Nick C. Ellis is a Welsh psycholinguist, Professor Emeritus of Psychology and Linguistics at the University of Michigan, and one of the architects of the usage-based turn in SLA. Oxford-trained (BA Psychology, Corpus Christi, 1974), he spent 1978 to 2004 at Bangor before moving to Michigan, where he ran a research programme that turned frequency, chunking, and associative learning into a workable account of how learners come to know a second language.
The CREED slogan captures the position: language learning is Construction-based, Rational, Exemplar-based, Emergent, and Dialectic. The same statistical and associative mechanisms that underwrite general cognition do the work, and grammatical structure emerges from the tracking of form-meaning contingencies across countless encounters. The 2009 Language as a Complex Adaptive System position paper (with Diane Larsen-Freeman and colleagues) is the public-facing version of the argument, and his 2019 Modern Language Journal piece "Essentials of a Theory of Language Cognition" is the compressed statement.
Ellis's most consequential idea for teaching is learned attention, borrowed from associative-learning theory. Because a learner's processing is tuned by the L1, cues that were reliable in the first language come to dominate attention and crowd out later, low-salience features of the L2, an effect he calls blocking: in his eye-tracking studies, prior experience with adverbial time markers (yesterday, tomorrow) blocks the acquisition of verb-tense morphology, since the adverb already does the temporal work and the inflection passes unnoticed (Ellis & Sagarra, 2010). The forms most vulnerable are exactly the redundant, non-salient ones that frequency alone never fixes.
This is where Ellis meets Long and focus on form. If attention is the bottleneck, then targeted form-focused instruction can in principle redirect it, pulling perception back to cues the L1 has taught the learner to ignore (Ellis, 2015, on explicit focus-on-form and learned attentional biases in L2 Latin). The shorthand for this claim, that a brief explicit intervention can "re-set the dial" of attention, is precisely what Geoff Jordan rejects in his critique of the Noticing Hypothesis: he doubts that form-focused interventions reset attentional biases in any durable way, and reads the appeal to noticing here as smuggling explicit grammar teaching back in under cognitive cover.