Have you ever realized that you’ve driven yourself home without really paying attention to the road? Scientists studying the brain have found that when our mind wanders, it switches to “autopilot” mode, allowing us to do our tasks efficiently, accurately, and without conscious effort. 

This is managed by a set of brain structures called the default mode network (DMN). It was discovered in the 1990s after researchers noticed brain activity in people, even though they weren’t doing anything. This detection was the first evidence that our brains are active even when we aren’t consciously putting them to work. 

Another reason why some things go unnoticed by us is called habituation. This near-universal law of psychology claims that we stop noticing something we see or hear repeatedly. Most of us are familiar with the Apple logo and see it every day, but chances are, we can't recall the details of it. And if you aren’t convinced, try doing this test. 

We often overlook trivial things in life, because they don’t matter as much. Let’s take the sound of an alarm clock in the morning as another example. When you choose a new ringtone for it, the noise wakes you up faster, as initially, you pay more attention to it, and it becomes distracting. After a while, you get used to the sound, and your response to it diminishes. 

As a result, this ability helps us to focus on the things that are more important. In fact, habituation happens regularly in our day-to-day lives when we are learning, even if we don’t realize it.

It allows us to tune out non-essential stimuli and focus on the tasks that really demand our attention. For instance, if you’re studying with the television playing in the background, the noise might be distracting at first, but your brain allows you to tune it out and center your focus on the material at hand. 

And if you ever feel like you can no longer smell your perfume, it’s not because it expired or you lost your sense of smell; most likely, you just stopped noticing it. Others around you still detect the smell, even though you aren’t aware of it.

This can also happen to our emotions when we’re constantly exposed to a large amount of bad news and negative social media posts. Interestingly, studies have shown that getting used to people experiencing negative things makes us less likely to help. For instance, street buskers and homeless people asking for money are such a common sight for individuals in big cities that they might feel less inclined to aid them.

Habituation can have several other real-life consequences, including our social interactions. It can decrease interest in or sensitivity to a partner’s needs or emotions. The significant other might be taken for granted, which can cause disagreements in the long run.