Reversal of the concreteness effect can be detected in the natural speech of older adults with amnestic, but not non-amnestic, mild cognitive impairment

INTRODUCTION

Patients with Alzheimer's disease present with difficulty in lexical retrieval and reversal of the concreteness effect in nouns. Little is known about the phenomena before the onset of symptoms. We anticipate early linguistic signs in the speech of people who suffer from amnestic mild cognitive impairment (MCI). Here, we report the results of a corpus-linguistic approach to the early detection of cognitive impairment.

METHODS

One hundred forty-eight English-speaking Singaporeans provided natural speech data, on topics of their choice; 74 were diagnosed with single-domain MCI (38 amnestic, 36 non-amnestic), 74 cognitively healthy. The recordings yield 267,310 words, which are tagged for parts of speech. We calculate the per-minute word counts and concreteness scores of all tagged words, nouns, and verbs in the dataset.

RESULTS

Compared to controls, subjects with amnestic MCI produce fewer but more abstract nouns. Verbs are not affected.

DISCUSSION

Slower retrieval of nouns and the reversal of the concreteness effect in nouns are manifested in natural speech and can be detected early through corpus-based analysis.

Highlights

Reversal of the concreteness effect is manifested in patients with Alzheimer's disease (AD) and semantic dementia.The paper reports a corpus-based analysis of natural speech by people with amnestic and non-amnestic mild cognitive impairment (MCI) and cognitively healthy controls.People with amnestic MCI produce fewer and more abstract nouns than people with non-amnestic MCI and healthy controls. Verbs appear to be unaffected.The imageability problem can be detected in natural everyday speech by people with amnestic MCI, which carries a higher risk of conversion to AD.

It's All in the Interaction: Early Acquired Words Are Both Frequent and Highly Imageable

Prior studies have found that children are more likely to learn words that are frequent in the input and highly imageable. Many theories of word learning, however, predict that these variables should interact, particularly early in development: frequency of a form is of little use if you cannot infer its meaning, and a concrete word cannot be acquired if you never hear it. The present study explores this interaction, how it changes over time and its relationship to syntactic category effects in children acquiring American English. We analyzed 1461 monolingual English-speaking children aged 1;4-2;6 from the MB-CDI norming study (Fenson et al., 1994). Word frequency was estimated from the CHILDES database, and imageability was measured using adult ratings. There was a strong over-additive interaction between frequency and imageability, such that children were more likely to learn a word if it was both highly imageable and very frequent. This interaction was larger in younger children than in older children. There were reliable differences between syntactic categories independent of frequency and imageability, which did not interact with age. These findings are consistent with theories in which children's early words are acquired by mapping frequent word forms onto concrete, perceptually available referents, such that highly frequent items are only acquired if they are also imageable, and vice versa.

The role of imageability in noun and verb acquisition in children with Down syndrome and their peers with typical development

Our main objective was to analyze the role of imageability in relation to the age of acquisition (AoA) of nouns and verbs in Spanish-speaking children with Down syndrome (DS) and their peers with typical development (TD). The AoA of nouns and verbs was determined using the MacArthur-Bates CDIs adapted to the profile of children with DS. The AoA was analyzed using a linear mixed-effect model, including factors of imageability, group, and word class, and controlling for word frequency and word length. This analysis showed that high imaginable and short words were acquired early. Children with DS acquired the words later than TD peers. An interaction between imageability and group indicated that the effect of imageability was greater in the DS group. We discuss this effect considering DS children's phonological memory difficulties. The overall results confirm the role that imageability and word length play in lexical acquisition, an effect that goes beyond word class.

Intact fluency in autism? A comprehensive approach of verbal fluency task including word imageability and concreteness

Verbal fluency is a cognitive function reflecting executive functions and the ability to retrieve the appropriate information from memory quickly. Previous studies reported conflicting results—impaired and intact verbal fluency—in autism spectrum disorder (ASD). Most studies concentrate on overall word productivity, errors, perseverations, clustering, or switching. We used a comprehensive approach to evaluate the reported discrepancy in the literature and introduced a new angle using the concept of word abstraction and imageability. Moreover, we analyzed the performance in two‐time intervals (0–30 s and 31–60 s) to assess the temporal dynamics of verbal fluency and a possible activation or initiation deficit in autism. Sixteen adults with ASD and 16 neurotypical control participants, matched by gender, age, and education level, participated in our study. Contrary to our expectations, we did not find a significant difference between groups in word productivity, the number of errors, clustering, or temporal dynamics, neither in semantic nor in phonemic fluency tasks. Surprisingly, the two study groups' performance did not differ in terms of imageability or concreteness characteristics either. Our results raise the possibility that verbal fluency performance is intact in autism. We also suggest using a comprehensive approach when measuring fluency in autism.

