If possible, what is the specific wording for the law(s) about bias in court, what are the repercussions for someone who is found guilty of bias in court, and do the laws extend to unconscious bias (i.e, would a trial be redone if it was found that unconscious bias had played a role in the final decision). This is for a research project lasting one year with the question to what extent does cognitive bias play a role in court/businesses?

  • 1
    I don't know of any jurisdiction where bias is a crime or a tort, so I don't think anyone is ever "found guilty of bias." Whose bias are you concerned with, and how does it become an issue in court? Are we talking about a mother taking the stand to defend the character of her son facing criminal charges? A judge who is sleeping with the plaintiff in a contract case? A juror who hates black people in an employment-discrimination case? If you can edit your question to clarify, you'll get higher-quality answers.
    – bdb484
    Nov 12, 2018 at 15:39
  • I know that it is illegal for judges to have any form of bias in court (racial/gender bias), but I'm not sure of the exact phrasing of the law(s) that exists to prevent this. I would also like to know if this law would prevent anyone from being unfairly judged in a trial due to cognitive/unconscious biases or if any judgment has been appealed/reconsidered due to cognitive bias playing a role in the outcome. I hope this makes my question clearer!
    – Conor Frow
    Nov 12, 2018 at 16:43

2 Answers 2


Bias in law is more restrictive than bias in psychology

Bias, in a legal sense refers to the inability of a judge to treat the parties equally and to be open to being persuaded by the merits of their case.

Cognitive biases are only relevant to the extent that they prevent the judge from doing this.

What the law says

The law in NSW, Australia says this.

Basically, a judicial officer must recuse themselves for:

  • actual bias: the case referenced is well worth a read - the appellant seems to believe that the justice system should work the way she wants rather than the way it does. Of interest are the following quotes:

    • an allegation of actual bias must be distinctly made and clearly proved; that such a finding should not be made lightly; and that cogent evidence is required

    • Where the issue is actual bias in the form of prejudgment, the appellant had to establish that the primary judge was “so committed to a conclusion already formed as to be incapable of alteration, whatever evidence or arguments may be presented”

    • “The question is not whether a decision-maker's mind is blank; it is whether it is open to persuasion.”

    • actual bias need not be confined to an intentional state of mind. Bias may be subconscious, provided it is real

  • apprehended bias:

    • The test for determining whether a judge should disqualify himself or herself by reason of apprehended bias is “whether a fair-minded lay observer might reasonably apprehend that the judge might not bring an impartial and unprejudiced mind to the resolution of the question the judge is required to decide”

Either party can apply for a judge to remove themselves for either (or both) types of bias. The judge then rules on whether they are biased or not, "A judge asked to disqualify himself or herself may need to apply the fair-minded observer test in respect of the evidence, in other words, unless the hypothetical observer would reject the evidence as entirely implausible the judge should consider whether, if accepted, it had the relevant quality to raise a reasonable apprehension of bias". Refusing to recuse oneself dos not, of itself give grounds for appeal.

In this context it is worth referring back to Collier v CWA (above) at [45]:

I am also mindful that it is my duty to determine matters which come before me as a member of this Court and also that it is my duty not to withdraw unless there are reasons which require me to do so. As Mason J said in Re JRL; Ex parte CJL:18

Although it is important that justice must be seen to be done, it is equally important that judicial officers discharge their duty to sit and do not, by acceding too readily to suggestions of appearance of bias, encourage parties to believe that by seeking the disqualification of a judge, they will have their case tried by someone thought to be more likely to decide the case in their favour.

Cases can be overturned where it can be demonstrated that a judge exhibited actual bias during the case.

A judge is not liable for bias.


The law doesn't directly address mental states, it addresses actions, and a law may (or may not) have a "mental state" requirement as part of the determination of liability. For example, abstractly hating a person for their race is not a crime and you cannot be sued for abstractly hating a person because of their race, but you can be punished or made to pay damages because of your actions – beating them or refusing to sell to them – and that mental state may figure into the determination of guilt. There are hate crimes laws in the US whereby criminal actions are given stiffer punishments, where in Washington the distinguishing element is motivation: "because of his or her perception of the victim's race, color, religion, ancestry, national origin, gender, sexual orientation, or mental, physical, or sensory handicap". The government must prove that the victim was assaulted because of his race, and not because the assailant thought the victim was an easy mark. This is an instance of the popular concept of "bias".

Cognitive bias, however, is extremely broad, and there are literally hundreds of possible answers. For example, cognitive bias figures into visual perception (let's say of color), which means the law has to have a way to deal with eyewitness testimony. Expert testimony could introduce reasonable doubt as to the reliability of witness testimony based on scientific testimony to the effect that humans have a cognitive bias in a particular direction, which may show that the eyewitness testimony is unreliable. What the law has to deal with is whether such scientific testimony is pertinent (admissible). There is a body of law surrounding the Daubert Standard which answers that question. The key here is that the attorney has to know to call up an appropriate expert witness to impeach eyewitness testimony. Or circumstantial evidence, when the evidence is based on a subjective assessment by an expert (that is, when a lab tech makes a professional judgment as to fact, such as whether this voiceprint matches that voiceprint).

Cognitive bias is a fact of human psychology and is not punished. A very narrow subset of biases may enter into a judgment of liability, just in case the bias is considered to be under volitional control and is heinous.

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