Neuroscience of Bias: Fast vs. Slow Brains

Anatomy of Decision Making

To understand why we make systematic errors of judgment in the work environment, we must analyze the biology of our thinking.

Our mind operates through two distinct systems, often described as the "fast brain" and the "slow brain."

The fast system is where biases are born; it operates automatically and unconsciously and involves primitive structures such as the amygdala (responsible for emotions), the hippocampus (memory) and the hypothalamus (relevance filter).

It is estimated that about 95% of the decisions we make on a daily basis occur in this fast system.

Imagine, for example, when we drive a car to work: we automatically brake at a red light or turn the steering wheel without conscious logical analysis of each movement; the brain automates these actions to be efficient.

This mechanism is vital for survival, designed to react in fractions of a second to imminent danger.

However, in the corporate world, where decisions require complex analysis of hiring, evaluation or strategy, relying on this automatic system can be counterproductive, as it applies mental shortcuts based on past experience or stereotypes rather than objective data.

Physiological Factors that Boost Error

The fast brain is not only the default mode, but becomes even more dominant under certain physiological conditions.

Factors such as hunger, fatigue, or extreme stress act as catalysts for bias.

This happens for a reason of biological economy: analytical and deliberate thinking (slow brain) consumes large amounts of glucose and oxygen.

When we are tired or hungry, the body tries to conserve energy by delegating control to the fast system, which is "cheaper" metabolically.

For example, if a manager must review a stack of resumes at the end of a grueling day and without having eaten, he or she is much more likely to rule out candidates based on "gut instincts" (biases) than if he or she were to perform the same task in the morning, rested and fed.

Haste is another critical factor; urgency forces the brain to look for known patterns to decide quickly, which increases the likelihood of error.

The goal, therefore, is not to biologically eliminate biases, which would be impossible and would prevent us from performing simple everyday tasks such as walking or eating, but to recognize when we are operating on "autopilot" during critical moments of professional decision making.

Summary

Our mind operates through two distinct systems: a fast, automatic one where biases reside, and a slow, analytical one. In complex corporate decisions, relying on the fast system leads to systematic errors based on stereotypes rather than objective data.

Physiological factors such as hunger, fatigue or extreme stress push the brain to use the fast system to save biological energy. A depleted manager is much more likely to rule out candidates based on biased instincts than on fair analysis.

Although we cannot biologically eliminate biases as they are survival mechanisms, we must recognize when we are operating on "autopilot." The goal is to identify these moments during critical career decisions to avoid unfair judgments and strategic errors.