Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 44
Filtrar
2.
PLoS One ; 18(12): e0295995, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38109367

RESUMEN

Research has found that humour styles can moderate the relationship between various facets of mental health and well-being. Most of these studies have used college student samples, however, and the generalizability of these findings has not been firmly established. This study examined how humour styles moderate the relationship between hopelessness and suicide ideation in both student and community samples. Community participants from the U.S. and Canada (n = 554) and student participants from a Canadian university (n = 208) completed several self-report measures including the Humor Styles Questionnaire. Analyses revealed differences in humour styles between the samples, as well as differences in humour styles between men and women. Regression analyses showed that self-defeating humour moderated the relationship between hopelessness and suicide ideation for student participants but not for community participants. Conversely, self-enhancing humour moderated the relationship between hopelessness and suicide ideation for community participants but not for student participants. These results suggest that high levels of self-defeating humour and self-enhancing humour may be uniquely maladaptive for these respective samples. These and other findings point to the necessity of recruiting diverse samples to better understand the beneficial and detrimental associations between humour styles and mental health. The potential to use measures of humour style as a tool to help identify at-risk individuals and to inform the development of intervention programs is discussed.


Asunto(s)
Autoimagen , Ideación Suicida , Masculino , Humanos , Femenino , Canadá , Afecto , Estudiantes , Factores de Riesgo
3.
Behav Res Methods ; 2023 Oct 06.
Artículo en Inglés | MEDLINE | ID: mdl-37801214

RESUMEN

The negative affective priming (NAP) task is a behavioral measure of inhibition of emotional stimuli. Previous studies using the NAP task have found that individuals with depression show reduced inhibition of negative stimuli, suggesting that inhibition biases may play a role in the etiology and maintenance of depression. However, the psychometric properties of the NAP task have not been evaluated or reported. In the present study, we report data on the association between NAP task performance and depression symptoms in three independent samples, and we evaluate the internal consistency and test-retest reliability of the NAP effect indices. The NAP effect for both negative and positive target words had poor internal consistency in all three samples, as well as poor 2-week (Study 2) and 6-month (Study 3) test-retest reliability. The internal consistency and test-retest reliability of response times (RT) for the individual trial types were moderate to high, as were the intercorrelations between trial types. This pattern of results indicates that overall RT is reliable but variance in RTs for the different trial types in the NAP task is indistinguishable from variance in overall RT. Depression symptom severity was not associated with the NAP effect for negative or positive target words in any of the samples, which could be due to the poor reliability of the NAP effect. Based on these findings, we do not recommend that researchers use the NAP task as a measure of individual differences in the inhibition of emotional stimuli.

4.
Addict Behav ; 139: 107575, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36528963

RESUMEN

Attentional biases for gambling-related stimuli are a robust correlate of problem gambling. Free-viewing eye-tracking paradigms are considered the gold standard for measuring attentional bias in addiction research, but their reliability in measuring biases for gambling-related stimuli remains unclear. Using secondary data from two different free-viewing eye-tracking paradigms (two-image and four-image displays), this study examined the internal consistency of fixation indices in samples with varying degrees of gambling involvement and problem gambling risk. Cronbach's alpha, McDonald's omega, and split-half reliability coefficients were used to assess internal consistency of several fixation indices (total dwell time, total dwell time percent, total fixation count, time of first fixation) for gambling-related images, neutral images, and computed attentional bias difference scores. For both two- and four-image displays, internal consistency estimates for total dwell time, total dwell time percent, and total fixation count were good to excellent for gambling-related images, neutral images, and attentional bias scores. Only time of first fixation exhibited low internal consistency. These findings indicate that both two-image and four-image free-viewing eye-tracking paradigms can reliably measure attentional biases for gambling-related stimuli among participants reporting varying degrees of gambling involvement and problem gambling risk.


