Why do people get addicted to scrolling on phones?

The brain is drawn to uncertain rewards, and apps often use that principle by delivering likes, messages, and new content at unpredictable times. Each refresh can promise a possible reward, which keeps the reward system engaged and encourages repeated checking. This does not mean everyone who uses a phone is addicted, but it does explain why scrolling can become compulsive. Behavioral scientists compare this pattern to variable reinforcement schedules, a concept studied for decades in psychology.