Word imageability is associated with expressive vocabulary in children with autism spectrum disorder

BACKGROUND & AIMS

Throughout typical development, children prioritize different perceptual, social, and linguistic cues to learn words. The earliest acquired words are often those that are perceptually salient and highly imageable. Imageability, the ease in which a word evokes a mental image, is a strong predictor for word age of acquisition in typically developing (TD) children, independent of other lexicosemantic features such as word frequency. However, little is known about the effects of imageability in children with autism spectrum disorder (ASD), who tend to have differences in linguistic processing and delayed language acquisition compared to their TD peers. This study explores the extent to which imageability and word frequency are associated with early noun and verb acquisition in children with ASD.

METHODS

Secondary analyses were conducted on previously collected data of 156 children (78 TD, 78 ASD) matched on sex and parent-reported language level. Total expressive vocabulary, as measured by the MacArthur Bates Communicative Development Inventory (MB-CDI), included 123 words (78 nouns, 45 verbs) that overlapped with previously published imageability ratings and word input frequencies. A two-step hierarchical linear regression was used to examine the relationship between word input frequency, imageability, and total expressive vocabulary. An F-test was then used to assess the unique contribution of imageability on total expressive vocabulary when controlling for word input frequency.

RESULTS

In both the TD and ASD groups, imageability uniquely explained a portion of the variance in total expressive vocabulary size, independent of word input frequency. Notably, imageability was significantly associated with noun vocabulary and verb vocabulary size alone, with imageability explaining a greater portion of the variance in total nouns produced than in total verbs produced.

CONCLUSIONS

Imageability was identified as a significant lexicosemantic feature for describing expressive vocabulary size in children with ASD. Consistent with literature on TD children, children with ASD who have small vocabularies primarily produce words that are highly imageable. Children who are more proficient word learners with larger vocabularies produce words that are less imageable, indicating a potential shift away from reliance on perceptual-based language processing. This was consistent across both noun and verb vocabularies.

IMPLICATIONS

Our findings contribute to a growing body of literature describing early word learning in children with ASD and provide a basis for exploring the use of multisensory language learning strategies.

Does visualisation help or hinder concrete word processing?

In an iconicity judgement task, participants were asked whether word pairs were iconic (e.g., nose-tongue; joy-sorrow) or reverse-iconic (e.g., tongue-nose; sorrow-joy), and an advantage for abstract word pairs (i.e., joy-sorrow) was found. Malhi and Buchanan proposed that this reverse concreteness, or abstractness, effect was the result of participants taking a visualisation/imagining (time-costly) approach towards the concrete word pairs and an emotional/intuitive (time-efficient) approach towards the abstract word pairs. This study tested this proposal by asking participants questions about strategy use (Experiment 1). In the forced-choice questions, all participants reported using a visualisation/imagining approach towards the concrete word pairs and most participants reported using an emotional/intuitive approach towards the abstract word pairs. In the open-ended responses, visual-spatial reasoning and real-life experience emerged as themes for the concrete word pairs and social norms and values emerged as themes for the abstract word pairs, adding to our understanding of the grounding of abstract words. In Experiment 2, participants were supplied with pictures as an aid to visualisation with the expectation that this would reduce the time required for concrete word processing. Supplying pictures made participants faster and more accurate at completing the task. Experiment 3 manipulated the type of visual aid by also supplying pictures that did not match the orientation of the word pairs. Participants were only more accurate when the pictures were in the correct and iconic spatial arrangement. A flexible abstractness and concreteness effects (FACE) theory is proposed which integrates symbolic and embodied accounts and introduces constructs such as direct and constrained imageability for concrete words and indirect and free imageability for abstract words.