Asunto(s)
Sesgo Atencional , Conducta Adictiva , Juego de Azar , Humanos , Reproducibilidad de los Resultados , Tecnología de Seguimiento Ocular
5.
Proc Natl Acad Sci U S A ; 119(51): e2211534119, 2022 12 20.
Artículo en Inglés | MEDLINE | ID: mdl-36508653

RESUMEN

Food fortification is an effective strategy to address vitamin A (VitA) deficiency, which is the leading cause of childhood blindness and drastically increases mortality from severe infections. However, VitA food fortification remains challenging due to significant degradation during storage and cooking. We utilized an FDA-approved, thermostable, and pH-responsive basic methacrylate copolymer (BMC) to encapsulate and stabilize VitA in microparticles (MPs). Encapsulation of VitA in VitA-BMC MPs greatly improved stability during simulated cooking conditions and long-term storage. VitA absorption was nine times greater from cooked MPs than from cooked free VitA in rats. In a randomized controlled cross-over study in healthy premenopausal women, VitA was readily released from MPs after consumption and had a similar absorption profile to free VitA. This VitA encapsulation technology will enable global food fortification strategies toward eliminating VitA deficiency.


Asunto(s)
Deficiencia de Vitamina A , Vitamina A , Femenino , Ratas , Animales , Alimentos Fortificados , Estudios Cruzados , Culinaria , Micronutrientes
6.
J Consult Clin Psychol ; 90(12): 911-924, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36395030

RESUMEN

OBJECTIVE: This cluster randomized controlled trial evaluated the efficacy of participation in the Body Project-a cognitive-dissonance-based preventive intervention that reduces self-reported body dissatisfaction-for reducing body-dissatisfaction-related attentional biases. We hypothesized that women in a Body Project condition would show a greater reduction in attentional biases to weight-related images and words at postintervention than women in a wait-list control condition. METHOD: Body-dissatisfied university women (N = 168; Mage = 20.50 ± 3.37 years; 42.0% White; MBMI = 23.08 ± 4.45 kg/m²) were randomly assigned to a Body Project, media psychoeducation (i.e., active control), or wait-list control condition. We assessed attentional biases via eye-gaze tracking and body satisfaction using the Body Shape Questionnaire, at baseline and postintervention. RESULTS: Self-reported outcomes from previous literature were replicated. Compared to wait-list, Body Project participation reduced attention to images of thin models (ps < .05; ds = .19, .24), but not to weight-related words. Compared to wait-list, the media psychoeducation condition reduced attention to fat-related images and words (ds = .17, .18). CONCLUSIONS: This study, which replicates previous self-report findings, is the first to find that two preventive interventions reduced an objective outcome (attentional bias to weight-related images) in body-dissatisfied women. (PsycInfo Database Record (c) 2023 APA, all rights reserved).


Asunto(s)
Sesgo Atencional , Insatisfacción Corporal , Trastornos de Alimentación y de la Ingestión de Alimentos , Femenino , Humanos , Adolescente , Adulto Joven , Adulto , Imagen Corporal , Universidades , Trastornos de Alimentación y de la Ingestión de Alimentos/prevención & control
7.
J Behav Addict ; 11(2): 386-395, 2022 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-35895477

RESUMEN

Background and aims: Attentional bias to gambling-related stimuli is associated with increased severity of gambling disorder. However, the addiction-related moderators of attentional bias among those who gamble are largely unknown. Impulsivity is associated with attentional bias among those who abuse substances, and we hypothesized that impulsivity would moderate the relationship between disordered electronic gaming machine (EGM) gambling and attentional bias. Methods: We tested whether facets of impulsivity, as measured by the UPPS-P (positive urgency, negative urgency, sensation seeking, lack of perseverance, lack of premeditation) and the Barratt Impulsiveness Scale-11 (cognitive, motor, non-planning) moderated the relationship between increased severity of gambling disorder, as measured by the Problem Gambling Severity Index (PGSI), and attentional bias. Seventy-five EGM players participated in a free-viewing eye-tracking paradigm to measure attentional bias to EGM images. Results: Attentional bias was significantly correlated with Barratt Impulsiveness Scale-11 (BIS-11) motor, positive urgency, and negative urgency. Only positive and negative urgency moderated the relationship between PGSI scores and attentional bias. For participants with high PGSI scores, higher positive and negative urgency were associated with larger attentional biases to EGM stimuli. Discussion: The results indicate that affective impulsivity is an important contributor to the association between gambling disorder and attentional bias.


