People who use Si take in what they are going through now by comparing it with what they have been through before. When they meet a new situation, they first recall a similar time.
Si is a way of perceiving that takes in the present by comparing it with past experience. When people who use Si meet a new situation, they first recall a similar time and check what went wrong then.
That is why it tries not to repeat the same mistake. It remembers what it has experienced down to the details, so next time it prepares for that part in advance.
It compares what is happening now with memory. It checks what is the same and what is different, and looks for risk in the parts that differ.
That is why it is strong with details. Even things others overlooked, it finds precisely if they caused problems before.
When people who use Si are offered a new method, they first think about what could go wrong with the change. So they want to check things first.
It is not opposition but a request to look into it further, though from outside the two are hard to tell apart. Explaining not only what will improve but also what could go wrong often gets agreement faster.
People who use Si are strong in work where getting things exactly right is the result itself, because they check everything to the end without missing anything.
It also suits work that has to be kept going for a long time. It keeps to a method once decided without changing it, which earns the trust of the people around it.
They use different standards. People who use Si compare what they are going through now with what they have been through before, and people who use Se look at what is happening now as it is.
So they react differently in new situations. People who use Si look for a similar time and respond based on it, while people who use Se judge as things happen. Both are sensing functions, but they refer to different things.
When Si is very strong, it is hard to change a method that has worked before. It is safe, but it sometimes means missing new opportunities.
At a moderate level, they use their experience while also trying new things. When Si is weak, they are more likely to repeat mistakes but accept new methods easily.
The assessment also measures how strong Si is. Even within the same type, people with different Si scores handle change very differently.
This page describes behavior patterns for self-understanding. It is not a medical or psychological diagnosis, and it does not replace professional care. If difficulties persist and disrupt daily life, please seek professional help.
This page covers the type in general. How it actually shows up in your own combination is what the measurement tells you.