Contagion is the spontaneous spread of emotions, behaviours, or conditions within a group or network, often occurring unconsciously. Important learnings include:• Emotional contagion involves automatic mimicry of others' expressions, postures, and vocalizations, influencing one's own emotional state. This can be positive (e.g., joy) or negative (e.g., anxiety), impacting workplaces, social media, and close relationships.Behavioural contagion shows that observing others' decisions, such as risk-taking, can alter an individual's behaviour, including triggering overconfidence.Unethical behaviour is particularly contagious. Individuals may display an 'underconfidence bias,' relying more on predecessors' actions to justify their own unethical choices, facilitating its spread. This can also manifest as unethical pro-organizational behaviour spreading from leaders.Bias contagion involves the subtle transmission of intergroup biases through nonverbal cues, affecting observers' implicit attitudes and behaviour even across racial group boundaries