基于客体工作记忆内容的保持对时间判断的影响

本研究通过操作工作记忆内容的有效性,探讨了记忆内容的保持对时间判断的影响。采用不规则的客体作为实验材料,使时间任务中的刺激与工作记忆内容匹配或不匹配。实验1采用工作记忆和时间判断的双任务范式,要求被试首先记忆一个客体,然后在每个试次的最后判断测试刺激是否与记忆项相同。在延迟阶段,被试判断连续出现的两个刺激的时距哪个更长（或更短）。实验2中,要求被试忽略第一个刺激,仅完成时间判断任务。结果发现,相比单任务的计时,双任务条件下,工作记忆内容的保持延长了时间判断的时间。而且,在记忆匹配和知觉匹配条件下,匹配刺激呈现的时间越长,正确率越低,反应时越长。这说明记忆内容的保持增加了决策的难度,工作记忆内容对时间判断的可能是由记忆内容引起的注意定向造成的。     

Inattention,working memory,and academic achievement in adolescents referred for attention deficit/hyperactivity disorder (ADHD)

This study investigated the role of inattention and working memory in predicting academic achievement in 145 adolescents aged 13 to 18 referred for attention deficit/hyperactivity disorder (ADHD). Path analysis was used to examine whether auditory-verbal and visual-spatial working memory would mediate the relationships between classroom inattention symptoms and achievement outcomes. Results provide support for the mediational model. Behavioral inattention significantly predicted both auditory-verbal and visual-spatial working memory performance. Auditory-verbal working memory was strongly associated with adolescents' achievement in reading and mathematics, while visual-spatial working memory was only associated with achievement in mathematics. The path from inattention symptoms to reading was partially mediated by the working memory variables, but the path from inattention to mathematics was not mediated by working memory. The proposed model demonstrated a good fit to the data and explained a substantial amount of variance in the adolescents' achievement outcomes. These findings imply that working memory is a risk factor for academic failure for adolescents with attentional problems.     

Relations between emotion,memory encoding,and time perception

This study examined duration judgments for taboo and neutral words in prospective and retrospective timing tasks. In the prospective task, participants attended to time from the beginning and generated shorter duration estimates for taboo than neutral words and for words that they subsequently recalled in a surprise free recall task. These findings suggested that memory encoding took priority over estimating durations, directing attention away from time and causing better recall but shorter perceived durations for taboo than neutral words. However, in the retrospective task, participants only judged durations in a surprise test at the end, and their duration estimates were longer for taboo than neutral words. Present findings therefore suggest that the same emotion-linked memory encoding processes can cause underestimation of durations in prospective tasks but overestimation in retrospective tasks, as if emotion enhances recall of ongoing events but causes overestimation of the durations of those events in retrospect.     

工作记忆的存储时间及目标时距对时间知觉的影响

本研究操作记忆信息与计时开始之间的时间间隔（ISI）和目标时距,探讨工作记忆影响时间判断的灵活性。被试首先记忆一个客体,然后在每个trial的最后判断测试刺激是否与记忆项相同;在延迟阶段,被试完成时间判断任务,即判断相继出现的两个刺激的时距哪个更长（或更短）。时间任务中的一个刺激与记忆内容完全相同,相应的另一个刺激与记忆内容在形状和颜色上都不同。重复条件下,被试忽略第一个刺激,仅完成时间判断任务。结果发现,时间间隔（ISI）短时,记忆匹配条件下的准确率更高,匹配刺激延长了知觉的时间;但随着时间间隔的增加,工作记忆匹配对时间判断的影响降低甚至消失。并且,长或短ISI,记忆任务或重复条件下,目标时距长时,记忆匹配反而缩短了知觉的时间。研究说明工作记忆对时间判断的影响是灵活的,受到注意或工作记忆等高级认知系统的调控。     

