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1.
bioRxiv ; 2024 May 29.
Article in English | MEDLINE | ID: mdl-38854026

ABSTRACT

A major mechanism of insecticide resistance in insect pests is knock-down resistance (kdr) caused by mutations in the voltage-gated sodium channel (Vgsc) gene. Despite being common in most malaria Anopheles vector species, kdr mutations have never been observed in Anopheles funestus, the principal malaria vector in Eastern and Southern Africa. While monitoring 10 populations of An. funestus in Tanzania, we unexpectedly found resistance to DDT, a banned insecticide, in one location. Through whole-genome sequencing of 333 An. funestus samples from these populations, we found 8 novel amino acid substitutions in the Vgsc gene, including the kdr variant, L976F (L1014F in An. gambiae), in tight linkage disequilibrium with another (P1842S). The mutants were found only at high frequency in one region, with a significant decline between 2017 and 2023. Notably, kdr L976F was strongly associated with survivorship to the exposure to DDT insecticide, while no clear association was noted with a pyrethroid insecticide (deltamethrin). Further study is necessary to identify the origin and spread of kdr in An. funestus, and the potential threat to current insecticide-based vector control in Africa.

2.
Parasit Vectors ; 17(1): 230, 2024 May 17.
Article in English | MEDLINE | ID: mdl-38760849

ABSTRACT

BACKGROUND: Anopheles funestus is a leading vector of malaria in most parts of East and Southern Africa, yet its ecology and responses to vector control remain poorly understood compared with other vectors such as Anopheles gambiae and Anopheles arabiensis. This study presents the first large-scale survey of the genetic and phenotypic expression of insecticide resistance in An. funestus populations in Tanzania. METHODS: We performed insecticide susceptibility bioassays on An. funestus mosquitoes in nine regions with moderate-to-high malaria prevalence in Tanzania, followed by genotyping for resistance-associated mutations (CYP6P9a, CYP6P9b, L119F-GSTe2) and structural variants (SV4.3 kb, SV6.5 kb). Generalized linear models were used to assess relationships between genetic markers and phenotypic resistance. An interactive R Shiny tool was created to visualize the data and support evidence-based interventions. RESULTS: Pyrethroid resistance was universal but reversible by piperonyl-butoxide (PBO). However, carbamate resistance was observed in only five of the nine districts, and dichloro-diphenyl-trichloroethane (DDT) resistance was found only in the Kilombero valley, south-eastern Tanzania. Conversely, there was universal susceptibility to the organophosphate pirimiphos-methyl in all sites. Genetic markers of resistance had distinct geographical patterns, with CYP6P9a-R and CYP6P9b-R alleles, and the SV6.5 kb structural variant absent or undetectable in the north-west but prevalent in all other sites, while SV4.3 kb was prevalent in the north-western and western regions but absent elsewhere. Emergent L119F-GSTe2, associated with deltamethrin resistance, was detected in heterozygous form in districts bordering Mozambique, Malawi and the Democratic Republic of Congo. The resistance landscape was most complex in western Tanzania, in Tanganyika district, where all five genetic markers were detected. There was a notable south-to-north spread of resistance genes, especially CYP6P9a-R, though this appears to be interrupted, possibly by the Rift Valley. CONCLUSIONS: This study underscores the need to expand resistance monitoring to include An. funestus alongside other vector species, and to screen for both the genetic and phenotypic signatures of resistance. The findings can be visualized online via an interactive user interface and could inform data-driven decision-making for resistance management and vector control. Since this was the first large-scale survey of resistance in Tanzania's An. funestus, we recommend regular updates with greater geographical and temporal coverage.


Subject(s)
Anopheles , Insecticide Resistance , Insecticides , Malaria , Mosquito Vectors , Animals , Anopheles/genetics , Anopheles/drug effects , Insecticide Resistance/genetics , Tanzania/epidemiology , Mosquito Vectors/genetics , Mosquito Vectors/drug effects , Insecticides/pharmacology , Malaria/transmission , Malaria/epidemiology , Genetic Markers , Pyrethrins/pharmacology , Genotype , Mutation
3.
Cortex ; 176: 242-259, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38760243

