Reader-response criticism is basically a way of looking at literature that says that it's not just the words on the page that matter, but also how we interpret them as readers.
Think about it this way - when you read a story or a poem, you might have a different reaction than someone else who reads the same thing. Maybe you find it really funny, but your friend thinks it's sad. That's because everyone brings their own experiences, feelings, and ideas to what they read.
Reader-response critics think that it's important to pay attention to this - to think about how readers are shaping and interpreting the text in their own unique ways. They might look at things like how different readers might respond to themes or characters in a book, or how people's real-life experiences might influence how they understand what they're reading.
So, basically, reader-response criticism is a way of saying that there's not just one "correct" way to read a book - that each person's interpretation is just as valuable as anyone else's. It's all about how we as readers bring the words on the page to life, based on our own experiences and perspectives.