Inattentional Blindness – Human Error that Costs Lives


Inattentional Blindness is a simple concept that is responsible for deaths from human error in healthcare. Simply put, we are prone to error when our attention is elsewhere. This is hardly a revelation. The real headline is just how ‘blind’ inattentional blindness can really make us – no matter how intelligent we are.

Largely in part to some people playing basketball and an ‘invisible gorilla’, Inattentional Blindness is a concept many people have seen demonstrated even if they are not consciously aware. In a paper titled ‘Gorillas in our midst: sustained inattentional blindness for dynamic events, Simons and Chabris showed that humans could fail to notice a gorilla right in front of their eyes when completing another task that required their attention.

Even though this experiment will never work on you now because I have brought the gorilla to your attention, this is a youtube video of the experiment that you can try on family and friends.

In this experiment roughly 50% of people failed to see the gorilla.

There is additional evidence that demonstrates that though we fail to consciously process an unusual stimuli whilst pre-occupied with another task the unusual stimuli is still subconsciously processed and can influence later behaviour. This would indicate that the Gorilla in this experiment was subconsciously detected but System 2 was distracted and dismissed the ‘ALERT’. Dismissing subconscious alerts leaves us open to error both in number and magnitude.

We have all experienced this human behaviour. Think of a time where you have made a mistake because you are simply overwhelmed with other engagements. Forgot to pick somebody up or that you had an appointment? The chances are that your subconscious had remembered but you were mentally preoccupied and dismissed these ‘alerts’.

A famous case of inattentional blindness was discussed in court in the US. A police officer was charged with perjury for claiming to have not ‘seen’ an assault that he had ran straight past. At the time he was chasing a suspect in a shooting and maintained that he had seen nothing of an assault that he passed directly by.  Simons & Chabris, recreated an approximation of the events as way of an experiment and showed that given similar circumstances only 35% of people noticed the assault. The experiment follows their trend of having great titles:

You do not talk about Fight Club if you do not notice Fight Club: Inattentional blindness for a simulated real-world assault.

This experiment was not mentioned in the trial or the appeal but the police officer in question had his conviction overturned.

Inattentional Blindness in Medicine

Unfortunately the examples of Inattentional Blindness in medical communication centre on the mistakes that occur when the phenomenon is in play.  A paper by Matthew Grissinger collated several examples.

I have unapologetically lifted his introduction as it is brilliantly constructed.

A nurse pulls a vial of heparin from an automated dispensing cabinet. She reads the label, prepares the medication, and administers it intravenously to an infant. The infant receives heparin in a concentration of 10,000 units/mL instead of 10 units/mL and dies.

A pharmacist enters a prescription for methotrexate daily into the pharmacy computer. A dose warning appears on the screen. The pharmacist sees the warning, bypasses it, and dispenses the medication as entered. The patient receives an overdose of the medication and dies.

A nurse reaches into the refrigerator for a piggyback antibiotic for her patient. She reads the label, spikes the bag with intravenous (IV) tubing, and administers the medication to her patient. The patient receives a neuromuscular blocking agent instead of the intended antibiotic and dies.

A pharmacy technician labels and delivers an IV infusion to the dialysis unit. The nurse reads the pharmacy label and hangs the bag while preparing her patient for dialysis. The patient receives sterile water for injection instead of 0.9% sodium chloride and dies.

A nurse picks out a prefilled syringe of pain medication for her patient. She reads the label and administers the medication intravenously. The patient receives hydromorphone instead of morphine and experiences a respiratory arrest.

All of these real-life errors, and many more in health care and other industries, have happened under similar circumstances: the person performing the task fails to see what should have been plainly visible, and later, they cannot explain the lapse. In many cases, people involved in the errors have been labeled as careless and negligent. However, these types of accidents are common and can even be made by intelligent, vigilant, and attentive people. The cause is usually rooted in “inattentional blindness,” a condition all people exhibit periodically.

Example of Utility


Looking at the aforementioned examples, neutralising inattentional blindness could and would save lives. Human error in healthcare cost lives and this is certainly a component. The research by Simons & Chabris has found that Inattentional Blindness is is proportionate to the demand of the primary task. I.e. The harder it is to count the passes made by the basketball players – the more invisible the Gorilla becomes. Logical really, the greater the distraction the more likely you are to miss something or make a mistake. Reducing the ‘distraction’ to reduce inattentional blindness has been in practice for years. Nurses and pharmacists carrying out the ‘medication run’ on hospital wards are protected from distraction with signs prohibiting people from interrupting or asking them questions whilst doing so.

Human Errors in HealthcareAnother approach is to demand greater ‘attention’ to be given to the most important task – thus ensuring that it becomes the primary task. Multiple name checks, checklists and administrative demands of drug administering have been imparted to draw significant attention to any procedural errors that may occur.

In the example of dismissed computer alerts, this may fall into the category of ‘too much feedback’ attenuates our response to feedback. The YO messaging app designed to alert Israeli people of incoming rocket attacks was suggested to lose its effectiveness because of too many alerts by Shlomo Bernatzi in his book The Smarter Screen. I would suggest that creators of this software should have varied alert prompts and varied input response requirements ensuring significant levels of attention are required to bypass them. This would in theory, reduce inattentional blindness errors. Discuss how I would remove errors in your organisation.


The ethical utility that immediately springs to mind is deliberately distracting people to keep their mind from a pre-consented but maybe unpleasant experience. E.g. playing music or engaging in conversation to distract a patient during conscious procedures such as a pacemaker implant or routine blood test. Toys are often used in this way during paediatric procedures where a distraction from a ‘pain’ stimulus in a child is ethically sound.

To utilise this phenomenon to deliberately distract people and pass something by their attention are mostly ethical flawed.