Age-related effects in compound production: Intact lexical representations but more effortful encoding

A cautionary note on the studies using the picture-word interference paradigm: the unwelcome consequences of the random use of "in/animates"

The picture-word interference (PWI) paradigm allows us to delve into the process of lexical access in language production with great precision. It creates situations of interference between target pictures and superimposed distractor words that participants must consciously ignore to name the pictures. Yet, although the PWI paradigm has offered numerous insights at all levels of lexical representation, in this work we expose an extended lack of control regarding the variable animacy. Animacy has been shown to have a great impact on cognition, especially when it comes to the mechanisms of attention, which are highly biased toward animate entities to the detriment of inanimate objects. Furthermore, animate nouns have been shown to be semantically richer and prioritized during lexical access, with effects observable in multiple psycholinguistic tasks. Indeed, not only does the performance on a PWI task directly depend on the different stages of lexical access to nouns, but also attention has a fundamental role in it, as participants must focus on targets and ignore interfering distractors. We conducted a systematic review with the terms "picture-word interference paradigm" and "animacy" in the databases PsycInfo and Psychology Database. The search revealed that only 12 from a total of 193 PWI studies controlled for animacy, and only one considered it as a factor in the design. The remaining studies included animate and inanimate stimuli in their materials randomly, sometimes in a very disproportionate amount across conditions. We speculate about the possible impact of this uncontrolled variable mixing on many types of effects within the framework of multiple theories, namely the Animate Monitoring Hypothesis, the WEAVER++ model, and the Independent Network Model in an attempt to fuel the theoretical debate on this issue as well as the empirical research to turn speculations into knowledge.

Cumulative semantic interference is blind to morphological complexity and originates at the conceptual level

When naming a sequence of pictures of the same semantic category (e.g., furniture), response latencies systematically increase with each named category member. This cumulative semantic interference effect has become a popular tool to investigate the cognitive architecture of language production. However, not all processes underlying the effect itself are fully understood, including the question where the effect originates from. While some researchers assume the interface of the conceptual and lexical level as its origin, others suggest the conceptual-semantic level. The latter assumption follows from the observation that cumulative effects, namely cumulative facilitation, can also be observed in purely conceptual-semantic tasks. Another unanswered question is whether cumulative interference is affected by the morphological complexity of the experimental targets. In two experiments with the same participants and the same material, we investigated both of these issues. Experiment 1, a continuous picture naming task, investigated whether morphologically complex nouns (e.g., kitchen table) elicit identical levels of cumulative interference to morphologically simple nouns (e.g., table). Our results show this to be the case, indicating that cumulative interference is unaffected by lexical information such as morphological complexity. In Experiment 2, participants classified the same target objects as either man-made or natural. As expected, we observed cumulative facilitation. A separate analysis showed that this facilitation effect can be predicted by the individuals’ effect sizes of cumulative interference, suggesting a strong functional link between the two effects. Our results thus point to a conceptual-semantic origin of cumulative semantic interference.

Mental chronometry of speaking in dialogue: Semantic interference turns into facilitation

Numerous studies demonstrate that the production of words is delayed when speakers process in temporal proximity semantically related words. Yet the experimental settings underlying this effect are different from those under which we typically speak. This study demonstrates that semantic interference disappears, and can even turn into facilitation, when semantically related words are embedded in a meaningful communicative exchange. Experiment 1 and 3 (each N = 32 university students) implemented a picture-word interference task in a game played between two participants: one named the distractor word and, after a stimulus-onset-asynchrony of -150 ms or -650 ms, the other named a semantically related or unrelated target picture. Semantic interference reappeared with identical experimental parameters in a single-person picture-word interference setting (Experiment 2, N = 32). We conclude that the inhibitory context effects leading to semantic interference in single-subject settings are attenuated whereas facilitatory effects are enhanced in communicative settings.

Internet-based language production research with overt articulation: Proof of concept, challenges, and practical advice

Language production experiments with overt articulation have thus far only scarcely been conducted online, mostly due to technical difficulties related to measuring voice onset latencies. Especially the poor audiovisual synchrony in web experiments (Bridges et al. 2020) is a challenge to time-locking stimuli and participants' spoken responses. We tested the viability of conducting language production experiments with overt articulation in online settings using the picture-word interference paradigm - a classic task in language production research. In three pre-registered experiments (N = 48 each), participants named object pictures while ignoring visually superimposed distractor words. We implemented a custom voice recording option in two different web experiment builders and recorded naming responses in audio files. From these stimulus-locked audio files, we extracted voice onset latencies offline. In a control task, participants classified the last letter of a picture name as a vowel or consonant via button-press, a task that shows comparable semantic interference effects. We expected slower responses when picture and distractor word were semantically related compared to unrelated, independently of task. This semantic interference effect is robust, but relatively small. It should therefore crucially depend on precise timing. We replicated this effect in an online setting, both for button-press and overt naming responses, providing a proof of concept that naming latency - a key dependent variable in language production research - can be reliably measured in online experiments. We discuss challenges for online language production research and suggestions of how to overcome them. The scripts for the online implementation are made available.