A comparison of working memory profiles in children with ADHD and DCD

The main objective of present study was to investigate whether the patterns of working memory performance differ as a function of attention and motor difficulties, and whether children with ADHD and DCD could be reliably discriminated on the basis of their memory deficits. A related aim was to investigate the link between their working memory profiles and academic attainment. Fifty children with ADHD-Combined, 55 children with DCD, and an age-matched group of 50 typically developing children with average working memory were assessed on standardized measures of working memory, IQ, and academic attainment (reading, spelling, comprehension, and math). The normal controls performed significantly better than both clinical groups on all working memory tests. Specific patterns emerged in the memory profile of the clinical groups: The children with DCD had a depressed performance in all working memory tests, with particularly low scores in visuospatial memory tasks; children with ADHD performed within age-expected levels in short-term memory but had a pervasive working memory deficit that impacted both verbal and visuospatial domains. The clinical groups could reliably be discriminated on the basis of their short-term memory scores. Their learning profiles were similar. It is possible that the working memory profiles of the children with ADHD and DCD are influenced by distinct underlying cognitive mechanisms, rather than a general neurodevelopmental delay. Despite these distinctive patterns of memory performance, both clinical groups performed similarly on academic attainments, suggesting that memory may underlie learning difficulties, independent of related clinical disorders.     

Written expression in boys with ADHD: The mediating roles of working memory and oral expression

The written expression difficulties experienced by children with ADHD are widely recognized; however, scant empirical evidence exists concerning the cognitive mechanisms and processes underlying these deficiencies. The current study investigated the independent and potentially interactive contributions of two developmentally antecedent cognitive processes – viz., working memory (WM) and oral expression – hypothesized to influence written expression ability in boys. Thirty-three boys with ADHD-Combined Presentation and 27 neurotypical (NT) boys 8–12 years of age were administered standardized measures of oral and written expression, and multiple counterbalanced tasks to assess WM central executive (CE) processes, WM phonological short-term memory (PH STM), and WM visuospatial short-term memory (VS STM). Bias-corrected bootstrapped mediation analyses revealed a significant mediation effect, wherein the independent and interactive effects of PH STM and oral expression collectively explained 76% of the diagnostic status to written expression relation. The implications of the obtained results for clinical practice suggest that children with ADHD may benefit by incorporating a blended approach that simultaneously strengthens PH STM capacity and oral expression abilities as antecedents to engaging in writing-related activities.     

Relationship between reaction time variability and motor skill development in ADHD

Slower and more variable reaction times to computerized tasks have been documented in children diagnosed with attention deficit/hyperactivity disorder (ADHD). Recent research supports a role for attentional lapses in generating abnormally variable and slow responses. However, given the association between ADHD and impairments in motor control, we hypothesized that slower or more variable reaction times might also correlate with motor development. The aim of this case-control study was to explore the relationship between motor function, reaction speed and variability, and ADHD. After comprehensive educational and clinical assessments, motor skill development was evaluated in 35 children ages 9 to 14 (19 with ADHD) using the Physical and Neurological Examination for Subtle Signs (PANESS) test battery. Finger-sequencing speed and variability were quantified with goniometers. Reaction times were measured with 20 trials each of computerized simple and choice (binary) tasks. Compared to healthy controls, children with ADHD had slower and more variable reaction times, and these findings correlated with impaired motor development (PANESS) and slow and variable finger sequencing (goniometers). Further studies of motor development in ADHD may identify factors influencing speed and variability of reaction times.     

Differences in cognitive control in children and adolescents with combined and inattentive subtypes of ADHD

The aim of the present study was to investigate the ability of children with attention deficit/hyperactivity disorder-combined subtype (ADHD-C) and predominantly inattentive subtype (ADHD-PI) to direct their attention and to exert cognitive control in a forced attention dichotic listening (DL) task. Twenty-nine, medication-naive participants with ADHD-C, 42 with ADHD-PI, and 40 matched healthy controls (HC) between 9 and 16 years were assessed. In the DL task, two different auditory stimuli (syllables) are presented simultaneously, one in each ear. The participants are asked to report the syllable they hear on each trial with no instruction on focus of attention or to explicitly focus attention and to report either the right- or left-ear syllable. The DL procedure is presumed to reflect different cognitive processes: perception (nonforced condition/NF), attention (forced-right condition/FR), and cognitive control (forced-left condition/FL). As expected, all three groups had normal perception and attention. The children and adolescents with ADHD-PI showed a significant right-ear advantage also during the FL condition, while the children and adolescents in the ADHD-C group showed a no-ear advantage and the HC showed a significant left-ear advantage in the FL condition. This suggests that the ADHD subtypes differ in degree of cognitive control impairment. Our results may have implications for further conceptualization, diagnostics, and treatment of ADHD subtypes.     

