The research on motivated reasoning — conducted by psychologists including Ziva Kunda, whose foundational work in the 1990s established the concept rigorously — shows that the motivation to believe something causes people to unconsciously search for reasons to support that belief and to dismiss or minimize reasons that challenge it.

The information is processed, but the standards applied to supporting evidence are much lower than the standards applied to challenging evidence.

In the Barclay case, Carey Gibson had an overwhelming motivation to believe that the young man in Spain was her brother.

She wanted it to be true with a depth and urgency that cannot be overstated — after three years of uncertainty and suspended grief, the possibility of resolution was intensely desirable.

Under these conditions, evidence that supported the identification — specific details about the family that “Nicholas” knew, his emotional distress, the general appearance of a teenage boy — would be processed with low standards: any plausible interpretation that supported the identity was accepted.