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Open Access Publications from the University of California

Scholarly Works (974 results)

  • Article
LBL Publications (2011)
    Cover page: Early evolution of the LIM homeobox gene family
    • Article
    LBL Publications (1977)
      Cover page: PROTON INDUCED SWELLING IN TYPE 316 STAINLESS STEEL
      • Article
      Lawrence Berkeley National Laboratory (2011)
        Cover page: The Amphimedon queenslandica genome and the evolution of animal complexity
        • Article
        Lawrence Berkeley National Laboratory (2008)
          Cover page: The Trichoplax Genome and the Nature of Placozoans
          • Article
          • Peer Reviewed
          Proceedings of the Annual Meeting of the Cognitive Science Society, Volume 39 (2017)
          The question of whether people store absolute magnitude information or relative local comparisons of magnitudeshas remained unanswered despite persistent efforts over the last three decades to resolve it. Absolute identification is one of themost rigorous experimental benchmarks for evaluating theories of magnitude representation. We characterize difficulties withboth absolute and relative accounts of magnitude representation and propose an alternative account that potentially resolvesthese difficulties. We postulate that people store neither long-term internal referents for stimuli, not binary comparisons ofsize between successive stimuli. Rather, they obtain probabilistic judgments of size differences between successive stimuliand encode these for future use, within the course of identification trials. We set up a Bayesian ideal observer model for theidentification task using this representation of magnitude and propose a memory-sampling based approximation for solving it.Simulations suggest that the model adequately captures human behavior patterns in absolute identification.
            Cover page: Memory of relative magnitude judgments informs absolute identification
            • Article
            • Peer Reviewed
            Proceedings of the Annual Meeting of the Cognitive Science Society, Volume 41 (2019)
            This paper provides empirical evidence that human decision- makers use prospective regret minimization as their dominant decision strategy when regret calculations are cognitively easier to perform, and use expected utility maximization when they aren't. We designed a simple decision problem wherein utility maximization and expected regret minimization yield distinctly difference choices, and manipulated the cognitive effort involved in making regret calculations across respondent samples to arrive at our results. While previous research has associated ecological considerations like sense of responsibility and familiarity with this difference, we show that, at least in experimental settings, cognitive calculability in regret space appears to predominantly drive this difference. We also show that this preference for regret minimization can be countermanded by changing the distribution of options presented to the respondent, posing a challenge to simple sequential accounts of strategy selection learning which sequence strategy selection and application in order.
              Cover page: Decision-makers minimize regret when calculating regret is easy
              • Article
              • Peer Reviewed
              Proceedings of the Annual Meeting of the Cognitive Science Society, Volume 41 (2019)
              The classic drift diffusion model of the 2AFC choice processassumes that observers select evidence accumulation thresh-olds to optimize some desired level of accuracy across the ex-periment. We argue that it is more ecologically natural to as-sume that decision-makers set this threshold adaptively, usinginformation from recent trials to adjust it for upcoming ones.To test this hypothesis, we designed and conducted a pair ofrandom dot motion discrimination experiment where the co-herence parameter that controls task difficulty varies across tri-als in a predictable manner. To analyze data from these exper-iments, we also designed a hierarchical drift diffusion modelthat allows decision-makers to adapt their evidence thresholdbased on the trend of difficulty of previous trials. Our resultssuggest that observers rationally integrate cross-trial informa-tion about trial difficulty into perceptual decision-making byadjusting their internal evidence thresholds. We briefly discussthe implications of the existence of such trial-level effort infer-ence on contemporary models of the choice process.
                Cover page: Evidence for effort prediction in perceptual decisions
                • Article
                • Peer Reviewed
                Proceedings of the Annual Meeting of the Cognitive Science Society, Volume 37 (2015)
                We present a series of propositions that explains why people find sitting quietly in a dark room strongly aversive (Wilson et al., 2014). (i) Conflict-monitoring is an essential cognitive function; likely performed at the level of information processing conflicts (Botvinick et al, 2001) (ii) Memory is sensitized to processing conflicts; if a conflict has not been resolved in real-time, it is recalled when the mind is disengaged (iii) This is mind-wandering (Smallwood et al, 2003) (iv) Since mind-wandering privileges conflict recall for resolution, and resolving conflicts requires effort, mind-wandering becomes aversive (v) To avoid mind-wandering, a common strategy is to increase intensity of activity, so mind has no time to wander (vi) But increasing density of activity increases the number of possible information conflicts, which further deepens aversion to sitting quietly (vii) This is anxiety Understanding the cognitive mechanics of this spiral of anxiety may help break it
                  Cover page: The spiral of anxiety: a cognitive account
                  • Article
                  • Peer Reviewed
                  Proceedings of the Annual Meeting of the Cognitive Science Society, Volume 37 (2015)
                  Studies show that people can recognize their own movements, such as their own walking (presented in silhouette using point lights), their own drawing (presented as a moving point light), own clapping, and their own piano playing. We extend this result to proprioceptive control, showing that people can recognize their own eye movements, when presented as just a point moving against a black background. Eye movements were recorded using a wearable eye tracking glass, while participants executed four tasks. A week later, participants were shown these videos, alongside another person's videos, for each task, and asked to recognize their own movements. Males recognized their own eye movements significantly above chance, but only for tasks with large and familiar body movements. Females performed below chance in these tasks. We argue that the standard common coding/motor simulation model does not account for this result, and propose an extension where eye movements and body movements are strongly coupled. In this model, eye movements automatically trigger covert motor activation, and thus participate directly in motor planning, simulations and the sense of agency
                    Cover page: Eye to I: Males Recognize Own Eye Movements, Females Inhibit Recognition
                    • Thesis
                    • Peer Reviewed
                    UC Irvine Electronic Theses and Dissertations (2016)