A/B型人格对时间性前瞻记忆的影响

通过对比A/B两种人格者在执行即无社会关系特征又无个人重要性的时间性前瞻记忆任务时的时间性前瞻记忆成绩和在执行时间性前瞻记忆过程中的时间监控模式,发现A/B型人格的背景任务成绩和TBPM任务成绩都没有显著差异,而时间监视模式有显著差异。说明A型人格被试能更高效的利用认知资源,以更高效和更策略的时间监控模式完成TBPM任务。也说明TBPM是一类与时间监控能力密切相关的前瞻记忆类型。     

Time Perception: Modality and Duration Effects in Attention-Deficit/Hyperactivity Disorder (ADHD)

Time perception performance was systematically investigated in adolescents with and without attention-deficit/hyperactivity disorder (ADHD). Specifically, the effects of manipulating modality (auditory and visual) and length of duration (200 and 1000 ms) were examined. Forty-six adolescents with ADHD and 44 controls were administered four duration discrimination tasks and two control tasks, and a set of standardized measures. Participants with ADHD had higher thresholds than controls on all of the duration discrimination tasks, with the largest effect size obtained on the visual 1000 ms duration discrimination task. No group differences were observed on the control tasks. Visual–spatial memory was found to be a significant predictor of visual and auditory duration discrimination at longer intervals (1000 ms) in the ADHD sample, whereas auditory verbal working memory predicted auditory discrimination at longer intervals (1000 ms) in the control sample. These group differences suggest impairments in basic timing mechanisms in ADHD.     

Perception of speech and nonspeech stimuli by children with and without reading disability and attention deficit hyperactivity disorder

The auditory temporal deficit hypothesis predicts that children with reading disability (RD) will exhibit deficits in the perception of speech and nonspeech acoustic stimuli in discrimination and temporal ordering tasks when the interstimulus interval (ISI) is short. Initial studies testing this hypothesis did not account for the potential presence of attention deficit hyperactivity disorder (ADHD). Temporal order judgment and discrimination tasks were administered to children with (1) RD/no-ADHD (n=38), (2) ADHD (n=29), (3) RD and ADHD (RD/ADHD; n=32), and (4) no impairment (NI; n=43). Contrary to predictions, children with RD showed no specific sensitivity to ISI and performed worse relative to children without RD on speech but not nonspeech tasks. Relationships between perceptual tasks and phonological processing measures were stronger and more consistent for speech than nonspeech stimuli. These results were independent of the presence of ADHD and suggest that children with RD have a deficit in phoneme perception that correlates with reading and phonological processing ability. (c) 2002 Elsevier Science (USA).     

Spatial awareness, alertness, and ADHD: the re-emergence of unilateral neglect with time-on-task

Studies examining a relationship between attention deficit hyperactivity disorder (ADHD) and relative visual inattention towards left space have produced inconsistent results. Here, based on previous studies with adult neurological patients who show very severe inattention to the left, we examine whether any spatial bias in ADHD may be modulated by changes in alertness levels. In a single case, we found that inattention to the left--that was intermittently apparent--dramatically increased as a function of time-on-task. No significant changes were observed on the right. The implications for clinical assessment and research design are discussed.     

