Think-aloud protocols and the selection task: Evidence for relevance effects and rationalisation processes

Two experiments are reported that employed think-aloud methods to test predictions concerning relevance effects and rationalisation processes derivable from Evans' (1996) heuristic-analytic theory of the selection task. Evans' account proposes that card selections are triggered by relevance-determining heuristics, with analytic processing serving merely to rationalise heuristically cued decisions. As such, selected cards should be associated with more references to both their facing and their hidden sides than rejected cards, which are not subjected to analytic rationalisation. Experiment 1 used a standard selection-task paradigm, with negative components permuted through abstract conditional rules. Support was found for all heuristic-analytic predictions. This evidence was shown to be robust in Experiment 2, where “select - don't select” decisions were enforced for all cards. Both experiments also clarify the role played by secondary heuristics in cueing the consideration of hidden card values during rationalisation. We suggest that whilst Evans' heuristic-analytic model and Oaksford and Chater's (e.g., 2003) optimal data selection model can provide compelling accounts of our protocol findings, the mental models theory fares less well as an explanation of our full dataset.     

Finding the Cause: Verbal Framing Helps Children Extract Causal Evidence Embedded in a Complex Scene

In making causal inferences, children must both identify a causal problem and selectively attend to meaningful evidence. Four experiments demonstrate that verbally framing an event (“Which animals make Lion laugh?”) helps 4-year-olds extract evidence from a complex scene to make accurate causal inferences. Whereas framing was unnecessary when evidence was isolated, children required it to extract and reason about evidence embedded in a more complex scene. Subtler framing stating the causal problem, but not highlighting the relevant variables, was equally effective. Simply making the causal relationship more perceptually obvious did facilitate children's inferences, but not to the level of verbal framing. These results illustrate how children's causal reasoning relies on scaffolding from adults.     

Extraversion and emotional reactivity

Six mood induction studies and a meta-analysis were conducted to test 2 models of the extraversion-pleasant affect relation. The affect-level model suggests that extraverts should be happier than introverts in both neutral and positive mood conditions. The reactivity model posits that extraverts react particularly strongly to pleasant stimuli and that they should be happier than introverts only in positive conditions. In all studies, extraverts failed to exhibit greater emotional reactivity when pleasantness items were analyzed. When activated positive affect items were analyzed, results were mixed. The meta-analysis confirmed that there is only a slight reactivity effect overall, and this effect emerges only in activated positive affect items. Furthermore, the meta-analysis showed that the correlation in neutral conditions is strong enough to support the affect-level model.     

Unemployment alters the set point for life satisfaction

Abstract— According to set-point theories of subjective well-being, people react to events but then return to baseline levels of happiness and satisfaction over time. We tested this idea by examining reaction and adaptation to unemployment in a 15-year longitudinal study of more than 24,000 individuals living in Germany. In accordance with set-point theories, individuals reacted strongly to unemployment and then shifted back toward their baseline levels of life satisfaction. However, on average, individuals did not completely return to their former levels of satisfaction, even after they became reemployed. Furthermore, contrary to expectations from adaptation theories, people who had experienced unemployment in the past did not react any less negatively to a new bout of unemployment than did people who had not been previously unemployed. These results suggest that although life satisfaction is moderately stable over time, life events can have a strong influence on long-term levels of subjective well-being.     

ERK1/2 activation is necessary for BDNF to increase dendritic spine density in hippocampal CA1 pyramidal neurons

Brain-derived neurotrophic factor (BDNF) is a potent modulator of synaptic transmission and plasticity in the CNS, acting both pre- and postsynaptically. We demonstrated recently that BDNF/TrkB signaling increases dendritic spine density in hippocampal CA1 pyramidal neurons. Here, we tested whether activation of the prominent ERK (MAPK) signaling pathway was responsible for BDNF's effects on spine growth. Slice cultures were transfected with enhanced yellow fluorescent protein (eYFP) by particle-mediated gene transfer, and CA1 pyramidal neurons were imaged by laser-scanning confocal microscopy. We confirmed that BDNF (24 h) increases spine density in apical dendrites of CA1 neurons. The MEK (ERK kinase) inhibitors PD98059 and U0126 completely prevented the increase in spine density induced by BDNF, without having an effect on spine density by themselves. In contrast to its actions on cortical pyramidal neurons, BDNF had minor and rather localized effects on dendritic complexity in hippocampal pyramidal neurons, increasing the total length, but not the branching of apical dendrites within CA1 stratum radiatum, without affecting basal dendrites in stratum oriens. Our results support the hypothesis that the ERK-signaling pathway not only mediates long-term synaptic plasticity and hippocampal-dependent learning, but it is also involved in the structural remodeling of excitatory spine synapses triggered by neurotrophins.     

Time does not heal all wounds

Cross-sectional studies show that divorced people report lower levels of life satisfaction than do married people. However, such studies cannot determine whether satisfaction actually changes following divorce. In the current study, data from an 18-year panel study of more than 30,000 Germans were used to examine reaction and adaptation to divorce. Results show that satisfaction drops as one approaches divorce and then gradually rebounds over time. However, the return to baseline is not complete. In addition, prospective analyses show that people who will divorce are less happy than those who stay married, even before either group gets married. Thus, the association between divorce and life satisfaction is due to both preexisting differences and lasting changes following the event.     

System-specific differences in behavior regulation: overrunning and underdrinking in molar nondepriving schedules

In two experiments we tested the molar regulation prediction that animals adjust schedule performance to reduce deviations from baseline response totals. Both experiments constrained the baseline drink-burst length under molar nondepriving schedules but allowed rats to continue running without drinking. In Experiment 1, rats were required to run in order to drink. In Experiment 2, water was delivered independently of running by fixed-time (FT) schedules. Under the run-to-drink contingency, rats exceeded their baseline amounts of running (overrunning) but failed to maintain their baseline water intake (underdrinking). The total amount of running that did not lead to drinking approximated baseline running. Under the FT schedules, rats again underdrank, but total running approximated baseline. These results do not support previous studies that have shown molar equilibrium effects under nondepriving reciprocal schedules. We conclude that (a) contingent running may not substitute for independent running; (b) intermittent access to water reduces the total instigation for drinking; (c) molar regulation differs under reciprocal and nonreciprocal schedules; and (d) more dynamic, system-specific regulatory models need to be developed.