Asunto(s)
Sesgo Atencional , Juego de Azar , Juegos de Video , Electrónica , Juego de Azar/psicología , Humanos , Conducta Impulsiva
8.
Cogn Emot ; 36(7): 1239-1254, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-35819001

RESUMEN

Previous research has found that depression is characterised by biased processing of emotional information. Although most studies have examined cognitive biases in isolation, simultaneous examination of multiple biases is required to understand how they may interact and influence one another to produce depression vulnerability. In this study, the attention and memory biases of currently depressed, previously depressed, and never depressed women were examined using the same stimuli and a unified methodology. Participants viewed negative, positive, and neutral words while their eye gaze was tracked and recorded. After a distraction task, participants completed an incidental recognition test that included words from the eye-tracking task and new words. The results supported the hypothesised mediation model for positive words: currently depressed women had a reduced attention bias for positive words and, in turn, had poorer memory for positive words relative to never depressed women. Previously depressed women, however, showed a lack of coherence between attention and memory biases for positive words. The groups did not differ in their attention or memory biases for negative words. The findings provide novel evidence in support of a causal link between the absence of protective attention and memory biases for positive information in clinical depression.


Asunto(s)
Trastorno Depresivo Mayor , Emociones , Humanos , Femenino , Trastornos de la Memoria/psicología , Fijación Ocular , Sesgo
9.
Nicotine Tob Res ; 24(9): 1439-1447, 2022 08 06.
Artículo en Inglés | MEDLINE | ID: mdl-35443034

RESUMEN

INTRODUCTION: This study examined attentional bias (AB) to e-cigarette cues among a sample of non-smoking daily e-cigarette users (n = 27), non-smoking occasional e-cigarette users (n = 32), and control participants (n = 61) who did not smoke or use e-cigarettes. The possibility that e-cigarette users develop a transference of cues to traditional cigarettes was also examined. METHODS: AB was assessed using a free-viewing eye-gaze tracking methodology, in which participants viewed 180 pairs of images for 4 seconds (e-cigarette and neutral image, e-cigarette and smoking image, smoking and neutral image). RESULTS: Daily and occasional e-cigarette users attended to pairs of e-cigarette and neutral images equally, whereas non-users attended to neutral images significantly more than e-cigarette images. All three groups attended to e-cigarette images significantly more than smoking images, with significantly larger biases for e-cigarette users. There were no between-group differences in attention to pairs of smoking and neutral images. A moderation analysis indicated that for occasional users but not daily users, years of vaping reduced the bias toward neutral images over smoking images. CONCLUSIONS: Taken together, the results indicate that the e-cigarette users exhibit heightened attention to e-cigarettes relative to non-users, which may have implications as to how they react to e-cigarette cues in real-world settings. AB for e-cigarettes did not transfer to traditional cigarette cues, which indicates that further research is required to identify the mechanisms involved in the migration of e-cigarettes to traditional cigarettes. IMPLICATIONS: This study is the first attempt to examine attentional biases for e-cigarette cues among non-smoking current e-cigarette users using eye-gaze tracking. The results contribute to the growing literature on the correlates of problematic e-cigarette use and indicate that daily and occasional e-cigarette use is associated with attentional biases for e-cigarettes. The existence of attentional biases in e-cigarette users may help to explain the high rate of failure to quit e-cigarettes and provides support for the utility of attentional bias modification in the treatment of problematic e-cigarette use.


