The Effect of Age on Rule-Based Category Learning

ABSTRACT

An explicit, rule-based, category-learning task with abstract visual stimuli was administered to 50 healthy older adults and 48 younger adults. Accuracy and reaction time (RT) were examined for the effects of age, perceptual abilities, rule memory, rule complexity, stimulus novelty, and response competition. Older adults performed at equivalent levels to younger adults when applying a simple rule, but showed performance decrements when applying a more complex rule. The age effect interacted with both stimulus novelty and response competition, and was not eliminated after controlling for basic perceptual abilities and rule memory. The authors suggest that older adults show category learning deficits in conditions that require enhanced cognitive control. These results are discussed in reference to the growing body of literature regarding age-related change in executive abilities and frontal lobe function.     

Moral reasoning,emotion understanding,and callous-unemotional traits in early-to-middle childhood

Relatively little is known about features of moral reasoning among young children with callous-unemotional (CU) traits (e.g., lack of guilt and empathy). This study tested associations between CU traits and emotion attributions (i.e., identification of others’ emotional states) and justifications (i.e., explanations for those emotional states), across social scenarios involving discreet versus salient distress cues. The participants were boys aged 6-to-10 years (N = 50; M_age = 7 years 7 months), who were interviewed about 12 hypothetical scenarios (eight with discreet and four with salient distress cues). Regression models indicated that CU traits, in interaction with high levels of antisocial behaviour, were associated with reduced emotion attributions of fear in discreet but not salient immoral scenarios. Higher CU traits were also associated with reduced justifications referencing others’ welfare in discreet scenarios, and increased references to action-orientated justifications in salient scenarios. These findings suggest that CU traits are associated with early moral reasoning impairments and that salience of distress may be important to these processes.     

SCV-A general subroutine for the selection of combinations of variables

SCV is a FORTRAN IV subroutine for sequencing combinations of variables. Selection of the combinations can be random with or without replacement and with equal or unequal frequencies of occurrence. Application is illustrated in terms of an interactive process-control experiment, but the subroutine is applicable to any problem requiring the generation of multidimensional sequences or the permutation of a set of numbers.     

Implicit sequence learning in ring‐tailed lemurs (Lemur catta)

Implicit learning involves picking up information from the environment without explicit instruction or conscious awareness of the learning process. In nonhuman animals, conscious awareness is impossible to assess, so we define implicit learning as occurring when animals acquire information beyond what is required for successful task performance. While implicit learning has been documented in some nonhuman species, it has not been explored in prosimian primates. Here we ask whether ring‐tailed lemurs (Lemur catta) learn sequential information implicitly. We tested lemurs in a modified version of the serial reaction time task on a touch screen computer. Lemurs were required to respond to any picture within a 2 × 2 grid of pictures immediately after its surrounding border flickered. Over 20 training sessions, both the locations and the identities of the images remained constant and response times gradually decreased. Subsequently, the locations and/or the identities of the images were disrupted. Response times indicated that the lemurs had learned the physical location sequence required in original training but did not learn the identity of the images. Our results reveal that ring‐tailed lemurs can implicitly learn spatial sequences, and raise questions about which scenarios and evolutionary pressures give rise to perceptual versus motor‐implicit sequence learning.