Illusion of Information Adequacy
Missing evidence does not feel like a gap. A coherent one-sided account can therefore produce the same sense of informational sufficiency as a more complete view.
People shown arguments from only one side of a proposed merger were just as likely as people given the broader case to say they had enough information. Seeing less did not make them feel less informed.
E1The evidence you cannot see creates no friction
You judge adequacy using the material available to your mind, not against an inventory of everything that could matter. When the visible facts form a coherent case, fluency is mistaken for completeness: the decision feels ready because the story has no obvious hole. But absent counterarguments cannot announce themselves. Unlike Confirmation Bias, which filters evidence through an existing belief, this illusion can arise before you have chosen a side—the partial evidence itself supplies both the conclusion and the confidence to stop looking.
E1More information is not always the cure
A decision can be sufficiently informed without being exhaustive; demanding every possible fact merely replaces premature certainty with paralysis. The relevant boundary is whether consequential perspectives are missing, not whether uncertainty has been eliminated—a distinction captured by the 70% Rule.
Request the strongest missing case
Before an important decision, write down which side of the evidence you have mostly encountered. Then obtain the strongest case for the other side and name one finding that would reverse your choice. If you cannot do either, treat your feeling of “enough information” as untested.
Episodes that teach this
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Feelings vs Facts? Science of Why We Make Bad Decisions - FutureIQ
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Participants given only pro-merge or anti-merge arguments were just as likely as the control group to say they had enough information.