How Fear Alters Perception

How Fear Alters Perception

I found the topic of perception the most interesting out of the topics that had been discussed thus far, but I was interested in knowing how the accuracy or normality of our perception can change depending on the stimuli.  I went to and searched for articles on perception.  An interesting articles that appeared in the results was “Phobias alter perception, German researchers say.”

In our lesson on perception, we learned of bottom-up processing and top-down processing.  In bottom-up processing we are taking in stimuli from the environment in the form of environmental energy through our sense organs.  Our sense organs then transform this environmental energy into action potential.  This action potential is sent to our brains where it is processed.  In top-down processing, we gain information from our experiences, knowledge, and expectations.  This information is used to help process the external stimuli.  With these processes combined, our brain can smoothly process both internal and external stimuli to help us understand and interact with the world.

The article I read was a summary of findings from a study that considered the individual differences of human perception.  The control group had no phobias and the test group suffered from arachnophobia.  The researchers found that phobia-related stimuli can alter the way that the brain processes vision (Osterath, 2014). This is significant because it helps to demonstrate what is occurring in the brain of someone with a phobia, which can further influence how treatment for their phobia is developed and applied.  One of the tests (and the one that specifically relates to these findings) that the psychologists performed was a test that showed two pictures at the same time.  According to the researchers, the brain cannot see two different pictures at the same time (Osterath, 2014).  Essentially, this means that we (subconsciously) make a decision on which picture to process first.  In the test, one of two pictures was a series of colored triangles; the other image was either a spider or a flower, alternating.  The test subjects pressed a button on which image they saw on the screen.

The researchers found that the Arachnophobe group processed the image of the spider almost twice as often as those in the control group (Osterath, 2014).  With these results, the researchers can hypothesize that fear and emotion play a large role in what stimuli the brain chooses to perceive.  The researchers believe that the amygdalae may be directly connected to the brain’s visual processing center.  This would mean that your brain will not let you miss something that you are afraid of, probably an evolutionary defense mechanism that went awry in the brains of those suffering from phobias (Osterath, 2014).  Researchers have yet to confirm this connection; this is speculation.

The results of this study can be a tool in understanding our lesson on perception.  Not only do we use bottom-up processing, but we use top-down processing.  So, while our brain is perceiving this image of a spider, it is using top-down processing to connect the spider with feelings and emotions of fear and distress.  Our brain knows we are afraid of it, and can use this top-down processing to communicate this with the body and let the body take the next steps (fight or flight).  With these findings, another door is opened in the research field of cognitive psychology and neuroscience.  We can hope that next someone will study the link between the amygdalae and the brain’s perception centers.  One of the most common mental health disorders is a phobia.  With more research concentrated on the things we are afraid of are perceived in the brain, we can help improve daily life with those who suffer from this disorder.




Osterath, B. (2014, January 09). Phobias alter perception, German researchers say. Retrieved from

Leave a Reply