Final answer:
The mass media, along with politicians and policy specialists, significantly shape public opinions and perceptions, especially on issues such as international affairs or topics where the public has minimal direct experience.
Step-by-step explanation:
According to the text, those who have significant control over shaping public opinions and perceptions are primarily politicians, policy specialists, and the mass media. Politicians and other political elites serve as opinion leaders, interpreting and shaping public opinion through platforms such as talk programs or opinion columns. Elite commentators like Jon Stewart or Stephen Colbert have historically provided cues that inform the public on how to react to current issues. However, the pervasive influence of the mass media is highlighted by the work of scholars like Robert Entman and V. O. Key, who assert that the media not only influence what people think about certain issues but also their political preferences, especially on topics like international affairs where the public has little personal experience.
Furthermore, as gatekeepers, media owners play a key role in dictating which topics receive attention and thus influence public policy discussions. The text acknowledges that the mass media plays a critical role in informing the public and potentially swaying public opinion on various issues. Therefore, the mass media has significant control over shaping public opinions and perceptions.