At the press meeting for Thawne (disguised as Wells) at the turning on of the Particle Accelerator, he noted that both Barry was there, along with Clifford DeVoe and his wife. Thawne was excited at this and even remarked that he was a fan of DeVoe and even said 'good luck' to DeVoe for the future, likely because since Thawne was from the future he knew DeVoe would one day become an enemy to The Flash.
The title is a reference to the philosophical proposition "I think, therefore I am", originally known in Latin as "Cogito ergo sum."
In DC comics, the Thinking Cap was the main source of the Thinker's abilities, which included telekinesis and mind control.
The scene from S1 E1 Pilot (2014) is shown again, however it continues on at the press conference after Barry runs after the thief.
Similar to the comics, Clifford DeVoe obtains his high levels of intellect through his developed and created: "The Thinking Cap", and he even names it this the same. Also like in the comics, its use has detrimental effects on the rest of his body, though instead of a slow cancer like in the comics, it is a fast-acting paralysis.