Violent shows can cause violent behavior in those people that watch the shows, especially if a child is the viewer. Many studies have been done to ascertain the effects of television on intelligence, although most of the studies focus on younger children and results are not always conclusive.
Even analysis of news and current events, introduces concepts that are complex and intellectually stimulating. Some blame the television for society's violence, consumerism, and misinformation, while others see it as a rich resource for education and global understanding.
One study published in the Journal of Social and Personal Relationships showed that viewers experienced the same negative reactions to the loss of an imaginary friendship with a character on television as they did when their real social relationships ended.
Lest I am accused of being biased, I must agree that the television can have harmful effects too, especially when it becomes addictive. Watching television fills the time a person might have spent doing important, enriching things like interacting socially with other human beings, being physically active, discovering the outdoors, reading, using one's own imagination, or accomplishing other things like working or doing homework or chores, or spending time with enriching hobbies like art, music, etc.
Excessive TV watching more than 3 hours a day can also contribute to sleep difficulties, behavior problems, lower grades, and other health issues. Although there are many benefits to healthcare students watching medical dramas there are definitely some downsides.
For young minds, watching TV in moderation can spark interests and even inspire further research on a topic.