Sensitivity to stimulus similarity is associated with greater sustained attention ability

Sustained attention is critical for tasks where perceptual information must be continuously processed, like reading or driving; however, the cognitive processes underlying sustained attention remain incompletely characterized. In the experiments that follow, we explore the relationship between sustaining attention and the contents and maintenance of task-relevant features in an attentional template. Specifically, we administered the gradual onset continuous performance task (gradCPT), a sensitive measure of sustained attention, to a large web-based sample (N>20,000) and a smaller laboratory sample for validation and extension. The gradCPT requires participants to respond to most stimuli (city scenes – 90 %) and withhold to rare target images (mountain scenes – 10 %). By using stimulus similarity to probe the representational content of task-relevant features—assuming either exemplar- or category-based feature matching—we predicted that RTs for city stimuli that were more “mountain-like” would be slower and “city-like” mountain stimuli would elicit more erroneous presses. We found that exemplar-based target-nontarget (T-N) similarity predicted both RTs and erroneous button presses, suggesting a stimulus-specific feature matching process was adopted. Importantly, individual differences in the degree of sensitivity to these similarity measures correlated with conventional measures of attentional ability on the gradCPT as well as another CPT that is perceptually less demanding. In other words, individuals with greater sustained attention ability (assessed by two tasks) were more likely to be influenced by stimulus similarity on the gradCPT. These results suggest that sustained attention facilitates the construction and maintenance of an attentional template that is optimal for a given task.     

Using an abbreviated assessment to identify effective error‐correction procedures for individual learners during discrete‐trial instruction

Previous research comparing the effectiveness of error‐correction procedures has involved lengthy assessments that may not be practical in applied settings. We used an abbreviated assessment to compare the effectiveness of five error‐correction procedures for four children with autism spectrum disorder or a developmental delay. During the abbreviated assessment, we sampled participants' responding with each procedure and completed the assessment before participants reached our mastery criterion. Then, we used the results of the abbreviated assessment to predict the most efficient procedure for each participant. Next, we conducted validation assessments, comparing the number of sessions, trials, and time required for participants to master targets with each procedure. Results showed correspondence between the abbreviated assessment and validation assessments for two of four participants and partial correspondence for the other two participants. Findings suggest that a brief assessment may be a useful tool for identifying the most efficient error‐correction procedure for individual learners.     

Similar stimulus features control visual classification in orangutans and rhesus monkeys

Many species classify images according to visual attributes. In pigeons, local features may disproportionately control classification, whereas in primates global features may exert greater control. In the absence of explicitly comparative studies, in which different species are tested with the same stimuli under similar conditions, it is not possible to determine how much of the variation in the control of classification is due to species differences and how much is due to differences in the stimuli, training, or testing conditions. We tested rhesus monkeys (Macaca mulatta) and orangutans (Pongo pygmaeus and Pongo abelii) in identical tests in which images were modified to determine which stimulus features controlled classification. Monkeys and orangutans were trained to classify full color images of birds, fish, flowers, and people; they were later given generalization tests in which images were novel, black and white, black and white line drawings, or scrambled. Classification in these primate species was controlled by multiple stimulus attributes, both global and local, and the species behaved similarly.     

The Implications of Two Conceptions of Happiness (Hedonic Enjoyment and Eudaimonia) for the Understanding of Intrinsic Motivation

The distinction between hedonic enjoyment and eudaimonia was evaluated in three data sets involving use of the Personally Expressive Activities Questionnaire—Standard Form (PEAQ-S) with college student samples (n > 200 in each sample). Indices of these two conceptions of happiness were strongly and reliably related across the three samples. Differences between these two conceptions of happiness were evaluated in two ways. First, we examined and compared correlations of hedonic enjoyment and eudaimonia with variables related to intrinsic motivation. Zero-order correlations involving hedonic enjoyment were significantly stronger with respect to measures of self-determination and interest than were the corresponding correlations involving feelings of personal expressiveness (eudaimonia). In contrast, correlations involving eudaimonia were significantly stronger with measures of the balance of challenges and skills, self-realization values, effort, and importance than were the corresponding correlations with hedonic enjoyment. Second, we empirically distinguished between activities for which both hedonic enjoyment and eudaimonia are present (intrinsically motivated activities) and activities for which hedonic enjoyment alone is present (hedonically enjoyed activities). Intrinsically motivated activities were judged to be significantly higher with respect to measures of the balance of challenges and skills, self-realization values, effort, importance, interest, and flow experiences. No differences between the two categories of activities were found for self-determination and the frequency with which activities were performed. Given these distinguishable patterns in the two conceptions of happiness, a reconceptualization for the understanding of intrinsic motivation is proposed.     

Stress and cardiac beta adrenoceptors

Most modern theories about stress recognize that although stress is not a disease, it may be the trigger for the majority of diseases when allostatic overload has been generated. During stress, the glucocorticoids and catecholamines play a key role in the regulation of physiological parameters and homeostasis during stress. In the heart, positive chronotropic, inotropic, and lusitropic responses to catecholamines are mediated by various subtypes of adrenergic receptors (beta-ARs), mainly beta1- and beta2-adrenergic receptors. beta-ARs also control cardiomyocyte growth and death, thus contributing to cardiac remodelling. The structural basis of each beta-AR subtype, as well as their signalling pathways, and adaptive responses to stress are discussed. The participation of beta3- and putative beta4-ARs in the control of cardiac function is also discussed, with emphasis on low affinity beta-AR isoforms and the role they play in the response to the catecholamines under stress. The changes in beta-AR signalling under pathogenic conditions as well as under stress are reviewed.     

Relational information processing of novel unrelated actions by infants

Declarative memory in infants is often assessed via deferred imitation. Not much is known about the information processing basis of the memory effect found in these experiments. While in the typical deferred imitation study the order of actions remains the same during demonstration and retrieval, in two experiments with n=30 respective n=25, 10- and 11-month-old infants, the order of novel unrelated actions in demonstration and retrieval was varied (same, reversed, mixed). This allowed a separation of item-specific from item-relational information processing. In both experiments best memory performance was found when the order of target actions remained the same during encoding and recall, demonstrating that infants seem to rely on item-specific as well as item-relational information which has to be ad hoc constructed while encoding.     

Effects of repetition and response deadline on item recognition in young and older adults

In the present study, we examined the joint effects of aging, repetition, and response deadline in a plurality discrimination task. Young and older adults studied lists of unrelated singular and plural nouns, with half presented once (weak items) and half presented five times (strong items). Test lists contained old (same) nouns, plurality-reversed nouns (changed lures), and unstudied nouns (new lures), and the participants were asked to respond old only to same items. In Experiment 1, the participants were tested with both short and long deadlines. In Experiment 2, the tests were unpaced. In both experiments, repetition increased hit rates for young and older adults. Young adults tested with a long deadline or no deadline showed invariant (Experiment 1) or reduced (Experiment 2) false alarms to changed lures when the nouns were studied more often. Young adults tested with a short deadline and older adults tested with both long and short deadlines had increased false alarm rates for strong changed lures; without time pressure to respond, older adults did not have a significant increase in false alarms for changed lures. Implications of these results for theories of cognitive aging are explored.