Jerry Fodor’s arguments for a language of thought (LOT) are largely theoretical. Is there any empirical evidence that supports the existence of LOT? There is. Research on Global Aphasia supports the existence of LOT. In this paper, I discuss this evidence and why it supports Fodor’s theory that there is a language of thought.

An elaboration on some loose ends in Grodzinsky's analysis shows that data from the field of aphasia contribute to the formulation of theoretical linguistic principles, and provides extra arguments in favor of Grodzinsky's claim that linguistic theory is the best tool for the investigation of aphasia. This illustrates and emphasizes the importance of communication between researchers in the field of (Broca's) aphasia and of theoretical linguistics.

To be able to read a precise and elaborate self-observation by someone who suffered for an extended period of time from that language affliction that has been called aphasia for more than one hundred years is such an extremely unusual occurrence that one would think such a work would attract the attention of all those persons, whether specialists or enlightened amateurs, interested in questions of language and in its eventual pathological aspects.

Jerry Fodor's arguments for a language of thought are largely theoretical. Is there any empirical evidence that supports the existence of LOT? There is. Research on Global Aphasia supports the existence of LOT. In this paper, I discuss this evidence and why it supports Fodor's theory that there is a language of thought.

Caplan & Waters's neuropsychological evidence for two types of verbal working memory rests entirely on a very restricted definition of “syntactic complexity,” one in terms of word order. This opens the possibility that the dissociation they observe relates to the differential use of word-order strategies rather than to the structure of verbal working memory.

Persons with aphasia suffer from a loss of communication ability as a consequence of a brain injury. A small strand of research indicates effec- tiveness of dialogic interventions for communication development for persons with aphasia, but a vast amount of research studies shows its effectiveness for other target groups. In this paper, we describe the main parts of the hitherto technological development of an application named Dialogica that is (i) aimed at facilitating increased communicative participation in dialogic settings (...) for persons with aphasia and other communication disorders, (ii) based on comput- er game technology as well as on theory in dialogic education and argumenta- tion theory, and (iii) designed for mobile devices with larger screens. (shrink)

If you were trained as a philosopher and were suddenly bereft of speech, writing and reading, how would you feel? Would you feel a sensation of death, or Nirvana, or unconscious or conscious loss of control? Would you feel scientifically objective, or full of Aristotelian wonder? Would you think you were having a supernatural experience?

We present a computational evaluation of three hypotheses about sources of deficit in sentence comprehension in aphasia: slowed processing, intermittent deficiency, and resource reduction. The ACT-R based Lewis and Vasishth model is used to implement these three proposals. Slowed processing is implemented as slowed execution time of parse steps; intermittent deficiency as increased random noise in activation of elements in memory; and resource reduction as reduced spreading activation. As data, we considered subject vs. object relative sentences, presented in a (...) self-paced listening modality to 56 individuals with aphasia and 46 matched controls. The participants heard the sentences and carried out a picture verification task to decide on an interpretation of the sentence. These response accuracies are used to identify the best parameters that correspond to the three hypotheses mentioned above. We show that controls have more tightly clustered parameter values than IWA; specifically, compared to controls, among IWA there are more individuals with slow parsing times, high noise, and low spreading activation. We find that individual IWA show differential amounts of deficit along the three dimensions of slowed processing, intermittent deficiency, and resource reduction, overall, there is evidence for all three sources of deficit playing a role, and IWA have a more variable range of parameter values than controls. An important implication is that it may be meaningless to talk about sources of deficit with respect to an abstract verage IWA; the focus should be on the individual's differential degrees of deficit along different dimensions, and on understanding the causes of variability in deficit between participants. (shrink)

People with aphasia use gestures not only to communicate relevant content but also to compensate for their verbal limitations. The Sketch Model (De Ruiter, 2000) assumes a flexible relationship between gesture and speech with the possibility of a compensatory use of the two modalities. In the successor of the Sketch Model, the AR‐Sketch Model (De Ruiter, 2017), the relationship between iconic gestures and speech is no longer assumed to be flexible and compensatory, but instead iconic gestures are assumed to (...) express information that is redundant to speech. In this study, we evaluated the contradictory predictions of the Sketch Model and the AR‐Sketch Model using data collected from people with aphasia as well as a group of people without language impairment. We only found compensatory use of gesture in the people with aphasia, whereas the people without language impairments made very little compensatory use of gestures. Hence, the people with aphasia gestured according to the prediction of the Sketch Model, whereas the people without language impairment did not. We conclude that aphasia fundamentally changes the relationship of gesture and speech. (shrink)

