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How Cognitive Biases Affect Your Personal Safety

August 17, 2016

brain-activity.jpgThis is part 1 of our workplace safety series on how cognitive biases affect safety. Click here to read Part 2, click here for Part 3, and here is Part 4.

Personal safety is an outcome of decision making. Consciously identifying and considering risk factors before acting will lower the odds of negative safety outcomes over time. Unfortunately, we humans aren’t completely rational decision makers. In fact, some neuroscience and psychological studies over the past decade indicate that our decision making is much more irrational than we previously would have imagined.

Nobel Prize winning, Princeton University Prof. Daniel Kahneman’s research indicates that we have two systems of thinking. One system is logical, deliberate, and analytically pursues rational answers to problems. We are aware of this part of our mind. It’s good at making decisions but it requires a lot of energy. If our mind is a computer the logical system is the program that causes our mind, fan spinning, to overheat with effort.

Our other system is intuitive. It is the irrational, fast, automatic thinking process. The intuitive system is extremely efficient. The logical system is difficult for our brains. Our brains evolved to survive by efficient problem solving. Like water running downhill, our brains take the path of least resistance. With an average of 50,000 thoughts per day, we wouldn’t be able to manage our lives with the logical system. Our intuitive system is in control most (some argue all) of the time efficiently making those thousands of daily decisions.

Fascinating, but what does this have to do with safety? Once you realize that your brain is on auto-pilot most of the time, you will begin to understand why we make those decisions that put us at a safety risk. Our brain doesn’t want to fire up the logical system. That’s way too hard and inefficient. Besides, we are behind schedule and have daily goals to meet!

Let's try an experiment

Before reading the rest of this post, watch the below video.

Did you notice anything strange in the video?


You didn't notice a gorilla on the screen? 

Don't worry, if you didn’t see the gorilla you are not alone. This video was part of a Harvard University study by psychologists Christopher Chabris and Daniel Simons. The study found that half of the people who watched the video and counted the basketball passes missed the gorilla.

This experiment shows that we miss so much that is going around us in plain sight. Do you see how this could impact our personal safety? Have you ever heard an injured person say “I never even saw it” while describing the factors that lead to the incident? This psychological factor is called inattentional blindness.

Our limited capacity to take in the sights, sounds, and other sensory inputs that bombard the senses every moment causes inattentional blindness. This is a feature of our intuitive system. The more sensory inputs, the more likely the blindness. Safety professionals should keep this in mind when creating JSAs and work procedures.

Inattentional blindness is especially powerful when a person is very focused on a specific thought or action – tunnel vision. Add stress and a noisy, chaotic, environment and it’s no wonder that injured employees “never even saw it”. What can you do during your next safety meeting to raise employees’ awareness of their surroundings? What can you do to remind workers to look for the "gorillas" on their jobsite?


The purpose of this blog series is to highlight some of the techniques that our intuitive, auto-pilot brains use to make decisions and how that can impact our personal safety. These phenomenon, commonly called heuristics and cognitive biases, are universal to humans. Without them we would not be able to get through the day – our logical system just can’t keep up with the daily cognitive load to function. However, these mental shortcuts can cause us to take unnecessary and seemingly foolish risks. Awareness of their existence is the first step in avoiding unnecessary risks to our personal safety.

Periodically, I will be posting a short blog that identifies one of our cognitive biases and how it can impact personal safety. A person’s brain is the ultimate safety leading indicator. Understanding the psychology of safety is the next step on our journey to zero incidents.

Blind Spots: 4 Psychological Factors That Can Get Your Injured

Brian Dishman Brian Dishman is a Senior Consultant at PSI. He educates safety leaders on the internal factors that impact employee safety. Brian focuses on safety leadership, safety culture development, and the psychology of safety.