Predictors of time-based prospective memory in children

This study identified age differences in time-based prospective memory performance in school-aged children and explored possible cognitive correlates of age-related performance. A total of 56 7- to 12-year-olds performed a prospective memory task in which prospective memory accuracy, ongoing task performance, and time monitoring were assessed. Additional tests of time estimation, working memory, task switching, and planning were performed. Results showed a robust relationship between age and prospective memory performance even after controlling for ongoing task performance. Developmental differences in time monitoring were also observed, with older children generally adopting a more strategic monitoring strategy than younger children. The majority of age-related variance in prospective memory task performance could be explained by cognitive resources, in particular planning and task switching. In contrast, no further independent contribution of time estimation was observed. Findings are in line with the development of strategic behavior, as well as executive functioning, in school-aged children.     

An investigation of the relations between stress and prospective memory

ABSTRACT

Prospective memory (PM), or remembering to perform intentions in the future, has important implications for one’s daily functioning and quality of life. Another common human experience is stress. Despite the significance and ubiquity of both PM and stress, our understanding of the relations between them is limited. The aim of the current study was to further delineate the relations between acute stress, chronic stress, non-focal event-based PM, and time-based PM. The results of the study revealed that acute stress induction after PM intention formation did not contribute to differences in non-focal event-based PM performance or time-based PM performance. However, self-reported chronic stress was significantly correlated with enhanced monitoring and time-based PM. In the present study, participants may have had optimal levels of enduring stress that contributed to enhanced monitoring behaviour (i.e. the prospective component of PM) and the ability to complete time-based intentions.     

Variability of kinematic graphomotor fluency in adults with ADHD

Although graphomotor differences and variability of performance have been observed in children with attention deficit hyperactivity disorder (ADHD), no study has investigated whether this variability manifests in the kinematic graphomotor domain in adults with ADHD. Fourteen ADHD and 20 control participants wrote a novel grapheme and common word on a digitizing tablet 30 times each, with ADHD participants counterbalanced on and off stimulant medication. Variability of graphomotor fluency was significantly greater in ADHD versus control participants only in the novel writing task, both on, F(1, 31) = 5.988, p = .020, and off stimulant medication, F(1, 32) = 8.789, p = .006. Results suggest that motor control differences in ADHD are not limited to childhood and extend into adulthood. Given sufficient additional research, variability of kinematic graphomotor fluency may increase the sensitivity/specificity of differential diagnoses and/or represent a biomarker for ADHD.     

Experiences of physical and relational victimization in children with ADHD: The role of social problems and aggression

The social risk factors for physical and relational peer victimization were examined within a mixed‐gender sample of children with and without attention‐deficit/hyperactivity disorder (ADHD). Participants were 124 children (ages 8–12 years; 48% boys), with 47% exhibiting sub‐clinical or clinical elevations in ADHD symptoms. ADHD and oppositional defiant disorder (ODD) symptom counts were assessed based on parent‐ and teacher‐reports; parents rated children's social problems and teachers rated children's use of physical and relational aggression and experiences of physical and relational victimization. A multiple mediator model was used to test whether there were indirect effects of ADHD or ODD symptoms on physical and relational victimization through social problems, physical aggression, or relational aggression. At the bivariate level, ADHD and ODD symptoms were both significantly associated with higher rates of physical and relational victimization. In the mediational model, there were significant indirect effects of ADHD symptoms on relational victimization via social problems, of ODD on relational victimization via relational aggression, and of ODD symptoms on physical victimization via physical aggression. Results suggest that there are distinct risk factors implicated in the physical and relational victimization of youth with ADHD and that the co‐occurrence of ODD symptoms is important to assess. Clinical implications for addressing victimization in children with ADHD are discussed.

