theories. From the perspective of the alarm system, discrepancy between actuality and desired standard can arouse alarm system, and then prompt people to handle negative emotion and eliminate the uncertainty by changing their attitudes and behaviors, which consequently influence people’s judgment and concern to the justice. Evidence from fMRI and ERP studies has indicated that the response to alarming situation is principally related to ACC activity. By conflict monitoring, emotion vocalization and integrated regulation, alarm system intrigues people’s concern to the justice, and leads to substitute process, primacy effect and extreme reaction in justice judgment.

Key words: justice judgment, fairness matters, alarm system, anterior cingulate cortex