logogens

Logogens are a theoretical construct in cognitive psychology, used to model how people recognize written words. The term refers to individual detectors, one for each word in a speaker's lexicon, proposed as part of the logogen model of word recognition developed by John Morton and colleagues in the late 1960s and 1970s. In this model, a perceived stimulus activates a set of logogens through feature-based inputs from perceptual detectors. Each logogen accumulates activation over time and decays when input is absent. Every logogen has a criterion or threshold; when its activation reaches this threshold, the corresponding word is recognized and a response is triggered. The first logogen to hit threshold typically determines the recognition decision, though multiple logogens may be briefly active.

Activation can be raised by bottom‑up sensory input, and lowered or offset by top‑down factors such as context or expectations. Word frequency is often represented as a lower threshold or faster accumulation for frequent words, making them reach recognition threshold more quickly. The model explains performance in lexical tasks, including reading under noisy conditions, the word superiority effect, and masked priming, by allowing simultaneous competition among many logogens.

Critics note that the logogen theory has limitations and has been superseded by more interactive, connectionist approaches in contemporary research. Nevertheless, the logogen framework influenced later models of lexical access and remains a foundational reference in the study of word recognition.