How Temporal Preparation Influences Spatial Selection

Studies provide evidence that temporal preparation facilitates spatial selection in visual search. According to visual search models, spatial selection of stimuli can be influenced by several factors such as bottom-up salience, top-down goals, and prior selection history. The question is how temporal preparation facilitates spatial selection. To this end, this dissertation investigated whether temporal preparation affects spatial selection by influencing bottom-up and/or top-down processing. To manipulate temporal preparation, a constant foreperiod (FP) paradigm was applied in which the interval between an auditory warning signal and a subsequent search display was varied (i.e., short or long FP). Study 1, a series of behavioral experiments, aimed to investigate whether temporal preparation interacts with target salience, examining bottom-up processing, or with prior knowledge of the target constancy, corresponding to the formation of a top-down representation. Participants’ (experiment 1: N = 24, experiment 2: N = 32) task was to find a pop-out target among homogeneous distractors. Replicating previous findings, Study 1 showed an FP effect in reaction time (RT), i.e., an indicator of temporal preparation. Most importantly, this FP effect did not interact with target salience or target constancy. These RT results do not support a direct influence of temporal preparation on bottom-up or top-down processing in visual search. In Study 2, event-related potentials (ERPs) were measured to investigate whether temporal preparation facilitates spatial selection as a function of target salience, and thus bottom-up processing. Participants (N = 24) searched for a salient target among homogeneous distractors, with the N2pc being measured as an index of spatial selection. Temporal preparation accelerated the spatial selection of the target, as indexed by a reduction of the onset latency of the target N2pc. Furthermore, temporal preparation reduced the onset latency of the N2pc to a greater extent for low salient targets than for high salient targets. This result provides evidence that temporal preparation facilitates spatial selection as a function of stimulus salience. In addition, Study 3 aimed to further investigate the influence of temporal preparation on bottom-up and top-down processes in spatial selection. Therefore, participants (N = 24) performed a visual search task for a shape target while ignoring a color singleton distractor. Interestingly, temporal preparation also modulated the amplitude of the N2pc elicited by the salient but task-irrelevant distractor. This finding supports the notion that temporal preparation influences the processing of all salient stimuli in spatial selection, regardless of their task-relevance. Taken together, the results of the two ERP studies (Studies 2 and 3) provide evidence that temporal preparation facilitates spatial selection by influencing bottom-up processing

From point to area: Upscaling approaches for Late Quaternary archaeological and environmental data

The study of past socio-environmental systems integrates a variety of terrestrial archives. To understand regional or continental socio-environmental interactions proxy data from local archives need to be transferred to larger spatial scales. System properties like spatial heterogeneity, historical and spatial contingency, nonlinearity, scale dependency or emergence make generalizations from local observations to larger scales difficult. As these are common properties of natural and social systems, the development of an interdisciplinary upscaling framework for socio-environmental systems remains a challenge. For example, the integration of social and environmental data is often hindered by divergent methodological, i.e. qualitative and quantitative, approaches and discipline-specific perceptions of spatial scales. Additionally, joint approaches can be hampered by differences in the predictability of natural systems, which are subject to physical laws, and social systems, which depend on humans' decisions and communication. Here we present results from an interdisciplinary discussion of upscaling approaches in socio-environmental research with a special focus on the migration of modern humans in Central Europe during the last 30,000 years. Based on case studies from different disciplines, we develop a classification system for upscaling approaches used in past socio-environmental research. Finally, we present an initial upscaling framework that fosters the development of an interdisciplinary concept of scales and allows for a consideration of system properties like scale dependency, nonlinearity and contingency. The upscaling framework includes the following steps: i) the identification of relevant spatial and temporal scales at which socio-environmental interactions operate; ii) the definition of appropriate parameters to describe scale-specific interactions; iii) a comparison of process and observation scales to evaluate the potential of local archive data for larger scale generalization and for reconstructing scale-specific past socio-environmental interactions; iv) the identification and adaption of appropriate upscaling approaches for the relevant scales; v) the development of scale-specific models of socio-environmental interactions, and vi) the connection of models in a nested hierarchy. Our intention is not to present final results, but rather to stimulate future discussions and to provide a basic reference on scale issues in the emerging field of integrated socio-environmental research