ABSTRACT

Previous research has suggested that self-bias (i.e., enhanced cognitive processing of self-versus other-relevant information) may be atypical in autism spectrum conditions (ASC), perhaps due to difficulties with self-other distinction. However, empirical evidence for this is inconsistent, and the neural basis of processing differences remains unknown. We present two experiments that aimed to test perceptual self-bias and familiarity effects in ASC using a perceptual-association task. Participants were asked to distinguish face/label associations of the self from those of other people of differing levels of familiarity (i.e., friend vs stranger). Experiment 1 took an individual differences approach by testing whether behavioural self-bias is associated with the number of autistic traits in a neurotypical adult sample (N = 59). Experiment 2 took a case-control approach by testing whether behavioural self-bias and associated ERP responses differ between neurotypical (N = 27) and autistic (N = 30) adults. Across both experiments, behavioural results showed that participants experienced a self-bias (self > friend and stranger) and a familiarity effect (e.g., friend > stranger); neither effect was affected by the number of autistic traits or autism diagnosis. In Experiment 2, analysis of N1, N2, and P3 ERP components revealed a typical self-bias in both groups (self distinct from friend and stranger), and only the autistic group showed evidence of a familiarity effect (N2 more negative-going for stranger than friend). The findings are discussed in relation to self-other distinction ability, and the relevance of other neuropsychological and psychiatric conditions such as anxiety and alexithymia are also considered.


Subject(s)
Autistic Disorder , Recognition, Psychology , Humans , Male , Female , Adult , Recognition, Psychology/physiology , Young Adult , Autistic Disorder/physiopathology , Autistic Disorder/psychology , Evoked Potentials/physiology , Electroencephalography/methods , Self Concept , Autism Spectrum Disorder/physiopathology , Autism Spectrum Disorder/psychology , Adolescent
4.
PLoS Negl Trop Dis ; 18(4): e0010932, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38683840

ABSTRACT

BACKGROUND: Dengue (DENV) transmission is endemic throughout coastal Ecuador, showing heterogeneous incidence patterns in association with fine-scale variation in Aedes aegypti vector populations and other factors. Here, we investigated the impact of micro-climate and neighbourhood-level variation in urbanization on Aedes abundance, resting behaviour and associations with dengue incidence in two endemic areas. METHODOLOGY/PRINCIPAL FINDINGS: Aedes aegypti were collected in Quinindé and Portoviejo, two urban cantons with hyperendemic dengue transmission in coastal Ecuador. Aedes vectors were sampled in and around houses within urban and peri-urban neighbourhoods at four time periods. We tested for variation in vector abundance and resting behaviour in relation to neighbourhood urbanization level and microclimatic factors. Aedes abundance increased towards the end of the rainy season, was significantly higher in Portoviejo than in Quinindé, and in urban than in peri-urban neighbourhoods. Aedes vectors were more likely to rest inside houses in Portoviejo but had similar abundance in indoor and outdoor resting collections in Quinindé. Over the study period, DENV incidence was lower in Quinindé than in Portoviejo. Relationships between weekly Ae. aegypti abundance and DENV incidence were highly variable between trapping methods; with positive associations being detected only between BG-sentinel and outdoor Prokopack collections. CONCLUSIONS/SIGNIFICANCE: Aedes aegypti abundance was significantly higher in urban than peri-urban neighbourhoods, and their resting behaviour varied between study sites. This fine-scale spatial heterogeneity in Ae. aegypti abundance and behaviour could generate site-specific variation in human exposure and the effectiveness of indoor-based interventions. The trap-dependent nature of associations between Aedes abundance and local DENV incidence indicates further work is needed to identify robust entomological indicators of infection risk.


Subject(s)
Aedes , Dengue , Mosquito Vectors , Animals , Aedes/virology , Aedes/physiology , Ecuador/epidemiology , Dengue/transmission , Dengue/epidemiology , Incidence , Mosquito Vectors/physiology , Mosquito Vectors/virology , Humans , Female , Seasons
5.
J Exp Psychol Gen ; 153(6): 1464-1488, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38602788

