Yes, it is entirely possible for an introvert to behave in an extroverted manner when meeting new people or in certain social situations, but then become more quiet and reserved as they get to know them better. This behavior is often referred to as being an "outgoing introvert" or an "ambivert."
Introversion and extroversion are not all-or-nothing traits, but rather exist on a spectrum. Many individuals display a mix of introverted and extroverted characteristics depending on the context, their comfort level, and the people they are interacting with.
Here's how this behavior can manifest:
Extroverted around new people: Some introverts feel more comfortable and confident when meeting new individuals or in social gatherings. They might engage actively in conversations, be more expressive, and appear outgoing. This can be a coping mechanism to handle the initial discomfort of meeting new people and to make a positive first impression.
Quiet and reserved with familiarity: As an introvert gets to know people better and becomes more comfortable in their company, they might gradually retreat into their more introverted tendencies. They may prefer deeper, one-on-one conversations over large social gatherings, and they might need more alone time to recharge their energy after spending time with others.
This behavior is not contradictory or uncommon; it simply shows that individuals can adapt their social behavior based on the situation and their level of comfort. It's important to remember that introversion and extroversion are about where people draw their energy from and how they recharge, rather than a strict set of behaviors. Being outgoing in certain situations doesn't necessarily change someone's core introverted nature.