Anxiety research is one of the major psychological research domains and looks back on decades of research activity. Traditionally, novel theories and approaches are tested utilizing animal models. One way to study inherent anxiety in rodents is the elevated plus-maze (EPM). The EPM is a plus-shaped platform with two closed, i.e., walled, arms and two open unwalled arms. If given the opportunity to freely explore the apparatus, rodents instinctively avoid the open arms to protect themselves from predators. Hence, they spent less time on open and more time on closed arms, which is behaviorally associated with general anxiety. In the course of the pharmacological validation, it was found that this exploratory pattern can be reversed by anxiolytic substances, e.g., benzodiazepines, or potentiated by anxiogenics. One of the significant advantages of the EPM is that no prior training session is required in contrast to conditioning studies, thus allowing to observe natural behavior. Therefore, together with the economic and uncomplicated setup, the EPM has become a standard preclinical rodent anxiety test over the decades. In order to validate these rodent anxiety tests, there have recently been attempts to retranslate them to humans. A paramount of cross-species validation is not only the simple transferability of these animal tests but also the observation of anxiety behaviors that are evolutionarily conserved across species. Accordingly, it could be possible to conclude various factors associated with the etiology and maintenance of anxiety disorders in humans. So far, convincing translations of the EPM to humans are still lacking. For that reason, the primary aim of this dissertation is to retranslate the EPM throughout three studies and to evaluate cross-species validity critically. Secondly, the undertaken studies are set out to observe ambulatory activity equivalent to rodent EPM behavior, i.e., open arm avoidance. Thirdly, the undertaken studies aimed to assess the extent to which trait anxiety influences human exploratory activity on the platform to associate it with the assumption that rodent EPM-behavior is a reflection of general anxiety. Finally, virtual reality (VR) was the method of choice to maintain the economic advantage and adjust the EPM size to humans. Study 1 (N = 30) was set up to directly transfer the rodent EPM regarding test design and experimental procedure using a Computer Automatic Virtual Environment (CAVE). The results revealed that humans unlike rodents display a general open arms approach during free exploration. However, open arm avoidance was associated with high trait anxiety and acrophobia (fear of height), which was initially assessed as a control variable due to the virtual platform height. Regression analyses and subjective anxiety ratings hinted at a more significant influence of acrophobia on open arm avoidance. In addition, it was assumed that the open arms approach might have resulted from claustrophobic tendencies experienced in the closed arms due to the high walls. Study 2 (N = 61) sought to differentiate the influence of trait anxiety and acrophobia and adapt the virtual EPM to humans. Therefore, parts of the platform held a semi-transparent grid-floor texture, and the wall height on the closed arms was reduced to standard handrail level. Moreover, participants were priorly screened to exclude clinically significant levels of acrophobia, claustrophobia, and agoraphobia. The data on general exploratory activity showed no arm preference. Regression analyses confirmed that acrophobia is related to open arm avoidance, corroborating the finding of Study 1. Surprisingly, for trait anxiety, the result of Study 1 could not be replicated. Instead, for trait anxiety, no significant effect was found indicating that predominantly fear of heights shapes human EPM behavior even on a subclinical stage. In Study 3 (N = 57), the EPM was embedded into a city setting to 1) create a more natural human environment and 2) eliminate height. Furthermore, a head-mounted display was utilized for VR presentation, and arousal ratings were introduced. Participants were screened for high and low levels of trait anxiety and agoraphobia, and claustrophobia. Replicating the findings of Study 2, no difference in open and closed arm activity was observed, and no effect was found in relationship with trait anxiety. The data on anxiety ratings and claustrophobia suggest a positive correlation indicating that in this city EPM, claustrophobic tendencies might play a role in closed arm avoidance. In summary, this thesis added valuable insights into the retranslation of a well-established standard anxiety test used in rodents. However, it also majorly challenges current findings on the cross-species validity of the EPM. Various explanatory models for the results are critically discussed and associated with clinical implications concerning future research.

Previous research has revealed changes in the perception of objects due to changes of object-oriented actions. In present study, we varied the arm and finger postures in the context of a virtual reaching and grasping task and tested whether this manipulation can simultaneously affect the perceived size and distance of external objects. Participants manually controlled visual cursors, aiming at reaching and enclosing a distant target object, and judged the size and distance of this object. We observed that a visual-proprioceptive discrepancy introduced during the reaching part of the action simultaneously affected the judgments of target distance and of target size (Experiment 1). A related variation applied to the grasping part of the action affected the judgments of size, but not of distance of the target (Experiment 2). These results indicate that perceptual effects observed in the context of actions can directly arise through sensory integration of multimodal redundant signals and indirectly through perceptual constancy mechanisms.

It has been proposed that statistical integration of multisensory cues may be a suitable framework to explain temporal binding, that is, the finding that causally related events such as an action and its effect are perceived to be shifted towards each other in time. A multisensory approach to temporal binding construes actions and effects as individual sensory signals, which are each perceived with a specific temporal precision. When they are integrated into one multimodal event, like an action-effect chain, the extent to which they affect this event's perception depends on their relative reliability. We test whether this assumption holds true in a temporal binding task by manipulating certainty of actions and effects. Two experiments suggest that a relatively uncertain sensory signal in such action-effect sequences is shifted more towards its counterpart than a relatively certain one. This was especially pronounced for temporal binding of the action towards its effect but could also be shown for effect binding. Other conceptual approaches to temporal binding cannot easily explain these results, and the study therefore adds to the growing body of evidence endorsing a multisensory approach to temporal binding.

The present study explored the origin of perceptual changes repeatedly observed in the context of actions. In Experiment 1, participants tried to hit a circular target with a stylus movement under restricted feedback conditions. We measured the perception of target size during action planning and observed larger estimates for larger movement distances. In Experiment 2, we then tested the hypothesis that this action specific influence on perception is due to changes in the allocation of spatial attention. For this purpose, we replaced the hitting task by conditions of focused and distributed attention and measured the perception of the former target stimulus. The results revealed changes in the perceived stimulus size very similar to those observed in Experiment 1. These results indicate that action's effects on perception root in changes of spatial attention.

According to the tripartite model of text representation (van Dijk & Kintsch, 1983), readers form representations of the text surface and textbase, and construct a situation model. In this study, an experiment was conducted to investigate whether these levels of representation would be affected by adding illustrations to narrative text and whether the order of text and illustrations would make a difference. Students aged between 7 and 13 years (N = 146) read 12 narrative texts, 4 of them with illustrations presented before their corresponding sentences, 4 with illustrations presented after, and 4 without any illustration. A sentence recognition task was used to assess the accuracy for text surface, textbase, and situation model. For the text surface and situation model, neither the presence of illustrations nor the order of text and illustrations influenced accuracy. However, the textbase was negatively affected by illustrations when they followed their corresponding sentences. We suggest that illustrations can initiate model inspection after situation model construction (Schnotz, 2014), a process that can make substantial changes to the textbase representation.