Final answer:
The effect of believing implausible information when presented alongside plausible information is linked to psychological phenomena like confirmation bias, which is the tendency to confirm one's pre-existing beliefs, and motivated reasoning, which is to accept preferable beliefs.
Step-by-step explanation:
The effect described in the question where a person is more likely to believe something implausible if they are simultaneously told something highly plausible is closely related to various psychological phenomena such as the confirmation bias and motivated reasoning. Confirmation bias is the tendency to search for, interpret, favor, and recall information in a way that confirms one's preconceptions or hypotheses. Motivated reasoning is the inclination to accept ideas that are preferable to us while discounting evidence that contradicts our beliefs. Both biases can lead individuals to form connections that are not backed by evidence or logic, such as when highly plausible information makes implausible information seem more credible.