A wholly empirical explanation of perceived motion

Because the retinal activity generated by a moving object cannot specify which of an infinite number of possible physical displacements underlies the stimulus, its real-world cause is necessarily uncertain. How, then, do observers respond successfully to sequences of images whose provenance is ambiguous? Here we explore the hypothesis that the visual system solves this problem by a probabilistic strategy in which perceived motion is generated entirely according to the relative frequency of occurrence of the physical sources of the stimulus. The merits of this concept were tested by comparing the directions and speeds of moving lines reported by subjects to the values determined by the probability distribution of all the possible physical displacements underlying the stimulus. The velocities reported by observers in a variety of stimulus contexts can be accounted for in this way.

Rates and the housing question in London : an argument for the rating of site values /

Reprinted by permission from the final volume of "Life and labour of the people of London."

Instructions for use in preparation for the rating of bugler, U.S. navy; a manual for buglers prepared under the supervision of the Bureau of navigation.

At head of title: United States Navy dept. Bureau of navigation.

Factory accounts, their principles and practie; a handbook for accountants and manufacturers with appendices on the nomenclature of machine details; the income tax acts, the rating of factories; fire and boiler insurance, etc.

Printed in Great Britain.

Rating of mines and quarries being a short treatise on the law of rating generally and in its special application to mines, iron works and quarries.

Mode of access: Internet.

Measurement and prediction of energy expenditure in males during household and garden tasks

Participation in at least 30 min of moderate intensity activity on most days is assumed to confer health benefits. This study accordingly determined whether the more vigorous household and garden tasks (sweeping, window cleaning, vacuuming and lawn mowing) are performed by middle-aged men at a moderate intensity of 3-6 metabolic equivalents (METs) in the laboratory and at home. Measured energy expenditure during self-perceived moderate-paced walking was used as a marker of exercise intensity. Energy expenditure was also predicted via indirect methods. Thirty-six males [Xmacr (SD): 40.0 (3.3) years; 179.5 (6.9) cm; 83.4 (14.0) kg] were measured for resting metabolic rate (RMR) and oxygen consumption (V.O-2) during the five activities using the Douglas bag method. Heart rate , respiratory frequency, CSA (Computer Science Applications) movement counts, Borg scale ratings of perceived exertion and Quetelet's index were also recorded as potential predictors of exercise intensity. Except for vacuuming in the laboratory, which was not significantly different from 3.0 METs (P=0.98), the MET means in the laboratory and home were all significantly greater than 3.0 (Pless than or equal to0.006). The sweeping and vacuuming MET means were significantly higher (P

Reacting to an assumed situation vs. conforming to an assumed reaction: The role of perceived speaker attitude in vicarious dissonance

Witnessing an ingroup member acting against his or her belief can lead individuals who identify with that group to change their own attitude in the direction of that counterattitudinal behavior. Two studies demonstrate this vicarious dissonance effect among high ingroup identifiers and show that this attitude change is not attributable to conformity to a perceived change in speaker attitude. Study I shows that the effect occurs-indeed, is stronger-even when it is clear that the speaker disagrees with the position espoused, and Study 2 shows that foreseeable aversive consequences bring about attitude change in the observer without any parallel impact on the perceived attitude of the speaker. Furthermore, the assumption that vicarious dissonance is at heart a group phenomenon is supported by the results indicating that attitude change is not impacted either by individual differences in dispositional empathy or measures of interpersonal affinity.

Why do people engage in collective action? Revisiting the role of perceived effectiveness

Research has shown limited support for the notion that perceived effectiveness of collective action is a predictor of intentions to engage in collective action. One reason may be that effectiveness has been in terms of whether the action will influence key decision makers. We argue that the effectiveness of collective action might be judged by other criteria, such as whether it influences third parties, builds an oppositional movement, and expresses values. Two hundred and thirty one attendees at a rally rated the effectiveness of the rally and their intentions to engage in future collective action. For those participants who were not members of an organization, intentions were linked to the perceived effectiveness of the rally in expressing values and influencing the public. For those who were members of an organization, intentions were linked only to the effectiveness of the rally in building an oppositional movement.

Multidimensional analysis of perceived risk in commercial air travel

This study attempts to assess the role of perceived risk in air passenger behaviour. A survey of 889 respondents is used to investigate a multidimensional concept of perceived risk and to analyse the differences between socio-demographic characteristics regarding passengers' risk assessment. The results indicate that financial risk and temporal risk are the most important in the context of commercial air travel. All perceived risk dimensions differ according gender, age, cultural background, income, previous experience, and reason for travelling. (C) 2006 Elsevier Ltd. All rights reserved.

Exploring the impact of perceived LMX variability within work teams

According to Leader-Member Exchange (LMX) theory, leaders develop different quaUt}' reladonships with the employees they supervise. To date, Utde research has invesdgated the impact of such differendadon by the leader on workplace outcomes. The current research proposes a novel way to capture the extent of LMX variabiUt}' within a single work team, and subsequently investigates the impact of perceived LMX variability on workplace outcomes. Across multiple employed samples, participants reported poorer team relations (as indicated by low team cohesion and high conflict) when they perceived LMX variability to be high. Perceptions of poor team relations further impacted negatively upon individual affect variables. The findings suggest that leaders may need to exercise caution when developing different quality relationships amongst individuals within the same work team.