ABSTRACT

Despite significantly increasing research efforts, the psychological effects of reading fiction remain under debate. We present two preregistered meta-analyses synthesizing cognitive effects and correlates of reading fiction. In Meta-Analysis 1 (371 effect sizes/70 experiments), reading fiction led to significant small-sized cognitive benefits, g = 0.14, 95% confidence interval (CI) [0.06, 0.21]. This effect of fiction reading was moderated by the comparison group (effects were greater when reading fiction was compared with watching fiction or reading nothing than when reading fiction was compared with reading nonfiction) and the outcome variable (significant effects emerged for empathy and mentalizing only). In Meta-Analysis 2 (559 effect sizes/114 studies reporting correlations), lifetime exposure to print fiction was linked with significant small-sized cognitive benefits, r = .16, 95% CI [0.13, 0.19]. This effect was moderated by outcome variable (effects were greatest for verbal abilities, followed by general cognitive abilities and empathy/mentalizing/outgroup judgments), fictionality of the print material (greater effects were found for fiction than nonfiction), publication status (published work exhibited greater effects than unpublished work), type of assessment measure (larger effects emerged when neither the outcome nor print exposure were assessed via self-report, than when either the outcome or print exposure were assessed via self-report), participant group (community samples showed greater effects than student samples), study design (greater effects were found for correlational than for experimental designs), and percentage of female participants (via a negative relationship with cognitive benefits). Together, these meta-analyses provide robust evidence for a small-sized positive relationship between reading fiction and cognitive benefits. (PsycInfo Database Record (c) 2024 APA, all rights reserved).


Subject(s)
Cognition , Reading , Humans , Empathy , Theory of Mind/physiology
7.
Parasit Vectors ; 17(1): 38, 2024 Jan 29.
Article in English | MEDLINE | ID: mdl-38287419

ABSTRACT

BACKGROUND: Anopheles funestus is a major malaria vector in Eastern and Southern Africa and is currently the dominant malaria-transmitting vector in many parts of Tanzania. Previous research has identified its preference for specific aquatic habitats, especially those that persist in dry months. This observation suggests the potential for targeted control through precise habitat mapping and characterization. In this study, we investigated the influence of habitat characteristics, land cover and human population densities on An. funestus distribution during dry seasons. Based on the results, we developed a habitat suitability model for this vector species in south-eastern Tanzania. METHODS: Eighteen villages in south-eastern Tanzania were surveyed during the dry season from September-December 2021. Water bodies were systematically inspected for mosquito larvae and characterized by their physico-chemical characteristics and surrounding environmental features. A generalized linear model was used to assess the presence of An. funestus larvae as a function of the physico-chemical characteristics, land use and human population densities. The results obtained from this model were used to generate spatially explicit predictions of habitat suitability in the study districts. RESULTS: Of the 1466 aquatic habitats surveyed, 440 were positive for An. funestus, with river streams having the highest positivity (74%; n = 322) followed by ground pools (15%; n = 67). The final model had an 83% accuracy in predicting positive An. funestus habitats, with the most important characteristics being permanent waters, clear waters with or without vegetation or movement and shading over the habitats. There was also a positive association of An. funestus presence with forested areas and a negative association with built-up areas. Human population densities had no influence on An. funestus distribution. CONCLUSIONS: The results of this study underscore the crucial role of both the specific habitat characteristics and key environmental factors, notably land cover, in the distribution of An. funestus. In this study area, An. funestus predominantly inhabits river streams and ground pools, with a preference for clear, perennial waters with shading. The strong positive association with more pristine environments with tree covers and the negative association with built-up areas underscore the importance of ecological transitions in vector distribution and malaria transmission risk. Such spatially explicit predictions could enable more precise interventions, particularly larval source management, to accelerate malaria control.


Subject(s)
Anopheles , Malaria , Humans , Animals , Seasons , Tanzania/epidemiology , Mosquito Vectors , Ecosystem , Rivers , Larva
8.
PLoS One ; 18(12): e0293898, 2023.
Article in English | MEDLINE | ID: mdl-38134192

ABSTRACT

Self-owned items are better remembered than other-owned items; this ownership effect reflects privileged processing of self-related information. The size of this ownership effect has been shown to decrease in neurotypical adults as the number of autistic traits increases, and is reduced in autistic adults. However, emerging evidence has questioned the reliability of these findings. This paper aimed to replicate previous work using well-powered, pre-registered designs, and Bayesian analyses. Experiment 1 (N = 100) found a significant ownership effect in neurotypical adults; however, the size of this was unrelated to individual differences in autistic traits. Experiment 2 (N = 56) found an ownership effect in neurotypical but not autistic adults. The findings suggest that individual differences in autistic traits in the neurotypical population do not impact the ownership effect, but a clinical diagnosis of autism might. We discuss how these findings can be explained by differences in psychological self-awareness in autism.


