By Michael T. Robinson
Introverted Sensing (Si) is one of your 8 cognitive functions. How you experience it and how useful it is for you depends on how well it is developed and that depends on mostly your age and what your 4 letter personality type is.
Introverted Sensing (Si) is one of the 4 ways to take in (perceive) information. The other ways are: Extraverted Sensing, Extraverted Intuiting, and Introverted Intuiting.
Introverted Sensing is best understood when compared to Extraverted Sensing. With Se, the individual perceives exactly what the senses are telling it, live and in real time.
With Si, the individual perceives mostly stored memories of previous sensory experiences.
Thus the person with dominant Introverted Sensing will experience something real time, but then they will quickly compare it to stored memories in their minds.
The perfect example is a quality assurance inspector in a widget factory. Their job is to look at widgets coming off the production line and then compare those widgets to a known perfect widget, an image of which they have stored in their minds.
They can easily detect any widgets coming off the production line that do not match the stored image of a perfect widget. Introverted Sensor's brains are wired for this.
Another example is a personal trainer in a gym who has been trained in anatomy and who knows the precise way to perform each exercise. When they are training someone on how to exercise, they have an image in their mind of how the person should move. How they should lift a weight. How they should hold their body. How they should be breathing. The Introverted Sensor trainer can then instruct the person in how to do the exercise perfectly and safely.
What makes Si so interested is that the individual's brain is wired make this comparison and to show them what is different between the new widget off the line and the memorized image.
Thus people with dominant Si usually have the ability to recall a past experience in great vivid detail, complete with any stored emotions. A dominant Si can re-experience a past event just as if it was happening live, complete with memories of how they were feeling at the time.
Some dominant Introverted Sensors describe this as if a movie was playing in their head, and it takes them back to the original event which they experience as if it were real.
Some Introverted Sensors also see the world in a surrealistic way. This is where images of the original event appear slightly skewed and distorted. Think of surrealistic paintings.
Introverted Sensors tend to have very good memories for details. They can easily recall details of things they are interested in: names of movies, actors in movies, names of football players, numbers, percentages, specifications, financial results and prices.
Remember that Introverted Sensing is focused internally. It's happening inside one's mind and is therefore difficult to observe from the outside.
Personality Types where Si is the dominant function are: ISTJ and ISFJ.
Personality Types where Si is the auxiliary function are: ESTJ and ESFJ.
Examples of well known people with dominant Introverted Sensing are: