The effects of age on associative and rule-based causal learning and generalization.

We assessed how age influences associative and rule-based processes in causal learning using the Shanks and Darby (1998) concurrent patterning discrimination task. In Experiment 1, participants were divided into groups based on their learning performance after 6 blocks of training trials. High discrimination mastery young adults learned the patterning discrimination more rapidly and accurately than moderate mastery young adults.

Aging and retrospective revaluation of causal learning.

In a 2-stage causal learning task, young and older participants first learned which foods presented in compound were followed by an allergic reaction (e.g., STEAK-BEANS→ REACTION) and then the causal efficacy of 1 food from these compounds was revalued (e.

Aging and integration of contingency evidence in causal judgment.

Age differences in causal judgment are consistently greater for preventative/negative relationships than for generative/positive relationships. In this study, a feature analytic procedure (Mandel & Lehman, 1998) was used to determine whether this effect might be due to differences in young and older adults' integration of contingency evidence during causal induction. To reduce the impact of age-related changes in learning/memory, the authors presented contingency evidence for preventative, noncontingent, and generative relationships in summary form; the meaningfulness of causal context was varied to induce participants to integrate greater or lesser amounts of this evidence.

The role of contingency and contiguity in young and older adults' causal learning.

Contingency and temporal contiguity are important "cues to causality." In this study, we examined how aging influences the use of this information in response-outcome causal learning. Young and older adults judged a generative causal contingency (i.

The role of age and prior beliefs in contingency judgment.

This experiment investigated how prior beliefs affect young and older adults' ability to detect differences in objective contingency. Participants received new evidence that the objective contingency between two events was positive, negative, or zero when they believed that there was a positive or negative relationship between events, when they believed that the events were unrelated, and when they had no knowledge of the relationship between the events. They were then asked to estimate the objective contingency and recall the contingency evidence.

Aging, working memory, and discrimination learning.

Older adults easily learn probabilistic relationships between cues and outcomes when the predictive event is the occurrence of a cue, but have greater difficulty when the predictive event is the nonoccurrence of a cue (Mutter & Pliske, 1996; Mutter & Plumlee, 2004; Mutter & Williams, 2004). This study explored whether this age-related deficit occurs in a simpler learning context and whether it might be related to working memory (WM) decline. We gave younger and older adults simultaneous discrimination tasks that allowed us to compare their ability to learn deterministic relationships when either the occurrence (feature positive; FP) or the nonoccurrence (feature negative; FN) of a distinctive feature predicted reinforcement.

High resolution inductively coupled plasma mass spectrometry allows rapid assessment of iron absorption in infants and children.

Stable isotope absorption studies of iron have been limited by the high cost and limited availability of isotope ratio analysis using thermal ionization MS (TIMS). The development of high-resolution double focusing inductively coupled plasma MS (ICP-MS) may permit more cost-efficient sample analysis due to its high throughput, lower cost, easy sample pretreatment, and greater availability. Our objective was to develop an ICP-MS methodology for the measurement of iron isotope ratios using very small blood volumes.