In hypothesis testing, two types of errors can occur when making a decision about the null hypothesis ($H_0$). Understanding these errors is crucial for interpreting research results correctly.
The question describes a scenario where the null hypothesis ($H_0$) is actually true, but the researcher decides to reject it. This specific situation corresponds to a well-defined statistical error.
When the null hypothesis ($H_0$) is true and is rejected by the researcher, it perfectly matches the definition of a Type I error. Therefore, the researcher is committing a Type I error.