Asunto(s)
Sesgo Atencional , Sistemas Electrónicos de Liberación de Nicotina , Cese del Hábito de Fumar , Vapeo , Tecnología de Seguimiento Ocular , Humanos , Fumadores , Cese del Hábito de Fumar/métodos
10.
Pain ; 163(2): e261-e273, 2022 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-34285155

RESUMEN

ABSTRACT: Attentional biases have been posited as one of the key mechanisms underlying the development and maintenance of chronic pain and co-occurring internalizing mental health symptoms. Despite this theoretical prominence, a comprehensive understanding of the nature of biased attentional processing in chronic pain and its relationship to theorized antecedents and clinical outcomes is lacking, particularly in youth. This study used eye-tracking to assess attentional bias for painful facial expressions and its relationship to theorized antecedents of chronic pain and clinical outcomes. Youth with chronic pain (n = 125) and without chronic pain (n = 52) viewed face images of varying levels of pain expressiveness while their eye gaze was tracked and recorded. At baseline, youth completed questionnaires to assess pain characteristics, theorized antecedents (pain catastrophizing, fear of pain, and anxiety sensitivity), and clinical outcomes (pain intensity, interference, anxiety, depression, and posttraumatic stress). For youth with chronic pain, clinical outcomes were reassessed at 3 months to assess for relationships with attentional bias while controlling for baseline symptoms. In both groups, youth exhibited an attentional bias for painful facial expressions. For youth with chronic pain, attentional bias was not significantly associated with theorized antecedents or clinical outcomes at baseline or 3-month follow-up. These findings call into question the posited relationships between attentional bias and clinical outcomes. Additional studies using more comprehensive and contextual paradigms for the assessment of attentional bias are required to clarify the ways in which such biases may manifest and relate to clinical outcomes.


Asunto(s)
Sesgo Atencional , Dolor Crónico , Adolescente , Ansiedad/etiología , Niño , Dolor Crónico/psicología , Tecnología de Seguimiento Ocular , Expresión Facial , Humanos
11.
Psychol Addict Behav ; 35(8): 961-973, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33749291

RESUMEN

Objective: Attentional biases (ABs) have been shown to develop in the context of substance use disorders. Relatively less focus has been paid toward the development of ABs in behavioral addictions such as gambling disorder (GD). Furthermore, the psychological predictors and moderators of AB in GD remain unknown. The present study addressed these empirical gaps. Methods: Fifty-two non-GD electronic gaming machine (EGM) players, 25 GD-EGM players, and 61 non-gamblers completed measures of gambling-related behaviors and cognitions (problem gambling severity, cravings, expectancies, motives) and substance use and mental health (alcohol use severity, depression symptoms). The relationships between these constructs and AB for EGM images were then assessed using a free-viewing eye-tracking paradigm. Results: Non-GD EGM players and GD-EGM players attended to EGM images significantly more than neutral images (with the largest AB for the EGM players with GD). For all EGM players, gambling expectancies regarding the negative emotional impact of gambling and alcohol use severity were associated with greater AB. For non-GD EGM players only, AB was moderated by the anticipation aspect of gambling craving and the self-enhancement aspect of gambling expectancies. Conclusion: The results provide further evidence that ABs develop in the context of excessive gambling and are associated with gambling and psychological variables. The findings support the incentive-salience theory of ABs in gambling and provide a rationale for the development of AB modification programs in the treatment of gambling disorder. Given the predominantly white sample, our results may not generalize to individuals of other ethnicities. (PsycInfo Database Record (c) 2021 APA, all rights reserved).


Asunto(s)
Sesgo Atencional , Conducta Adictiva , Juego de Azar , Juegos de Video , Electrónica , Humanos
12.
Pain ; 161(10): 2263-2273, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-32427746

RESUMEN

Attentional biases are posited to play a key role in the development and maintenance of chronic pain in adults and youth. However, research to date has yielded mixed findings, and few studies have examined attentional biases in pediatric samples. This study used eye-gaze tracking to examine attentional biases to pain-related stimuli in a clinical sample of youth with chronic pain and pain-free controls. The moderating role of attentional control was also examined. Youth with chronic pain (n = 102) and pain-free controls (n = 53) viewed images of children depicting varying levels of pain expressiveness paired with neutral faces while their eye gaze was recorded. Attentional control was assessed using both a questionnaire and a behavioural task. Both groups were more likely to first fixate on high pain faces but showed no such orienting bias for moderate or low pain faces. Youth with chronic pain fixated longer on all pain faces than neutral faces, whereas youth in the control group exhibited a total fixation bias only for high and moderate pain faces. Attentional control did not moderate attentional biases between or within groups. The results lend support to theoretical models positing the presence of attentional biases in youth with chronic pain. Further research is required to clarify the nature of attentional biases and their relationship to clinical outcomes.


