Social Coordination in Older Adulthood: A Dual-Process Model

Individual differences in working memory and semantic fluency predict younger and older adults' multimodal recipient design in an interactive spatial task

Aging appears to impair the ability to adapt speech and gestures based on knowledge shared with an addressee (common ground-based recipient design) in narrative settings. Here, we test whether this extends to spatial settings and is modulated by cognitive abilities. Younger and older adults gave instructions on how to assemble 3D-models from building blocks on six consecutive trials. We induced mutually shared knowledge by either showing speaker and addressee the model beforehand, or not. Additionally, shared knowledge accumulated across the trials. Younger and crucially also older adults provided recipient-designed utterances, indicated by a significant reduction in the number of words and of gestures when common ground was present. Additionally, we observed a reduction in semantic content and a shift in cross-modal distribution of information across trials. Rather than age, individual differences in verbal and visual working memory and semantic fluency predicted the extent of addressee-based adaptations. Thus, in spatial tasks, individual cognitive abilities modulate the interactive language use of both younger and older adults.

Pragmatic inferences in aging and human-robot communication

Despite the increase in research on older adults' communicative behavior, little work has explored patterns of age-related change in pragmatic inferencing and how these patterns are adapted depending on the situation-specific context. In two eye-tracking experiments, participants followed instructions like "Click on the greenhouse", which were either played over speakers or spoken live by a co-present robot partner. Implicit inferential processes were measured by exploring the extent to which listeners temporarily (mis)understood the unfolding noun to be a modified phrase referring to a competitor object in the display (green hat). This competitor was accompanied by either another member of the same category or an unrelated item (tan hat vs. dice). Experiment 1 (no robot) showed clear evidence of contrastive inferencing in both younger and older adults (more looks to the green hat when the tan hat was also present). Experiment 2 explored the ability to suppress these contrastive inferences when the robot talker was known to lack any color perception, making descriptions like "green hat" implausible. Younger but not older listeners were able to suppress contrastive inferences in this context, suggesting older adults could not keep the relevant limitations in mind and/or were more likely to spontaneously ascribe human attributes to the robot. Together, the findings enhance our understanding of pragmatic inferencing in aging.

Linguistic Redundancy and its Effects on Younger and Older Adults' Real-Time Comprehension and Memory

Redundant modifiers can facilitate referential interpretation by narrowing attention to intended referents. This is intriguing because, on traditional accounts, redundancy should impair comprehension. Little is known, however, about the effects of redundancy on older adults' comprehension. Older adults may show different patterns due to age-related decline (e.g., processing speed and memory) or their greater proclivity for linguistic redundancy, as suggested in language production studies. The present study explores the effects of linguistic redundancy on younger and older listeners' incremental referential processing, judgments of informativity, and downstream memory performance. In an eye tracking task, gaze was monitored as listeners followed instructions from a social robot referring to a unique object within a multi-object display. Critical trials were varied in terms of modifier type ("…closed/purple/[NONE] umbrella") and whether displays contained another object matching target properties (closed purple notebook), making modifiers less effective at narrowing attention. Relative to unmodified descriptions, redundant color modifiers facilitated comprehension, particularly when they narrowed attention to a single referent. Descriptions with redundant state modifiers always impaired real-time comprehension. In contrast, memory measures showed faster recognition of objects previously described with redundant state modifiers. Although color and state descriptions had different effects on referential processing and memory, informativity judgments showed participants perceived them as informationally redundant to the same extent relative to unmodified descriptions. Importantly, the patterns did not differ by listener age. Together, the results show that the effects of linguistic redundancy are stable across adulthood but vary as a function of modifier type, visual context, and the measured phenomenon.

The pressure to communicate efficiently continues to shape language use later in life

Language use is shaped by a pressure to communicate efficiently, yet the tendency towards redundancy is said to increase in older age. The longstanding assumption is that saying more than is necessary is inefficient and may be driven by age-related decline in inhibition (i.e. the ability to filter out irrelevant information). However, recent work proposes an alternative account of efficiency: In certain contexts, redundancy facilitates communication (e.g., when the colour or size of an object is perceptually salient and its mention aids the listener's search). A critical question follows: Are older adults indiscriminately redundant, or do they modulate their use of redundant information to facilitate communication? We tested efficiency and cognitive capacities in 200 adults aged 19-82. Irrespective of age, adults with better attention switching skills were redundant in efficient ways, demonstrating that the pressure to communicate efficiently continues to shape language use later in life.

