Non-living Categories Research Articles

The assessment of severe lexical disorders in Italian individuals with aphasia.

Tests and batteries used in the evaluation of language impairments are overly complex and often ineffective (too difficult) in the assessment of post-stroke patients affected by severe aphasia (global aphasia). The present study reports details on the construction and standardization of a new Italian battery of tasks, specifically designed to assess severe lexical disorders in acquired aphasia (Battery for the Assessment of Severe Acquired Lexical Damage in Italian, BASALDI). The battery is composed of a common set of 64 stimuli (concrete nouns), belonging to both living and non-living categories, and consists of four lexical tasks assessing picture naming, repetition, reading aloud, and oral comprehension. The item selection was based on word frequency, word length, and phonological-articulatory complexity, namely the presence of continuant vs. plosive phones, a variable that may interact with word production in case of severe language damage. Standardization (naming agreement) of a new set of 64 colored images and normative data on Italian healthy subjects pooled across homogenous subgroups for age, gender, and education are reported. Finally, for the four tasks, percentile ranks and z-scores were calculated from a pool of 92 left brain-damaged patients affected by aphasia of different types and severity. The battery allows a fine investigation of lexical disorders, being suitable for diagnostic assessment of mild-to-moderate and severe aphasic lexical deficits, detection of changes over time, and possible dissociations between tasks.

A new set of tasks for the assessment of lexical disorders in Italian

A new set of tasks for the assessment of lexical disorders in Italian

The ontological and functional status of robots: How firm our representations are?

Robot representation is a moving target: according to our previous experience and to the context of use, we constantly reinvent what we consider to be ‘robot’. In this paper we investigate teenagers’ robot representation, with special concerns to educational robots. By robot representation we mean its (i) ontological and (ii) functional status. Particularly, we seek to understand whether teenagers’ judgment about (i) and (ii) changes when they become acquainted with robots. To this aim, we carried out an experimental study with pre- and post-questionnaires with 79 participants during a robotic event: the RoboParty®. Results show that building and programming a robot fosters a more nuanced judgment about robots’ belonging to the living and non-living categories but, on the other side, a more definite judgment about the educative functions that a robot may serve. Thus, at this stage of technology development in contemporary society, robots seem to share something with living entities and some other things with non-living ones. Just like living entities, robots hold an ontological status that admits degrees; similarly to non-living entities, robots need to have a precise function in order for users to have a meaningful interaction with them. Moreover, contrary to our prediction and to current literature, no new category – beyond those of living and non-living ones-seems to emerge in teenagers’ ontology. However, cues pointing out that dealing with robots might have an impact on traditional boundaries of common-sense ontology are discussed.

A SIMPLE TEST OF EPISODIC MEMORY PREDICTS CONVERSION TO DISEASE (MCI/AD) A DECADE LATER: DATA FROM THE WOMEN’S HEALTHY AGEING PROJECT (WHAP)

the words produced by younger adults and older adults. Nine of the categories (3 living categories, 3 non-living categories and 3 mixed categories) least influenced by normal ageing were then selected to be administered to patients with MCI prodromal to AD. Conclusions: Performance on the altered version of the CFT is unaffected by normal ageing effects and will further help in understanding the automatic and executive semantic impairment in pathological ageing due to AD. It may also be more sensitive to the earliest preclinical and presymptomatic changes caused byADwhen applied in patients with MCI. The practical implications for diagnosis of this modified neuropsychological instrument are important since it will improve the identification of people at risk during the earliest stage of the disease before irreversible neural damage occurs. This will allow for timely therapeutic intervention should disease modifying drugs become available in the future.

