Numerical cognition in ageing : investigating the impact of cognitive ageing on foundational non-symbolic and symbolic numerical abilities

Healthy ageing is associated with a gradual decline in several cognitive functions, including processing speed, inhibitory control, memory, executive functions, and problem solving. However, the trajectory of ability in numerical cognition in older age remains unclear. Some research investigating exact skills such as arithmetical problem solving have found declined numerical abilities in older age due to reduced access to effective strategies. However, other research has indicated stable or even enhanced mathematical and arithmetical abilities in older age. Furthermore, limited research is available on the impact of ageing on foundational numerical abilities. The effect of cognitive ageing on such foundational abilities poses an interesting question due to the innate, evolutionary nature of foundational numerical skills. It is possible that such automatic, innate and primitive abilities may be spared in ageing, alongside emotional processing, autobiographical memory, and vocabulary and verbal skills.Available studies investigating basic numerical abilities in ageing present contradictory results and methodological variation. Furthermore, although a limited number of studies have investigated foundational non-symbolic abilities in ageing, the effect of older age on foundational symbolic abilities is yet to be directly tested. The thesis therefore explicitly investigated the impact of healthy ageing on foundational non-symbolic and symbolic numerical processing with a series of experiments. Chapter 2 presents the first study to use classic numerosity discrimination paradigms to compare the non-symbolic and symbolic foundational numerical skills of a group of younger and older adults. Chapter 3 served to further investigate enhanced symbolic numerical abilities in older age found in chapter 2 using a number priming paradigm. The impact of life experience using numbers on foundational numerical skills in older age was studied in chapter 4, whereby older adults with a degree in mathematics were compared with those without explicit further mathematical education. The final two experimental chapters of the thesis examine the reliable measurement of the Approximate Number System in ageing, considering the impact of inhibitory control and mathematical achievement on acuity. Chapter 5 compares non-symbolic acuity in younger and older adults when using either spatially separated or intermixed non-symbolic dot displays. Finally, chapter 6 directly studies the impact of perceptual variables on ANS acuity in ageing, specifically focusing on total cumulative area, dot size, and convex hull (perimeter) congruency.The series of experiments presented in the thesis indicate that foundational numerical abilities are preserved in healthy ageing. Specifically, non-symbolic numerical abilities remain stable in older age, whereas foundational symbolic abilities are enhanced, possibly due to lifetime exposure to and experience with symbolic numbers. Furthermore, the thesis demonstrates the importance of task design in measuring non-symbolic numerical abilities in ageing, identifying methodological aspects which may lead to poorer acuity in older adults as a result of decline in other cognitive functions (e.g. inhibitory control). The thesis therefore contributes to the literature regarding numerical cognition in ageing, with foundational numerical abilities found to be preserved in healthy ageing. Preservation of such abilities in healthy ageing poses implications for pathological ageing, in that declined foundational numerical skills may serve to indicate pathological processes

Supporting autistic adults’ episodic memory recall in interviews:The role of executive functions, theory of mind, and language abilities

Autistic people have difficulties recalling episodic memories, including retrieving fewer or less specific and detailed memories compared to typically developing people. However, the ability to effectively recall episodic memories is crucial in many real-world contexts, such as the criminal justice system, medical consultations, and employment interviews. Autistic people’s episodic memory difficulties are most apparent when open, unsupportive questions are used. The ‘Task Support Hypothesis’ posits that autistic people can recall as much information as typically developing people with more supportive questioning. Alongside problems retrieving episodic memories, autistic people also experience difficulties with executive functioning, theory of mind, and expressive language. The current study aimed to assess the impact of these abilities on recall in two previous studies by the authors that compared autistic and typically developing adults on recall specificity in police, healthcare, and employment interviews, and recall quality in employment interviews under unsupported and supported questioning. Under unsupported questioning only, autistic adults’ episodic autobiographical memory recall specificity was predicted by expressive language, whereas for the typically developing group, only theory of mind was a significant predictor. No other predictors were significant across the study. Implications for the task support hypothesis are discussed. LAY ABSTRACT: Autistic people have difficulties recalling episodic memories (memories of specific events) compared to typically developing people. However, being able to effectively recall such memories is important in many real-world situations, for example, in police interviews, during medical consultations, and in employment interviews. Autistic people’s episodic memory difficulties are most noticeable when they are responding to open, unsupportive questions. However, the ‘Task Support Hypothesis’ indicates that autistic people are able to recall as much information as typically developing people, as long as they are asked more supportive questions. Autistic people also experience difficulties with executive functioning (cognitive abilities which allow us to plan, hold information in mind, inhibit interruptions, etc.), theory of mind (the ability to understand others’ perspectives and intentions), and spoken language. The current study aimed to investigate the impact of these cognitive abilities on memory recall in two previous studies which compared autistic and typically developing adults on how specific their recall was in police, healthcare, and employment interviews, and the quality of responses during an employment interview when both unsupportive and supportive questioning was used. The results show that while typically developing people may rely on theory of mind abilities, autistic people may rely more on language abilities when performing in interviews, potentially to compensate for their episodic memory difficulties, and that this effect is most apparent during more unsupportive recall (e.g. when a brief, open question is asked) compared to when open questions are followed by prompts (e.g. ‘tell me about who as there’, ‘what happened?’, etc.)

