Using a virtual reality system to study balance and walking in a virtual outdoor environment: a pilot study.

Falls and fall-related injuries are a major problem for elderly persons. Most falls occur during walking and turning, and the risk of falling increases when attention is diverted to something besides walking. It is often difficult to standardize methods for testing balance and fall tendency in a clinically relevant setting. We describe the development of a system using a virtual environment (VE) to assess how attention demanding and unexpected events influence a person's capacity to control balance and movement. The hardware in the system consists of a head-mounted display (HMD), a magnetic tracker system, and two SGI computers. The software consists of the image generation of the VE and the management and visualization of motion tracking data. In a preliminary pilot study eight subjects (age 23-80) participated. Each subject walked on a normal floor and was visually presented a familiar outdoor environment in the HMD. They were exposed to different unexpected events, such as a virtual snowfall and tilting of the VE. Disturbances of balance and walking patterns such as changes in speed, stride length and balance reactions like slipping were observed. Two subjects experienced symptoms of cyber sickness with a SSQ score above 25 points. Walking with sensors only did not affect walking time, but in VE the subjects generally walked more slowly. Virtual tilting of the environment had an impact on balance performance during walking. This effect was not observed while the test subjects were walking in a virtual snowfall. The model needs further development but may hold a potential for clinical use.     

Testing for the presence of 1/f noise in continuation tapping data.

A number of recent papers have suggested that the series of time intervals produced in continuation tapping may have fractal properties. This proposition, nevertheless, was only based on the visual appraisal of graphical results, and was not statistically supported. In the present study, we applied the ARMA/ARFIMA modeling procedures proposed by Wagenmakers, Farrell, and Ratcliff (2005) to test for the presence of long-range dependencies in continuation tapping data. Our results demonstrate the presence of long-range dependencies in most series and offer strong support for the hypothesis that fluctuations in tapping series are fractal in nature.     

Radical Innovation and End-User Involvement: The Ambilight Case

To make technology research more effective and to deal with fierce cost competition, technology research should be more focused on radical innovation and needs to adopt a more end-user-focused approach. Product improvement is already quite often building on knowledge collected around consumers’ experiences with these products to come with a next, improved generation of products. However, in case of creating novel products from “scratch,” this will be more difficult. The user-centered research approach including insights, scenarios, and experience prototypes provides a good method to incorporate the consumer perspective in the earliest stages of the product creation process. The development of the Ambilight TV will be used as a case to illustrate this approach.     

Defining task-set reconfiguration: The case of reference point switching

Some researchers argue that task switching involves task-set reconfiguration-that is, changing the existing task set to perform a different task. Although this idea is intriguing, it is often unclear what is reconfigured and which processes are involved in reconfiguration. We addressed these issues by defining task sets, identifying differences between them, and obtaining evidence that was diagnostic of reconfiguration. In two experiments, subjects performed relative judgment tasks that involved comparing a target with a reference point that repeated or switched across trials. The task was the same on every trial, but the task set was not, because a task-set parameter-the reference point-had to be changed. Target-reference point distance effects that changed with the reference point provided diagnostic evidence that reconfiguration occurred, and this reconfiguration led to switch costs. We discuss how our approach can be generalized to define reconfiguration more clearly in other task-switching situations. nt|mis|This research was supported by Grants BCS 0133202 and BCS 0446806 from the National Science Foundation to G.D.L.     

Seven principles of goal activation: a systematic approach to distinguishing goal priming from priming of non-goal constructs.

Countless studies have recently purported to demonstrate effects of goal priming; however, it is difficult to muster unambiguous support for the claims of these studies because of the lack of clear criteria for determining whether goals, as opposed to alternative varieties of mental representations, have indeed been activated. Therefore, the authors offer theoretical guidelines that may help distinguish between semantic, procedural, and goal priming. Seven principles that are hallmarks of self-regulatory processes are proposed: Goal-priming effects (a) involve value, (b) involve postattainment decrements in motivation, (c) involve gradients as a function of distance to the goal, (d) are proportional to the product of expectancy and value, (e) involve inhibition of conflicting goals, (f) involve self-control, and (g) are moderated by equifinality and multifinality. How these principles might help distinguish between automatic activation of goals and priming effects that do not involve goals is discussed.     

