The Halo Effect

The halo effect is a cognitive bias where a single positive trait or initial impression of a person, brand, or product influences, or "haloes," the overall perception of their other, unknown characteristics.

Coined by Edward Thorndike in 1920, it causes people to generalize positive feelings, assuming that if someone is, for example, attractive, they are also intelligent or kind.

It extends to negative feelings as well. It is known as the "horn effect," where a single negative trait leads to an overall negative judgment of a person or item.

Brands leverage this by having one popular product improve the reputation of their entire product line.

I don't always see it as a bias. Because this judgment is usually based on past experience and patterns that couldn't really be described easily but that we feel internally.