What’s the difference?

A bias is a tendency or inclination that affects our judgment or decision-making process, often in an unconscious way. It’s about how we filter or interpret information based on our experiences, beliefs, or preferences, leading to systematic deviations from a standard of rationality or good judgment.

A fallacy, on the other hand, is a flaw or error in reasoning. It’s a logical misstep in constructing an argument that makes the argument invalid or unsound. Fallacies are often used intentionally or unintentionally in arguments to persuade others with faulty reasoning.

So, the key difference lies in that biases affect our thought processes from within, often unconsciously, while fallacies are mistakes in the way an argument is constructed or presented, typically in a more conscious or deliberate manner.

Examples

The most common biases include:

• Confirmation bias, where people seek information that confirms their existing beliefs, and availability bias, where people rely on readily available information rather than considering all relevant facts.
• Anchoring bias, where people rely too heavily on the first piece of information they receive, and hindsight bias, where events seem more predictable after they’ve already occurred.

For an extensive list of biases check out the great https://yourbias.is.

Some common fallacies include:

• Ad hominem, where someone attacks the person making an argument rather than the argument itself.
• Slippery slope, where it’s assumed that one thing will lead to another without sufficient evidence.
• Appeal to authority, where someone claims something is true because an authority figure says so.
• False cause fallacy, where a causal relationship is assumed without evidence.
• Sunk cost fallacy, when someone continues a behavior or endeavor as a result of previously invested resources (time, money, or effort), rather than on the current and future costs and benefits.

Why?

As humans, we’ve been conditioned to these biases and fallacies. For example, looking at the sunk cost fallacy from an evolutionary perspective, the tendency to stick with a decision due to past investments could be linked to our ancestors’ need for consistency and commitment to their choices. In environments where resources were scarce and decisions could not be easily reversed, committing to a chosen path, even in the face of some losses, might have been more advantageous than constantly changing strategies, which could lead to even greater losses or missed opportunities.

Additionally, the aversion to loss, a key component of the sunk cost fallacy, is deeply ingrained in human psychology. Our brains tend to react more strongly to losses than to gains, a trait that could have helped our ancestors prioritize avoiding threats and losses in a dangerous and unpredictable world. This sensitivity to loss might make it harder for people to let go of past investments, as doing so is perceived as a loss that they are evolutionarily conditioned to avoid.

Overall, these behaviors that now manifest as the sunk cost fallacy could have had adaptive value in the ancestral environments, contributing to their persistence in modern humans despite the sometimes irrational outcomes.