Despite the ubiquity of inner speech in our mental lives, methods for objectively assessing inner speech capacities remain underdeveloped. The most common means of assessing inner speech is to present participants with tasks requiring them to silently judge whether two words rhyme. We developed a version of this task to assess the inner speech of a population of patients with aphasia and corresponding language production deficits. As expected, patients’ performance on the silent rhyming task was severely impaired relative to (...) controls. More surprisingly, however, patients’ performance on this task did not correlate with their performance on a variety of other standard tests of overt language abilities. In particular, patients who were generally unimpaired in their abilities to overtly name objects during confrontation naming tasks, and who could reliably judge when two words spoken to them rhymed, were still severely impaired (relative to controls) at completing the silent rhyme task. This seems to suggest that inner speech was more severely impaired in these patients than outer speech. However, these results should also cause us to critically reflect on the relation between inner speech and silent rhyme judgments more generally. (shrink)

Aphasia is an acquired impairment of language functions resulting from a brain lesion. It is usually accompanied by deficits in non-linguistic cognitive processes. This study aimed to investigate in patients with aphasia the complex interrelationships between selected cognitive functions: auditory speech comprehension, working memory, and temporal information processing in the millisecond time range. Thirty right-handed subjects aged from 27 to 82 years suffering from post-stroke aphasia participated in the study. Verbal working memory and spatial working memory were (...) assessed with: a receptive verbal test and the Corsi Block-Tapping Test, respectively. Both these WM tests used the forward tasks and backward tasks. Auditory comprehension was assessed by receptive language tests, and TIP efficiency was assessed by auditory perception of temporal order in the millisecond time range. We observed better performance of forward WM tasks than backward ones, independently of the type of material used. Furthermore, the severity of auditory comprehension impairment correlated with the efficiency on both forward and backward VWM tasks and the backward SWM task. Further analysis revealed that TIP plays a crucial role only in the latter task. These results indicate the divergent pattern of interactions between WM and TIP depending on the type of WM tasks. Level of verbal competency appeared to play an important role in both VWM tasks, whereas TIP appeared to be important for SWM, but only on the backward task. (shrink)

Investigating instances where lexical selection fails can lead to deeper insights into the cognitive machinery and architecture supporting successful word retrieval and speech production. In this paper, we used a multiplex lexical network approach that combines semantic and phonological similarities among words to model the structure of the mental lexicon. Network measures at different levels of analysis (degree, network distance, and closeness centrality) were used to investigate the influence of network structure on picture naming accuracy and errors by people with (...) Anomic, Broca's, Conduction, and Wernicke's aphasia. Our results reveal that word retrieval is influenced by the multiplex lexical network structure in at least two ways—(a) the accuracy of production and error type on incorrect productions were influenced by the degree and closeness centrality of the target word, and (b) error type also varied in terms of network distance between the target word and produced error word. Taken together, the analyses demonstrate that network science techniques, particularly the use of the multiplex lexical network to simultaneously represent semantic and phonological relationships among words, reveal how the structure of the mental lexicon influences language processes beyond traditionally examined psycholinguistic variables. We propose a framework for how the multiplex lexical network approach allows for understanding the influence of mental lexicon structure on word retrieval processes, with an eye toward a better understanding of the nature of clinical impairments, like aphasia. (shrink)

Language-related potentials are increasingly used to objectify adaptive neuroplasticity in stroke-related aphasia recovery. Using preattentive [mismatch negativity ] and attentive phonologically related paradigms, neuroplasticity in sensory memory and cognitive functioning underlying phonological processing can be investigated. In aphasic patients, MMN amplitudes are generally reduced for speech sounds with a topographic source distribution in the right hemisphere. For P300 amplitudes and latencies, both normal and abnormal results have been reported. The current study investigates the preattentive and attentive phonological discrimination ability (...) in 17 aphasic patients at two timepoints during aphasia recovery. Between the two timepoints, a significant improvement of behavioral language performance in both languages is observed in all patients with the MMN latency at timepoint 1 as a predictive factor for aphasia recovery. In contrast to monolinguals, bilingual aphasic patients have a higher probability to improve their processing speed during rehabilitation, resulting in a shortening of the MMN latency over time, which sometimes progresses toward the normative values. (shrink)

_Linguistics and Aphasia_ is a major study of recent developments in applying psycholinguistics and pragmatics to the study of acquired language disorders and their remediation. Psycholinguistic analyses of aphasia interpret disorders in terms of damaged modules and processes within what was once a normal language system. These analyses have progressed to the point that they now routinely provide a model-based rationalefor planning patient therapy. Through a series of case studies, the authors show how the psycholinguistic analysis of aphasia (...) can be assessed for its effectiveness in clinical practice. Pragmatic approaches to the study of aphasia are of more recent origin. Ruth Lesser and Lesley Milroy evaluate their considerable significance to the study of aphasia and their relevance to practical issues of diagnosis and treatment. Controversial analysis, in particular, offers a fruitful and productive framework within which to assess the functional adequacy of the language used by aphasic speakers in everyday contexts. (shrink)