Language Difficulty and Prior Learning Influence Foreign Vocabulary Acquisition

When learning a foreign language, words that are the hardest to learn are often the easiest to forget. Yet, there is also evidence that more challenging learning contexts can lead to greater long-term retention. Here, we investigate the effect of language difficulty on vocabulary retention by teaching participants novel words that varied in both imageability and similarity to a known language over a period of four weeks. We found that easier words (high-imageability and familiar) were generally retained better than harder words (low-imageability and unfamiliar). However, when words were fully learned during training, the more difficult unfamiliar words were later recalled with higher accuracy than easier familiar words. The effect of language difficulty on vocabulary retention therefore varies depending on how well words were initially encoded. We conclude that greater challenges can reap greater long-term rewards so long as learners establish a strong foundation during initial acquisition.

Incidental memory for colour word associates processed in colour naming and reading aloud tasks: is a blue ocean more memorable than a yellow one?

Congruency effects for colour word associates (e.g., ocean) have been reported in Stroop colour naming tasks. However, incidental memory for such words after word reading and colour naming tasks has not been examined. In the current study, participants incidentally recalled colour word associates (e.g., ocean) and neutral words (e.g., lawyer) immediately after naming their font colour (Experiment 1a) or reading them aloud (Experiment 1b). In both tasks, recall was better for congruent colour word associates (e.g., ocean appearing in blue) than incongruent colour word associates (e.g., ocean appearing in green) or neutral items (lawyer appearing in blue). This outcome is consistent with the idea that co-activation of a semantic colour code and a lexical representation strengthens the episodic memory representation and makes it more accessible.

The Effect of Training-Induced Visual Imageability on Electrophysiological Correlates of Novel Word Processing

The concreteness effect (CE) describes a processing advantage for concrete over abstract words. Electrophysiologically, the CE manifests in higher N400 and N700 amplitudes for concrete words. The contribution of the stimulus-inherent imageability to the electrophysiological correlates of the CE is not yet fully unraveled. This EEG study focused on the role of imageability irrespective of concreteness by examining the effects of training-induced visual imageability on the processing of novel words. In two training sessions, 21 healthy participants learned to associate novel words with pictures of novel objects as well as electron-microscopical structures and were additionally familiarized with novel words without any picture association. During a post-training EEG session, participants categorized trained novel words with or without picture association, together with real concrete and abstract words. Novel words associated with novel object pictures during the training elicited a higher N700 than familiarized novel words without picture-association. Crucially, this training-induced N700 effect resembled the CE found for real words. However, a CE on the N400 was found for real words, but no effect of imageability in novel words. The results suggest that the N400 CE for real words depends on the integration of multiple semantic features, while mere visual imageability might contribute to the CE in the N700 time window.

Validating the psycholinguistic aspects of LITMUS-CLT: Evidence from Polish and Norwegian

The novel assessment tool Cross-Linguistic Lexical Tasks (LITMUS-CLT) aims for comparable cross-linguistic assessment of multilingual children's lexical skills by basing each language version on two language-specific variables: age of acquisition (AoA) and complexity index (CI), a novel measure related to phonology, morphology, exposure and etymology. This article investigates the validity of this methodology, asking whether the underlying properties are robust predictors of children's performance. The Polish and Norwegian CLTs were used to assess 32 bilingual Polish-Norwegian, 34 monolingual Norwegian and 36 monolingual Polish children. The effects of AoA and CI were contrasted with frequency in child directed speech (CDS) and imageability, two known predictors of lexical development. AoA was a reliable predictor of performance within all parts of CLT, in contrast to CI. Apart from AoA, only exposure and CDS frequency had a significant effect within both monolinguals and bilinguals. These results indicate that CLT assesses lexical skills in a cross-linguistically comparable manner, but suggest a revision of the CI measure.

Seeing the Meaning: Top-Down Effects on Letter Identification

Most models of reading agree that visual word recognition is underpinned by a highly interactive network in which both bottom–up and top–down processes contribute. What remains unknown is whether evidence of top–down effects upon letter processing are restricted to word-form level information, or whether meaning-level information also plays a role. Here we sought to investigate top–down semantic influences upon letter detection using semantic manipulations of real word imageability and semantic priming, as well as a manipulation of nonword orthographic and phonological composition which varied degree of similarity to real words. A continuous adaptive staircase procedure was used, allowing us to assess the exposure duration needed for accurate letter perception in different stimulus types. Results revealed that in terms of both exposure duration and decision reaction times, words showed an advantage over pseudohomophones and pseudowords, which in turn showed advantages over consonant strings. High imageability words were processed more efficiently than low imageability words, both in terms of the exposure duration required for accurate letter identification and also decision reaction times. The presence of a related as opposed to unrelated semantic prime significantly shortened exposure duration, but also lengthened decision reaction times. This inhibitory semantic priming effect in reaction time was attributed to the interference at the decision stage by stronger activation of the prime letters in the case of related relative to unrelated trials. Taken together, the present results establish for the first time that the semantic dimensions of imageability and semantic priming exert significant effects on letter identification, indicating meaning-level influences on the very earliest stages of written word recognition.

