1. Author / Editor
To find out if a journal is peer reviewed, you can either look at a print copy of the journal or find the journal's website and check to see if there is a review process. Another option is to look up the journal in Ulrich's Periodicals Directory to see if the journal is refereed.
In addition to being aware of filter bubbles and potential biases in information sources, it is also helpful to understand our own biases and how our brains respond to new, potentially inconsistent and/or emotionally charged information.
The links below may help: