Why interleaving enhances inductive learning: The roles of discrimination and retrieval

Kornell and Bjork (Psychological Science 19:585–592, 2008) found that interleaving exemplars of different categories enhanced inductive learning of the concepts based on those exemplars. They hypothesized that the benefit of mixing exemplars from different categories is that doing so highlights differences between the categories. Kang and Pashler (Applied Cognitive Psychology 26:97–103, 2012) obtained results consistent with this discriminative-contrast hypothesis: Interleaving enhanced inductive learning, but temporal spacing, which does not highlight category differences, did not. We further tested the discriminative-contrast hypothesis by examining the effects of interleaving and spacing, as well as their combined effects. In three experiments, using photographs of butterflies and birds as the stimuli, temporal spacing was harmful when it interrupted the juxtaposition of interleaved categories, even when total spacing was held constant, supporting the discriminative-contrast hypothesis. Temporal spacing also had value, however, when it did not interrupt discrimination processing.     

Organizational factors and mental health in community volunteers. The role of exposure,preparation, training,tasks assigned,and support

During disasters, aid organizations often respond using the resources of local volunteer members from the affected population who are not only inexperienced, but who additionally take on some of the more psychologically and physically difficult tasks in order to provide support for their community. Although not much empirical evidence exists to justify the claim, it is thought that preparation, training, and organizational support limit (or reduce) a volunteer's risk of developing later psychopathology. In this study, we examined the effects of preparation, training, and organizational support and assigned tasks on the mental health of 506 Indonesian Red Cross volunteers who participated in the response to a massive earthquake in Yogyakarta, Indonesia, in 2006. Controlling for exposure level, the volunteers were assessed for post-traumatic stress disorder (PTSD), anxiety, depression, and subjective health complaints (SHCs) 6, 12, and 18 months post-disaster. Results showed high levels of PTSD and SHCs up to 18 months post-disaster, while anxiety and depression levels remained in the normal range. Higher levels of exposure as well as certain tasks (e.g., provision of psychosocial support to beneficiaries, handling administration, or handing out food aid) made the volunteers more vulnerable. Sense of safety, expressed general need for support at 6 months, and a lack of perceived support from team leaders and the organization were also related to greater psychopathology at 18 months. The results highlight the importance of studying organizational factors. By incorporating these results into future volunteer management programs the negative effects of disaster work on volunteers can be ameliorated.     

Retrieval experience as a modifier of future encoding: another test effect

Research on how individuals monitor their level of comprehension during study paints a picture of learners as being insensitive to many of the factors or conditions of learning that can enhance long-term retention and transfer. In previous research, however, deWinstanley and Bjork (2004) demonstrated that learners--if made sensitive to the memorial benefits of generation in the context of an informative test following study of a text passage in which they had encoded both to-be-read and to-be-generated critical items--then became more effective processors of future to-be-read information presented in a 2nd text passage. In Experiments 1 and 2 of the present research, we explored the potential applicability of this effect by testing whether it could survive certain types of activity-filled delays. In Experiments 3 and 4, we tested whether enhanced processing of contextual information, an encoding strategy that could possibly have been discovered by participants during the testing episode for the 1st text passage, was a potential underlying cause of this effect. Together, our results bring to light an additional benefit of test taking and point to what might be considered necessary and sufficient conditions for leading learners to become more effective processors of future to-be-learned information.     

The costs and benefits of testing text materials

Tests have been shown to improve the later recall of tested information, a result known as the testing effect. Tests, however, can also impair the later recall of related information, an effect known as retrieval-induced forgetting. Although retrieval-induced forgetting has been demonstrated using a wide variety of materials, recent work suggests that learning information in the context of a coherent text passage may afford protection from retrieval-induced forgetting. In four experiments we explored the conditions under which retrieval-induced forgetting does and does not occur with such materials. We found that two factors-the coherence of the to-be-learned material and the competitiveness of retrieval practice-are important in determining whether retrieval-induced forgetting does or does not occur. Furthermore, even if retrieval-induced forgetting does occur, having the opportunity to restudy the forgotten information can prevent that forgetting from persisting. Taken together, these findings provide greater understanding of the costs and benefits of testing text materials, with possible implications for the optimisation of testing as a tool for learning in educational contexts.