Spatial and temporal features of superordinate semantic processing studied with fMRI and EEG

The relationships between the anatomical representation of semantic knowledge in the human brain and the timing of neurophysiological mechanisms involved in manipulating such information remain unclear. This is the case for superordinate semantic categorization—the extraction of general features shared by broad classes of exemplars (e.g., living vs. non-living semantic categories). We proposed that, because of the abstract nature of this information, input from diverse input modalities (visual or auditory, lexical or non-lexical) should converge and be processed in the same regions of the brain, at similar time scales during superordinate categorization—specifically in a network of heteromodal regions, and late in the course of the categorization process. In order to test this hypothesis, we utilized electroencephalography and event related potentials (EEG/ERP) with functional magnetic resonance imaging (fMRI) to characterize subjects' responses as they made superordinate categorical decisions (living vs. non-living) about objects presented as visual pictures or auditory words. Our results reveal that, consistent with our hypothesis, during the course of superordinate categorization, information provided by these diverse inputs appears to converge in both time and space: fMRI showed that heteromodal areas of the parietal and temporal cortices are active during categorization of both classes of stimuli. The ERP results suggest that superordinate categorization is reflected as a late positive component (LPC) with a parietal distribution and long latencies for both stimulus types. Within the areas and times in which modality independent responses were identified, some differences between living and non-living categories were observed, with a more widespread spatial extent and longer latency responses for categorization of non-living items.

Toward a neurolexicology

This article analyzes the organization of the mental lexicon based on neurophysiological data. The neuroscience literature has devoted many studies to the semantic processing of words. However, the research remains specific to certain categories, studied separately, and does not address the lexicon as a system. In order to provide further insight into the neuronal organization of the lexicon, we conducted an EEG-based semantic decision experiment using words from eight categories (four living and four nonliving categories) as the material. A data-analysis method (correspondence analysis or CA) commonly used in computational linguistics was applied to the electrophysiological signals. The results revealed a two-factor structure: an ontological organization separating the living from the nonliving, and an organization with a human referential structured by proximity to the person. A comparison of the ERP-CA and the linguistic-CA data revealed organizational analogies. Lastly, a tomography software (Loreta®) was used to estimate the cerebral sources associated with the ERP signals.

An Italian battery for the assessment of semantic memory disorders

We report the construction and standardization of a new comprehensive battery of tests for the assessment of semantic memory disorders. The battery is constructed on a common set of 48 stimuli, belonging to both living and non-living categories, rigidly controlled for several confounding variables, and is based on an empirically derived corpus of semantic features. It includes six tasks, in order to assess semantic memory through different modalities of input and output: two naming tasks, one with colored pictures and the other in response to an oral description, a word-picture matching task, a picture sorting task, a free generation of features task and a sentence verification task. Normative data on 106 Italian subjects pooled across homogenous subgroups for age, sex and education are reported. The new battery allows an in-depth investigation of category-specific disorders and of progressive semantic memory deficits at features level, overcoming some of the limitations of existing tests.

Feature types and object categories: Is sensorimotoric knowledge different for living and nonliving things?

ABSTRACTSome models of semantic memory claim that items from living and nonliving domains have different feature-type profiles. Data from feature generation and perceptual modality rating tasks were compared to evaluate this claim. Results from two living (animals, fruits/vegetables) and two nonliving (tools, vehicles) categories showed that sensorimotoric features were important in object knowledge across both domains. In addition, significant cross-domain similarities and within-domain differences indicated that feature profiles were not determined simply as a function of the living and nonliving domain distinction. The current data support a model of semantic memory rooted in perceptual and motor processes with reduced salience for the “living/nonliving” construct.