Subject(s)
Autism Spectrum Disorder , Autistic Disorder , Child Development Disorders, Pervasive , Adult , Child , Humans , Autistic Disorder/psychology , Ownership , Bayes Theorem , Reproducibility of Results
9.
Autism ; : 13623613231216052, 2023 Dec 28.
Article in English | MEDLINE | ID: mdl-38153207

ABSTRACT

LAY ABSTRACT: People with autism spectrum conditions (ASC) have difficulties imagining events, which might result from difficulty mentally generating and maintaining a coherent spatial scene. This study compared this scene construction ability between autistic (N = 55) and neurotypical (N = 63) adults. Results showed that scene construction was diminished in autistic compared to neurotypical participants, and participants with fewer autistic traits had better scene construction ability. ASC diagnosis did not influence the frequency of mentions of the self or of sensory experiences. Exploratory analysis suggests that scene construction ability is associated with the ability to understand our own and other people's mental states, and that these individual-level preferences/cognitive styles can overrule typical group-level characteristics.

10.
Malar J ; 22(1): 346, 2023 Nov 10.
Article in English | MEDLINE | ID: mdl-37950315

ABSTRACT

Studies on the applications of infrared (IR) spectroscopy and machine learning (ML) in public health have increased greatly in recent years. These technologies show enormous potential for measuring key parameters of malaria, a disease that still causes about 250 million cases and 620,000 deaths, annually. Multiple studies have demonstrated that the combination of IR spectroscopy and machine learning (ML) can yield accurate predictions of epidemiologically relevant parameters of malaria in both laboratory and field surveys. Proven applications now include determining the age, species, and blood-feeding histories of mosquito vectors as well as detecting malaria parasite infections in both humans and mosquitoes. As the World Health Organization encourages malaria-endemic countries to improve their surveillance-response strategies, it is crucial to consider whether IR and ML techniques are likely to meet the relevant feasibility and cost-effectiveness requirements-and how best they can be deployed. This paper reviews current applications of IR spectroscopy and ML approaches for investigating malaria indicators in both field surveys and laboratory settings, and identifies key research gaps relevant to these applications. Additionally, the article suggests initial target product profiles (TPPs) that should be considered when developing or testing these technologies for use in low-income settings.


Subject(s)
Culicidae , Malaria , Animals , Humans , Artificial Intelligence , Evidence Gaps , Malaria/epidemiology , Mosquito Vectors , Spectrophotometry, Infrared/methods
11.
Sci Rep ; 13(1): 18499, 2023 10 28.
Article in English | MEDLINE | ID: mdl-37898634

ABSTRACT

Mid-infrared spectroscopy (MIRS) combined with machine learning analysis has shown potential for quick and efficient identification of mosquito species and age groups. However, current technology to collect spectra is destructive to the sample and does not allow targeting specific tissues of the mosquito, limiting the identification of other important biological traits such as insecticide resistance. Here, we assessed the use of a non-destructive approach of MIRS for vector surveillance, micro diffuse reflectance spectroscopy (µDRIFT) using mosquito legs to identify species, age and cuticular insecticide resistance within the Anopheles gambiae s.l. complex. These mosquitoes are the major vectors of malaria in Africa and the focus on surveillance in malaria control programs. Legs required significantly less scanning time and showed more spectral consistence compared to other mosquito tissues. Machine learning models were able to identify An. gambiae and An. coluzzii with an accuracy of 0.73, two ages groups (3 and 10 days old) with 0.77 accuracy and we obtained accuracy of 0.75 when identifying cuticular insecticide resistance. Our results highlight the potential of different mosquito tissues and µDRIFT as tools for biological trait identification on mosquitoes that transmit malaria. These results can guide new ways of identifying mosquito traits which can help the creation of innovative surveillance programs by adapting new technology into mosquito surveillance and control tools.


Subject(s)
Anopheles , Insecticides , Malaria , Animals , Mosquito Vectors , Insecticide Resistance , Spectrophotometry, Infrared , Insecticides/pharmacology , Mosquito Control/methods
12.
Parasit Vectors ; 16(1): 388, 2023 Oct 27.
Article in English | MEDLINE | ID: mdl-37891582