     

Emotional stimuli facilitate time perception in children with attention‐deficit/hyperactivity disorder

The aim of this study was to compare the effect of different emotional stimuli (neutral, positive, and negative) on time perception in children with attention‐deficit/hyperactivity disorder (ADHD) and normal children in dual‐task form. Five hundred and ninety‐nine students from primary schools were randomly selected. The Conner's Teacher Rating Scale (CTRS) questionnaire was completed by teachers. A total of 100 children with a score above the cut‐off point for the CTRS were further assessed using the Child Symptom Inventory‐4 (CSI‐4). A total of 34 children with ADHD and 31 controls completed an emotional time discrimination task in two blocks of 1000 and 2000 ms duration. Children were asked to compare three image groups: neutral with neutral, neutral with positive, and neutral with negative images. Children with ADHD had significantly better performance in the emotional time discrimination task across all conditions when compared with controls: On average, discrimination thresholds were approximately 35 ms shorter for the children with ADHD. Our results indicate that children with ADHD have higher sensitivity to time relative to controls in a situation in which they must distribute resources between temporal and emotional processing. On the basis of the interference effect and the working memory capacity hypothesis, this dividing of attention causes a decrease of time accuracy in normal children.     

Working Memory Deficits in Boys with Attention-deficit/Hyperactivity Disorder (ADHD): The Contribution of Central Executive and Subsystem Processes

The current study investigated contradictory findings from recent experimental and meta-analytic studies concerning working memory deficits in ADHD. Working memory refers to the cognitive ability to temporarily store and mentally manipulate limited amounts of information for use in guiding behavior. Phonological (verbal) and visuospatial (nonverbal) working memory were assessed across four memory load conditions in 23 boys (12 ADHD, 11 typically developing) using tasks based on Baddeley's (Working memory, thought, and action, Oxford University Press, New York, 2007) working memory model. The model posits separate phonological and visuospatial storage and rehearsal components that are controlled by a single attentional controller (CE: central executive). A latent variable approach was used to partial task performance related to three variables of interest: phonological buffer/rehearsal loop, visuospatial buffer/rehearsal loop, and the CE attentional controller. ADHD-related working memory deficits were apparent across all three cognitive systems--with the largest magnitude of deficits apparent in the CE--even after controlling for reading speed, nonverbal visual encoding, age, IQ, and SES.     

Working memory and behavioral inhibition in children with attention-deficit/hyperactivity disorder (ADHD): an examination of varied central executive demands,construct overlap,and task impurity

The stop-signal paradigm is the premier metric of behavioral inhibition in contemporary attention-deficit/hyperactivity disorder (ADHD) research. The stop-signal paradigm’s choice-reaction time component, however, arguably places greater demands on working memory processes (e.g., controlled-focused attention) relative to alternative inhibition metrics (i.e., go/no-go (GNG) tasks), and consequently obscures conclusions about inhibition and working memory deficits in affected children. The current study, therefore, aimed to determine whether shared variance between stop-signal behavioral inhibition and working memory performance in children with ADHD reflects overlap between the working memory and inhibition constructs or insufficient specificity of the stop-signal paradigm. Fifty-five children (8–12 years) with and without ADHD were administered established phonological (PH) and visuospatial (VS) working memory measures, as well as stop-signal and GNG tasks that vary with respect to demands on controlled-focused attention. Although working memory and GNG performance each uniquely predicted children’s inattention, stop-signal task performance was not a significant predictor of unique variance in inattention, above and beyond variance associated with working memory. Collectively, these findings suggest that performance on the stop-signal task, compared to the GNG task, is confounded by greater demands associated with working memory and consequently reflects an impure estimate of the inhibition construct.     

Spatial and visual working memory ability in children with difficulties in arithmetic word problem solving

Although various studies support the multicomponent nature of visuospatial working memory, to date there is no general consensus on the distinction of its components. A difference is usually proposed between visual and spatial components of working memory, but the individual roles of these components in mathematical learning disabilities remains unclear. The present study aimed to examine the involvement of visual and spatial working memory in poor problem-solvers compared with children with normal level of achievement. Fourth-grade participants were presented with tasks measuring phonological loop, central executive, and visual versus spatial memory. In two separate experiments, both designed to distinguish visual and spatial component involvement, poor problem-solvers specifically failed on spatial—but not visual or phonological—working memory tasks. Results are discussed in the light of possible working memory models, and specifically demonstrate that problem-solving ability can benefit from analysis of spatial processes, which involves ability to manipulate and transform relevant information; instead, no benefit is gained from the analysis of visual pictorial detail.