“The statement ‘Hitler loved dogs and little children’ is shocking no matter how many times you hear it, because any trace of kindness in someone so evil violates the expectations set up by the Halo Effect.” – Daniel Kahneman. The Halo Effect describes how a positive impression of a person, thing, or company in one area will result in overall positive perceptions of other unrelated areas.  IMPRESSIONS FORM MENTAL MODELS.  The Halo Effect is a cognitive heuristic or bias that can be understood in the broader context of Behavioural Economics and Fast and Slow Thinking. The point is that your brain instinctively constructs Mental Models from limited information so that you can take action and make snap judgments. Like all heuristics, it has value as a shortcut, and can be disastrous in a range of contexts. See the Origins tab below for Edwards Thorndike’s original military research and subsequent studies which have revealed that strong impressions, and particularly first impressions, tend to define broader perceptions.  NEGATIVE AND REVERSE HALO EFFECT.  The Negative Halo Effect, sometimes referred to as the ‘Horn’ or ‘Devil’ Effect, is where a negative impression drives a range of negative assumptions. For example, meeting someone who has a crooked nose or is constantly sniffing, and subconsciously making assumptions about their ethics or intelligence. We know, it sounds petty, but your subconscious will go there. The Reverse Halo Effect is still built on a positive impression but might lead to negative treatment. So the Halo Effect might lead to an attractive person being treated disproportionately well because of assumptions about their positive character, whereas the Reverse Halo Effect might see an attractive person not getting a job role because of assumptions that they were vain or overqualified.  APPLICATIONS. This cognitive bias infiltrates countless domains, including: Brand and marketing: the Halo Effect is much sought after in branding to lock in customer loyalty. Companies will pay high sums to associate themselves with other 'Halo brands', including celebrity endorsements.  Management: busy managers will often reject new ideas or suggestions based on who has put them forward. Politics: devotees of a particular political figure will find it impossible to believe that they have been at fault elsewhere in their lives - thus the common rejection of tax, financial, or sex scandals by a politician's base. Education: a number of studies have shown that teachers favor students based on their perceived attractiveness. The Halo Effect also applies when a teacher is influenced by a first exam result when marking subsequent ones.  Medicine: a medical practitioner might assume mental health based on an individual's physical strength.  The list continues with hiring, law, and any domain involving people making snap judgments of others — so life! See Actionable Takeaways below for strategies on how to interrupt and mitigate the Halo Effect.  IN YOUR LATTICEWORK.  We’ve mentioned Fast and Slow Thinking as the framer of all cognitive biases, and in that realm, the Halo Effect is quite connected to the Confirmation Heuristic and Anchoring Heuristic. Beyond that, the Map vs Territory, which is one of our favourite models, goes a long way to explaining the Halo Effect. It’s a reminder that our mental models of reality are not in fact reality.  In a business context, the Halo Effect might help to explain the Lock-In Effect and customer loyalty. It is also an important factor in developing influence and could be used in conjunction with Cialdini's Six Principles of Influence, particularly likability.