Conceptualization and implementation of a multi-agent model to simulate whale-watching tours in the St. Lawrence Estuary in Quebec, Canada

The Saguenay St. Lawrence Marine Park (SSLMP) and the adjacent Marine Protected Area (MPA) in the St. Lawrence Estuary, in Quebec, cover a territory of exceptional biodiversity including 12 species of marine mammals, nearly half of which are considered to be endangered species. Whale-watching trips and other human activities related to commercial shipping, tourism, and recreation generate very intensive traffic in the area, which pose cumulative threats to the marine wildlife. This study has been undertaken in collaboration with the Marine Park and the MPA managers to develop a multi-agent system (MAS) to investigate the interactions between the traffic and the marine mammals in the estuary. This paper describes the first prototype version of the proposed MAS model where the focus is on the whale-watching boats. It discusses the conceptual model with its principal components: the physical environment and the boat agents and whale entities, and the implementation of the model with the behavior rules of the agents. In this version of the MAS, the whale-watching boats are represented as cognitive agents while the whales are simple reactive entities. The prototype model was implemented in the agent-based modeling platform RePast. An index, the happiness factor (i.e., the ratio of whale observation time over the trip duration) was designed to measure how successful the boat agents are in achieving their goal. Simulations were run to assess different decision strategies of the boat agents and their impacts on the whales. Results show that cooperative behavior that involves a combination of innovator and imitator strategies yields a higher average happiness factor over non-cooperative, purely innovators, behavior. However, this cooperative behavior creates increased risk for the whale populations in the estuary.     

Fluency heuristic: A model of how the mind exploits a by-product of information retrieval.

Boundedly rational heuristics for inference can be surprisingly accurate and frugal for several reasons. They can exploit environmental structures, co-opt complex capacities, and elude effortful search by exploiting information that automatically arrives on the mental stage. The fluency heuristic is a prime example of a heuristic that makes the most of an automatic by-product of retrieval from memory, namely, retrieval fluency. In 4 experiments, the authors show that retrieval fluency can be a proxy for real-world quantities, that people can discriminate between two objects' retrieval fluencies, and that people's inferences are in line with the fluency heuristic (in particular fast inferences) and with experimentally manipulated fluency. The authors conclude that the fluency heuristic may be one tool in the mind's repertoire of strategies that artfully probes memory for encapsulated frequency information that can veridically reflect statistical regularities in the world. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Bayesian model for implicit effects in perceptual identification.

Retrieving effectively from memory (REM; R. M. Shiffrin & M. Steyvers, 1997), an episodic model of memory, is extended to implicit memory phenomena, namely the perceptual identification studies reported in R. Ratcliff and G. McKoon (1997). In those studies, the influence of prior study was greatest when words were presented most briefly and when forced-choice targets and foils were most similar. R. Ratcliff and G. McKoon use these data to argue against models in which prior study changes a word's representation. A model in which prior study changes a word's representation by adding context information is fit to their data; at test, the model uses a Bayesian decision process to compare the perceptual and context features associated with the test flash to stored traces. The effects of prior study are due to matching extra context information and are larger when alternatives share many features, thereby reducing noise that attenuates these effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The aging decision maker: Cognitive aging and the adaptive selection of decision strategies.

Are older adults' decision abilities fundamentally compromised by age-related cognitive decline? Or can they adaptively select decision strategies? One study (N = 163) investigated the impact of cognitive aging on the ability to select decision strategies as a function of environment structure. Participants made decisions in either an environment that favored the use of information-intensive strategies or one favoring the use of simple, information-frugal strategies. Older adults tended to (a) look up less information and take longer to process it and (b) use simpler, less cognitively demanding strategies. In accordance with the idea that age-related cognitive decline leads to reliance on simpler strategies, measures of fluid intelligence explained age-related differences in information search and strategy selection. Nevertheless, both young and older adults seem to be equally adapted decision makers in that they adjust their information search and strategy selection as a function of environment structure, suggesting that the aging decision maker is an adaptive one. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Connections between the pontine central gray and the ventromedial hypothalamus are essential for lordosis in female rats.