Asunto(s)
Sesgo Atencional , Dolor Crónico , Adolescente , Atención , Niño , Movimientos Oculares , Tecnología de Seguimiento Ocular , Humanos
13.
Forensic Sci Int Genet ; 44: 102162, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31604203

RESUMEN

Despite advances in genotyping technologies, traditional kinship analysis tools utilized in forensic identification have seen limited evolution and lack measures of accuracy. Here, we leverage artificial intelligence (AI) and extend the Elston-Stewart algorithm to deliver a method that provides an unprecedented level of flexibility to matching individuals with pedigrees by likelihood ratio. We designed an AI that utilizes a prediction cascade based on gradient descent logistic regression which allows for iterative solution of multi missing person scenarios. Furthermore, the AI can quantify the confidence underlying likelihood ratios across the spectrum of pedigrees, regardless of the amount of genetic information available and the number of missing persons. The algorithm accommodates an arbitrary number of generations and ancestral relationships, including multiple marriages, mutations, and consanguinity. We demonstrate that a properly trained AI significantly and reproducibly outperforms a human interpreter. We discuss published limitations of existing tools and demonstrate that they are not amenable to the size and complexity of this study. This novel method significantly improves the trade-off between sensitivity and specificity beyond the limits of traditional kinship analysis tools and introduces opportunities beyond the field of forensic genetics.


Asunto(s)
Algoritmos , Inteligencia Artificial , Dermatoglifia del ADN , Genética Forense/métodos , Linaje , Conjuntos de Datos como Asunto , Humanos , Funciones de Verosimilitud , Modelos Logísticos , Repeticiones de Microsatélite
14.
Sci Transl Med ; 11(518)2019 11 13.
Artículo en Inglés | MEDLINE | ID: mdl-31723037

RESUMEN

Micronutrient deficiencies affect up to 2 billion people and are the leading cause of cognitive and physical disorders in the developing world. Food fortification is effective in treating micronutrient deficiencies; however, its global implementation has been limited by technical challenges in maintaining micronutrient stability during cooking and storage. We hypothesized that polymer-based encapsulation could address this and facilitate micronutrient absorption. We identified poly(butylmethacrylate-co-(2-dimethylaminoethyl)methacrylate-co-methylmethacrylate) (1:2:1) (BMC) as a material with proven safety, offering stability in boiling water, rapid dissolution in gastric acid, and the ability to encapsulate distinct micronutrients. We encapsulated 11 micronutrients (iron; iodine; zinc; and vitamins A, B2, niacin, biotin, folic acid, B12, C, and D) and co-encapsulated up to 4 micronutrients. Encapsulation improved micronutrient stability against heat, light, moisture, and oxidation. Rodent studies confirmed rapid micronutrient release in the stomach and intestinal absorption. Bioavailability of iron from microparticles, compared to free iron, was lower in an initial human study. An organotypic human intestinal model revealed that increased iron loading and decreased polymer content would improve absorption. Using process development approaches capable of kilogram-scale synthesis, we increased iron loading more than 30-fold. Scaled batches tested in a follow-up human study exhibited up to 89% relative iron bioavailability compared to free iron. Collectively, these studies describe a broad approach for clinical translation of a heat-stable ingestible micronutrient delivery platform with the potential to improve micronutrient deficiency in the developing world. These approaches could potentially be applied toward clinical translation of other materials, such as natural polymers, for encapsulation and oral delivery of micronutrients.


