Am gooimg to give you a detailed answer with a relevant example
Mundane realism refers to the degree to which an experiment resembles everyday situations and activities. In other words, it measures how closely the experimental setting mirrors the real world. For example, an experiment that uses a realistic setting, such as a grocery store, to test the effectiveness of a new marketing strategy would have high mundane realism.
Ecological validity, on the other hand, refers to the degree to which an experiment measures behaviors and outcomes that are relevant to the real world. This means that the experiment is designed in a way that allows for valid conclusions to be drawn about how people behave and make decisions in real-life situations. For example, an experiment that measures how people choose between healthy and unhealthy snacks in a laboratory setting might have low ecological validity if the results do not generalize to how people actually make food choices in their everyday lives