Anyone who has ever seen an episode of Law and Order or CSI will tell you that evidence is the most crucial part of a criminal case. However, those shows are fictional and, as such, often gloss over the reality: evidence is only as effective as its presentation.

As we’ve written before, witness testimony is often unreliable, not out of any malice, but because of simple human faults. Among these faults is confirmation bias, which is shared by not just witnesses and jurors, but also law enforcement. As a result of this psychological blind spot, the story “presented” by the evidence, may not be the most likely or even the most convincing.

What is confirmation bias

Confirmation bias can manifest in someone as intuition, a “gut feeling” or a “hunch,” yet it is far less mysterious than those terms sound. Confirmation bias is the tendency for people to accept what they believe as true and discount any alternate interpretations. Essentially, if you think a thing seems right, you tend not to question it.

Confirmation bias and police

When the police get involved in virtually any situation, the individual officer or investigator makes any number of assumptions very quickly. However, a speedy assumption is one ripe for distortion by an internal bias, and can “lock in” law enforcement on a single target, leading to faulty convictions.

When law enforcement is guided by what they expect to see, it can lead to many troubling circumstances, such as:

  • Misleading drug tests: The presence of any narcotic in a blood test becomes evidence of intoxication, regardless of concentration.
  • Bad DNA results: For years, police and prosecutors accepted favorable DNA results at face value, despite any inconsistencies.
  • Problematic searches: What is probable cause other than an officer’s snap decision that something is “suspicious?”

In each of the above cases, the investigators have an idea of what should be and use any available evidence to support it. Even if that evidence is just “a feeling.”

Bias cannot withstand scrutiny

However, if you face charges based on a biased investigation, you have hope. Your attorney can forcefully and convincingly, offer a new perspective on evidence, highlight evidence that prosecutors ignore and help you take control of your story.