In information technology, a notification system is a combination of software and hardware that provides a means of delivering a message to a set of recipients. It commonly shows activity related to an account. Such systems constitute an important aspect of modern Web applications.
 Within the 20th century, one of the most important scientific breakthroughs has been the invention of notifications. A notification is a combination of software, hardware, and psychology that provides a means of delivering a message to a group of recipients. Notifications show activity that relate to an event, account, or person. A push notification is a message that appears on a mobile device such as a text, sports score, limited-time deal, or an e-mail announcing when a computer network will be down for a scheduled maintenance. Notifications are sent from app publishers at any time, in an effort to get users to open up their app or website. Notifications appear on a user's lock screen and also at the top of their phone screen when the phone is unlocked and in use. Push notifications can be valuable and convenient for both the app user and the developer due to the immediacy and display location of notifications. Notifications also pair with sounds to reach multiple senses of a user and get maximum attention. For app publishers, push notifications are a way for them to speak directly to the user without being caught by spam filters or being pushed to the side by the flood of emails within an inbox. Because of this, these push click-through rates can be twice as high as email. They invite users to open an app or spend time and money in a certain way by the app publisher, even when the app isn’t open. This means that for developers, publishers, and businesses, notifications are the most effective way to take attention and ultimately make money.
 Notifications utilize a concept known as variable rewards, which is a technique that slot machines use to hook gamblers. Similarly, variable reward systems keep users compulsively checking their phones due to the possibility of social approval awaiting them. Notifications have taken over our world and are now utilized by every software, website, program, and person in the world.
 Ramsay Brown, co-founder of FKA Dopamine Lab, CEO of Mission Control, and leader of AI Responsibility Lab, says “The brain isn’t particularly craving any one little feel-good signal as much as it does a good rhythm and pattern”. Social media apps cater to the timing of the notifications that they deliver to deliver literal hits of dopamine to users at algorithmically determined times. Oftentimes these companies will stockpile these notifications before delivering them all in a batch in order to maximize the emotional impact that a user experiences. Another man, Jonathan Haidt, who is a social psychologist at NYU Stern School of Business points to concerns of mental health directly relating to social media and the notification system. He points to the increase in depression and suicide rates among teens and young adults since the early 2000s and Haidy states that this trend starts the year social media was made available on cell phones. Tristan Harris, former design ethicist at Google and co-founder of the Center for Human Technology states that there is a “disinformation-for-profit business model” and companies profit by allowing “unregulated messages to reach anyone for the best price”. This becomes problematic as companies have unlimited and often unwarranted access to you and your focus through the notification system. This is always used to drive larger profits, whether that means that companies use notifications to simply promote their newest product, or if they subtly try to get you back onto the app in order to take more of your time. There is overwhelming evidence that notifications are associated with decreased productivity, poorer concentration, and increased distraction at work, school, and home.