Simulation à la Goldman: pretend and collapse

Theories of mind draw on processes that represent mental states and their computational connections; simulation, in addition, draws on processes that replicate (Heal 1986) a sequence of mental states. Moreover, mental simulation can be triggered by input from imagination instead of real perceptions. To avoid confusion between mental states concerning reality and those created in simulation, imagined contents must be quarantined. Goldman bypasses this problem by giving pretend states a special role to play in simulation (Goldman 2006). We argue that this path leads to the resurgence of the threat of collapse (Davies 1994), diluting the principled distinction between simulation and theory use. Exploration of a related method of real-mental states operating in a pretend mode leads to a factually untenable model. Our main goal here is to raise this problem as a challenge for Goldman’s reconfigured simulation theory. Only at the end we will briefly sketch a possible alternative way of quarantine that preserves the replicative element of simulation and avoids collapse. Figure 1 provides a guide to our argument. Fig. 1 Structure of argument

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Automated gait analysis in the open-field test for laboratory mice

In this article, an automated and accurate mouse observation method, based on a conventional test for motor function evaluation, is outlined. The proposed measurement technique was integrated in a regular open-field test, where the trajectory and locomotion of a free-moving mouse were measured simultaneously. The system setup consisted of a transparent cage and a camera placed below it with its lens pointing upward, allowing for images to be captured from underneath the cage while the mouse was walking on the transparent cage floor. Thus, additional information was obtained about the position of the limbs of the mice for gait reconstruction. In a first step, the camera was calibrated as soon as it was fixed in place. A linear calibration factor, relating distances in image coordinates to real-world dimensions, was determined. In a second step, the mouse was located and its body contour segmented from the image by subtracting a previously taken “background” image of the empty cage from the camera image. In a third step, the movement of the mouse was analyzed and its speed estimated from its location in the past few images. If the speed was above a 1-sec threshold, the mouse was recognized to be running, and the image was further processed for footprint recognition. In a fourth step, color filtering was applied within the recovered mouse region to measure the position of the mouse’s paws, which were visible in the image as small pink spots. Paws that were detected at the same location in a number of subsequent images were kept as footprints—that is, paws in contact with the cage floor. The footprints were classified by their position relative to the mouse’s outline as corresponding to the front left or right paw or the hind left or right paw. Finally, eight parameters were calculated from the footprint pattern to describe the locomotion of the mouse: right/left overlap, front/hind base, right/left front limb stride, and right/left hind limb stride. As an application, the system was tested using normal mice and mice displaying pentobarbital-induced ataxia. The footprint parameters measured using the proposed system showed differences of 10% to 20% between normal and ataxic mice.     

Episodic memory development: theory of mind is part of re‐experiencing experienced events

Two experiments with 3½‐ to 6½‐year‐old children showed that theory‐of‐mind development is associated with the growth of episodic memory. Episodic memory was assessed by manipulating informational conditions such that they permit or prevent the formation of episodic memories in terms of re‐experiencing the recalled event. Only experienced events, e.g. seeing how one puts a picture of a frog into a box, can be remembered by re‐experience. Events known through indirect information cannot be re‐experienced, e.g. putting pictures into the box when blindfolded and being later shown on video what was on these cards. Children were also tested on a battery of theory‐of‐mind tasks assessing their understanding of the origins of knowledge. There was a significant interaction in both experiments showing that recall of directly experienced items improved in relation to indirectly presented items the higher children's theory‐of‐mind scores. The discussion suggests that episodic memory development is specifically linked to the growing ability to introspect an ongoing experience and interpret it as representing an actual past event. Copyright © 2007 John Wiley & Sons, Ltd.     

Der biopsychosoziale Krankheitsbegriff in der Praxis

Many of the recent approaches in diagnostics and therapy, e. g. the behavioral medicine, consider themselves as “holistic” or “multidimensional”. By closer consideration, however, it turns out, that while more or less referring back to the system-theoretically founded “bio-psycho-social model” (Engel, Weiner et al.) its implications are not taken seriously in practice. Presenting a concrete work project (“simultaneous diagnostics”) we will show, how to implement this (theoretically potent) bio-psycho-social conception of disease in clinical practice. It can be clearly seen, that it cannot replace the conventional reductional approach of medicine which focusses on the examination of single processes and structures under simplified conditions. On the contrary, such reductionism remains indispensable, because to be able to grasp any higher (more complex) structure one has to know its elements. Comprehensive explanation of phenomena, however, is not possible in a reductionist way. Therefore, the bio-psycho-social disease model in its operationalization is not a new way of medicine, rather an expanded approach to diagnostical and therapeutic issues.     

Use of current explanations in multicausal abductive reasoning

In multicausal abductive tasks a person must explain some findings by assembling a composite hypothesis that consists of one or more elementary hypotheses. If there are n elementary hypotheses, there can be up to 2ⁿ composite hypotheses. To constrain the search for hypotheses to explain a new observation, people sometimes use their current explanation—the previous evidence and their present composite hypothesis of that evidence; however, it is unclear when and how the current explanation is used. In addition, although a person's current explanation can narrow the search for a hypothesis, it can also blind the problem solver to alternative, possibly better, explanations. This paper describes a model of multicausal abductive reasoning that makes two predictions regarding the use of the current explanation. The first prediction is that the current explanation is not used to explain new evidence if there is a simple (i.e., nondisjunctive, concrete) hypothesis to account for that evidence. The second prediction is that the current explanation is used when attempting to discriminate among several alternative hypotheses for new evidence. These hypotheses were tested in three experiments. The results are consistent with the second prediction: the current explanation is used when discriminating among alternative hypotheses. However, the first prediction—that the current explanation is not used when a simple hypothesis can account for new data—received only limited support. Participants used the current explanation to constrain their interpretation of new data in 46.5% of all trials. This suggests that context-independent strategies compete with context-dependent ones—an interpretation that is consistent with recent work on strategy selection during problem solving.