PT  - JOURNAL ARTICLE
AU  - Susanne Eisenhauer
AU  - Christian J. Fiebach
AU  - Benjamin Gagl
TI  - Dissociable prelexical and lexical contributions to visual word recognition and priming: Evidence from MEG and behavior
AID  - 10.1101/410795
DP  - 2018 Jan 01
TA  - bioRxiv
PG  - 410795
4099  - http://biorxiv.org/content/early/2018/09/12/410795.short
4100  - http://biorxiv.org/content/early/2018/09/12/410795.full
AB  - Visual word recognition is facilitated by word knowledge (i.e., word familiarity) and predictive context, as reflected in faster reading times and reduced neuronal activation for highly familiar or predictable words. Previous studies could not dissociate whether knowledge- and context-based facilitation requires semantic knowledge or can also stem from prelexical sources of information. Here, we experimentally separate prelexical (i.e., orthographic/phonological) and semantic knowledge in two repetition priming experiments, to investigate their role for knowledge- and context-based facilitation. Experiment 1 investigates repetition suppression effects (i.e., reduced activation for predictable stimuli) in magnetoencephalographic brain responses of human participants (N=38) and Experiment 2 uses response times to investigate behavioral priming effects (N=24). To disentangle prelexical and semantic knowledge, we realized a pseudoword familiarization procedure in both experiments and contrasted familiarized pseudowords with novel pseudowords (unfamiliar, no semantic knowledge) and words (semantics available). In Experiment 2, one further set of pseudowords was additionally associated with semantic information (i.e., objects). We found, in both experiments, a general context effect for all letter strings, which was specifically enhanced when semantic information was available. A knowledge effect for pseudowords was found (familiarized vs. novel pseudowords) but prelexical (i.e., orthographic/phonological) knowledge alone did not enhance context effects. We conclude that knowledge- and context-based facilitation in visual word recognition can be achieved without semantic information processing, i.e., exclusively on the basis of prelexical perceptual knowledge. Semantic knowledge, however, drastically enhances context-based facilitation.Significance Statement The goal of reading is the extraction of meaning from script. This highly automatized process relies on facilitation based on word familiarity and text context. Here we use repetition priming to show that context-based facilitation is increased when semantic knowledge is present. This was demonstrated by enhanced context effects for letter strings with semantic associations. Still, earlier context effects (∼80 ms) and orthographic knowledge effects were found irrespective of semantic processing. Our findings highlight the stronger role of semantic knowledge for achieving facilitated visual word recognition in contrast to semantic-free knowledge. Our findings suggest predictive coding as a potential mechanism that underlies efficient visual word recognition.