Focus of attention and choice of text modality in multimedia learning

The term ‘modality effect’ in multimedia learning means that students learn better from pictures combined with spoken rather than written text. The most prominent explanations refer to the split attention between visual text reading and picture observation which could affect transfer of information into working memory, maintenance of information in working memory or the effective size of working memory. The assumption of a continuous need for split attention is questionable, however. Learners can keep pictorial information in working memory, when they have seen the picture before, especially if they have higher prior knowledge. Instead of suffering from a permanent split attention, learners frequently show tendencies to simply ignore pictures. This suggests guiding learners towards picture analysis by picture-related text paragraphs. We assume that these paragraphs are associated with stronger modality effects than content-related paragraphs, especially if the pictures are new to learners. These assumptions were tested in an experiment with 120 students learning about volcanism from illustrated text consisting of segments each including a content-related paragraph followed by a picture-related paragraph describing the accompanying visualization. Content-related and picture-related paragraphs were presented as visual or auditory texts leading to 2x2 conditions of text presentation. Picture novelty was manipulated by presenting a picture throughout the whole segment or only when the picture-related paragraph was read. As expected, picture-related paragraphs were associated with stronger modality effects than content-related paragraphs if picture novelty is high. The distinction between different kinds of paragraphs seems to be important for the prediction of modality effects.     

Hardness measurement of natural and hybrid turf soccer fields

Understanding the surface hardness of soccer fields is essential to evaluate the risk of injury and also its influence on the playing behavior of soccer players. In this context, newly developed hybrid turf systems have to be tested for their surface hardness with regard to the increased risk of injury on hard sports surfaces. The hardness of a soccer field can be quantitatively measured using an apparatus with a cylindrical weight that is dropped from a defined height. Since this procedure was first used for road construction, there are few studies investigating its use on sports grounds. This has led to inconsistencies in methodology and the absence of evaluation guidelines for classifying the hardness of soccer fields. This paper considers how turf systems (natural turf and hybrid turf) differ in their hardness and how this method can be used for different soccer turf systems. Natural turf systems, stitched turf systems, hybrid turf-bearing layer systems and woven mat systems were investigated. The assessment results from a comparative representation of hardness values of different soccer fields. By comparison, natural turf systems were found to be the softest, while woven mat systems were the hardest. Furthermore, the parameters that might affect the hardness were investigated. The influence of the measured soil parameters decreases with an increasing number of measurements per measuring point. Turf system-specific correlations make it possible to reduce the amount of measurement effort.