The Halo Effect is the academic (and not really intuitive) name for the human tendencies to use the characteristic of someone or something in one domain to infer positive or negative attributes in other, unrelated domains. It’s widely used to associate brands or products with positive aspects, like the color green for healthy or environmentally-friendly products.
The origin of the term is given by wikipedia:
The halo effect is a cognitive bias in which an observer’s overall impression of a person, company, brand, or product influences the observer’s feelings and thoughts about that entity’s character or properties. It was named by psychologist Edward Thorndike in reference to a person being perceived as having a halo. […] The halo effect is a specific type of confirmation bias, wherein positive feelings in one area cause ambiguous or neutral traits to be viewed positively. Edward Thorndike originally coined the term referring only to people; however, its use has been greatly expanded especially in the area of brand marketing.
The term “halo” is used in analogy with the religious concept: a glowing circle that can be seen floating about the heads of saints in countless medieval and Renaissance paintings. The saint’s face seems bathed in heavenly light from his or her halo. Thus, by seeing that somebody was painted with a halo, the observer can tell that this must have been a good and worthy person. In other words, the observer is transferring their judgment from one easily observed characteristic of the person (painted with a halo) to a judgment of that person’s character.
The halo effect works in both positive and negative directions (the horns effect): If the observer likes one aspect of something, they will have a positive predisposition toward everything about it. If the observer dislikes one aspect of something, they will have a negative predisposition toward everything about it.
Please see the full entry for more details about this well-known and over-exploited human tendency.