Semantic category effects modulate visual priming in neglect patients

Previous studies indicate that extinguished stimuli can still be unconsciously processed, leading to implicit priming effects. Here we investigated whether these implicit effects might be modulated by the semantic nature of the stimuli. Five neglect patients and ten controls performed an identification task of items belonging to living and non-living categories. In the study phase photographs of animals and artifacts were presented either to the left visual field (LVF) or to the right visual field (RVF). In the identification phase, each stimulus was displayed centrally and was revealed in a sequence of frames where the item was represented by an increasingly less and less filtered image up to a complete version. The results showed that lateralized stimuli differentially affected controls’ and neglect patients’ memory retrieval. In controls memory traces from the study phase served as efficient primes, thereby reducing the amount of information necessary for the identification of both stimulus categories. Moreover, hemispheric differences emerged with an advantage of the RVF/left hemisphere for artifact items, while no difference was found for living things. Neglect patients showed a priming effect for artifact items presented either to the RVF/left hemisphere or LVF/right hemisphere, as well as for living items presented to the RVF/left hemisphere, but not for living items presented to the LVF/right hemisphere. The priming effect observed for extinguished artifacts is consistent with the evidence of the existence of a specific mechanism destined to analyze, in an automatic and implicit fashion, motor-relevant information of manipulable objects and tools, which are important for identification process. Results are discussed in relation to current models of organization of conceptual knowledge within the framework of different processes performed by the two hemispheres.

Relevant Category-Specific Effect on Naming in Alzheimer’s Disease

Aim: To determine category effect on naming in Alzheimer’s disease (AD) and its relation with severity of the disease or naming deficit. Methods: A group of 50 patients suffering from probable AD was tested in a naming task involving 99 pictures of items belonging to living and non-living categories. Parameters relating to pictures (percentage of majority responses, familiarity, visual complexity and image agreement) were determined using a control group and parameters relating to words (frequency, age of acquisition, number of letters and syllables) were controlled. Results: A category-specific effect was demonstrated and individual stepwise logistic regression demonstrated a significant category effect in 9 cases (living items more failed than non-living). Conclusion: Our results suggest a categorical effect on naming in favor of the non-living items, especially for mild AD with predominant naming deficit.

Disruption of the prefrontal cortex function by rTMS produces a category-specific enhancement of the reaction times during visual object identification

Object identification is enabled through a distributed neural network but the relative contribution of the single components of this network is largely unknown. In the present study, we used online interference by repetitive transcranial magnetic stimulation (rTMS) to investigate the role of the dorso-lateral prefrontal cortex (DLPFC) in identifying semantically different stimuli presented as to make the decision process easy or difficult, according to the amount of sensory information available. Nineteen healthy volunteers performed an object identification task. Stimuli belonging to living and non-living categories were presented at different levels of spatial filtering following a coarse-to-fine order that gradually integrated spatial information. Six-pulse trains of 10-Hz rTMS were delivered at an intensity of 90% resting motor threshold simultaneously to the picture presentation. rTMS of either the left or right DLPFC produced a significant lengthening in the identification process of spatially filtered living stimuli, as shown by the increase in the reaction time, but not of non-filtered living stimuli or of non-living objects. rTMS over the vertex did not interfere with the identification task. These data indicate that DLPFC role in the network underlying object recognition is more crucial when this neural process is challenged by the level of sensory information available to the observer. Specificity of this effect for living objects is discussed taking into account the crucial role of DLPFC in recruitment of cognitive resources for accomplishing perceptual decision-making.

An ERP study of low and high relevance semantic features

It is believed that the N400 elicited by concepts belonging to living is larger than N400 to non-living. This is considered as evidence that concepts are organized, in the brain, on the basis of categories. We conducted a feature-verification experiment where living and non-living concepts were matched for relevance of semantic features. Relevance is a measure of the contribution of semantic features to the “core” meaning of a concept. We found that when relevance is low the N400 is large. In addition, we found that when the two categories of living and non-living are equated for relevance the seemingly category effect at behavioral and neural level disappeared. In sum, N400 is sensitive, rather than to categories, to semantic features, thus showing that previously reported effects of semantic categories may arise as a consequence of the differing relevance of concepts belonging to living and non-living categories.

