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  • Dr. Piotr Solowiej PT, DPT

Dynamics of Perception

Optical Face Illusion

Which way is this gentleman facing: To the right, or straight at you? The answer - it depends.

As much as we would like to believe that we are rationale and impartial decision makers and thinkers, nothing could be further from the truth. I hate to be the one to break it to you, but You are Not So Smart.

I read a decent amount about psychology and brain function, in general. While I am by no means an expert on these topics, I've learned some valuable lessons about myself, but also about common patterns of human thought and function (at least to the level of current scientific understanding). Most people have had some exposure to an optical illusion in their life. In that context, it's not hard to believe the brain can play tricks on what you see. The purpose of this post is to take the dynamics of perception and apply them (in concord with scientific evidence) to a different context, in an effort to improve understanding and communication in the healthcare setting.

1 + 1 = 2. Two. Twu. Tu. Turtle.

In an optics domain, what you see is largely dependent on your past experiences. It is rather a subjective perception, along a continuum, of an objective reality. In the picture above, there is only one picture. Yet it can be perceived in two related, but different ways.

Shifts occur between two of the most stable possibilities: man looking straight, and man looking to the right. The physiology of which is dependent on a complex system of dynamic interactions, in multiple regions of the brain.

Your perception can, additionally, be heavily influenced by the environment. In a physical therapy environment, the suggestions of your therapist (also considered part of "the environment") can shape the way you interpret exercises and information (good vs bad). Think looking at a Rorschach inkblot, or the shape of clouds - you may see a face in the sky, but now that your friend mentions it, it does sort of look like a.....turtle.

Are My Ears Deceiving Me?

Just like optics and vision, auditory stimuli and their perception are not immune to this phase shifting phenomenon.

Language can be taken for granted in the patient-provider interaction. It is a double-edged sword having both the power to improve patient expectations, but also negatively impact the perceived prognosis. Over the last two decades, studies focused on the science of pain have helped awareness of the potential negative effect of language (nocebo) grow.

In regards to language, I want to highlight a potential assumption many of us may carry - that exactly what we say, is then interpreted in the exact same manner. AKA a 1:1 relationship of information transfer. The reality is that this process is nonlinear. Even in the most simple of scenarios.

I invite the reader to review the following study for elucidation:

  • Subjects in a speech perception study were tasked with identifying an auditory stimulus: switch #1 for "say" or switch #2 for "stay." Simple.

  • Sensors were used to record brain activity while listeners were given the stimulus repetitively, with parameters of stimulus delivery, being manipulated:

  • Same stimulus - one word "say."

  • Different delivery

  • The manipulation was a time delay (msec) after the "s" syllable:

  • Below a certain time delay, the majority of listeners perceived "say." Above it, the majority of listeners perceived "stay." Two stable options (just like the picture of our friend above).

  • At a particular, critical, value of time delay: 50% of stimuli were perceived as "say," and the other 50% as "stay."

Here's what the brain activity looked like during this critical stimulus:

Brain activity during auditory stimulus

Same. Exact. Stimulus. Perceived in two completely different ways.

Keep in mind this was an artificially created environment. Lots of variables were controlled for. And it involved only a 3-4 letter word. Or, depending on how you may see it, a 4 -3 letter word:

Physical Therapy Implications

The authors of the study caution the reader to consider the additional variables that can be encountered in a real world environment: stress, attention level, fatigue, boredom, etc.

The implications for communication and physical therapy are many. Imagine how vastly perceptual paths can diverge on entire concepts and ideas. Suddenly, explaining and re-explaining the centralization phenomenon (ad nauseam), while still a bit irritating, is at least understandable.

If nothing else, I hope this post provides the reader with ample reason to approach all communication with more compassion. Misunderstanding in a relationship is not necessarily the fault of either person involved. It just indicates that some more effort need be put forth to listen to each other and get on the same page.

This all blows my mind.

I'm not that smart either, but I'm alright with that.

Thanks for reading,

Dr. Piotr

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