Age-Dependent Changes of Thinking about Verbs

We investigated the knowledge of emotional and motor verbs in children and adolescents from three age ranges (8–11, 12–15, 16–19 years). Participants estimated the verbs familiarity, age of acquisition, valence, arousal, imageability, and motor- and emotion-relatedness. Participants were familiar with the verbs in our dataset. The younger (8–11) attributed an emotional character to the verbs less frequently than the middle (12–15) and the older (16–19) groups. In the 8–11 group males rated the verbs as emotion-related less frequently than females. Results indicate that processing verbal concepts as emotion-related develops gradually, and after 12–15 is rather stable. The age of acquisition (AoA) develops late: the older (16–19) had a higher awareness in reporting that they learnt the verbs earlier as compared to the estimations made by the younger (8–11 and 12–15). AoA positively correlated with attribution of emotion relatedness meaning that emotion-related verbs were learned later. Arousal was comparable across ages. Also it increased when attributing motor relatedness to verbs and decreased when attributing emotion relatedness. Reporting the verbs' affective valence (happy vs. unhappy) changes with age: younger (8–11) judged the verbs generally more “happy” than both the older groups. Instead the middle and the older group did not show differences. Happiness increased when processing the verbs as motor related and decreased when processing the verbs as emotion related. Age affected imageability: the younger (8–11) considered the verbs easier to be imagined than the two older groups, suggesting that at this age vividness estimation is still rough, while after 12–15 is stable as the 12–15 and 15–19 group did not differ. Imageability predicted arousal, AoA, emotion- and motor-relatedness indicating that this index influences the way verbs are processed. Imageability was positively correlated to emotion relatedness, indicating that such verbs were harder to be imagined, and negatively to motor relatedness. Imageablity positively correlated with valence meaning that verbs receiving positive valence were also those that were hard to be imagined, and negatively correlated with arousal, meaning that verbs that were harder to be imagined elicited low physiological activation. Our results give an insight in the development of emotional and motor-related verbs representations.

Imaging Imageability: Behavioral Effects and Neural Correlates of Its Interaction with Affect and Context

The construct of imageability refers to the extent to which a word evokes a tangible sensation. Previous research (Westbury et al., 2013) suggests that the behavioral effects attributed to a word's imageability can be largely or wholly explained by two objective constructs, contextual density and estimated affect. Here, we extend these previous findings in two ways. First, we show that closely matched stimuli on the three measures of contextual density, estimated affect, and human-judged imageability show a three-way interaction in explaining variance in LD RTs, but that imagebility accounts for no additional variance after contextual density and estimated affect are entered first. Secondly, we demonstrate that the loci and functional connectivity (via graphical models) of the brain regions implicated in processing the three variables during that task are largely over-lapping and similar. These two lines of evidence support the conclusion that the effect usually attributed to human-judged imageability is largely or entirely due to the effects of other correlated measures that are directly computable.

Development of Embodied Word Meanings: Sensorimotor Effects in Children's Lexical Processing

Previous research showed an effect of words’ rated body–object interaction (BOI) in children’s visual word naming performance, but only in children 8 years of age or older (Wellsby and Pexman, 2014a). In that study, however, BOI was established using adult ratings. Here we collected ratings from a group of parents for children’s BOI experience (child-BOI). We examined effects of words’ child-BOI and also words’ imageability on children’s responses in an auditory word naming task, which is suited to the lexical processing skills of younger children. We tested a group of 54 children aged 6–7 years and a comparison group of 25 adults. Results showed significant effects of both imageability and child-BOI on children’s auditory naming latencies. These results provide evidence that children younger than 8 years of age have richer semantic representations for high imageability and high child-BOI words, consistent with an embodied account of word meaning.

