Which physiological sign may indicate deception?

The physiological sign that may indicate deception is flush or pale skin. When an individual is experiencing high levels of stress or anxiety, which can occur when they are being deceptive, their body may respond by altering blood flow. This could manifest as flushed skin due to increased blood flow to the face or neck or pale skin when there is a drop in blood pressure. These physiological reactions are part of the body's fight-or-flight response, which can be triggered when someone feels threatened or guilty about lying.

Other options, such as increased calmness, constant eye contact, and deep breathing, might not necessarily point to deception. Increased calmness could indicate that someone is comfortable or relaxed, which may not align with typical stress responses associated with lying. Constant eye contact could be a strategy employed to appear sincere, but it does not definitively indicate deception since some individuals maintain eye contact regardless of their honesty. Deep breathing could be a technique used to calm oneself down, but it is not a specific indicator of deception instead it often reflects an individual trying to manage their physiological responses.