Learning and using knowledge about what other people do and don't know despite amnesia

MEM&SO protocol: understanding the determinants of social learning in neurodegenerative diseases

BACKGROUND

People with neurodegenerative diseases may have difficulty learning new information, owing to their cognitive impairments. Teaching them techniques for learning in social contexts could alleviate this difficulty. The present study will examine the performances of patients with Alzheimer's disease and patients with the semantic variant of primary progressive aphasia on a memory test administered in three social contexts. The protocol will make it possible to identify determinants of social interactions, social abilities, cognition, and personality that can explain the potentially beneficial effect of social context on learning in these patients.

METHODS

Thirty dyads (patient with primary memory impairment who meets criteria for Alzheimer's disease paired with caregiver), 16 dyads (patient meeting criteria for semantic variant of primary progressive aphasia paired with caregiver), and 46 dyads (healthy controls with no cognitive complaints) will be recruited. A nonverbal memory test (social memory task) will be administered to each dyad in three different social contexts (presence-only, observation, collaboration). Patients and healthy controls will also undergo a neuropsychological assessment to measure social (interactions and abilities), cognitive and personality aspects. Patients will be compared with controls on differential social scores calculated between the presence-only and collaboration contexts, and between the presence-only and observation contexts. A multiple comparative case study will be conducted to identify social, cognitive and personality variables that potentially explain the differential scores in the collaboration and observation contexts.

DISCUSSION

For the first time, memory will be assessed in patients with Alzheimer's disease and patients with the semantic variant of primary progressive aphasia in three different contexts (presence-only, observation, collaboration). The multiple comparative case study will make it possible to identify the determinants of memory performance in the social context, in order to create the most beneficial learning context for individual patients, according to their profile.

TRIAL REGISTRATION

This study was approved by the Ile de France XI institutional review board (2022-A00198-35), and registered on ClinicalTrials.gov (no. NCT05800028), on April 27, 2023.

Keeping track of who knows what in multiparty conversation despite severe memory impairment

Language use has long been understood to be tailored to the intended addressee, a process termed audience design. Audience design is reflected in multiple aspects of language use, including adjustments based on the addressee's knowledge about the topic at hand. In group settings, audience design depends on representations of multiple individuals, each of whom may have different knowledge about the conversational topic. A central question, then, concerns how these representations are encoded and retrieved in multiparty conversation where successful conversation requires keeping track of who knows what. In the present research, we probe the biological memory systems that are involved in this process of multiparty audience design. We present the results of two experiments that compare language use in persons with bilateral hippocampal damage and severe declarative memory impairment (amnesia), and demographically matched neurotypical comparison participants. Participants played a game in which they discussed abstract images with one partner in conversation, and then discussed the images again with the same partner or with a new partner in a three-party conversation. Neurotypical participants' language use reflected newly formed representations of which partner was familiar with which images. Participants with amnesia showed evidence of partner-specific audience design in multiparty conversation but it was attenuated, especially when success required rapid alternations between representations of common ground. The findings suggest partial independence of the formation and use of partner-specific representations from the hippocampal-dependent declarative memory system and highlight the unique contributions of the declarative memory system to flexible and dynamic language use.

Direct and indirect linguistic measures of common ground in dialogue studies involving a matching task: A systematic review

During dialogue, speakers attempt to adapt messages to their addressee appropriately by taking into consideration their common ground (i.e., all the information mutually known by the conversational partners) to ensure successful communication. Knowing and remembering what information is part of the common ground shared with a given partner and using it during dialogue are crucial skills for social interaction. It is therefore important to better understand how we can measure the use of common ground and to identify the potential associated psychological processes. In this context, a systematic review of the literature was performed to list the linguistic measures of common ground found in dialogue studies involving a matching task and to explore any evidence of cognitive and social mechanisms underlying common ground use in this specific experimental setting, particularly in normal aging and in neuropsychological studies. Out of the 23 articles included in this review, we found seven different linguistic measures of common ground that were classified as either a direct measure of common ground (i.e., measures directly performed on the referential content) or an indirect measure of common ground (i.e., measures assessing the general form of the discourse). This review supports the idea that both types of measures should systematically be used while assessing common ground because they may reflect different concepts underpinned by distinct psychological processes. Given the lack of evidence for the implication of other cognitive and social functions in common ground use in studies involving matching tasks, future research is warranted, particularly in the clinical field.

Alcohol and common ground: The effects of intoxication on linguistic markers of shared understanding during social exchange

OBJECTIVE

Most alcohol consumption takes place in social contexts, and the belief that alcohol enhances social interactions has been identified as among the more robust predictors of alcohol use disorder (AUD) development. Yet, we know little of how alcohol affects mental representations of others-what we share and do not share-nor the extent to which intoxication might impact the development of shared understanding (i.e., common ground) between interaction partners. Employing a randomized experimental design and objective linguistic outcome measures, we present two studies examining the impact of alcohol consumption on the development and use of common ground.

