Acquisition vs. Memorization Trade-Offs Are Modulated by Walking Distance and Pattern Complexity in a Large-Scale Copying Paradigm

In a “block-copying paradigm”, subjects were required to copy a configuration of colored blocks from a model area to a distant work area, using additional blocks provided at an equally distant resource area. Experimental conditions varied between the inter-area separation (walking distance) and the complexity of the block patterns to be copied. Two major behavioral strategies were identified: in the memory-intensive strategy, subjects memorize large parts of the pattern and rebuild them without intermediate visits at the model area. In the acquisition-intensive strategy, subjects memorize one block at a time and return to the model after having placed this block. Results show that the frequency of the memory-intensive strategy is increased for larger inter-area separations (larger walking distances) and for simpler block patterns. This strategy-shift can be interpreted as the result of an optimization process or trade-off, minimizing combined, condition-dependent costs of the two strategies. Combined costs correlate with overall response time. We present evidence that for the memory-intensive strategy, costs correlate with model visit duration, while for the acquisition-intensive strategy, costs correlate with inter-area transition (i.e., walking) times

Places - Routes - Maps: Acquisition, structure and usage of place representations in spatial cognition

Für das Leben und überleben von Tieren und Menschen sind nur wenige kognitive Mechanismen so fundamental wie die Fähigkeit sich in der Umwelt zu orientieren. Diese Orientierungsfähigkeit bildete den Rahmen der vorliegenden Arbeit, die sich auf die Erkennung und die kognitive Repräsentation von Orten konzentrierte. Das einzelne Orte bereits mit geringer sensorischer und verarbeitender Kapazität erkannt und unterschieden werden können, konnte in einer Computersimulation zum Orientierungsverhalten von Wüstenameisen gezeigt werden. Einfache visuelle Merkmale, wie sie in der natürlichen Umgebung der Tiere vorkommen, sind dabei für die Orientierung ausreichend. In einem Verhaltensexperiment beim Menschen konnte nicht nur der Aufbau von einzelnen Ortsrepräsentationen, sondern auch deren Integration in Routen- und Kartenrepräsentationen beobachtet werden. Dabei zeigte sich, dass abhängig davon, ob vermehrt lokale oder globale Strukturen zur Orientierung genutzt wurden, auch verstärkt eine Routen- oder Kartenrepräsentation aufgebaut wurde. Die verschiedenen Raumrepräsentationen selbst stehen in Verbindung mit unterschiedlich komplexen Verhaltensmustern und der Interaktion zwischen Arbeits- und Langzeitgedächtnis. Auf Grundlage dieser Zusammenhänge wurde ein allgemeiner Rahmen formuliert, in dem Orientierungsverhalten, ökologische Voraussetzungen und neuronale Mechanismen diskutiert wurden. In einem weiteren Experiment konnte gezeigt werden, dass der Abruf von Ortswissen aus dem Langzeitgedächtnis in perspektivischer egozentrischer Form erfolgt, wobei eine bevorzugte Perspektive nicht nur von den Strukturen eines Ortes bestimmt wurde, sondern auch situations- und aufgabenabhängig war. Die einzelnen Arbeiten der vorliegenden kumulativen Dissertation zeigen die unterschiedlichen Stufen von einfacher Ortserkennung über den Aufbau einer Raumrepräsentation bis hin zu Verwendung solcher Repräsentationen aus dem Langzeitgedächtnis. Dabei wurden sowohl bestehende Konzepte der Raumkognition diskutiert und ergänzt, als auch weitere Grundlagen für die Entwicklung theoretischer Modelle und künstlicher Systeme geschaffen.Finding one's way in the environment is a core cognitive function in animal kingdom. The underlying navigational abilities are the basis of the present work that explores recognition abilities and cognitive representations of place knowledge. Single places can be recognised already with a basic sensor system and low processing capacity as shown in a computer simulation of navigational abilities of desert ants. Basic visual features of the animal's environment (i.e. the skyline) are sufficient for distinction and recognition of places. In a behavioural study with humans could not only the acquisition of place knowledge be observed but as well the integration of places into route and survey representations. Results show that participants built up route knowledge or survey knowledge depending on wether they use local or global structures of the environment for wayfinding. Different mental representations of spatial knowledge are linked to behavioural patterns of different complexity and the interaction of working and long-term memory. On basis of these interactions an overall framework of spatial cognition is provided with respect to navigational abilities, ecological requirements and neuronal mechanisms Further, place knowledge recalled from existing long-term representations exhibit a viewdependent egocentric characteristic. The preferred perspective depends not only on the structure of the recalled place but also on the current task and situational state. The presented projects of this dissertation show an increasing complexity beginning with simple place recognition and acquisition of spatial knowledge up to recall of spatial long-term memory. Existing concepts of spatial cognition are discussed and extended as well as novel design concepts for the development of theoretical models and artificial systems are presented

Prefrontal cortical mechanisms underlying individual differences in cognitive flexibility and stability