Opposing effects of semantic diversity in lexical and semantic relatedness decisions

Semantic ambiguity has often been divided into 2 forms: homonymy, referring to words with 2 unrelated interpretations (e.g., bark), and polysemy, referring to words associated with a number of varying but semantically linked uses (e.g., twist). Typically, polysemous words are thought of as having a fixed number of discrete definitions, or "senses," with each use of the word corresponding to one of its senses. In this study, we investigated an alternative conception of polysemy, based on the idea that polysemous variation in meaning is a continuous, graded phenomenon that occurs as a function of contextual variation in word usage. We quantified this contextual variation using semantic diversity (SemD), a corpus-based measure of the degree to which a particular word is used in a diverse set of linguistic contexts. In line with other approaches to polysemy, we found a reaction time (RT) advantage for high SemD words in lexical decision, which occurred for words of both high and low imageability. When participants made semantic relatedness decisions to word pairs, however, responses were slower to high SemD pairs, irrespective of whether these were related or unrelated. Again, this result emerged irrespective of the imageability of the word. The latter result diverges from previous findings using homonyms, in which ambiguity effects have only been found for related word pairs. We argue that participants were slower to respond to high SemD words because their high contextual variability resulted in noisy, underspecified semantic representations that were more difficult to compare with one another. We demonstrated this principle in a connectionist computational model that was trained to activate distributed semantic representations from orthographic inputs. Greater variability in the orthography-to-semantic mappings of high SemD words resulted in a lower degree of similarity for related pairs of this type. At the same time, the representations of high SemD unrelated pairs were less distinct from one another. In addition, the model demonstrated more rapid semantic activation for high SemD words, thought to underpin the processing advantage in lexical decision. These results support the view that polysemous variation in word meaning can be conceptualized in terms of graded variation in distributed semantic representations.

Norwegian words: A lexical database for clinicians and researchers

All words have properties linked to form, meaning and usage patterns which influence how easily they are accessed from the mental lexicon in language production, perception and comprehension. Examples of such properties are imageability, phonological and morphological complexity, word class, argument structure, frequency of use and age of acquisition. Due to linguistic and cultural variation the properties and the values associated with them differ across languages. Hence, for research as well as clinical purposes, language specific information on lexical properties is needed. To meet this need, an electronically searchable lexical database with more than 1600 Norwegian words coded for more than 12 different properties has been established. This article presents the content and structure of the database as well as the search options available in the interface. Finally, it briefly describes some of the ways in which the database can be used in research, clinical practice and teaching.

Auditory and motion metaphors have different scalp distributions: an ERP study

While many links have been established between sensory-motor words used literally (kick the ball) and sensory-motor regions of the brain, it is less clear whether metaphorically used words (kick the habit) also show such signs of “embodiment.” Additionally, not much is known about the timing or nature of the connection between language and sensory-motor neural processing. We used stimuli divided into three figurativeness conditions—literal, metaphor, and anomalous—and two modality conditions—auditory (Her limousine was a privileged snort) and motion (The editorial was a brass-knuckle punch). The conditions were matched on a large number of potentially confounding factors including cloze probability. The electroencephalographic response to the final word of each sentence was measured at 64 electrode sites on the scalp of 22 participants and event-related potentials (ERPs) calculated. Analysis revealed greater amplitudes for metaphorical than literal sentences in both 350–500 ms and 500–650 ms timeframes. Results supported the possibility of different neural substrates for motion and auditory sentences. Greater differences for motion sentences were seen in the left posterior and left central electrode sites than elsewhere on the scalp. These findings are consistent with a sensory-motor neural categorization of language and with the integration of modal and amodal information during the N400 and P600 timeframes.

The meaning of 'life' and other abstract words: Insights from neuropsychology

There are a number of long‐standing theories on how the cognitive processing of abstract words, like ‘life’, differs from that of concrete words, like ‘knife’. This review considers current perspectives on this debate, focusing particularly on insights obtained from patients with language disorders and integrating these with evidence from functional neuroimaging studies. The evidence supports three distinct and mutually compatible hypotheses. (1) Concrete and abstract words differ in their representational substrates, with concrete words depending particularly on sensory experiences and abstract words on linguistic, emotional, and magnitude‐based information. Differential dependence on visual versus verbal experience is supported by the evidence for graded specialization in the anterior temporal lobes for concrete versus abstract words. In addition, concrete words have richer representations, in line with better processing of these words in most aphasic patients and, in particular, patients with semantic dementia. (2) Abstract words place greater demands on executive regulation processes because they have variable meanings that change with context. This theory explains abstract word impairments in patients with semantic‐executive deficits and is supported by neuroimaging studies showing greater response to abstract words in inferior prefrontal cortex. (3) The relationships between concrete words are governed primarily by conceptual similarity, while those of abstract words depend on association to a greater degree. This theory, based primarily on interference and priming effects in aphasic patients, is the most recent to emerge and the least well understood. I present analyses indicating that patterns of lexical co‐occurrence may be important in understanding these effects.

