Opposite of White Bear principle? Is there any phrase/term to describe the opposite of White Bear principle (also known as ironic process principle)? 
I'm looking for a word to describe the process where something eludes you the more you try to think of it (or remember it). I think I may have come across a term to describe this phenomenon but I'm not sure if such a phrase/term exists.
Short answer
Over-thinking

Background
Unconscious recall of information can be more effective than conscious recall of that same information. Disruption of the activity of the dorsolateral prefrontal cortex (by TMS) improved image-recall in healthy subjects (source: UC Santa Barbara). The dorsolateral prefrontal cortex is associated with executive functions including working memory and selective attention (Lehner et al., 2016). The effect over paying too much attention in an attempt to remember something has been referred to as over-thinking.

Reference
- Lehner et al., Genomics, Circuits, and Pathways in Clinical Neuropsychiatry, 1st ed. Elsevier (2016)