The metrics of spatial situation models.

The authors investigated the metrics of spatial distance represented in situation models of narratives. In 3 experiments, a spatial gradient of accessibility in situation models was observed: The accessibility of objects contained in the situation model decreased with increasing spatial distance between the object and the reader's focus of attention. The first 2 experiments demonstrated that this effect of spatial distance was purely categorical rather than Euclidean: Accessibility depended on the number of rooms located between the object and the focus of attention, not on the size of the rooms. Experiment 3 revealed, however, that participants were able to use information about Euclidean distance in a secondary task when necessary. The implications of these results for theories of narrative comprehension and hierarchical versus nonhierarchical theories of spatial memory are discussed.

Monitoring retrieval from long-term memory by slow event-related brain potentials.

Slow event-related brain potentials of nine subjects were recorded in an experimentally controlled long-term memory retrieval task (the Fan paradigm) from electrode sites F3, Fz, F4, Cz, P3, Pz, and P4. In all retrieval conditions, a very pronounced DC-like negative potential appeared over the left frontal cortex. This negativity was switched on with the presentation of the probe stimuli and prevailed in some conditions throughout the total recording epoch of 14 s. Particular retrieval conditions became manifest in distinct slow wave effects. The amplitude of a bilaterally distributed frontal negative slow wave increased when a more diversified associative structure had to be searched. The amplitude of another negative slow wave, which peaked bilaterally over parietal areas, was affected by the type of concepts that had to be retrieved. The amplitude was larger with general concepts (category labels) and smaller with specific concepts (category exemplars). These results suggest that distinct strategies are invoked when subjects are required to draw conclusions about different contents stored permanently in an associative network.

[Cognitive structuring by statistical graphics: effects on understanding and retention]. / Wissensstrukturierung durch statistische Graphen: Auswirkungen auf das Verstehen und Behalten.

We investigated how displaying the same set of data using different line graphs affects comprehension and retention of the data. In line graphs, the results of two-factor experiments can be displayed and structured in different ways by locating either one or the other independent variable on the abscissa. The experiment showed that the level of measurement as well as the number of levels of each independent variable affected comprehension and retention. Comprehension of graphs and retention of the information was better, if the graph showed an independent variable on the abscissa which was measured using an interval scale rather than a nominal scale, and when there were four rather than two levels. To account for the results, we propose a process model of graph comprehension.

Mood-congruent and mood-incongruent learning.

We report two experiments that investigate the effect of an induced mood on the incidental learning of emotionally toned words. Subjects were put in a happy or sad mood by means of a suggestion technique and rated the emotional valence of a list of words. Later on, they were asked to recall the words in a neutral mood. For words with a strong emotional valence, mood-congruent learning was observed: strongly unpleasant words were recalled better by sad subjects and strongly pleasant words were recalled better by happy subjects. The reverse was true for slightly toned words: here, mood-incongruent learning was observed. Both effects are predicted by a two-component processing model that specifies the effect of the mood on the cognitive processes during learning. Further evidence for the model is given by rating times measured in Experiment 2.