Interviewing autistic adults: Adaptations to support recall in police, employment, and healthcare interviews

Recalling specific past experiences is critical for most formal social interactions, including when being interviewed for employment, as a witness or defendant in the criminal justice system, or as a patient during a clinical consultation. Such interviews can be difficult for autistic adults under standard open questioning, yet applied research into effective methods to facilitate autistic adults’ recall is only recently beginning to emerge. The current study tested the efficacy of different prompting techniques to support autistic adults’ recall of specific personal memories; 30 autistic and 30 typically developing adults (intelligence quotients > 85) were asked to recall specific instances from their past, relevant to criminal justice system, healthcare, and employment interviews. Questions comprised ‘open questions’, ‘semantic prompting’ (where semantic knowledge was used to prompt specific episodic retrieval) and ‘visual–verbal prompting’ (a pie-diagram with prompts to recall specific details, for example, who, what, and where). Half the participants received the questions in advance. Consistent with previous research, autistic participants reported memories with reduced specificity. For both groups, visual–verbal prompting support improved specificity and episodic relevance, while semantic prompting also aided recall for employment questions (but not health or criminal justice system). Findings offer new practical insight for interviewers to facilitate communication with typically developing and autistic adults. Lay abstract: During many types of interviews (e.g. in employment, with the police, and in healthcare), we need to recall detailed memories of specific events, which can be difficult for autistic people in response to commonly used questions. This is especially because these tend to be open questions (i.e. very broad). Autistic people have disproportionately high rates of physical and mental health conditions, are more likely to interact with police, and are the most underemployed disability group. However, interviewers are often unsure about how to adapt their communication for autistic people. Our research tested whether different types of prompts enabled autistic people to recall specific memories (memories of a single event within one day). Participants were asked about situations relating to witnessing a crime (e.g. at the bank), physical or mental health scenarios and employment interviews (e.g. a time you’ve met a deadline). We tested the following: Open questions: basic questions only (e.g. ‘tell me about a time you went to the cinema’), Semantic prompting: a general prompt (e.g. ‘do you enjoy going to the cinema?’) before asking for a specific instance (‘tell me about a time you went to the cinema?’), Visual–verbal prompting: asking participants to recall when it happened, who was there, the actions that occurred, the setting, and any objects. With visual–verbal prompting, autistic and typically developing participants’ memories were more specific and detailed. Semantic prompting was also effective for employment questions. Our study shows that autistic people can recall specific memories when they are appropriately prompted. Visual–verbal prompting may be effective across different situations. © The Author(s) 2020

Interviewing autistic adults: Adaptations to support recall in police, employment, and healthcare interviews

Recalling specific past experiences is critical for most formal social interactions, including when being interviewed for employment, as a witness or defendant in the Criminal Justice System (CJS), or as a patient during a clinical consultation. Such interviews can be difficult for autistic adults under standard open questioning, yet applied research into effective methods to facilitate autistic adults’ recall is beginning to emerge. The current study tested the efficacy of different prompting techniques to support autistic adults’ recall of specific personal memories. Thirty autistic and 30 typically developing (TD) adults (IQs > 85) were asked to recall specific instances from their past, relevant to CJS, healthcare, and employment interviews. Questions comprised ‘open questions’, ‘semantic prompting’ (where semantic knowledge was used to prompt specific episodic retrieval), and ‘visual-verbal prompting’ (V-VP; a pie-diagram with prompts to recall specific details, e.g., who, what, where, etc). Half the participants received the questions in advance. Consistent with previous research, autistic participants reported memories with reduced specificity. For both groups, V-VP support improved specificity and episodic-relevance, while semantic prompting also aided recall for employment questions (but not health or CJS). Findings offer new practical insight for interviewers to facilitate communication with TD and autistic adults