ABSTRACT

BACKGROUND: Chromosomal inversion polymorphisms have been associated with adaptive behavioral, physiological, morphological and life history traits in the two main Afrotropical malaria vectors, Anopheles coluzzii and Anopheles gambiae. The understanding of the adaptive value of chromosomal inversion systems is constrained by the feasibility of cytological karyotyping. In recent years in silico and molecular approaches have been developed for the genotyping of most widespread inversions (2La, 2Rb and 2Rc). The 2Ru inversion, spanning roughly 8% of chromosome 2R, is commonly polymorphic in West African populations of An. coluzzii and An. gambiae and shows clear increases in frequency with increasing rainfall seasonally and geographically. The aim of this work was to overcome the constraints of currently available cytological and high-throughput molecular assays by developing a simple PCR assay for genotyping the 2Ru inversion in individual specimens of both mosquito species. METHODS: We designed tetra-primer amplification refractory mutation system (ARMS)-PCR assays based on five tag single-nucleotide polymorphisms (SNPs) previously shown to be strongly correlated with 2Ru inversion orientation. The most promising assay was validated against laboratory and field samples of An. coluzzii and An. gambiae karyotyped either cytogenetically or molecularly using a genotyping-in-thousands by sequencing (GT-seq) high-throughput approach that employs targeted sequencing of multiplexed PCR amplicons. RESULTS: A successful assay was designed based on the tag SNP at position 2R, 31710303, which is highly predictive of the 2Ru genotype. The assay, which requires only one PCR, and no additional post-PCR processing other than electrophoresis, produced a clear banding pattern for 98.5% of the 454 specimens tested, which is a 96.7% agreement with established karyotyping methods. Sequences were obtained for nine of the An. coluzzii specimens manifesting 2Ru genotype discrepancies with GT-seq. Possible sources of these discordances are discussed. CONCLUSIONS: The tetra-primer ARMS-PCR assay represents an accurate, streamlined and cost-effective method for the molecular karyotyping of the 2Ru inversion in An. coluzzii and An. gambiae. Together with approaches already available for the other common polymorphic inversions, 2La, 2Rb and 2Rc, this assay will allow investigations of the adaptive value of the complex set of inversion systems observed in the two major malaria vectors in the Afrotropical region.


Subject(s)
Anopheles , Malaria , Animals , Anopheles/genetics , Chromosome Inversion/genetics , Mosquito Vectors/genetics , Karyotyping , Polymerase Chain Reaction/methods , Polymorphism, Single Nucleotide
14.
Malar J ; 22(1): 238, 2023 Aug 16.
Article in English | MEDLINE | ID: mdl-37587487

ABSTRACT

BACKGROUND: The use of insecticide-treated nets for malaria control has been associated with shifts in mosquito vector feeding behaviour including earlier and outdoor biting on humans. The relative contribution of phenotypic plasticity and heritability to these behavioural shifts is unknown. Elucidation of the mechanisms behind these shifts is crucial for anticipating impacts on vector control. METHODS: A novel portable semi-field system (PSFS) was used to experimentally measure heritability of biting time in the malaria vector Anopheles arabiensis in Tanzania. Wild An. arabiensis from hourly collections using the human landing catch (HLC) method were grouped into one of 3 categories based on their time of capture: early (18:00-21:00), mid (22:00-04:00), and late (05:00-07:00) biting, and placed in separate holding cages. Mosquitoes were then provided with a blood meal for egg production and formation of first filial generation (F1). The F1 generation of each biting time phenotype category was reared separately, and blood fed at the same time as their mothers were captured host-seeking. The resultant eggs were used to generate the F2 generation for use in heritability assays. Heritability was assessed by releasing F2 An. arabiensis into the PSFS, recording their biting time during a human landing catch and comparing it to that of their F0 grandmothers. RESULTS: In PSFS assays, the biting time of F2 offspring (early: 18:00-21:00, mid: 22:00-04:00 or late: 05:00-07:00) was significantly positively associated with that of their wild-caught F0 grandmothers, corresponding to an estimated heritability of 0.110 (95% CI 0.003, 0.208). F2 from early-biting F0 were more likely to bite early than F2 from mid or late-biting F0. Similarly, the probability of biting late was higher in F2 derived from mid and late-biting F0 than from early-biting F0. CONCLUSIONS: Despite modest heritability, our results suggest that some of the variation in biting time is attributable to additive genetic variation. Selection can, therefore, act efficiently on mosquito biting times, highlighting the need for control methods that target early and outdoor biting mosquitoes.