Feature type effects in semantic memory: An event related potentials study

It is believed that the N400 elicited by concepts belonging to Living things is larger than the N400 to Non-living things. This is considered as evidence that concepts are organized, in the brain, on the basis of categories. Similarly, differential N400 to Sensory and Non-sensory semantic features is taken as evidence for a neural organisation of conceptual memory based on semantic features. We conducted a feature-verification experiment where Living and Non-living concepts are described by Sensory and Non-sensory features and were matched for Age-of-Acquisition, typicality and familiarity and finally for relevance of semantic features. Relevance is a measure of the contribution of semantic features to the “core” meaning of a concept. We found that when Relevance is low then the N400 is large. In addition, we found that when the two categories of Living and Non-living concepts are matched for relevance the seemingly category effect at the neural level disappeared. Also no difference between Sensory and Non-sensory descriptions was detected when relevance was matched. In sum, N400 does not differ between categories or feature types. Previously reported effects of semantic categories and feature type may have arisen as a consequence of the differing Relevance of concepts belonging to Living and Non-living categories.

Conceptions of objects across categories: Childhood patterns resemble those of adults

Studies of category-specific disorders have suggested that categories of living and non-living things vary in the properties that are most salient to recognition. Studies of the object features generated by normal adults have also revealed different patterns of responses to different categories. These adult patterns are likely to originate in childhood, but there are few reports of children's verbal conceptions of objects, and none at present of objects from different categories. This paper investigates the development of object conceptions, in a large group of children, aged 3 years 7 months to 11 years 6 months, in response to 'What is a -- ?' questions directed to 72 objects, selected from two categories of living things (animals and fruit/vegetables) and two categories of artifacts (implements and vehicles). Proportions of perceptual-to-functional features provided by the children to living and non-living things varied with the range of features defined as functions, just as studies of adults have found. Apart from the distribution of superordinate responses, which were significantly more salient to living than to non-living categories, no other property separated the two categories. Only the category of implements could be distinguished from the other categories on the basis of the features generated. It is argued that the perceptual-functional theory of category-specific disorders receives little support from this study, but that in general the distribution of features generated by young children is similar to that produced by normal adults.

Sex differences in lexical size across semantic categories

Abstract Recent studies have reported that males show better naming of nonliving things than females, while females show better naming of living things than males. Such effects may reflect sex differences in the size of lexicons across categories or their access/retrieval strategies. These possibilities were examined in three experiments using semantic fluency tasks for two living (animals, fruits) and two nonliving (tools, vehicles) categories. Experiment 1 documented better fluency for ‘fruits’ in females ( n =300) and for ‘tools’ and ‘vehicles’ in males ( n =300). Experiment 2 examined fluency consistency by re-testing a subgroup of subjects again 30 min later. This confirmed the pattern across sex and revealed that subjects reproduced 70% of the same words (even when not instructed to do so). Finally, in Experiment 3, a new sample of male and female subjects was tested for 4 min to exhaust their fluency lexicons and overcome access/strategy effects. This confirmed the female advantage for fruits and male advantage for tools. These findings are consistent with differences in the size of lexicons for males and females and are attributed to sex differences in domain-specific processing systems.

Intentional and automatic measures of specific-category effect in the semantic impairment of patients with Alzheimer’s disease

The breakdown of semantic knowledge relative to living and non-living categories was studied in patients with Alzheimer’s disease (AD). The same living and non-living items were used in a semantic battery and in a semantic priming paradigm exploring automatic access to the semantic system. Although AD patients showed a semantic deficit on the intentional semantic battery, they demonstrated normal semantic facilitation on the priming task. In the AD group as a whole, the semantic impairment did not preferentially affect the living category either in the intentional or automatic condition. Instead, a prevalent deficit for the living category was found in three AD patients (14% of the group) on the intentional semantic tasks, but not on the automatic one. These findings support the view that the category effect may not be a generalised phenomenon in AD but may be restricted to a limited number of patients. The intentional/automatic dissociation of the semantic breakdown demonstrated by AD patients is discussed in relation to different theories regarding the organisation of semantic memory.

Modulation of reach-to-grasp parameters: semantic category, volumetric properties and distractor interference?