Reply to Crawford et al.: Why Trap-Neuter-Return (TNR) Is an Ethical Solution for Stray Cat Management

The recently published article, ‘A Case of Letting the Cat out of the Bag—Why Trap-Neuter-Return Is Not an Ethical Solution for Stray Cat (Felis catus) Management,’ by Crawford et al. warrants rebuttal. The case presented in the paper, opposing the initiation of TNR trials in Australia, ignores peer-reviewed evidence which substantiates the effectiveness of TNR at reducing unowned urban cat numbers. In addition, the paper’s authors offer a number of unrealistic recommendations, which are little more than a rebranding of the failed status quo. Urban stray cats have long been considered a problem across Australia. Current practice calls for the trapping and killing of thousands of healthy urban stray cats and kittens each year with no apparent effect on the total population. In contrast, the literature offers numerous examples, including two recent studies in Australia, of reductions in urban stray cat numbers where TNR has been implemented. TNR has also been associated with reduced feline intake and euthanasia at shelters, which improves both animal welfare and the well-being of shelter staff. A large-scale trial of TNR in an urban Australian context is scientifically justified and long overdue

The measurement of approximate number system acuity across the lifespan is compromised by congruency effects

Recent studies have highlighted the influence of visual cues such as dot size and cumulative surface area on the measurement of the approximate number system (ANS). Previous studies assessing ANS acuity in ageing have all applied stimuli generated by the Panamath protocol, which does not control nor measure the influence of convex hull. Crucially, convex hull has recently been identified as an influential visual cue present in dot arrays, with its impact on older adults’ ANS acuity yet to be investigated. The current study therefore investigated the manipulation of convex hull by the Panamath protocol, and its effect on the measurement of ANS acuity in younger and older participants. Firstly, analyses of the stimuli generated by Panamath revealed a confound between numerosity ratio and convex hull ratio. Secondly, although older adults were somewhat less accurate than younger adults on convex hull incongruent trials, ANS acuity was broadly similar between the groups. These findings have implications for the valid measurement of ANS acuity across all ages, and suggest that the Panamath protocol produces stimuli that do not adequately control for the influence of convex hull on numerosity discrimination

Perceptions of autistic and non-autistic adults in employment interviews:The role of impression management

Background: Social communication and interaction differences can make employment interviews particularly challenging for autistic people, who may be less able to modulate their Impression Management (IM). This makes autism a relevant test case of the extent to which behavioral IM influences perceptions of job candidates.Method: Two studies are reported. In Study 1, lay-raters watched a video of autistic and non-autistic mock candidates’ interviews, and assessed their verbal, non-verbal, and para-verbal behaviors, and likelihood of social approach/avoidance. In Study 2, the presence of behavioral cues was manipulated by using either the interview videos (behavioral cues present) or transcripts (cues absent). Employers rated their overall impression of the candidates (e.g., perceived confidence, conscientiousness, competence, communication skills, etc).Results: In study 1, autistic candidates were perceived as having a more monotonous tone of voice, being less composed and focused, and displaying less natural eye contact and gestures than their non-autistic counterparts, and received lower ratings for likelihood of social approach. For non-autistic interviewees, relationships were also found between ratings for verbal, para-verbal, and non-verbal behaviors, and social awkwardness and attractiveness. In study 2, non-autistic (but not autistic) interviewees received higher ratings of their confidence and communication skills when assessed by video than by transcript, but this advantage was not found for the autistic candidates.Conclusions: Results indicate that observers may use different information when evaluating autistic compared with non-autistic interviewees, possibly due to qualitative differences in behavior. Implications of different behavioral presentations in autistic candidates are discussed, including the potential benefits of using transcripts or more structured interviews to enable recruiters to focus on interviewee answers, whilst being less influenced by non-verbal and para-verbal behaviors

Lacking Pace but Not Precision: Age-Related Information Processing Changes in Response to a Dynamic Attentional Control Task