Measuring inconsistencies can lead you forward: Imageability and the x-ception theory

According to the traditional view, both imageability and concreteness ratings reflect the way word meanings rely on information mediated by the senses. As a consequence, the two measures should and do correlate. The link between these two indexes was already hypothesized and demonstrated by Paivio et al. (1968) in a seminal article, where they introduced the idea of imageability ratings for the first time. However, in this first study, they also noted a contrasting pattern in the ratings for imageability and concreteness with some words that refer to affective attitudes or emotional states receiving high imageability but low concreteness ratings. Recent studies confirm this inconsistency (e.g., Altarriba and Bauer, 2004) leading to the claim that emotion words form a particular class of terms different from both concrete and abstract words. Here we use the MRC psycholinguistic database to show that the there are other classes of terms for which imageability and concreteness are uncorrelated. We show that the common feature of these word classes is that they directly or indirectly refer to proprioceptive, interoceptive, or affective states, i.e., to internal, body-related, sensory experiences. Thus, imageability and concreteness can no longer be considered interchangeable constructs; rather, imageability is a different, and perhaps more interesting, measure: it not only reflects the ease with which memories of external events come to mind, as previously hypothesized, but also reflects the ease with which memories of internal events come to mind.

Now you see it, now you don't: on emotion, context, and the algorithmic prediction of human imageability judgments

Many studies have shown that behavioral measures are affected by manipulating the imageability of words. Though imageability is usually measured by human judgment, little is known about what factors underlie those judgments. We demonstrate that imageability judgments can be largely or entirely accounted for by two computable measures that have previously been associated with imageability, the size and density of a word's context and the emotional associations of the word. We outline an algorithmic method for predicting imageability judgments using co-occurrence distances in a large corpus. Our computed judgments account for 58% of the variance in a set of nearly two thousand imageability judgments, for words that span the entire range of imageability. The two factors account for 43% of the variance in lexical decision reaction times (LDRTs) that is attributable to imageability in a large database of 3697 LDRTs spanning the range of imageability. We document variances in the distribution of our measures across the range of imageability that suggest that they will account for more variance at the extremes, from which most imageability-manipulating stimulus sets are drawn. The two predictors account for 100% of the variance that is attributable to imageability in newly-collected LDRTs using a previously-published stimulus set of 100 items. We argue that our model of imageability is neurobiologically plausible by showing it is consistent with brain imaging data. The evidence we present suggests that behavioral effects in the lexical decision task that are usually attributed to the abstract/concrete distinction between words can be wholly explained by objective characteristics of the word that are not directly related to the semantic distinction. We provide computed imageability estimates for over 29,000 words.

A selective deficit in imageable concepts: a window to the organization of the conceptual system

Nissim, a 64 years old Hebrew-speaking man who sustained an ischemic infarct in the left occipital lobe, exhibited an intriguing pattern. He could hold a deep and fluent conversation about abstract and complex issues, such as the social risks in unemployment, but failed to retrieve imageable words such as ball, spoon, carrot, or giraffe. A detailed study of the words he could and could not retrieve, in tasks of picture naming, tactile naming, and naming to definition, indicated that whereas he was able to retrieve abstract words, he had severe difficulties when trying to retrieve imageable words. The same dissociation also applied for proper names—he could retrieve names of people who have no visual image attached to their representation (such as the son of the biblical Abraham), but could not name people who had a visual image (such as his own son, or Barack Obama). When he tried to produce imageable words, he mainly produced perseverations and empty speech, and some semantic paraphasias. He did not produce perseverations when he tried to retrieve abstract words. This suggests that perseverations may occur when the phonological production system produces a word without proper activation in the semantic lexicon. Nissim evinced a similar dissociation in comprehension—he could understand abstract words and sentences but failed to understand sentences with imageable words, and to match spoken imageable words to pictures or to semantically related imageable words. He was able to understand proverbs with imageable literal meaning but abstract figurative meaning. His comprehension was impaired also in tasks of semantic associations of pictures, pointing to a conceptual, rather than lexical source of the deficit. His visual perception as well as his phonological input and output lexicons and buffers (assessed by auditory lexical decision, word and sentence repetition, and writing to dictation) were intact, supporting a selective conceptual system impairment. He was able to retrieve gestures for objects and pictures he saw, indicating that his access to concepts often sufficed for the activation of the motoric information but did not suffice for access to the entry in the semantic lexicon. These results show that imageable concepts can be selectively impaired, and shed light on the organization of conceptual-semantic system.