METHOD

In Study 1, groups of strangers or friends were administered either alcohol (target Breath Alcohol Content = .08%) or a control beverage, following which they completed a task requiring them to develop a shared language to describe ambiguous images and then describe those images to either a knowledgeable or a naïve partner. The same procedures were completed in Study 2 using a within-subjects alcohol administration design and all-stranger groups.

RESULTS

Study 1 findings did not reach significance but suggested that alcohol may facilitate common ground development selectively among stranger groups. This effect emerged as significant in the context of the within-subjects design of Study 2, b = -0.19, p = .007, with participants demonstrating greater facility in establishing common ground during alcohol versus control sessions.

CONCLUSIONS

Results suggest that alcohol facilitates the development of shared linguistic understanding in novel social spaces, indicating common ground as one potential mechanism to consider in our broader examination of alcohol reinforcement and AUD etiology. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The Multiple Perspectives Theory of Mental States in Communication

Inspired by early proposals in philosophy, dominant accounts of language posit a central role for mutual knowledge, either encoded directly in common ground, or approximated through other cognitive mechanisms. Using existing empirical evidence from language and memory, we challenge this tradition, arguing that mutual knowledge captures only a subset of the mental states needed to support communication. In a novel theoretical proposal, we argue for a cognitive architecture that includes separate, distinct representations of the self and other, and a cognitive process that compares these representations continuously during conversation, outputting both similarities and differences in perspective. Our theory accounts for existing data, interfaces with findings from other cognitive domains, and makes novel predictions about the role of perspective in language use. We term this new account the Multiple Perspectives Theory of mental states in communication.

MEMCONS: How Contemporaneous Note-Taking Shapes Memory for Conversation

Written memoranda of conversations, or memcons, provide a near-contemporaneous record of what was said in conversation, and offer important insights into the activities of high-profile individuals. We assess the impact of writing a memcon on memory for conversation. Pairs of participants engaged in conversation and were asked to recall the contents of that conversation 1 week later. One participant in each pair memorialized the content of the interaction in a memcon shortly after the conversation. Participants who generated memcons recalled more details of the conversations than participants who did not, but the content of recall was equally and largely accurate for both participants. Remarkably, only 4.7% of the details of the conversation were recalled by both of the partners after a week delay. Contemporaneous note-taking appears to enhance memory for conversation by increasing the amount of information remembered but not the accuracy of that information. These findings have implications for evaluating the testimony of participants on conversations with major political or legal ramifications.

Evidence of Audience Design in Amnesia: Adaptation in Gesture but Not Speech

Speakers design communication for their audience, providing more information in both speech and gesture when their listener is naïve to the topic. We test whether the hippocampal declarative memory system contributes to multimodal audience design. The hippocampus, while traditionally linked to episodic and relational memory, has also been linked to the ability to imagine the mental states of others and use language flexibly. We examined the speech and gesture use of four patients with hippocampal amnesia when describing how to complete everyday tasks (e.g., how to tie a shoe) to an imagined child listener and an adult listener. Although patients with amnesia did not increase their total number of words and instructional steps for the child listener, they did produce representational gestures at significantly higher rates for the imagined child compared to the adult listener. They also gestured at similar frequencies to neurotypical peers, suggesting that hand gesture can be a meaningful communicative resource, even in the case of severe declarative memory impairment. We discuss the contributions of multiple memory systems to multimodal audience design and the potential of gesture to act as a window into the social cognitive processes of individuals with neurologic disorders.

Detecting Alzheimer's Disease Using Natural Language Processing of Referential Communication Task Transcripts

BACKGROUND

People with Alzheimer's disease (AD) often demonstrate difficulties in discourse production. Referential communication tasks (RCTs) are used to examine a speaker's capability to select and verbally code the characteristics of an object in interactive conversation.

OBJECTIVE

In this study, we used contextualized word representations from Natural language processing (NLP) to evaluate how well RCTs are able to distinguish between people with AD and cognitively healthy older adults.

METHODS

We adapted machine learning techniques to analyze manually transcribed speech transcripts in an RCT from 28 older adults, including 12 with AD and 16 cognitively healthy older adults. Two approaches were applied to classify these speech transcript samples: 1) using clinically relevant linguistic features, 2) using machine learned representations derived by a state-of-art pretrained NLP transfer learning model, Bidirectional Encoder Representation from Transformer (BERT) based classification model.

RESULTS

The results demonstrated the superior performance of AD detection using a designed transfer learning NLP algorithm. Moreover, the analysis showed that transcripts of a single image yielded high accuracies in AD detection.

CONCLUSION

The results indicated that RCT may be useful as a diagnostic tool for AD, and that the task can be simplified to a subset of images without significant sacrifice to diagnostic accuracy, which can make RCT an easier and more practical tool for AD diagnosis. The results also demonstrate the potential of RCT as a tool to better understand cognitive deficits from the perspective of discourse production in people with AD.