Asunto(s)
Calor , Micronutrientes/administración & dosificación , Microesferas , Administración Oral , Animales , Disponibilidad Biológica , Transporte Biológico , Preparaciones de Acción Retardada , Liberación de Fármacos , Femenino , Humanos , Ácido Hialurónico/química , Absorción Intestinal , Intestinos/fisiología , Hierro/metabolismo , Metacrilatos/química , Ratones , Oxidación-Reducción , Rayos Ultravioleta , Vitamina A/metabolismo , Agua
15.
Behav Res Methods ; 51(6): 2748-2760, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-30350023

RESUMEN

Cognitive theories of anxiety disorders and depression posit that attentional biases play a role in the development, maintenance, and recurrence of these disorders. Several paradigms have been used to examine attentional biases in anxiety and depression, but information on the reliability of different attentional bias indices is limited. In this study we examined the internal consistency and 6-month test-retest reliability of attentional bias indices derived from a free-viewing eye-tracking paradigm. Participants completed two versions of an eye-tracking task-one that used naturalistic images as stimuli, and one that used face images. In both tasks, participants viewed displays of four images, each display consisting of one threat image, one sad image, one positive/happy image, and one neutral image. The internal consistency of the fixation indices (dwell time and number of fixations) for threat, sad, and positive images over the full 8-s display was moderate to excellent. When the 8-s display was divided into 2-s intervals, the dwell times for the 0- to 2-s and 2- to 4-s intervals showed lower reliability, particularly for the face images. The attentional bias indices for the naturalistic images showed adequate to good stability over the test-retest period, whereas the test-retest reliability estimates for the face images were in the low to moderate range. The implications of these results for attentional bias research are discussed.


Asunto(s)
Sesgo Atencional , Emociones/fisiología , Movimientos Oculares , Adolescente , Adulto , Ansiedad , Depresión , Cara , Femenino , Felicidad , Humanos , Masculino , Reproducibilidad de los Resultados
16.
PLoS One ; 13(1): e0190614, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29385164

RESUMEN

A growing body of research indicates that gamblers develop an attentional bias for gambling-related stimuli. Compared to research on substance use, however, few studies have examined attentional biases in gamblers using eye-gaze tracking, which has many advantages over other measures of attention. In addition, previous studies of attentional biases in gamblers have not directly matched type of gambler with personally-relevant gambling cues. The present study investigated the specificity of attentional biases for individual types of gambling using an eye-gaze tracking paradigm. Three groups of participants (poker players, video lottery terminal/slot machine players, and non-gambling controls) took part in one test session in which they viewed 25 sets of four images (poker, VLTs/slot machines, bingo, and board games). Participants' eye fixations were recorded throughout each 8-second presentation of the four images. The results indicated that, as predicted, the two gambling groups preferentially attended to their primary form of gambling, whereas control participants attended to board games more than gambling images. The findings have clinical implications for the treatment of individuals with gambling disorder. Understanding the importance of personally-salient gambling cues will inform the development of effective attentional bias modification treatments for problem gamblers.


Asunto(s)
Atención , Movimientos Oculares , Juego de Azar , Adulto , Estudios de Casos y Controles , Humanos , Masculino , Adulto Joven
17.
PLoS One ; 13(2): e0192914, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29447251

RESUMEN

Understanding the cognitive processes underlying body dissatisfaction provides important information on the development and perpetuation of eating pathology. Previous research suggests that body-dissatisfied women process weight-related information differently than body-satisfied women, but the precise nature of these processing differences is not yet understood. In this study, eye-gaze tracking was used to measure attention to weight-related words in body-dissatisfied (n = 40) and body-satisfied (n = 38) women, before and after exposure to images of thin fashion models. Participants viewed 8-second displays containing fat-related, thin-related, and neutral words while their eye fixations were tracked and recorded. Based on previous research and theory, we predicted that body-dissatisfied women would attend to fat-related words more than body-satisfied women and would attend to thin-related words less. It was also predicted that exposure to thin model images would increase self-rated body dissatisfaction and heighten group differences in attention. The results indicated that body-dissatisfied women attended to both fat- and thin-related words more than body-satisfied women and that exposure to thin models did not increase this effect. Implications for cognitive models of eating disorders are discussed.