Background: Many people with aphasia and people without brain injury talk to themselves in their heads, i.e., have “inner speech.” Inner speech may be more preserved compared with spoken speech for some people with aphasia and may serve a variety of functions (e.g., emotion regulation), which motivates us to provide a high-fidelity characterization of it. Researchers have used multiple methods to measure this internal phenomenon in the past, which we combine here for the first time in a single (...) study. -/- Aims: We compare performance between individuals with and without aphasia on inner speech tasks that assess inner speech “inthe- moment” to general subjective impressions of inner speech to tease apart the relationship of aphasia severity to inner speech. Methods and Procedures: Twenty people with mild-moderate aphasia and twenty neurotypical controls completed several inner speech tasks, including objective silent rhyme judgements (picture, written, and auditory), subjective reports of inner speech during naming, and subjective rating scales about inner speech experience more generally. -/- Outcomes and Results: In-the-moment inner speech during silent rhyming tasks was associated with aphasia severity only for picture and written rhyming but not auditory rhyming. In-the-moment inner speech reports during silent naming were not associated with aphasia severity, nor were the subjective ratings about general inner speech experience. Individuals with and without aphasia demonstrated a variety of subjective general inner speech experiences, demonstrating heterogeneity of this phenomenon more broadly. -/- Conclusions: Methods of measuring inner speech complement each other and speak to different facets of the inner speech phenomenon, and clinicians and researchers must carefully choose the method(s) that will provide the information about inner speech that they desire. (shrink)

In recent years, language has been shown to play a number of important cognitive roles over and above the communication of thoughts. One hypothesis gaining support is that language facilitates thought about abstract categories, such as democracy or prediction. To test this proposal, a novel set of semantic memory task trials, designed for assessing abstract thought non-linguistically, were normed for levels of abstractness. The trials were rated as more or less abstract to the degree that answering them required the participant (...) to abstract away from both perceptual features and common setting associations corresponding to the target image. The normed materials were then used with a population of people with aphasia to assess the relationship of abstract thought to language. While the language-impaired group with aphasia showed lower overall accuracy and longer response times than controls in general, of special note is that their response times were significantly longer as a function of a trial’s degree of abstractness. Further, the aphasia group’s response times in reporting their degree of confidence (a separate, metacognitive measure) were negatively correlated with their language production abilities, with lower language scores predicting longer metacognitive response times. These results provide some support for the hypothesis that language is an important aid to abstract thought and to metacognition about abstract thought. (shrink)

Individuals with agrammatic Broca's aphasia experience difficulty when processing reversible non-canonical sentences. Different accounts have been proposed to explain this phenomenon. The Trace Deletion account attributes this deficit to an impairment in syntactic representations, whereas others propose that the underlying structural representations are unimpaired, but sentence comprehension is affected by processing deficits, such as slow lexical activation, reduction in memory resources, slowed processing and/or intermittent deficiency, among others. We test the claims of two processing accounts, slowed processing and intermittent (...) deficiency, and two versions of the Trace Deletion Hypothesis, in a computational framework for sentence processing implemented in ACT-R. The assumption of slowed processing is operationalized as slow procedural memory, so that each processing action is performed slower than normal, and intermittent deficiency as extra noise in the procedural memory, so that the parsing steps are more noisy than normal. We operationalize the TDH as an absence of trace information in the parse tree. To test the predictions of the models implementing these theories, we use the data from a German sentence—picture matching study reported in Hanne, Sekerina, Vasishth, Burchert, and De Bleser. The data consist of offline and online measures. From among the models considered, the model assuming that both slowed processing and intermittent deficiency are present emerges as the best model of sentence processing difficulty in aphasia. The modeling of individual differences suggests that, if we assume that patients have both slowed processing and intermittent deficiency, they have them in differing degrees. (shrink)

Three types of problems are raised in this commentary: On the linguistic side, we emphasize the importance of an appropriate definition of the different domains of linguistics. This is needed to define the domains (lexicon-syntax-semantics) to which transformational relations apply. We then question the concept of Broca's aphasia as a “functional” syndrome, associated with a specific lesion. Finally, we discuss evidence from functional brain imaging. The breadth and potential impact of such evidence has grown considerably in the last few (...) years, expanding our knowledge of the multiple contributions of the “Broca's region” to phonological, lexical-semantic, and syntactic processing. “Lumping” under diagnostic labels, such as Broca's aphasia, should be replaced by more detailed linguistic and neurological descriptions of the clinical cases. (shrink)