Contains fulltext : 102813-OA.pdf (publisher's version ) (Open Access)The pFC is critical for cognitive flexibility (i.e., our ability to flexibly adjust behavior to changing environmental demands), but also for cognitive stability (i.e., our ability to follow behavioral plans in the face of distraction). Behavioral research suggests that individuals differ in their cognitive flexibility and stability, and neurocomputational theories of working memory relate this variability to the concept of attractor stability in recurrently connected neural networks. We introduce a novel task paradigm to simultaneously assess flexible switching between task rules (cognitive flexibility) and task performance in the presence of irrelevant distractors (cognitive stability) and to furthermore assess the individual "spontaneous switching rate" in response to ambiguous stimuli to quantify the individual dispositional cognitive flexibility in a theoretically motivated way (i.e., as a proxy for attractor stability). Using fMRI in healthy human participants, a common network consisting of parietal and frontal areas was found for task switching and distractor inhibition. More flexible persons showed reduced activation and reduced functional coupling in frontal areas, including the inferior frontal junction, during task switching. Most importantly, the individual spontaneous switching rate antagonistically affected the functional coupling between inferior frontal junction and the superior frontal gyrus during task switching and distractor inhibition, respectively, indicating that individual differences in cognitive flexibility and stability are indeed related to a common prefrontal neural mechanism. We suggest that the concept of attractor stability of prefrontal working memory networks is a meaningful model for individual differences in cognitive stability versus flexibility.15 p

ARE WE PLAYING YET? A REVIEW OF GAMIFIED ENTERPRISE SYSTEMS

Gamification as the application of game elements to non-game contexts tries to take advantage of the increasing popularity of video games in order to motivate people. It thus bears the potential to be effectively applied to companies, in particular to gamify enterprise systems, which are embedded into organizational processes. Based on insights from previous research concerning game elements (i.e., mechanics and dynamics; short M&Ds), we provide an overview of M&Ds actually integrated in enterprise systems to increase employee motivation and engagement, while at the same time providing implications for future applications of and research on Gamification

Task setup and analysis of walking trajectory.

<p>a) Scheme of the experimental setup with the spatial arrangement of the three operating areas (M: model, W: workspace, R: resource area, S: start and end point of a subjects' trajectory) for the two distance conditions (black boxes: far distance condition, gray boxes: near distance condition). b) Example of a subject's single trial trajectory in the long distance and complex pattern condition. Temporal course is coded with a gray-scale gradient. b) Relevant sub-strategies (together with their names) and their demand on WM from low to high usage. The W-M-W sub-strategy was applied as ‘control’ strategy without any block operation. ‘Other’ denotes all remaining sub-strategies which had individual frequencies of occurrence below 2% (for a detailed explanation see section ‘walking sub-strategies’).</p

Sub-strategy characterization.

<p>Characterization of all sub-strategies used by subjects for the purpose of copying a block regarding the involvement of memory (M: model, W: workspace, and R: resource area). Each sub-strategy is given a name which is used throughout the manuscript.</p

Task performance: error rate and overall response time.

<p>a) Box-Whisker plot of proportion of errors made during copying the ten simple patterns (left) and the ten complex patterns (right) for the far and the near distance conditions. Black boxes display the pattern errors: the proportion of false on all patterns (n = 10) averaged over subjects of the respective group. White boxes display the block errors: the proportion of false blocks on all blocks in all ten patterns (n = 6 blocks×10 patterns = 60) averaged over subjects of the respective group. b) Box-Whisker plot of response time to complete a single trial averaged over all subjects of the respective group for the simple (left) and complex (right) pattern situations and for the far (black boxes) and near (gray boxes) distance conditions. Statistical effects (post-hoc analyses) are presented for each pattern complexity/distance combination (^★p<.05; ^★★p<.01; ^★★★ p<.001).</p

Proportion of walking sub-strategies.

<p>Box-Whisker plot of proportion of walking sub-strategies used by subjects during copying the simple patterns (left) and the complex patterns (right) averaged over all subjects of the respective group. Black boxes display the frequencies of walking sub-strategies for the far distance condition and gray boxes these for the near distance condition. Post-hoc analyses are calculated for ‘low-memory’ and ‘high-memory’ referring the proportion of walking sub-strategies between far and near and simple and complex pattern conditions (^★p<.05; ^★★p<.01; ^★★★ p<.001; n.s. not significant). The characteristics of all individual sub-strategies are explained in detail in the results chapter (see section ‘walking sub-strategies’).</p

Linear cost optimization.

<p>Experimental data for a) costs for memorization (i.e., duration of 1st model visit) with power function fits for simple (dashed line) and complex (dotted line) patterns, b) costs for acquisition (i.e., overall time for transitions) with linear regression lines for near (gray) and far conditions (black), and c) total time costs (i.e., overall response time; regressions indicate quadratic functions). All data are shown as a function of the ratio between ‘high-memory’ and ‘low-memory’ sub-strategies. d) Model: Total costs are divided in costs for memorization (C<b>_Me</b>) and acquisition (C<b>_Ac</b>). If more information is processed at each model visit (i.e., if the task is solved with fewer visits), memory costs increase while acquisition costs decrease. These individual costs vary also with the experimental conditions for walking distance (near and far) and pattern complexity (simple and complex). Total costs for the complex/far condition are depicted as the sum of the according individual cost curves (blue line), leading to an optimum of processed information per model visit at point <i>b</i>. The location of each optimum for the four experimental groups is indicated with <i>a–d</i>.</p