In the two experiments of this study, we assessed the influence of target size and semantic category on the expression of reach-to-grasp kinematic parameters. Moreover, we investigated the influence of size and semantic category of distractors on reaches to the target. The experimental objects represented living and non-living categories and wide and narrow grasp sizes. Participants reached for and picked up mid-sagittally placed targets, which were either alone or flanked by distractors congruent or incongruent to semantic category and size of the target. In experiment 1, movement duration was faster to living objects. We could not replicate this, however, in experiment 2. Conversely, significant and reliable Category x Size interactions for grasp were obtained in experiment 1 and replicated in experiment 2. The pattern of the means in these interactions coincided with the absolute volumetric properties of the stimuli, indicating that the size of the stimuli was the main determinant of the expression of kinematic parameters. We conclude that volumetric properties such as size, rather than semantic category, are the crucial features in the programming and execution of movement to targets. As regards the category and size of the distractor, interference effects were evident: both category and size exerted a comparable influence on reaches to the target. The direction of interference, however, was not systematic. The interference effects are discussed in the context of visual search models of attention.

A Case of Prevailing Deficit of Nonliving Categories or a Case of Prevailing Sparing of Living Categories?

We describe a new case of semantic deficit in which nonliving categories are disproportionately impaired. PL, a woman affected by progressive degeneration of the left temporal lobe, was examined twice, at a distance of 1 year. The deficit was first apparent on naming and on a verbal semantic questionnaire, but a year later nonliving categories were disproportionately affected also on verbal comprehension (word/picture matching task). Body parts and musical instruments were also investigated: the former was the best preserved category, whereas the latter was the most severely affected. Considering all categories, functional and perceptual information was not differently affected, but there was a trend toward a worse score for nonliving category functional questions. Discussing the current hypotheses on the genesis of category dissociations, we conclude that nonliving categories might not be a true domain, and that their impairment could simply derive from the relative sparing of the domains of the living categories, for which separate cognitive and anatomical representations can be better postulated. Finally, we discuss the problems raised by published cases in an attempt to find a consistent anatomical substrate for category dissociations.

Living musical instruments and inanimate body parts?

In the literature about category effects in semantic memory, body parts and musical instruments are often considered atypical, because in cases with a disproportionate impairment of living categories body parts are relatively spared, while musical instruments are often severely defective. In this study the performance of 57 subjects affected by diseases generally associated with lexical-semantic impairment, for the most part Alzheimer's disease and other forms of cortical degeneration, but also herpetic encephalitis and traumatic brain damage are analyzed. The subjects were given a picture naming task tapping eight categories: three living categories (animals, fruits and vegetables) and three non-living categories (tools, furniture and vehicles), plus body parts and musical instruments. On a preliminary analysis at the group level, body parts were the least impaired category and musical instruments the most severely impaired, the six living and non-living categories being intermediate. However, these differences disappeared after covariance for lexical frequency, name agreement and age of acquisition. The relationship between living categories, non-living categories, musical instruments and body parts was investigated by means of a Lisrel model of Confirmatory Factor Analysis. Two latent variables related to living and non-living categories respectively were defined, and it was found that both body parts and musical instruments were significantly related only with non-living categories. The results showed that the definition of the latent variable expressing the substrate of non-living categories was less satisfactory than that expressing the living categories. On this basis, the conclusions of this study appear statistically definite but their psychological interpretation is less straightforward.

Abnormal Semantic Network for “Animals” But not “Tools” in Patients with Alzheimer's Disease

The effects of Alzheimer's disease (AD) on the organization of semantic knowledge (i.e., the semantic network) for living (e.g., animals) and non-living (e.g., tools) categories was examined. Multidimensional scaling and Pathfinder analyses of data from triadic comparison tasks showed that the semantic network for “animals”, but not the network for “tools”, was abnormal in patients with AD. Specifically, patients with AD tended to use a different primary dimension than control subjects for categorizing animals and their network was characterized by atypical associations between concepts. The differences in the integrity of the AD patients' networks for “animals” and “tools” was not likely to be an artifact of differences in the difficulty in identifying the stimuli in the two categories as all stimuli were identified on simple naming or matching tasks. These findings support the results of previous studies that have shown the presence of category-specific semantic deficits in patients with AD.