What can we learn about integration of novel words into semantic memory from automatic semantic priming?

According to the Complementary Learning Systems model of word learning, only integrated novel words can interact with familiar words during lexical selection. The pre-registered study reported here is the first to examine behavioural and electrophysiological markers of integration in a task that relies primarily on automatic semantic processing. 71 young adults learned novel names for two sets of novel concepts, one set on each of two consecutive days. On Day 2, learning was followed by a continuous primed lexical decision task with EEG recording. In the N400 window, novel names trained immediately before testing differed from both familiar and untrained novel words, and, in the time window between 500–800 ms post onset, they also differed from novel names that had undergone a 24-hour consolidation, for which a small behavioural priming effect was observed. We develop an account that attributes the observed effects to processes rooted in episodic, rather than semantic, memory.