New directions in cognitive training: on methods, transfer, and application

Research on cognitive interventions and training-induced changes in brain and behavior has been of growing interest in psychology and neuroscience over the last decade (for reviews see Hertzog, Kramer, Wilson, & Lindenberger, 2009; Lustig, Shah, Seidler, & Reuter-Lorenz, 2009; Chein & Morrison, 2010; for meta-analyses see Karbach & Verhaeghen, 2014; Melby-Lervag & Hulme, 2013). The interest in these studies is to a large extent related to empirical reports and observations, which suggest that appropriate training interventions can produce broad learning effects and may generalize to other non-trained tasks (e.g., Bergman-Nutley et al., 2011; Green & Bavelier, 2003; Jaeggi, Buschkuehl, Jonides, & Perrig, 2008; Klingberg, 2010; Strobach, Frensch, & Schubert, 2012, and many others). These training and transfer effects are often observed in studies using process-based training; this training is based on the assumption that practice and learning may improve relevant processes in one task situation and the improvement may generalize to another task situation if there is a process overlap between situations (Schmidt & Bjork, 1992; Taatgen, 2013). This kind of training must be distinguished from (rather traditional) strategy-based training approaches, which usually focus on the training of task-specific procedures and strategies improving the performance in the given task without transferring broadly to other tasks (i.e., Klauer, 1989; Kliegl & Baltes, 1987; Kliegl, Smith, & Baltes, 1990; Rebok, Carlson, & Langbaum, 2007). In particular, the implications of broad transfer as a result of process-based and other trainings are manifold and have given rise to the increasing interest in current training research. First of all, since many of the reported training effects are related to basic cognitive domains like attention, working memory, executive functions, and intelligence, recent cognitive training studies seem to promise a training-related boost of the cognitive machinery on a broad scale and functioning. Broad training effects have been reported across the whole life span from the young to the elderly brain, although with different degrees of efficiency. This offers even a life-span perspective of the occurrence of training-related boosting effects (e.g., Brehmer et al., 2008, for reviews see Diamond, 2012; Hertzog et al., 2009 and others). Second, a further and more theoretical appeal of this new training research originates from the fact that its findings may challenge two cornerstones of knowledge that guided theoretical and empirical research in experimental psychology and cognitive neuroscience so far: Ad one, for a long time, it was as given that cognitive capabilities usually mature at the end of adolescence because the growth of cognitive functions is due to an increase in cognitive capacity that has finished at that age, and a further remarkable boost of cognitive capacity is not possible. Ad two, if there is cognitive plasticity beyond adolescence then this is either reflected in cognitive improvements due to highly specific learning of task-specific algorithms and knowledge, or in impairments of cognitive functions resulting from an age-related decline. Yet, the results of studies on cognitive T. Schubert (&) T. Strobach Department of Psychology, Humboldt-Universitat zu Berlin, Rudower Chaussee 18, 12489 Berlin, Germany e-mail: torsten.schubert@psychologie.hu-berlin.de