Cognitive and Neuroanatomic Accounts of Referential Communication in Focal Dementia

The primary function of language is to communicate—that is, to make individuals reach a state of mutual understanding about a particular thought or idea. Accordingly, daily communication is truly a task of social coordination. Indeed, successful interactions require individuals to (1) track and adopt a partner’s perspective and (2) continuously shift between the numerous elements relevant to the exchange. Here, we use a referential communication task to study the contributions of perspective taking and executive function to effective communication in nonaphasic human patients with behavioral variant frontotemporal dementia (bvFTD). Similar to previous work, the task was to identify a target object, embedded among an array of competitors, for an interlocutor. Results indicate that bvFTD patients are impaired relative to control subjects in selecting the optimal, precise response. Neuropsychological testing related this performance to mental set shifting, but not to working memory or inhibition. Follow-up analyses indicated that some bvFTD patients perform equally well as control subjects, while a second, clinically matched patient group performs significantly worse. Importantly, the neuropsychological profiles of these subgroups differed only in set shifting. Finally, structural MRI analyses related patient impairment to gray matter disease in orbitofrontal, medial prefrontal, and dorsolateral prefrontal cortex, all regions previously implicated in social cognition and overlapping those related to set shifting. Complementary white matter analyses implicated uncinate fasciculus, which carries projections between orbitofrontal and temporal cortices. Together, these findings demonstrate that impaired referential communication in bvFTD is cognitively related to set shifting, and anatomically related to a social-executive network including prefrontal cortices and uncinate fasciculus.

Impact of Aging on Empathy: Review of Psychological and Neural Mechanisms

Empathy in aging is a key capacity because it affects the quality of older adults' relationships and reduced levels are associated with greater loneliness. Many older adults also find themselves in the role of a caregiver to a loved one, and thus empathy is critical for the success of the caregiver-patient relationship. Furthermore, older adults are motivated to make strong emotional connections with others, as highlighted in the socioemotional selectivity theory. Consequently, reductions in empathy could negatively impact their goals. However, there is growing evidence that older adults experience at least some changes in empathy, depending on the domain. Specifically, the state of the research is that older adults have lower cognitive empathy (i.e., the ability to understand others' thoughts and feelings) than younger adults, but similar and in some cases even higher levels of emotional empathy (i.e., the ability to feel emotions that are similar to others' or feel compassion for them). A small number of studies have examined the neural mechanisms for age-related differences in empathy and have found reduced activity in a key brain area associated with cognitive empathy. However, more research is needed to further characterize how brain changes impact empathy with age, especially in the emotional domain of empathy. In this review, we discuss the current state of the research on age-related differences in the psychological and neural bases of empathy, with a specific comparison of the cognitive versus emotional components. Finally, we highlight new directions for research in this area and examine the implications of age-related differences in empathy for older adults.

Individual differences in switching and inhibition predict perspective-taking across the lifespan

Studies exploring the influence of executive functions (EF) on perspective-taking have focused on inhibition and working memory in young adults or clinical populations. Less consideration has been given to more complex capacities that also involve switching attention between perspectives, or to changes in EF and concomitant effects on perspective-taking across the lifespan. To address this, we assessed whether individual differences in inhibition and attentional switching in healthy adults (ages 17-84) predict performance on a task in which speakers identified targets for a listener with size-contrasting competitors in common or privileged ground. Modification differences across conditions decreased with age. Further, perspective taking interacted with EF measures: youngest adults' sensitivity to perspective was best captured by their inhibitory performance; oldest adults' sensitivity was best captured by switching performance. Perspective-taking likely involves multiple aspects of EF, as revealed by considering a wider range of EF tasks and individual capacities across the lifespan.