Subject(s)
Anopheles , Malaria , Humans , Animals , Anopheles/genetics , Mosquito Vectors/genetics , Malaria/prevention & control , Feeding Behavior , Adaptation, Physiological
15.
Malar J ; 22(1): 230, 2023 Aug 08.
Article in English | MEDLINE | ID: mdl-37553665

ABSTRACT

Anopheles mosquitoes present a major public health challenge in sub-Saharan Africa; notably, as vectors of malaria that kill over half a million people annually. In parts of the east and southern Africa region, one species in the Funestus group, Anopheles funestus, has established itself as an exceptionally dominant vector in some areas, it is responsible for more than 90% of all malaria transmission events. However, compared to other malaria vectors, the species is far less studied, partly due to difficulties in laboratory colonization and the unresolved aspects of its taxonomy and systematics. Control of An. funestus is also increasingly difficult because it has developed widespread resistance to public health insecticides. Fortunately, recent advances in molecular techniques are enabling greater insights into species identity, gene flow patterns, population structure, and the spread of resistance in mosquitoes. These advances and their potential applications are reviewed with a focus on four research themes relevant to the biology and control of An. funestus in Africa, namely: (i) the taxonomic characterization of different vector species within the Funestus group and their role in malaria transmission; (ii) insecticide resistance profile; (iii) population genetic diversity and gene flow, and (iv) applications of genetic technologies for surveillance and control. The research gaps and opportunities identified in this review will provide a basis for improving the surveillance and control of An. funestus and malaria transmission in Africa.


Subject(s)
Anopheles , Insecticides , Malaria , Humans , Animals , Malaria/epidemiology , Mosquito Vectors/genetics , Insecticides/pharmacology , Insecticide Resistance/genetics , Africa, Southern
16.
PLoS Comput Biol ; 19(6): e1010684, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37307282

ABSTRACT

The Ross-Macdonald model has exerted enormous influence over the study of malaria transmission dynamics and control, but it lacked features to describe parasite dispersal, travel, and other important aspects of heterogeneous transmission. Here, we present a patch-based differential equation modeling framework that extends the Ross-Macdonald model with sufficient skill and complexity to support planning, monitoring and evaluation for Plasmodium falciparum malaria control. We designed a generic interface for building structured, spatial models of malaria transmission based on a new algorithm for mosquito blood feeding. We developed new algorithms to simulate adult mosquito demography, dispersal, and egg laying in response to resource availability. The core dynamical components describing mosquito ecology and malaria transmission were decomposed, redesigned and reassembled into a modular framework. Structural elements in the framework-human population strata, patches, and aquatic habitats-interact through a flexible design that facilitates construction of ensembles of models with scalable complexity to support robust analytics for malaria policy and adaptive malaria control. We propose updated definitions for the human biting rate and entomological inoculation rates. We present new formulas to describe parasite dispersal and spatial dynamics under steady state conditions, including the human biting rates, parasite dispersal, the "vectorial capacity matrix," a human transmitting capacity distribution matrix, and threshold conditions. An [Formula: see text] package that implements the framework, solves the differential equations, and computes spatial metrics for models developed in this framework has been developed. Development of the model and metrics have focused on malaria, but since the framework is modular, the same ideas and software can be applied to other mosquito-borne pathogen systems.


Subject(s)
Culicidae , Malaria, Falciparum , Malaria , Adult , Animals , Humans , Malaria/epidemiology , Culicidae/physiology , Ecology , Ecosystem
17.
Br J Psychol ; 114(3): 731-748, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37022204

ABSTRACT

Loneliness describes a negative experience associated with perceived social disconnection. Despite the clear links between loneliness and mental and physical health, relatively little is known about how loneliness affects cognition. In this study, we tested the effect of loneliness on cognitive distance between the self and others, using a task in which participants completed a surprise memory task for adjectives implicitly encoded in relation to the self, a close friend or a celebrity. We assessed item memory sensitivity, metacognitive sensitivity, metacognitive efficiency and source memory for positive and negative words. In addition, participants reported their trait loneliness and depression. Results revealed an overall self-referential advantage compared with both friend and celebrity encoded items. Likewise, a friend-referential advantage was identified compared to celebrity-encoded items. Individuals who experienced more loneliness showed a greater self-referential bias in comparison to words encoded in relation to a close friend, and a smaller friend-referential bias in comparison to words encoded in relation to celebrity. These findings suggest that loneliness is reflected in a greater cognitive distance between the self and close friends in relation to memory biases. The results have important implications for understanding the social contextual effects on memory and the cognitive ramifications of loneliness.