What are friends for? The impact of friendship on communicative efficiency and cortisol response during collaborative problem solving among younger and older women

Conversation is a skilled activity that depends on cognitive and social processes, both of which develop through adulthood. We examined the effects of age and partner familiarity on communicative efficiency and cortisol reactivity. Younger and older women interacted with familiar or unfamiliar partners in a dyadic collaborative conversation task (N = 8 in each group). Regardless of age, referential expressions among familiar and unfamiliar partners became more efficient over time, and cortisol concentrations were lower for speakers interacting with familiar partners. These findings suggest that communicative effectiveness is largely preserved with age, as is the stress-buffering effect of a familiar partner.

Partner-Specific Communication Deficits in Individuals With Alzheimer's Disease

Purpose Speakers adjust referential expressions to the listeners' knowledge while communicating, a phenomenon called "audience design." While individuals with Alzheimer's disease (AD) show difficulties in discourse production, it is unclear whether they exhibit preserved partner-specific audience design. The current study examined if individuals with AD demonstrate partner-specific audience design skills. Method Ten adults with mild-to-moderate AD and 12 healthy older adults performed a referential communication task with two experimenters (E1 and E2). At first, E1 and participants completed an image-sorting task, allowing them to establish shared labels. Then, during testing, both experimenters were present in the room, and participants described images to either E1 or E2 (randomly alternating). Analyses focused on the number of words participants used to describe each image and whether they reused shared labels. Results During testing, participants in both groups produced shorter descriptions when describing familiar images versus new images, demonstrating their ability to learn novel knowledge. When they described familiar images, healthy older adults modified their expressions depending on the current partner's knowledge, producing shorter expressions and more established labels for the knowledgeable partner (E1) versus the naïve partner (E2), but individuals with AD were less likely to do so. Conclusions The current study revealed that both individuals with AD and the control participants were able to acquire novel knowledge, but individuals with AD tended not to flexibly adjust expressions depending on the partner's knowledge state. Conversational inefficiency and difficulties observed in AD may, in part, stem from disrupted audience design skills.

Other 'routes in'? Has the 'fast' in the fast mapping concept led us astray?

The notion of fast mapping originated in an effort to explain the remarkable adeptness and acceleration with which toddlers learn new words. Yet, by abstracting selected elements of fast mapping away from the embodied, richly concrete, intermeshed social-interactional experiences of the word-learning child, we may be missing opportunities to understand how adults with amnesia also may acquire new semantic knowledge.

Gesture height reflects common ground status even in patients with amnesia

When we communicate, we alter our language and gesture based on the mutually shared knowledge - common ground - that we have with our listener. How memory supports these alterations remain unclear. We asked healthy adults and patients with hippocampal amnesia to engage in a referential communication task. Previous work suggests that common ground can be encoded by distinct memory systems; Amnesic patients show normal learning and referential label use as common ground increases, but inconsistently mark these labels with definite determiners (e.g., the vs. a windmill). Which memory systems support the ability to mark common ground via hand gesture? We found that gestures of both healthy participants and amnesic patients reflected common ground status. Both groups produced high gestures when common ground was lacking, and were less likely to do so as common ground increased. These findings suggest that gesture can reflect common ground status during conversation, potentially via non-declarative memory.

Changes in discourse structure over time following traumatic brain injury

The objective of the present study was to investigate structural changes in the narrative discourse of individuals with penetrating traumatic brain injury (pTBI) following immediate and delayed story retellings. Additionally, the potential influence of immediate memory, working memory, and executive functions on narrative discourse performance were examined. The narrative discourse of two groups, 123 with pTBI and 44 non-brain injured (NBI), was sampled. Participants were asked to retell a wordless picture story immediately after viewing it and again 30-min later. Story narratives were analyzed using a variety of microlinguistic and macrostructural measures. Results revealed significant group differences of both microlinguistic and macrostructural measures following the immediate retell, but not following the delayed retell. Regression analyses revealed that immediate memory accounted for a modest degree of the explained variance for the production of critical content during narrative discourse. The observed deficits were relatively stable over a short delay (30 min) and appeared attributable, in part, to difficulty with the encoding and consolidation of story content.

Distinguishable memory retrieval networks for collaboratively and non-collaboratively learned information

Learning often occurs in communicative and collaborative settings, yet almost all research into the neural basis of memory relies on participants encoding and retrieving information on their own. We investigated whether learning linguistic labels in a collaborative context at least partly relies on cognitively and neurally distinct representations, as compared to learning in an individual context. Healthy human participants learned labels for sets of abstract shapes in three different tasks. They came up with labels with another person in a collaborative communication task (collaborative condition), by themselves (individual condition), or were given pre-determined unrelated labels to learn by themselves (arbitrary condition). Immediately after learning, participants retrieved and produced the labels aloud during a communicative task in the MRI scanner. The fMRI results show that the retrieval of collaboratively generated labels as compared to individually learned labels engages brain regions involved in understanding others (mentalizing or theory of mind) and autobiographical memory, including the medial prefrontal cortex, the right temporoparietal junction and the precuneus. This study is the first to show that collaboration during encoding affects the neural networks involved in retrieval.