Here are the corrections for the mistakes in the passage:

1. **raise** → **rise** (Correct phrase: "with the rise of muckraking")
2. **impacted concerned** → **concerned about** (Correct phrase: "elites concerned about the effects")
3. **politics decision-making** → **political decision-making** (Correct phrase: "on political decision-making")
4. **wide available** → **widely available** (Correct phrase: "became widely available")
5. **theories concerned** → **theories concerning** (Correct phrase: "to draw up theories concerning the use")
6. **when media affects people** → **how media affects people** (Correct phrase: "watch how media affects people")
7. **has** → **have** (Correct phrase: "the myriad forms of mass communication available today have also encouraged")
8. **begin** → **to begin** (Correct phrase: "encouraged some researchers to begin to investigate")
9. **the impacts** → **the impact** (Correct phrase: "the impact of mass media")
10. **1990s, researchers began** → **1990s, researchers began** (No change needed here; this is correct as is).

Here is the corrected passage with all changes included:

Research on the impacts of mass media began in the 1920s and 1930s, with the rise of muckraking journalism—elites concerned about the effects of investigative reporting in magazines such as McClure's on political decision-making. Mass media became a prominent focus of study in the 1950s after television became widely available, and academic departments dedicated to communication studies were created. These early studies investigated the cognitive, emotional, attitudinal, and behavioral effects of media in both children and adults; in the 1990s, researchers began to use those earlier studies to draw up theories concerning the use of media today. In the 1970s, theorists such as Marshall McLuhan and Irving J. Rein warned that media critics needed to watch how media affects people. Today, this remains a key concern; much attention has been taken, for example, to the impact on the 2016 election of false messaging distributed on social media. But the myriad forms of mass communication available today have also encouraged some researchers to begin to investigate "what people do with media."