Building words and phrases in the left temporal lobe

Abstract

A central part of knowing a language is the ability to combine basic linguistic units to form complex representations. While our neurobiological understanding of how words combine into larger structures has significantly advanced in recent years, the combinatory operations that build words themselves remain unknown. Are complex words such as tombstone and starlet built with the same mechanisms that construct phrases from words, such as grey stone or bright star? Here we addressed this with two magnetoencephalography (MEG) experiments, which simultaneously varied demands associated with phrasal composition, and the processing of morphological complexity in compound and suffixed nouns. Replicating previous findings, we show that portions of the left anterior temporal lobe (LATL) are engaged in the combination of modifiers and monomorphemic nouns in phrases (e.g., brown rabbit). As regards compounding, we show that semantically transparent compounds (e.g., tombstone) also engage left anterior temporal cortex, though the spatiotemporal details of this effect differed from phrasal composition. Further, when a phrase was constructed from a modifier and a transparent compound (e.g., granite tombstone), the typical LATL phrasal composition response appeared at a delayed latency, which follows if an initial within-word operation (tomb + stone) must take place before the combination of the compound with the preceding modifier (granite + tombstone). In contrast to compounding, suffixation (i.e., star + let) did not engage the LATL in any consistent way, suggesting a distinct processing route. Finally, our results suggest an intriguing generalization that morpho-orthographic complexity that does not recruit the LATL may block the engagement of the LATL in subsequent phrase building. In sum, our findings offer a detailed spatiotemporal characterization of the lowest level combinatory operations that ultimately feed the composition of full sentences.

Prefix Stripping Re-Re-Revisited: MEG Investigations of Morphological Decomposition and Recomposition

“…We find a left hemisphere, posterior TL response sensitive to mismatches between the grammatical category required by the affix, and the category of the stem between 200 and 300 ms – the same time window and brain area associated with category-based licensing by Neophytou et al (2018) for suffixed pseudowords in Greek. This region has also been associated with syntactic composition effects in sentence processing (Flick et al, 2018). There are no differences between the three prefixes we investigated in this study, despite the fact that the actual category of the “illegal” stems varied by prefix: while re- and out- were attached to unambiguous, monomorphemic adjectives to create category violating items, un- was attached to unambiguous, monomorphemic nouns.…”

Neural basis of basic composition: what we have learned from the red–boat studies and their extensions

“…Crosslinguistically, the LATL effect generalizes not only to languages that are typologically far from English, like Arabic [27], but also to American Sign Language [25], which in addition uses a different articulator. Across constructions, we know that the effect obtains not only for noun phrases but also for verb phrases [27,28] and noun-noun compounds [29,30]. These extensions are crucial for understanding function, but in the remainder of this text I shall focus on the computational limits of this activity, that is, the situations in which the effect disappears.…”

Conceptual and Perceptual Dimensions of Word Meaning Are Recovered Rapidly and in Parallel during Reading

“…Further studies shall parametrically modulate these variables to compare their effects on the latency with which we access specific dimensions of the semantic space. As done here, care needs to be taken while selecting the stimuli as multiple psycholinguistic variables might interfere with early semantic effects, for instance, morphological effects are known to modulate brain activity within the first ∼ 170 msec after stimuli onset (Flick et al, 2018;Gwilliams & Marantz, 2018;Brooks & Cid de Garcia, 2015;Pylkkänen & Marantz, 2003).…”