The multilingual naming test in Alzheimer's disease: clues to the origin of naming impairments

The current study explored the picture naming performance of patients with Alzheimer’s disease (AD). First, we evaluated the utility of the multilingual naming test (MINT; Gollan et al., 2011), which was designed to assess naming skills in speakers of multiple languages, for detecting naming impairments in monolingual AD and amnestic mild cognitive impairment (MCI). If the MINT were sensitive to linguistic impairment in AD, using it in clinical practice might have advantages over using tests exclusively designed for English monolinguals. We found that the MINT can be used with both monolinguals and bilinguals: A 32-item subset of the MINT is best for distinguishing monolingual patients from controls, while the full MINT is best for assessing degree of bilingualism and language dominance in bilinguals. We then investigated the cognitive mechanisms underlying naming impairment in AD. To this end, we explored which MINT item characteristics best predicted performance differences between monolingual patients and controls. We found that contextual diversity and imageability, but not word frequency (nor words’ number of senses), contributed unique variance to explaining naming impairments in AD. These findings suggest a semantic component to the naming impairment in AD (modulated by names’ semantic richness and network size).

Effects of emotional and sensorimotor knowledge in semantic processing of concrete and abstract nouns

There is much empirical evidence that words’ relative imageability and body-object interaction (BOI) facilitate lexical processing for concrete nouns (e.g., Bennett et al., 2011). These findings are consistent with a grounded cognition framework (e.g., Barsalou, 2008), in which sensorimotor knowledge is integral to lexical processing. In the present study, we examined whether lexical processing is also sensitive to the dimension of emotional experience (i.e., the ease with which words evoke emotional experience), which is also derived from a grounded cognition framework. We examined the effects of emotional experience, imageability, and BOI in semantic categorization for concrete and abstract nouns. Our results indicate that for concrete nouns, emotional experience was associated with less accurate categorization, whereas imageability and BOI were associated with faster and more accurate categorization. For abstract nouns, emotional experience was associated with faster and more accurate categorization, whereas BOI was associated with slower and less accurate categorization. This pattern of results was observed even with many other lexical and semantic dimensions statistically controlled. These findings are consistent with Vigliocco et al.’s (2009) theory of semantic representation, which states that emotional knowledge underlies meanings for abstract concepts, whereas sensorimotor knowledge underlies meanings for concrete concepts.

A normative study of acronyms and acronym naming

Acronyms are an idiosyncratic part of our everyday vocabulary. Research in word processing has used acronyms as a tool to answer fundamental questions such as the nature of the word superiority effect (WSE) or which is the best way to account for word-reading processes. In this study, acronym naming was assessed by looking at the influence that a number of variables known to affect mainstream word processing has had in acronym naming. The nature of the effect of these factors on acronym naming was examined using a multilevel regression analysis. First, 146 acronyms were described in terms of their age of acquisition, bigram and trigram frequencies, imageability, number of orthographic neighbors, frequency, orthographic and phonological length, print-to-pronunciation patterns, and voicing characteristics. Naming times were influenced by lexical and sublexical factors, indicating that acronym naming is a complex process affected by more variables than those previously considered.

An abundance of riches: cross-task comparisons of semantic richness effects in visual word recognition

There is considerable evidence (e.g., Pexman et al., 2008) that semantically rich words, which are associated with relatively more semantic information, are recognized faster across different lexical processing tasks. The present study extends this earlier work by providing the most comprehensive evaluation to date of semantic richness effects on visual word recognition performance. Specifically, using mixed effects analyses to control for the influence of correlated lexical variables, we considered the impact of number of features, number of senses, semantic neighborhood density, imageability, and body-object interaction across five visual word recognition tasks: standard lexical decision, go/no-go lexical decision, speeded pronunciation, progressive demasking, and semantic classification. Semantic richness effects could be reliably detected in all tasks of lexical processing, indicating that semantic representations, particularly their imaginal and featural aspects, play a fundamental role in visual word recognition. However, there was also evidence that the strength of certain richness effects could be flexibly and adaptively modulated by task demands, consistent with an intriguing interplay between task-specific mechanisms and differentiated semantic processing.