Age-related decline in information processing can have a substantial impact on activities such as driving. However, the assessment of these changes is often carried out using cognitive tasks that do not adequately represent the dynamic process of updating environmental stimuli. Equally, traditional tests are often static in their approach to task complexity, and do not assess difficulty within the bounds of an individual’s capability. To address these limitations, we used a more ecologically valid measure, the Swansea Test of Attentional Control (STAC), in which a threshold for information processing speed is established at a given level of accuracy. We aimed to delineate how older, compared to younger, adults varied in their performance of the task, while also assessing relationships between the task outcome and gender, general cognition (MoCA), perceived memory function (MFQ), cognitive reserve (NART), and aspects of mood (PHQ-9, GAD-7). The results indicate that older adults were significantly slower than younger adults but no less precise, irrespective of gender. Age was negatively correlated with the speed of task performance. Our measure of general cognition was positively correlated with the task speed threshold but not with age per se. Perceived memory function, cognitive reserve, and mood were not related to task performance. The findings indicate that while attentional control is less efficient in older adulthood, age alone is not a defining factor in relation to accuracy. In a real-life context, general cognitive function, in conjunction with dynamic measures such as STAC, may represent a far more effective strategy for assessing the complex executive functions underlying driving ability

Reaction time decomposition as a tool to study subcortical ischemic vascular cognitive impairment

Background: The study of reaction time (RT) and its intraindividual variability (IIV) in aging, cognitive impairment, and dementia typically fails to investigate the processing stages that contribute to an overall response. Applying “mental chronometry” techniques makes it possible to separately assess the role of processing components during environmental interaction. Objective: To determine whether RT and IIV-decomposition techniques can shed light on the nature of underlying deficits in subcortical ischemic vascular cognitive impairment (VCI). Using a novel iPad task, we examined whether VCI deficits occur during both initiation and movement phases of a response, and whether they are equally reflected in both RT and IIV. Methods: Touch cancellation RT and its IIV were measured in a group of younger adults (n = 22), cognitively healthy older adults (n = 21), and patients with VCI (n = 21) using an iPad task. Results: Whereas cognitively healthy aging affected the speed (RT) of response initiation and movement but not its variability (IIV), VCI resulted in both slowed RT and increased IIV for both response phases. Furthermore, there were group differences with respect to response phase. Conclusion: These results indicate that IIV can be more sensitive than absolute RT in separating VCI from normal aging. Furthermore, compared to cognitively healthy aging, VCI was characterized by significant deficits in planning/initiating action as well as performing movements. Such deficits have important implications for real life actions such as driving safety, employment, and falls risk

The Up-Scale Manufacture of Chondrocytes for Allogeneic Cartilage Therapies

Background: Allogeneic chondrocyte therapies need to be developed to allow more individuals to be treated with a cell therapy for cartilage repair and to reduce the burden and cost of current two-stage autologous procedures. Up-scale manufacture of chondrocytes using a bioreactor could help provide an off-the-shelf allogeneic chondrocyte therapy with many doses being produced in a single manufacturing run. Here we assess a Good Manufacturing Practice compliant hollow-fibre bioreactor (Quantum®) for adult chondrocyte manufacture. Methods: Chondrocytes were isolated from knee arthroplasty derived cartilage (n=5) and expanded in media supplemented with 10% fetal bovine serum (FBS) or 5% human platelet lysate (hPL) on tissue culture plastic (TCP) for a single passage. hPL supplemented cultures were then expanded in the Quantum® bioreactor for a further passage. Matched, parallel cultures in hPL or FBS were maintained on TCP. Chondrocytes from all culture conditions were characterised in terms of growth kinetics, morphology, immunoprofile, chondrogenic potential (chondrocyte pellet assays) and single telomere length analysis. Results: Quantum® expansion of chondrocytes resulted in 86.4±38.5x106 cells in 8.4±1.5 days, following seeding of 10.2±3.6 x106 cells. This related to 3.0±1.0 population doublings in the Quantum® bioreactor, compared with 2.1±0.6 and 1.3±1.0 on TCP in hPL and FBS supplemented media, respectively. Quantum® and TCP expanded cultures retained equivalent chondropotency and mesenchymal stromal cell markers immunoprofiles, with only integrin marker, CD49a, decreasing following Quantum® expansion. Quantum® expanded chondrocytes demonstrated equivalent chondrogenic potential (as assessed by ability to form and maintain chondrogenic pellets) with matched hPL TCP populations. hPL manufacture however, led to reduced chondrogenic potential and increased cell surface positivity of integrins CD49b, CD49c and CD51/61 compared with FBS cultures. Quantum® expansion of chondrocytes did not result in shortened 17p telomere length when compared with matched TCP cultures. Discussion: This study demonstrates that large numbers of adult chondrocytes can be manufactured in the Quantum® hollow-fibre bioreactor. This rapid, up-scale expansion, does not alter chondrocyte phenotype when compared with matched TCP expansion. Therefore, the Quantum® provides an attractive method of manufacturing chondrocytes for clinical use. Media supplementation with hPL for chondrocyte expansion may, however, be unfavourable in terms of retaining chondrogenic capacity