When comprehension elicits incomprehension: Deterioration of semantic categorisation in the absence of stimulus repetition

Abstract

Repetition improves retrieval from memory; however, under some circumstances, it can also impair performance. Separate literatures have investigated this phenomenon, including studies showing subjective loss of meaning following 'semantic satiation', slowed naming and categorisation when semantically related items are repeated and semantic 'access deficits' in aphasia. Such effects have been variously explained in terms of habituation of repeatedly accessed representations, increased interference from strongly activated competitors and long-term weight changes reflecting the suppression of non-targets on earlier trials (i.e., retrieval-induced forgetting). While studies of semantic satiation involve massed repetition of individual items, competition and weight changes at the conceptual level should elicit declining comprehension for non-repeated items: this pattern has been demonstrated for picture naming but effects in categorisation are less clear. We developed a paced serial semantic task (PSST), in which participants identified category members among distracters. Performance in healthy young adults deteriorated with ongoing retrieval for non-repeated words belonging to functional categories (e.g., picnic), taxonomic categories (e.g., animal) and feature-based categories (e.g., colour red - 'tomato', 'post box'). This decline was greatest at fast presentation speeds (when there was less time to overcome competition/inhibition) and for strongly associated targets (which may have accrued more inhibition to facilitate earlier target categorisation). Deteriorating performance was also seen across words and pictures, consistent with a conceptual locus. We observed a release from deteriorating categorisation following a switch to a new category, demonstrating that this was not a general effect of time on task. Patients with semantic aphasia, who have deficient semantic control, maintained their performance throughout the categories, unlike younger adults: this finding is hard to reconcile with accounts of declining performance that propose a build-up of competition, since the patients should have had greater difficulty resolving such competition. These results instead suggest that declining performance on our goal-driven categorisation task was linked to the use of a controlled retrieval strategy by healthy young adults. Patients may not have inhibited related non-target knowledge to facilitate initial categorisation like younger volunteers, and consequently they were less vulnerable to declining comprehension in this paradigm. Together, these results demonstrate circumstances which produce declines in continuous categorisation in healthy adults.

Intrinsic connectivity of left ventrolateral prefrontal cortex predicts individual differences in controlled semantic retrieval

“…Fifteen categories labels (e.g., Bakery ) were selected from the task used by Nathaniel et al. (2018) , with each category containing 60 items.…”

“…In line with this suggestion, the activation in LIFG is modulated by semantic distance, with parametric increases in the response of this region as the strength of semantic association decreases ( Gao et al., 2021 ; Zhang et al., 2020 ). (ii) Recent or sustained retrieval of related representations can also increase the requirements for controlled retrieval ( Anderson, 2003 ; MacLeod et al., 2003 ; Nathaniel et al., 2018 ; Runnqvist et al., 2012 ; Wimber et al., 2008 ). This can arise within tasks such as picture naming when semantically-related items are presented in quick succession, creating ‘blocking’ effects that reflect temporary inaccessibility of information ( Nathaniel et al., 2018 ).…”

“…(ii) Recent or sustained retrieval of related representations can also increase the requirements for controlled retrieval ( Anderson, 2003 ; MacLeod et al., 2003 ; Nathaniel et al., 2018 ; Runnqvist et al., 2012 ; Wimber et al., 2008 ). This can arise within tasks such as picture naming when semantically-related items are presented in quick succession, creating ‘blocking’ effects that reflect temporary inaccessibility of information ( Nathaniel et al., 2018 ). This pattern may occur because retrieval involves suppressing semantic neighbours of targets, which then cannot be easily accessed; in addition, the earlier activation of related concepts may create competition that increases subsequent control demands ( Jefferies et al., 2007 ; Schnur et al., 2006 ; Thompson et al., 2015 ).…”

“…Moreover, some paradigms require participants to maintain an appropriate attentional focus on specific semantic information, and this may become more difficult over time. A recent study by Nathaniel et al. (2018) used a ‘paced serial semantic task’ that required participants to sustain attention to a semantic target category and detect relevant items at a rapid pace: healthy participants were less efficient at retrieving weak than strong associations, and showed within-category declines in target detection suggesting that they had greater difficulty sustaining attention or overcoming competition and/or retrieval-induced forgetting towards the end of each category.…”

“…In the current study, we used functional neuroimaging to examine the neurocognitive mechanisms that contribute to individual differences in the paced serial semantic task used by Nathaniel et al. (2018) .…”