Can sentence comprehension impairments in aphasia be explained by difficulties arising from dependency completion processes in parsing? Two distinct models of dependency completion difficulty are investigated, the Lewis and Vasishth (2005) activation-based model and the direct-access model (DA; McElree, 2000). These models' predictive performance is compared using data from individuals with aphasia (IWAs) and control participants. The data are from a self-paced listening task involving subject and object relative clauses. The relative predictive performance of the models is evaluated (...) using k-fold cross-validation. For both IWAs and controls, the activation-based model furnishes a somewhat better quantitative fit to the data than the DA. Model comparisons using Bayes factors show that, assuming an activation-based model, intermittent deficiencies may be the best explanation for the cause of impairments in IWAs, although slowed syntax and lexical delayed access may also play a role. This is the first computational evaluation of different models of dependency completion using data from impaired and unimpaired individuals. This evaluation develops a systematic approach that can be used to quantitatively compare the predictions of competing models of language processing. (shrink)

Can sentence comprehension impairments in aphasia be explained by difficulties arising from dependency completion processes in parsing? Two distinct models of dependency completion difficulty are investigated, the Lewis and Vasishth (2005) activation‐based model and the direct‐access model (DA; McElree, 2000). These models' predictive performance is compared using data from individuals with aphasia (IWAs) and control participants. The data are from a self‐paced listening task involving subject and object relative clauses. The relative predictive performance of the models is evaluated (...) using k‐fold cross‐validation. For both IWAs and controls, the activation‐based model furnishes a somewhat better quantitative fit to the data than the DA. Model comparisons using Bayes factors show that, assuming an activation‐based model, intermittent deficiencies may be the best explanation for the cause of impairments in IWAs, although slowed syntax and lexical delayed access may also play a role. This is the first computational evaluation of different models of dependency completion using data from impaired and unimpaired individuals. This evaluation develops a systematic approach that can be used to quantitatively compare the predictions of competing models of language processing. (shrink)

n the philosophy of language, there are many ongoing controversies that stem from relying too heavily on an utterance-based framework. The traditional approach of rigidly partitioning the utterance’s meaning into what is grammatically determined from what is not may not fully capture the complexity of human language in real-world communicative contexts. To address this issue, we suggest shifting focus toward a broader analysis level encompassing conversations and discourses. From this broader perspective, it is possible to obtain a more integrated view (...) of how linguistic and extra-linguistic aspects dynamically interact and thus reconsider semantics/pragmatics dichotomy as complementary dimensions. Meaning is not confined to linguistic structures alone but emerges from the dynamic interplay of words, sociocultural knowledge, discursive situations, and psychological dispositions of speakers. Substantiating this perspective calls for embracing an interdisciplinary approach that synthesizes research from various domains, including linguistics, cognitive psychology, and philosophy of language. This paper focuses on a particularly compelling case study: aphasia. Speeches produced by individuals with aphasia represent complex scenarios where the balance between linguistic and extra-linguistic aspects is notably compromised, often to the former’s detriment. Aphasics’ productions represent a vivid example of how the interpretation of speeches can be far from involving fixed and static operations. Instead, it entails continuously reallocating cognitive resources toward the most readily available and accessible sources for the speakers. This case study ultimately demonstrates that the influence of semantic and pragmatic processes in shaping and conveying meanings displays remarkable adaptability, continuously adjusting to the ever changing demands placed upon speakers. -/- . (shrink)

This commentary focuses on the larger implications of Grodzinsky's hypothesis. Although Grodzinsky argues persuasively that the syntactic comprehension deficits in Broca's aphasia involve mainly an inability to comprehend sentences requiring a transformational movement of phrasal constituents, his larger claim for a distinct and dedicated “language organ” in the left hemisphere is much less tenable.

Understanding between care providers and patients with stroke and aphasia: a phenomenological hermeneutic inquiry The present study illuminates the understanding in communication between formal care providers and patients with stroke and aphasia. Five care providers and three such patients participated in the study. Video recordings were made during conversations about pictures (n = 15), and the care providers were also interviewed (n = 15) after the video‐recorded conversations. A phenomenological hermeneutic method of interpretation of the interview text was (...) used. The findings showed that a range of conditions for ‘understanding and being understood’ in the communication on the part of the care providers exists. These different conditions are: lacking both knowledge and understanding; having knowledge but not necessarily accompanied by understanding; and being in understanding. Within the condition ‘being in understanding’, the care providers create a feeling of at‐homeness in a relaxed atmosphere and thus have the opportunity to be in ‘understanding and being understood’ together with the patient. The condition ‘being in understanding’ appears in connection with the care providers’ creating of a ‘calm liturgy of caring’ by mediating humility and calm vitality affects to the patients, and further, when needed, being present on the level of mystery, i.e. caring communion. (shrink)