Subject(s)
Memory, Episodic , Humans , Loneliness , Self Concept , Cognition , Language
18.
J Exp Psychol Gen ; 152(5): 1420-1438, 2023 May.
Article in English | MEDLINE | ID: mdl-36862493

ABSTRACT

Taking another person's perspective provides a means to infer their beliefs and intentions (known as Theory of Mind), which is an essential part of social interaction. In this article, we examined how different subcomponents of perspective-taking change beyond childhood in a large sample (N = 263) of adolescents, young adults, and older adults, and tested the degree to which age-related changes in perspective-taking are mediated by executive functions. Participants completed three tasks that assessed: (a) the likelihood of making social inferences, (b) judgments about an avatar's visual and spatial perspective, and (c) their ability to use an avatar's visual perspective to assign reference in language. Results revealed that while the likelihood of correctly inferring others' mental states increased linearly between adolescence and older adulthood (likely reflecting accumulating social experience over the lifespan), the ability to judge an avatar's perspective and use this to assign reference was subject to developmental changes from adolescence to older age, with performance peaking in young adulthood. Correlation and mediation analyses incorporated three measures of executive functioning (inhibitory control, working memory, and cognitive flexibility) and revealed that executive functions contribute to perspective-taking ability in these tasks (particularly during development), but largely do not mediate the effect of age on perspective-taking. We discuss how these results fit with models of mentalizing that predict distinct patterns of social development depending on the maturation of cognitive and language mechanisms. (PsycInfo Database Record (c) 2023 APA, all rights reserved).


Subject(s)
Judgment , Theory of Mind , Humans , Young Adult , Adolescent , Aged , Adult , Executive Function , Memory, Short-Term , Social Interaction
19.
Behav Res Methods ; 55(1): 103-134, 2023 01.
Article in English | MEDLINE | ID: mdl-35277842

ABSTRACT

We report a study testing the validity of the three most commonly used indicators of lifetime exposure to print fiction, namely a self-report scale, an author recognition test (ART), and book counting, in a sample of older adults (N=306; Mage = 59.29 years, SDage = 7.01). Convergent validity of the self-report scale and book counting was assessed through correlations with the fiction sub-score of the ART; divergent validity of these two indicators was examined via correlations with the non-fiction sub-score of that ART. We also assessed criterion-related validity by testing the degree to which each of the three indicators predicted participants' performance in a vocabulary test. The self-report scale and book counting were significantly more positively associated with the ART fiction sub-score than the ART non-fiction sub-score. Regression analyses, controlling for gender and non-fiction exposure, revealed that the ART fiction sub-score had the highest explanatory power among all indicators under investigation for predicting vocabulary test performance. The present results suggest that only ARTs may have satisfactory levels of both construct and criterion-related validity. Recommendations for the assessment of fiction exposure and future directions are discussed.


Subject(s)
Reading , Vocabulary , Humans , Aged , Middle Aged , Child , Self Report , Books , Regression Analysis
20.
J Exp Psychol Learn Mem Cogn ; 49(6): 959-973, 2023 Jun.
Article in English | MEDLINE | ID: mdl-36548095

ABSTRACT

Perspective-taking plays an important role in daily life, allowing consideration of other people's perspectives and viewpoints. This study used a large sample of 265 community-based participants (aged 20-86 years) to examine changes in perspective-taking abilities-a component of "Theory of Mind"-across adulthood, and how these changes may relate to individual differences in executive functions at different ages. Participants completed a referential-communication task (the "Director" task) while behavioral responses and eye movements were recorded, along with four measures of executive functions (inhibitory control, working memory, cognitive flexibility, and planning). Results revealed a quadratic fit of age in egocentric errors; performance on the task plateaued between 20 to ~37 years old but showed a substantial decline from ~38 years onward (i.e., increased egocentric errors). A similar pattern was established in eye-movement measures, demonstrating that advancing age led to a decrease in efficient attention orientation to a target. In other words, older adults were more distracted by a hidden competitor object (egocentric interference) and were therefore delayed in orienting their attention to the correct target object. Mediation analyses revealed that executive functions partially mediated the effect of age on perspective-taking abilities. Importantly, however, the relationship between age and egocentric bias in task performance remained significant when controlling for changes in executive functions, indicating a decline in social cognition abilities with advancing age that was independent of age-related declines in more domain-general abilities, such as executive functions. (PsycInfo Database Record (c) 2023 APA, all rights reserved).


Subject(s)
Cognition , Eye-Tracking Technology , Humans , Aged , Adult , Cognition/physiology , Executive Function/physiology , Eye Movements , Communication
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