                    Modeling capacity is an integral component towards multiple traffic engineering objectives such as design and evaluation of control strategies. Traffic dynamics at bottlenecks, both on freeways and on arterial networks, influenced by bounded acceleration and lane-changing, affect the capacity in intriguing ways. This research attempts to capture these impacts of the bounded acceleration behavior and its interplay with lane-changing, by constructing a modeling framework that accurately models traffic dynamics at bottlenecks.

                    Towards this goal, first a modified Cell Transmission Model (CTM) is proposed, by substituting the traditionally constant demand function with a linearly decreasing function for congested traffic. The jam-density discharge flow-rate is introduced as an additional parameter to characterize the macroscopic bounded acceleration effects. Analytically the new model is shown to reproduce observed features in the discharge flow-rate and headway at signalized intersections. Calibration with observations from existing studies, as well as new observations, further suggests that the model can reasonably capture all traffic queue discharge features.

                    The demand function is further modified by integrating macroscopic lane-changing effects on capacity. The Lane Changing Bounded Acceleration CTM (LCBA-CTM) thus developed, is shown to realistically model the capacity drop phenomenon at active freeway lane-drop bottlenecks in stationary states. The capacity drop magnitude is determined by macroscopic bounded acceleration and lane-changing characteristics. Constant loading problems are analytically solved to reveal the onset and recession processes of congestion.

                    An addition to the framework connects microscopic acceleration profiles of vehicles to modified demand functions. This completes the framework presented by offering a mechanism to start from any acceleration model.

                    Finally, two applications of the modified CTM are presented illustrating the use of the framework: a) to model impacts of improved vehicle acceleration on traffic dynamics at intersections; and b) to create Macroscopic Fundamental Diagrams (MFDs) for arterial networks and compare their accuracy with traditional CTM methods.

                    This dissertation offers a systematic approach to incorporating bounded acceleration and lane-changing into the CTM demand functions. Such an approach is shown to capture important static and dynamic features at critical bottlenecks, including lost time and queue discharge features at signalized intersections, as well as capacity drop magnitude and the onset of capacity drop at active freeway bottlenecks. The consistency between the modified demand function and microscopic bounded acceleration models is also established.

                      Cover page: Modified Cell Transmission Model for Bounded AccelerationCreative Commons 'BY' version 4.0 license
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