The impact of visual media on viewers can be attributed to all of the mentioned factors, but if I were to choose the most significant option, I would say:
By showing a compelling and complex story.
This is because a well-crafted narrative engages viewers on an emotional level, encourages empathy, and allows them to reflect on their own experiences and perspectives. However, the other factors—common experiences for connection, sensory depictions of events, and shocking or unusual content—also play important roles in how visual media affects viewers. Each of these elements contributes to the overall effectiveness and impact of visual storytelling.