Lesions and knife cuts were used to study central gray (CG) and ventromedial hypothalamic (VMH) mediation of sexual receptivity in female rats. Lesions of the midbrain–pontine CG eliminated lordosis in female rats. Bilateral sagittal knife cuts that bracketed the rostral pontine CG also eliminated lordosis, and an experiment with the retrograde tracer Fluoro-Gold confirmed the effectiveness of these cuts in severing the lateral connections linking the VMH and the CG. Finally, females with a unilateral hypothalamic cut combined with a contralateral CG transection almost never showed lordosis. Each cut, at a different level for each side of the brain, transected axons linking the VMH and the CG. The demonstration that this combination eliminated lordosis provides new evidence that the lateral connections between the VMH and the CG are essential for the display of sexual receptivity in female rats. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive niches: An ecological model of strategy selection.

How do people select among different strategies to accomplish a given task? Across disciplines, the strategy selection problem represents a major challenge. We propose a quantitative model that predicts how selection emerges through the interplay among strategies, cognitive capacities, and the environment. This interplay carves out for each strategy a cognitive niche, that is, a limited number of situations in which the strategy can be applied, simplifying strategy selection. To illustrate our proposal, we consider selection in the context of 2 theories: the simple heuristics framework and the ACT–R (adaptive control of thought—rational) architecture of cognition. From the heuristics framework, we adopt the thesis that people make decisions by selecting from a repertoire of simple decision strategies that exploit regularities in the environment and draw on cognitive capacities, such as memory and time perception. ACT–R provides a quantitative theory of how these capacities adapt to the environment. In 14 simulations and 10 experiments, we consider the choice between strategies that operate on the accessibility of memories and those that depend on elaborate knowledge about the world. Based on Internet statistics, our model quantitatively predicts people's familiarity with and knowledge of real-world objects, the distributional characteristics of the associated speed of memory retrieval, and the cognitive niches of classic decision strategies, including those of the fluency, recognition, integration, lexicographic, and sequential-sampling heuristics. In doing so, the model specifies when people will be able to apply different strategies and how accurate, fast, and effortless people's decisions will be. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

笔记本电脑重返“大”时代

“起点即是终点，终点即是起点。”许多事物都在经历着无限的反复轮回，如此的实例我们看得太多，也听得太多。随着三星宣布世界上第一款19英寸笔记本电脑M70的诞生，我们看到，笔记本电脑也开始踏入新的轮回之中。     

Cognitive aging and the adaptive use of recognition in decision making.

The recognition heuristic, which predicts that a recognized object scores higher on some criterion than an unrecognized one, is a simple inference strategy and thus an attractive mental tool for making inferences with limited cognitive resources—for instance, in old age. In spite of its simplicity, the recognition heuristic might be negatively affected in old age by too much knowledge, inaccurate memory, or deficits in its adaptive use. Across 2 studies, we investigated the impact of cognitive aging on the applicability, accuracy, and adaptive use of the recognition heuristic. Our results show that (a) young and old adults’ recognition knowledge was an equally useful cue for making inferences about the world; (b) as with young adults, old adults adjusted their use of the recognition heuristic between environments with high and low recognition validities; and (c) old adults, however, showed constraints in their ability to adaptively suspend the recognition heuristic on specific items. Measures of fluid intelligence mediated these age-related constraints. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A signal-detection analysis of fast-and-frugal trees.

Models of decision making are distinguished by those that aim for an optimal solution in a world that is precisely specified by a set of assumptions (a so-called “small world”) and those that aim for a simple but satisfactory solution in an uncertain world where the assumptions of optimization models may not be met (a so-called “large world”). Few connections have been drawn between these 2 families of models. In this study, the authors show how psychological concepts originating in the classic signal-detection theory (SDT), a small-world approach to decision making, can be used to understand the workings of a class of simple models known as fast-and-frugal trees (FFTs). Results indicate that (a) the setting of the subjective decision criterion in SDT corresponds directly to the choice of exit structure in an FFT; (b) the sensitivity of an FFT (measured in d′) is reflected by the order of cues searched and the properties of cues in an FFT, including the mean and variance of cues' individual d′s, the intercue correlation, and the number of cues; and (c) compared with the ideal and the optimal sequential sampling models in SDT and a majority model with an information search component, FFTs are extremely frugal (i.e., do not search for much cue information), highly robust, and well adapted to the payoff structure of a task. These findings demonstrate the potential of theory integration in understanding the common underlying psychological structures of apparently disparate theories of cognition. (PsycINFO Database Record (c) 2011 APA, all rights reserved)