Using the Internet to find offline sex partners.

We aimed to expand upon the demographic characteristics and gender differences among those who have met someone on the Internet who they later met offline and had sex with as well as any relationship with cybersex, sexually transmitted infections, and online sexual problems. We analyzed data collected through an online questionnaire in 2002 in Sweden including a total population of 1836 respondents of which 1458 used the Internet for sexual purposes. Of those, 35% men and 40% women reported to have met offline sex partners online. The majority reported an occurrence of one to two times, whereas 10% reported six or more times. The analysis suggested women aged 34-49 and 50-65 years, homo- and bisexual men, and singles more likely to have this experience. They were also more likely to have engaged in cybersex. No relationships were found with sexually transmitted infections or online sexual problems. The results suggest that using the Internet to find sex partners may be less hazardous for the general Internet users than pointed out by prior research about this behavior often focusing on specific sub groups of Internet users.     

Feeling of knowing for names in response to faces

Participants were asked to recall the names when shown photographs of faces in both a semantic task (Experiment 1) and an episodic task (Experiments 2 and 3). When recall failed, feeling of knowing (FOK) ratings were solicited. In addition, participants reported on the strategies that they used to make their ratings, whether they could recall other pieces of information (the target-accessibility strategy, e.g., Koriat, A. (1993). How do we know that? The accessibility model of the feeling of knowing. Psychological Review, 100, 609–639) or whether the faces simply looked familiar (the cue-familiarity strategy, e.g., Schwartz, B. L., & Metcalfe, J. (1992). Cue familiarity but not target accessibility enhances feeling of knowing ratings. Journal of Experimental Psychology: Learning, Memory, and Cognition, 18, 1074–1083). In all experiments, FOK ratings were fairly accurate in that participants were successful in predicting their performance on a subsequent recognition test. More importantly, participants reported using the cue-familiarity strategy more often, although they gave higher FOK ratings when they reported using the target-accessibility strategy. The FOK ratings that were given using the two strategies were equally accurate.     

Mereological vagueness and existential vagueness

It is often assumed that indeterminacy in mereological relations—in particular, indeterminacy in which collections of objects have fusions—leads immediately to indeterminacy in what objects there are in the world. This assumption is generally taken as a reason for rejecting mereological vagueness. The purpose of this paper is to examine the link between mereological vagueness and existential vagueness. I hope to show that the connection between the two forms of vagueness is not nearly so clear-cut as has been supposed.     

A Structural Analysis of the Phlogiston Case

The incommensurability thesis, as introduced by T.S. Kuhn and P.K. Feyerabend, states that incommensurable theories are conceptually incompatible theories which share a common domain of application. Such claim has often been regarded as incoherent, since it has been understood that the determination of a common domain of application at least requires a certain degree of conceptual compatibility between the theories. The purpose of this work is to contribute to the defense of the notion of local or gradual incommensurability, as proposed by late Kuhn. The application of this notion would allow to render the incommensurability thesis coherent. To support this view, a typical example of incommensurability will be formally analyzed by applying the structuralist metatheory developed, among others by W. Balzer, C.U. Moulines and J.D. Sneed. The structural reconstruction of the relation between the phlogiston theory and the oxygen theory offered here will reveal that they are locally incommensurable, and will even make possible to determine the ontological reduction relation that they also exemplify.

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A standardized set of 260 pictures for Modern Greek: Norms for name agreement, age of acquisition, and visual complexity

The appropriate selection of both pictorial and linguistic experimental stimuli requires a previous languagespecific standardization process of the materials across different variables. Considering that such normative data have not yet been collected for Modern Greek, in this study normative data for the color version of the Snodgrass and Vanderwart picture set (Rossion & Pourtois, 2004) were collected from 330 native Greek adults. Participants named the pictures (providing name agreement ratings) and rated them for visual complexity and age of acquisition. The obtained measures represent a useful tool for further research on Greek language processing and constitute the first picture normative study for this language. The picture norms from this study and previous ones may be downloaded from brm.psychonomic-journals.org/content/supplemental.