A tutorial on cue combination and Signal Detection Theory: Using changes in sensitivity to evaluate how observers integrate sensory information

Many sensory inputs contain multiple sources of information (‘cues’), such as two sounds of different frequencies, or a voice heard in unison with moving lips. Often, each cue provides a separate estimate of the same physical attribute, such as the size or location of an object. An ideal observer can exploit such redundant sensory information to improve the accuracy of their perceptual judgments. For example, if each cue is modeled as an independent, Gaussian, random variable, then combining Ncues should provide up to a √N improvement in detection/discrimination sensitivity. Alternatively, a less efficient observer may base their decision on only a subset of the available information, and so gain little or no benefit from having access to multiple sources of information. Here we use Signal Detection Theory to formulate and compare various models of cue-combination, many of which are commonly used to explain empirical data. We alert the reader to the key assumptions inherent in each model, and provide formulas for deriving quantitative predictions. Code is also provided for simulating each model, allowing expected levels of measurement error to be quantified. Based on these results, it is shown that predicted sensitivity often differs surprisingly little between qualitatively distinct models of combination. This means that sensitivity alone is not sufficient for understanding decision efficiency, and the implications of this are discussed

QuestPlus: A MATLAB Implementation of the QUEST+ adaptive Psychometric Method

QuestPlus is a MATLAB implementation of the QUEST+ adaptive psychometric method. It provides a rapid and flexible method of estimating the parameters of a psychophysical model, and is also capable of advising the user on the most appropriate stimuli to present, and on when to terminate testing. Of particular note is the algorithm’s ability to use prior information, its ability to determine the maximally informative stimulus on each trial, its ability to fit arbitrarily complex models, and its ability to vary multiple stimulus properties simultaneously

Helmet assembly and latch means therefor Patent

Transparent polycarbonate resin, shell helmet and latch design for high altitude and space fligh

Forward bearing reactor mechanism for Titan 3-E/Centaur D-1T space launch vehicle

System between the Titan/Centaur launch vehicle and its aerodynamic shroud is described. The system provides a precise spring constant and is capable of being inactivated during flight. Design requirements, design details, and the test program are discussed. The conventional English system of units was used during this development program for all principal measurements and calculations

A note on the Howson property in inverse semigroups

An algebra has the Howson property if the intersection of any two finitely generated subalgebras is finitely generated. A simple necessary and sufficient condition is given for the Howson property to hold on an inverse semigroup with finitely many idempotents. In addition, it is shown that any monogenic inverse semigroup has the Howson property.Comment: 6 page

New method for determining thermophysical properties of test specimens

Model can be tested directly, which eliminates costly, time-consuming, and inaccurate method of making test models solely for purpose of determining thermophysical properties. Method is adaptable to numerous modifications and variations

The Urban Crisis And The Federal Government\u27s Retreat: Catalyzing Public Policy Choices To Save Our Cities

Sections of our cities have been abandoned to a host of poverty-related social ills whose causes have as much to do with the state of the national and regional economies, structural changes in the job market, and political decision-making as they have to do with individual life-histories and personal misfortune. Bleak outcomes are not inevitable and can be reversed by understanding why faulty policy options were adopted and what it will take to formulate new policies. This essay argues for the need of proactive solutions like in combating our urban povery problem by using, (1) a Marshall Plan for cities, (2) using politics as a mechanism for change, and (3) using nonprofit social agencies and other community service organizations to help move the political agenda