The aims of this study were to investigate semantic retrieval processes and errors across time during a semantic fluency task and to specify their components (i.e., executive vs. semantic). To do so, we analyzed the productions of 50 healthy participants (using the "supermarket" fluency task). The scores were compared before and after a 30-s interval. Across time, the results showed a decrease in the number of words produced and hard switching. Cluster switching and the number of intrusions remained constant, while clustering, and both the number of exemplars and repetitions increased. These results are discussed in terms of a progressive involvement of a semantic cognitive strategy of retrieval.

The aim of this study was to determine whether verbal knowledge can compensate for the age-related decline in word production during a fluency test. We assessed the performance of 20 young and 20 old subjects in standard letter and semantic fluency tasks over time (T1: 0-30 s vs. T2: 31-60 s). The number of words produced, switching, and clustering components (Troyer et al. Neuropsychology, 11(1): 138-146, 1997) were investigated. Correlations between age and cognitive factors (processing speed, executive functions, and vocabulary level) were analyzed. The results revealed a knowledge compensation mechanism in elderly subjects, but only in letter fluency productions. It only occurred during the second period and was related to an increase in the clustering component and a positive correlation between age and vocabulary level. The differences between letter and semantic fluency performances are discussed in terms of the nature of the nonsemantic and semantic components involved in these tasks.Keywords Aging Á Verbal fluency Á Clustering and switching across time It has often been stated in aging literature that old adults present some declines in cognitive functions. Particularly, numerous studies have demonstrated a reduction in the execution speed of cognitive operations and a deficit in the executive processes needed for temporary information storage and simultaneous performance of several tasks (Barringer et al

The use of virtual reality in the area of spatial cognition raises the question of the quality of learning transfer from a virtual to a real environment. Among the challenges, one is to determine the best cognitive aids to improve the quality of transfer and the conditions in which this is best achieved. The purpose of this study was to investigate the impact of passive and active exploration mode on quality of transfer in three different spatial recall tasks when the route was simple or complex. Ninety subjects (45 men and 45 women) participated in the experiment. Spatial learning was evaluated by 3 tasks: Wayfinding (route reproduction in reality), Sketch-mapping (free hand drawing) and Scene-classification (make a series of pictures in chronological order) in the context of the district of Bordeaux. In the Wayfinding task, active learning in a Virtual Environment (VE) increased performances compared to the passive learning condition, irrespective of the route complexity factor. In the Sketch-mapping task, active learning in a VE induced better performances than the passive condition, but only for complex routes. In the Picture classification task, no benefit was observed from active learning with both simple and complex routes. These results are discussed in terms of the functional demands of the three tasks and the route complexity dimension.

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The overall results from CHARM simulations are in accordance with both the ADH and ESH hypotheses and provide discussion on the formal connections between these two main aging explanations.