Parallel versus serial processing and individual differences in high-speed search in human memory

Many mental tasks that involve operations on a number of items take place within a few hundred milliseconds. In such tasks, whether the items are processed simultaneously (in parallel) or sequentially (serially) has long been of interest to psychologists. Although certain types of parallel and serial models have been ruled out, it has proven extremely difficult to entirely separate reasonable serial and limited-capacity parallel models on the basis of typical data. Recent advances in theory-driven methodology now permit strong tests of serial versus parallel processing in such tasks, in ways that bypass the capacity issue and that are distribution and parameter free. We employ new methodologies to assess serial versus parallel processing and find strong evidence for pure serial or pure parallel processing, with some striking apparent differences across individuals and interstimulus conditions.     

Transitions in caregivers' use of paid home help: associations with stress appraisals and well-being

This study examines the associations between transitions in paid home care and stress appraisals and psychological well-being of family caregivers of dementia relatives. The sample consisted of 264 caregivers who completed up to 3 interviews during 1 year. Longitudinal analyses (i.e., generalized estimating equations) showed that the onset of paid home care was associated with increases in feelings of worry and strain and a worsening in positive affect. Ending paid home care was strongly associated with a decrease in depressive symptoms, whereas sustained use of paid home care was related to reduced overload. Several possible mechanisms for the complex relationship of paid home care and family caregivers' stress appraisals and well-being are discussed.     

Longitudinal patterns of risk for depression in dementia caregivers: objective and subjective primary stress as predictors

The present study examined how patterns of risk for depression over 1 year in 188 dementia caregivers (consistently asymptomatic, n = 88; consistently symptomatic, n = 40; changing risk, n = 60) could be predicted by objective (behavior problems of the relative) and subjective (role captivity and overload) primary stress. Results reveal that all primary stressors differentiated caregivers who remained at low levels of symptomatology over the course of 1 year from those who were at risk for experiencing a depressive disorder. In addition, caregivers' subjective experience of role captivity predicted the chronicity of risk. Findings extend prior caregiving research on patterns of depressive symptomatology by highlighting the relationship between subjective primary stressors and stability and change in caregivers' mental health.     

Some characteristics of visual whole report behavior

A whole report experiment is reported that obtained joint serial position accuracy data, with probability-correct curves as functions of stimulus duration. A second experimental phase compared a condition in which the left part of the linear display was shielded from view during the last part of the stimulus exposure, with a condition in which the right part of the display was shielded from view during the early portion of the stimulus exposure interval, and with a control condition in which no shield was used. A noisy mask came on with the termination of the letter display, in both phases. The bounded performance model, possessing the characteristics of parallelness, independence and limited capacity, was in good accord with the data and fit better than the multicomponent model.     

Phenotypic profiles of language-impaired children based on genetic/family history

Although etiological influences in developmental language impairment (dysphasia) are not well defined, a significant increase of family aggregation for the disorder has been reported. We report data from a large cohort of language-impaired (LI) children participating in the San Diego longitudinal study in which we examined whether children with or without positive family histories show different phenotypic profiles. Due to the longitudinal design of the study, questions pertaining to change over time are also addressed. Second, a subgroup of the most impaired children were reevaluated to obtain additional information pertaining to family history and phenotypic outcome. Approximately 70% of the LI children met criteria for inclusion as family history positive, with fathers reporting a history of language or learning problems one and a half to two times as frequently as mothers. LI children with or without a positive family history were not significantly different on language skills or IQ. However, subjects having a positive family history for developmental language/learning problems were significantly lower in socioeconomic status and were rated by parents and teachers as having more attention-related behavior problems than their family history negative counterparts. Similarly, family history positive LI children performed more poorly on standardized academic tests as well as on tests of auditory processing and attention.     

Familial Handedness and Access to Words, Meaning, and Syntax during Sentence Comprehension

We compared right-handed familial dextral (FS-) and familial sinistral (FS+) participants who were aged either 10-13 years (children) or 18-23 years (adults). In word probe and associative probe tasks, FS+ adults responded faster than all other groups and FS+ children responded more slowly than all other groups. In the word probe task, only the FS- adults showed a significant effect of the serial position of the target word. We interpret these differences to support an analysis-by-synthesis model of comprehension in which individuals who differ in familial handedness and age emphasize different linguistic representations during comprehension. In general, FS+ individuals focus on words and meaning, while FS- individuals focus on syntactic representations. In FS+ individuals, age-related experiences with language produce a shift in responding from compositional meaning to words and their associations. In FS- individuals, age-related experiences with language produce a shift toward responding based more on detailed syntactic representations, including the serial order of words and possibly the structural roles of clauses.     

A clarification of self-terminating versus exhaustive variances in serial and parallel models

A recent study published in Perception & Psychophysics (Donnelly, Found, & Müller, 1999) employs response time (RT) variances (in the form of standard deviations) in addition to mean RTs. Variances can contribute greatly to model testing. However, there is a danger of perpetuating the kinds of logical and methodological errors that have long attended research employing mean RTs alone. This commentary clarifies the theoretical and methodological issues, points out some new results concerning variability in search processes, and indicates how to resolve the global and specific challenges associated with identifying psychological mechanisms.     

The accuracy of lay integrity assessments in simulated employment interviews

Two studies were conducted to determine if lay judges could accurately assess another individual’s integrity level when using overt and covert integrity inventories. In Study 1, participants took part in simulated employment interviews and then both the participants and lay interviewers completed an overt integrity test comparable to the Reid Report integrity survey [Reid London House. (2004). Abbreviated Reid Report. Minneapolis, MN: NCS Pearson]. Self-lay judge agreement and peer-lay judge agreement were used as the criteria for accuracy. In Study 2, participants took part in either a simulated structured, unstructured or informal employment interview format and completed both overt and covert integrity inventories. The results suggest that lay judges (as well as acquaintances) are fairly accurate in assessing others’ integrity levels based upon a very brief 10-min interaction with an individual, when using either an overt or covert integrity inventory. The findings also suggest that the informal interview format can significantly enhance the accuracy of a lay-judge’s assessment of the participant’s integrity level when a covert measure of integrity is used.     

Establishing a generalized repertoire of helping behavior in children with autism

The present study used a multiple baseline across participants design to assess whether 4 children with autism could learn a generalized repertoire of helping adults with different tasks through the use of a multicomponent teaching package. Different helping responses were taught in the presence of multiple exemplars of discriminative stimuli drawn from experimenter-defined categories of helping behavior (e.g., locating objects, putting away items, setting up an activity). During the training condition, video models, prompting, and reinforcement were used. The results showed that all 4 children learned to emit appropriate helping responses in the presence of discriminative stimuli from the helping categories used during training. Generalization of helping responses was observed in the presence of untrained discriminative stimuli during additional probe conditions. Additional pre- and postintervention generalization trials showed that the frequency of helping responses also increased in the presence of novel stimuli, in a novel setting, and with a novel instructor.