Tracking the affective state of unseen persons.

Emotion recognition is an essential human ability critical for social functioning. It is widely assumed that identifying facial expression is the key to this, and models of emotion recognition have mainly focused on facial and bodily features in static, unnatural conditions. We developed a method called affective tracking to reveal and quantify the enormous contribution of visual context to affect (valence and arousal) perception. When characters' faces and bodies were masked in silent videos, viewers inferred the affect of the invisible characters successfully and in high agreement based solely on visual context. We further show that the context is not only sufficient but also necessary to accurately perceive human affect over time, as it provides a substantial and unique contribution beyond the information available from face and body. Our method (which we have made publicly available) reveals that emotion recognition is, at its heart, an issue of context as much as it is about faces

Curiosity Based Exploration for Learning Terrain Models

We present a robotic exploration technique in which the goal is to learn to a visual model and be able to distinguish between different terrains and other visual components in an unknown environment. We use ROST, a realtime online spatiotemporal topic modeling framework to model these terrains using the observations made by the robot, and then use an information theoretic path planning technique to define the exploration path. We conduct experiments with aerial view and underwater datasets with millions of observations and varying path lengths, and find that paths that are biased towards locations with high topic perplexity produce better terrain models with high discriminative power, especially with paths of length close to the diameter of the world.Comment: 7 pages, 5 figures, submitted to ICRA 201

Attention gates visual coding in the human pulvinar.

The pulvinar nucleus of the thalamus is suspected to have an important role in visual attention, based on its widespread connectivity with the visual cortex and the fronto-parietal attention network. However, at present, there remain many hypotheses on the pulvinars specific function, with sparse or conflicting evidence for each. Here we characterize how the human pulvinar encodes attended and ignored objects when they appear simultaneously and compete for attentional resources. Using multivoxel pattern analyses on data from two functional magnetic resonance imaging (fMRI) experiments, we show that attention gates both position and orientation information in the pulvinar: attended objects are encoded with high precision, while there is no measurable encoding of ignored objects. These data support a role of the pulvinar in distractor filtering--suppressing information from competing stimuli to isolate behaviourally relevant objects

Restaurant Managerial Style: How Effective? How Versatile?

Restaurant management and the leadership styles of men and women who serve as hosts to the dining public are the subject of this study. The author asks: What kind of managers are they? What are the operational results of their efforts? Is there a relationship between managerial style and operational outcomes? How are managerial styles themselves related to each other

Differentiating the absolutely continuous invariant measure of an interval map f with respect to f

Let the map $f:[-1,1]\to[-1,1]$ have a.c.i.m. $\rho$ (absolutely continuous $f$-invariant measure with respect to Lebesgue). Let $\delta\rho$ be the change of $\rho$ corresponding to a perturbation $X=\delta f\circ f^{-1}$ of $f$. Formally we have, for differentiable $A$, $$\delta\rho(A)=\sum_{n=0}^\infty\int\rho(dx) X(x){d\over dx}A(f^nx)$$ but this expression does not converge in general. For $f$ real-analytic and Markovian in the sense of covering $(-1,1)$ $m$ times, and assuming an {\it analytic expanding} condition, we show that $$\lambda\mapsto\Psi(\lambda)=\sum_{n=0}^\infty\lambda^n \int\rho(dx) X(x){d\over dx}A(f^nx)$$ is meromorphic in ${\bf C}$, and has no pole at $\lambda=1$. We can thus formally write $\delta\rho(A)=\Psi(1)$.Comment: 10 pages, plain Te

Serial dependence in a simulated clinical visual search task.

In everyday life, we continuously search for and classify objects in the environment around us. This kind of visual search is extremely important when performed by radiologists in cancer image interpretation and officers in airport security screening. During these tasks, observers often examine large numbers of uncorrelated images (tumor x-rays, checkpoint x-rays, etc.) one after another. An underlying assumption of such tasks is that search and recognition are independent of our past experience. Here, we simulated a visual search task reminiscent of medical image search and found that shape classification performance was strongly impaired by recent visual experience, biasing classification errors 7% more towards the previous image content. This perceptual attraction exhibited the three main tuning characteristics of Continuity Fields: serial dependence extended over 12 seconds back in time (temporal tuning), it occurred only between similar tumor-like shapes (feature tuning), and only within a limited spatial region (spatial tuning). Taken together, these results demonstrate that serial dependence influences shape perception and occurs in visual search tasks. They also raise the possibility of a detrimental impact of serial dependence in clinical and practically relevant settings, such as medical image perception

Better Ballots

Literacy tests to gain access to the polls were banned in the United States in 1965 with the passage of the Voting Rights Act.99 But in November 2008, eight years after an election debacle of historic proportions, millions of voters across the United States will face a literacy test of a different sort after they've stepped into the voting booth. Their intended choices may be recorded only if they can understand instructions written at a high reading level, often using legal and election terminology. And they will only be counted if they successfully navigate ballot designs that are needlessly complicated, where candidates for the same offi ce may be listed on multiple columns or pages, or different contests are inconsistently formatted. As we have tried to demonstrate in this report, ballot design and instructions can have a huge impact on election results. We sampled some of the more "high profi le" ballot design disasters over the last several years; this is not a comprehensive analysis of the cost of poor ballot design on elections and votes counted. But, the examples illustrate how dramatically poor ballot design can affect vote totals -- particularly when a number of design fl aws appear on the same ballot. Not surprisingly, when these mistakes affected many ballots (by appearing on a signifi cant percentage of the ballots in large counties like Los Angeles or Palm Beach, or on most of the ballots in a particular state), tens of thousands -- and sometimes hundreds of thousands -- of votes in a single federal or statewide race have been lost. This does not even include the voters who may have been so confused by a ballot design that they cast their ballot for a candidate for whom they did not intend to vote (for obvious reasons, it is far more diffi cult to determine this than to know when a voter failed to successfully cast a vote at all). Better ballot design will make it far more likely that the preferred candidates of all voters will be declared winners of their contests. Palm Beach County 2000 should have been a wake-up call to legislators, election offi cials, and watchdog groups that ensuring good ballot design is a critical election administration issue that needs to be systematically addressed. Unfortunately, for the last eight years, it has continued to be largely ignored. The predictable result has disproportionately affected low-income and elderly voters, and thrown several important elections into turmoil. The good news is that there is still time before November 2008 to ensure that ballot design fl aws do not throw the results of another closely contested race into doubt, as has happened in several federal and state races in the last decade. And unlike changes to equipment (which, there is no question, could make systems more secure, accessible and usable), improving ballot design and instructions is possible for little or no cost, and a relatively small-scale investment of time

Radial Forcing and Edgar Allan Poe's Lengthening Pendulum

Inspired by Edgar Allan Poe's The Pit and the Pendulum, we investigate a radially driven, lengthening pendulum. We first show that increasing the length of an undriven pendulum at a uniform rate does not amplify the oscillations in a manner consistent with the behavior of the scythe in Poe's story. We discuss parametric amplification and the transfer of energy (through the parameter of the pendulum's length) to the oscillating part of the system. In this manner radial driving may easily and intuitively be understood, and the fundamental concept applied in many other areas. We propose and show by a numerical model that appropriately timed radial forcing can increase the oscillation amplitude in a manner consistent with Poe's story. Our analysis contributes a computational exploration of the complex harmonic motion that can result from radially driving a pendulum, and sheds light on a mechanism by which oscillations can be amplified parametrically. These insights should prove especially valuable in the undergraduate physics classroom, where investigations into pendulums and oscillations are commonplace.Comment: 16 page