Bias

A particular influential power which sways the judgment; the inclination or propensity of the mind towards a particular object; adopted in Willis v. State, 12 Ga. 449. Justice requires that the judge should have no bias for or against any individual. and that his mind should be perfectly free to act as the law requires. There is, however, one kind of bias which the courts suffer to influence them in their judgments: it is a bias favorable to a class of cases, or persons, as distinguished from an individual case or person.

A few examples will explain this

A bias is felt on account of convenience; 1 Ves. Sen. 13; 3 Atk. 524. It is also felt in favor of the heir at law, as when there is an heir on one side and a mere volunteer on the other; 1 W. Bla. 256; 1 Ball & B. 309; 1 Wils. 310. On the other hand, the court leans against double portions for children; 13 Price 599; against double provisions, and double satisfactions; 3 Atk. 421; and against forfeitures; 3 Term 172.