On the lexical representation of compound nouns: Evidence from a picture-naming task with compound targets and gender-marked determiner primes in aphasia

Our study examines the lexical representation and processing of compounds in participants with aphasia (PWA) and language-unimpaired control speakers. Participants were engaged in primed picture-naming in German, a language that marks for grammatical gender. Gender-marked determiners served as primes (der_masc, die_fem, das_neut [the]) and noun-noun compounds as targets (e.g., Gold_neutfisch_masc [goldfish]). Experiment 1 tested whether the compound's constituents are activated at a lexical-syntactic level during production. Primes were gender-congruent either with the morphological head of the target compound (e.g., der_masc for the target Gold_neutfisch_masc), or its modifier (das_neut for Gold_neutfisch_masc), or incongruent with both (die_fem). Head congruency of prime and target produced strong facilitatory effects across groups. Modifier congruent primes produced contrasting effects. Modifier congruency speeded up picture naming in the controls and PWA with isolated deficits of lexical access (PWA-lex) but they delayed picture naming in PWA with additional deficits of phonological encoding (PWA-pho). Both patterns suggest that the lemmas of both constituents of compound targets and their grammatical gender are activated during compound retrieval, in line with a multiple-lemma representation of compounds. Experiment 2 explored the nature of the observed effects compared to a gender-neutral control condition. While facilitatory effects were shown by PWA-lex and the controls, PWA-pho did not profit from congruent primes but showed inhibitory effects by incongruent primes, exclusively. Inhibitory effects were also attested for the controls but not for PWA-lex. The functional origin of determiner priming effects and their theoretical and clinical implications are discussed in the framework of current accounts.

Aging affects steaks more than knives: Evidence that the processing of words related to motor skills is relatively spared in aging

Lexical-processing declines are a hallmark of aging. However, the extent of these declines may vary as a function of different factors. Motivated by findings from neurodegenerative diseases and healthy aging, we tested whether 'motor-relatedness' (the degree to which words are associated with particular human body movements) might moderate such declines. We investigated this question by examining data from three experiments. The experiments were carried out in different languages (Dutch, German, English) using different tasks (lexical decision, picture naming), and probed verbs and nouns, in all cases controlling for potentially confounding variables (e.g., frequency, age-of-acquisition, imageability). Whereas 'non-motor words' (e.g., steak) showed age-related performance decreases in all three experiments, 'motor words' (e.g., knife) yielded either smaller decreases (in one experiment) or no decreases (in two experiments). The findings suggest that motor-relatedness can attenuate or even prevent age-related lexical declines, perhaps due to the relative sparing of neural circuitry underlying such words.

Morphological facilitation and semantic interference in compound production: An ERP study

This study investigates the production of nominal compounds (Experiment 1) and simple nouns (Experiment 2) in a picture-word interference (PWI) paradigm to test models of morpho-lexical representation and processing. The continuous electroencephalogram (EEG) was registered and event-related brain potentials [ERPs] were analyzed in addition to picture-naming latencies. Experiment 1 used morphologically and semantically related distractor words to tap into different pre-articulatory planning stages during compound production. Relative to unrelated distractors, naming was speeded when distractors corresponded to morphemes of the compound (sun or flower for the target sunflower), but slowed when distractors were from the same semantic category as the compound (tulip ➔ sunflower). Distractors from the same category as the compound's first constituent (moon ➔ sunflower) had no influence. The diverging effects for semantic and morphological distractors replicate results from earlier studies. ERPs revealed different effects of morphological and semantic distractors with an interesting time course: morphological effects had an earlier onset. Comparable to the naming latencies, no ERP effects were obtained for distractors from the same semantic category as the compound's first constituent. Experiment 2 investigated the effectiveness of the latter distractors, presenting them with pictures of the compounds' first constituents (e.g., moon ➔ sun). Interference was confirmed both behaviorally and in the ERPs, showing that the absence of an effect in Experiment 1 was not due to the materials used. Considering current models of speech production, the data are best explained by a cascading flow of activation throughout semantic, lexical and morpho-phonological steps of speech planning.

Age-related effects in compound production: Evidence from a double-object picture naming task

This study investigated effects of healthy ageing and of non-verbal attentional control on speech production. Young and older speakers participated in a picture-word interference (PWI) task with compound targets. To increase the processing load, the two pictures of the compounds’ constituents were presented side-by-side for spoken naming (e.g., a picture of a sun + a picture of a flower to be named with sunflower). Written distractors either corresponded to the first or second constituent ( sun or flower → sunflower), or were semantically related either to the first constituent of the target ( moon → sunflower) or to the second constituent/whole word ( tulip → sunflower). Morpho-phonological facilitation was obtained for both constituents, whereas semantic interference was restricted to first-constituent-related semantic distractors. Furthermore, a trend towards facilitation was obtained for distractors that were semantically related to the whole word. Older speakers were slower and produced more errors than young speakers. While morphological effects of first-constituent distractors were stronger for the elderly, the semantic effects were not affected by age. Non-verbal attentional control processes, measured in the Simon task, significantly contributed to morpho-phonological priming in the elderly, but they did not affect semantic interference or semantic facilitation. With a picture naming task that increases the semantic and lexical processing load, we corroborate earlier evidence that word-finding difficulties in the elderly result from deficient phonological encoding, whereas lexical-semantic and morpho-phonological representations remain stable with age.