On the need for Embodied and Dis-Embodied Cognition

This essay proposes and defends a pluralistic theory of conceptual embodiment. Our concepts are represented in at least two ways: (i) through sensorimotor simulations of our interactions with objects and events and (ii) through sensorimotor simulations of natural language processing. Linguistic representations are "dis-embodied" in the sense that they are dynamic and multimodal but, in contrast to other forms of embodied cognition, do not inherit semantic content from this embodiment. The capacity to store information in the associations and inferential relationships among linguistic representations extends our cognitive reach and provides an explanation of our ability to abstract and generalize. This theory is supported by a number of empirical considerations, including the large body of evidence from cognitive neuroscience and neuropsychology supporting a multiple semantic code explanation of imageability effects.

Comprehension of concrete and abstract words in semantic dementia

The vast majority of brain-injured patients with semantic impairment have better comprehension of concrete than abstract words. In contrast, several patients with semantic dementia (SD), who show circumscribed atrophy of the anterior temporal lobes bilaterally, have been reported to show reverse imageability effects, that is, relative preservation of abstract knowledge. Although these reports largely concern individual patients, some researchers have recently proposed that superior comprehension of abstract concepts is a characteristic feature of SD. This would imply that the anterior temporal lobes are particularly crucial for processing sensory aspects of semantic knowledge, which are associated with concrete not abstract concepts. However, functional neuroimaging studies of healthy participants do not unequivocally predict reverse imageability effects in SD because the temporal poles sometimes show greater activation for more abstract concepts. The authors examined a case-series of 11 SD patients on a synonym judgment test that orthogonally varied the frequency and imageability of the items. All patients had higher success rates for more imageable as well as more frequent words, suggesting that (1) the anterior temporal lobes underpin semantic knowledge for both concrete and abstract concepts, (2) more imageable items--perhaps because of their richer multimodal representations--are typically more robust in the face of global semantic degradation and (3) reverse imageability effects are not a characteristic feature of SD.

Imageability effects on sentence judgement by right-brain-damaged adults

BACKGROUND: For decades researchers assumed visual image generation was the province of the right hemisphere. The lack of corresponding evidence was only recently noted, yet conflicting results still leave open the possibility that the right hemisphere plays a role. This study assessed imagery generation in adult participants with and without right hemisphere damage (RHD). Imagery was operationalised as the activation of representations retrieved from long-term memory similar to those that underlie sensory experience, in the absence of the usual sensory stimulation, and in the presence of communicative stimuli. AIMS: The primary aim of the study was to explore the widely held belief that there is an association between the right hemisphere and imagery generation ability. We also investigated whether visual and visuo-motor imagery generation abilities differ in adults with RHD. METHODS #ENTITYSTARTX00026; PROCEDURES: Participants included 34 adults with unilateral RHD due to cerebrovascular accident and 38 adults who served as non-brain-damaged (NBD) controls. To assess the potential effects of RHD on the processing of language stimuli that differ in imageability, participants performed an auditory sentence verification task. Participants listened to high- and low-imageability sentences from Eddy and Glass (1981) and indicated whether each sentence was true or false. The dependent measures for this task were performance accuracy and response times (RT). OUTCOMES #ENTITYSTARTX00026; RESULTS: In general, accuracy was higher, and response time lower, for low-imagery than for high-imagery items. Although NBD participants' RTs for low-imagery items were significantly faster than those for high-imagery items, this difference disappeared in the group with RHD. We confirmed that this result was not due to a speed-accuracy trade-off or to syntactic differences between stimulus sets. A post hoc analysis also suggested that the group with RHD was selectively impaired in motor, rather than visual, imagery generation. CONCLUSIONS: The disproportionately high RT of participants with RHD in response to low-imagery items suggests that these items had other properties that made their verification difficult for this population. The nature and extent of right hemisphere patients' deficits in processing different types of imagery should be considered. In addition, the capacity of adults with RHD to generate visual and motor imagery should be investigated separately in future studies.