Face and tone of voice in the communication of deception.

An experiment with 60 senders and 9 judges (undergraduates) examined the contributions of face and tone of voice (TOV; filtered speech) to the communication of honest and deceptive messages. TOV was a better source of deception and leakage than the face. Judgments of the combined audiovisual channel (AVC) was better predicted from their TOV judgments when the message was deceptive and from their judgments of the face when the message was honest. When verbal content was available, the face became less important. Judges obtained more information from facial cues that were added to filtered speech than from those added to full voice. Judgments of the AVC without content were better predicted from judgments of filtered speech. The relative importance of face and TOV was also determined by the affect that was communicated. TOV was a better source of information about dominance and submission; the face revealed more information and was more highly correlated with the combined AVC for communication of liking and disliking. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Grouping and emergent features in vision: Toward a theory of basic Gestalts.

Gestalt phenomena are often so powerful that mere demonstrations can confirm their existence, but Gestalts have proven hard to define and measure. Here we outline a theory of basic Gestalts (TBG) that defines Gestalts as emergent features (EFs). The logic relies on discovering wholes that are more discriminable than are the parts from which they are built. These wholes contain EFs that can act as basic features in human vision. As context is added to a visual stimulus, a hierarchy of EFs appears. Starting with a single dot and adding a second yields the first two potential EFs: the proximity (distance) and orientation (angle) between the two dots. A third dot introduces two more potential EFs: symmetry and linearity; a fourth dot produces surroundedness. This hierarchy may extend to collinearity, parallelism, closure, and more. We use the magnitude of Configural Superiority Effects to measure the salience of EFs on a common scale, potentially letting us compare the strengths of various grouping principles. TBG appears promising, with our initial experiments establishing and quantifying at least three basic EFs in human vision. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Global and local precedence: Selective attention in form and motion perception.

Five experiments traced the causes of the discrepancy in research that showed both local and global precedence in selective attention tasks. The effects of the relative discriminabilities of the local and global levels of the stimuli and the differences between Stroop-type interference (attributable to incongruity on the irrelevant dimension) and Garner-type interference (attributable to variability on the irrelevant dimension) were explored. The experiments also examined whether the precedence effects previously examined in form perception generalize to motion perception. 45 Ss, most of whom were college students, participated. Ss viewed stimuli on an oscilloscope under 9 conditions. Results show that (a) some cases of global precedence were due solely to the greater perceptual discriminability of the global level; (b) instances of both local and global precedence could be demonstrated for certain types of stimuli, even when the discriminabilities of their local and global levels had been equated; and (c) the Stroop and Garner measures of selective attention were not equivalent but instead measured different types of interference. It is concluded that cases of both local and global precedence have been amply documented but that no general theory can account for why or when these effects will appear until a better understanding is gained of both the nature of part–whole relationships and the perceptual processes that are tapped by different measures of selective attention. (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cool surfaces and shade trees to reduce energy use and improve air quality in urban areas

Elevated summertime temperatures in urban ‘heat islands’ increase cooling-energy use and accelerate the formation of urban smog. Except in the city’s core areas, summer heat islands are created mainly by the lack of vegetation and by the high solar radiation absorptance by urban surfaces. Analysis of temperature trends for the last 100 years in several large U.S. cities indicate that, since 1940, temperatures in urban areas have increased by about 0.5–3.0°C. Typically, electricity demand in cities increases by 2–4% for each 1°C increase in temperature. Hence, we estimate that 5–10% of the current urban electricity demand is spent to cool buildings just to compensate for the increased 0.5–3.0°C in urban temperatures. Downtown Los Angeles (L.A.), for example, is now 2.5°C warmer than in 1920, leading to an increase in electricity demand of 1500 MW. In L.A., smoggy episodes are absent below about 21°C, but smog becomes unacceptable by 32°C. Because of the heat-island effects, a rise in temperature can have significant impacts. Urban trees and high-albedo surfaces can offset or reverse the heat-island effect. Mitigation of urban heat islands can potentially reduce national energy use in air conditioning by 20% and save over $10B per year in energy use and improvement in urban air quality. The albedo of a city may be increased at minimal cost if high-albedo surfaces are chosen to replace darker materials during routine maintenance of roofs and roads. Incentive programs, product labeling, and standards could promote the use of high-albedo materials for buildings and roads. Similar incentive-based programs need to be developed for urban trees.     

Function-Private Functional Encryption in the Private-Key Setting

Functional encryption supports restricted decryption keys that allow users to learn specific functions of the encrypted messages. Although the vast majority of research on functional encryption has so far focused on the privacy of the encrypted messages, in many realistic scenarios it is crucial to offer privacy also for the functions for which decryption keys are provided. Whereas function privacy is inherently limited in the public-key setting, in the private-key setting it has a tremendous potential. Specifically, one can hope to construct schemes where encryptions of messages \(\mathsf{m}_1, \ldots , \mathsf{m}_T\) together with decryption keys corresponding to functions \(f_1, \ldots , f_T\), reveal essentially no information other than the values \(\{ f_i(\mathsf{m}_j)\}_{i,j\in [T]}\). Despite its great potential, the known function-private private-key schemes either support rather limited families of functions (such as inner products) or offer somewhat weak notions of function privacy. We present a generic transformation that yields a function-private functional encryption scheme, starting with any non-function-private scheme for a sufficiently rich function class. Our transformation preserves the message privacy of the underlying scheme and can be instantiated using a variety of existing schemes. Plugging in known constructions of functional encryption schemes, we obtain function-private schemes based either on the learning with errors assumption, on obfuscation assumptions, on simple multilinear-maps assumptions, and even on the existence of any one-way function (offering various trade-offs between security and efficiency).