Who first used the term 'filter' in cognitive science context? Donald Broadbent's 1958 book Perception and Communication is the oldest work I can find that makes use of this term.

However, I wonder if perhaps someone else had used the term earlier, or if Broadbent had used the term in published work before that date.
Colin Cherry coined the phrase the Cocktail party effect to describe the ability for people to tune or filter out distraction and focus on one thing; the illustration being able to focus on a conversation amidst all the background noise at a cocktail party. 

Broadbent's filter model of attention  was developed from Cherry's work proposing the concept filtering information. Cherry first used the idea of a filter.  Broadbent was the first person to officially coin the term filter as it is used within this context and within a cognitive model.