Asunto(s)
Atención , Imagen Corporal/psicología , Satisfacción Personal , Psicolingüística , Percepción Social , Percepción Visual , Medidas del Movimiento Ocular , Femenino , Fijación Ocular , Humanos , Pruebas Psicológicas , Lectura , Memoria Implícita , Encuestas y Cuestionarios , Adulto Joven
18.
Artículo en Inglés | MEDLINE | ID: mdl-29083260

RESUMEN

Two experiments examined age differences in the effect of a sad mood induction (MI) on attention to emotional images. Younger and older adults viewed sets of four images while their eye gaze was tracked throughout an 8-s presentation. Images were viewed before and after a sad MI to assess the effect of a sad mood on attention to positive and negative scenes. Younger and older adults exhibited positively biased attention after the sad MI, significantly increasing their attention to positive images, with no evidence of an age difference in either experiment. A test of participants' recognition memory for the images indicated that the sad MI reduced memory accuracy for sad images for younger and older adults. The results suggest that heightened attention to positive images following a sad MI reflects an affect regulation strategy related to mood repair. The implications for theories of the positivity effect are discussed.


Asunto(s)
Envejecimiento/psicología , Atención , Emociones , Percepción Visual , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Medidas del Movimiento Ocular , Movimientos Oculares , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Reconocimiento en Psicología , Adulto Joven
19.
Proc Biol Sci ; 284(1868)2017 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-29212720

RESUMEN

We used randomizations to analyse patterns of co-occurrence of sexual and apomictic (asexual) members of the North American Crepis agamic complex (Asteraceae). We expect strong asymmetry in reproductive interactions in Crepis: apomicts produce clonal seeds with no need for pollination and are not subject to reproductive interference from co-occurring relatives. However, because they still produce some viable pollen, apomicts can reduce reproductive success of nearby sexual relatives, potentially leading to eventual local exclusion of sexuals. Consistent with this, randomizations reveal that sexuals are over-represented in isolated sites, while apomicts freely co-occur. Incorporation of taxonomic and phylogenetic evidence indicates that this pattern is not driven by local origins of asexuals. Our evidence that patterns of local co-occurrence are structured by reproductive interference suggests an underappreciated role for these interactions in community assembly, and highlights the need for explicit tests of the relative contributions of ecological and reproductive interactions in generating patterns of limiting similarity.


Asunto(s)
Asteraceae/fisiología , Dispersión de las Plantas , Polinización , Simpatría , Reproducción Asexuada
20.
Am J Bot ; 103(7): 1289-99, 2016 07.
Artículo en Inglés | MEDLINE | ID: mdl-27313196

RESUMEN

PREMISE OF THE STUDY: Babcock and Stebbins coined the term agamic complex in their 1938 monograph of the North American Crepis agamic complex. Despite the historical role that this complex holds in the evolutionary literature, it has not been reexamined in over 75 years. We present a thorough reevaluation of the complex to test hypotheses proposed by Babcock and Stebbins about its origins and spread, the relationships of diploids, and the nature and origins of polyploids. METHODS: We used flow cytometry to infer ploidy of roughly 600 samples spanning the morphological and taxonomic diversity of the complex and a phylogenetic analysis of plastid DNA variation to infer maternal relationships among diploids and to infer maternal origins of polyploids. KEY RESULTS: We identified populations of all seven recognized diploids plus one new lineage. Phylogenetic analysis of plastid DNA variation in diploids revealed a well-resolved, but moderately supported phylogeny, with evidence for monophyly of the North America Crepis agamic complex and no evidence of widespread homoploid hybridization. Polyploids showed evidence of multiple origins and a pattern of frequent local co-occurrence consistent with repeated colonization of suitable sites. CONCLUSIONS: Our findings agree broadly with the distribution and variation of ploidy within and among species described by Babcock and Stebbins. One key difference is finding support for monophyly of North American species, and refuting their hypothesis of polyphyly. Our results provide an explicit phylogenetic framework for further study of this classic agamic complex.


Asunto(s)
Crepis/genética , Genoma de Planta/genética , Ploidias , Evolución Biológica , Diploidia , Genética de Población , Haplotipos , Hibridación Genética , América del Norte , Filogenia , Plastidios/genética , Poliploidía
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA