Engineering data compendium. Human perception and performance. User's guide

The concept underlying the Engineering Data Compendium was the product of a research and development program (Integrated Perceptual Information for Designers project) aimed at facilitating the application of basic research findings in human performance to the design and military crew systems. The principal objective was to develop a workable strategy for: (1) identifying and distilling information of potential value to system design from the existing research literature, and (2) presenting this technical information in a way that would aid its accessibility, interpretability, and applicability by systems designers. The present four volumes of the Engineering Data Compendium represent the first implementation of this strategy. This is the first volume, the User's Guide, containing a description of the program and instructions for its use

Aerospace medicine and biology: A continuing bibliography with indexes, supplement 125

This special bibliography lists 323 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1974

The perception of stereoscopic surfaces

Human stereoscopic vision depends upon the slightly different geometrical projections of the world to the two eyes. Horizontal disparities between the eyes produce the sensation of depth. But what is stereopsis for. One theory is that stereopsis extracts the spatial derivatives of horizontal disparity for the perception of shape and surface orientation. Discrimination tasks are devised here which compare sensitivity to the slant and curvature of stereoscopic surfaces with sensitivity to relative depth, both within and across tasks. Contrary to previous studies, where cues other than the second derivative were available, best Weber fractions for disparity curvature disrimination by these methods are no better than 15%. This compares with 6% for disparity gradient and 3.5 % for relative disparity. Discrimination of the orientation, size (or separation) and position of cyclopean corrugated surfaces reveals these stimulus attributes are discriminated as accurately as their counterparts in the luminance domain, provided the spatial scale is quite coarse. Other analogous results include the independence of spatial discriminations on relative disparity, the meridional anisotropy for cyclopean orientation discrimination and a range of relative disparity effects analogous to classical simultaneous contrast effects in luminance vision. It was also found, contrary to a previous study, that cyclopean textures could be segregated pre-attentively. These findings taken together imply that disparity is processed by spatial filters in a similar manner to luminance. This view of stereoscopic vision allows a fresh look at an old phenomenon: the stereoscopic slant anisotropy. An explanation is proposed on the basis of interactions between cyclopean spatial filters and a representation of disparity upon which they act. If sensitivity is a guide to function, stereopsis is for estimating the position, location, size and orientation of nearby objects, but probably not for estimating their shape

Engineering Data Compendium. Human Perception and Performance, Volume 1

The concept underlying the Engineering Data Compendium was the product an R and D program (Integrated Perceptual Information for Designers project) aimed at facilitating the application of basic research findings in human performance to the design of military crew systems. The principal objective was to develop a workable strategy for: (1) identifying and distilling information of potential value to system design from existing research literature, and (2) presenting this technical information in a way that would aid its accessibility, interpretability, and applicability by system designers. The present four volumes of the Engineering Data Compendium represent the first implementation of this strategy. This is Volume 1, which contains sections on Visual Acquisition of Information, Auditory Acquisition of Information, and Acquisition of Information by Other Senses

Rotation and translation effects on stereoscopic acuity

This study examined the effects of rotation or translation on the detectability of a dotted target plane embedded in a dotted masking cube. Julesz-type stereograms were generated in real time, using a small laboratory computer. Subjects displayed an excellent ability to compensate for x-y projected density variations produced by changes in the angle of rotation of the target plane so that performance was equal at all rotations. This finding indicates that dot density is being processed in a three- rather than a two-dimensional manner. Translation of a frontoparallel plane from the back of the stereoscopically defined cube to its front produced systematic changes in performance. Performance was best at the central fixation distance and decreased as either crossed or uncrossed disparity increased. Thus, it appears that stereo acuity decreases symmetrically with increases in disparity in either direction.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22020/1/0000436.pd

Looming motion primes the visuomotor system.

A wealth of evidence now shows that human and animal observers display greater sensitivity to objects that move toward them than to objects that remain static or move away. Increased sensitivity in humans is often evidenced by reaction times that increase in rank order from looming, to receding, to static targets. However, it is not clear whether the processing advantage enjoyed by looming motion is mediated by the attention system or the motor system. The present study investigated this by first examining whether sensitivity is to looming motion per se or to certain monocular or binocular cues that constitute stereoscopic motion in depth. None of the cues accounted for the looming advantage. A perceptual measure was then used to examine performance with minimal involvement of the motor system. Results showed that looming and receding motion were equivalent in attracting attention, suggesting that the looming advantage is indeed mediated by the motor system. These findings suggest that although motion itself is sufficient for attentional capture, motion direction can prime motor responses. © 2013 American Psychological Association

Quantifying Grassland-to-Woodland Transitions and the Implications for Carbon and Nitrogen Dynamics in the Southwest United States

Replacement of grasslands and savannas by shrublands and woodlands has been widely reported in tropical, temperate and high-latitude rangelands worldwide (Archer 1994). These changes in vegetation structure may reflect historical shifts in climate and land use; and are likely to influence biodiversity, productivity, above- and below ground carbon and nitrogen sequestration and biophysical aspects of land surface-atmosphere interactions. The goal of our proposed research is to investigate how changes in the relative abundance of herbaceous and woody vegetation affect carbon and nitrogen dynamics across heterogeneous savannas and shrub/woodlands. By linking actual land-cover composition (derived through spectral mixture analysis of AVIRIS, TM, and AVHRR imagery) with a process-based ecosystem model, we will generate explicit predictions of the C and N storage in plants and soils resulting from changes in vegetation structure. Our specific objectives will be to (1) continue development and test applications of spectral mixture analysis across grassland-to-woodland transitions; (2) quantify temporal changes in plant and soil C and N storage and turnover for remote sensing and process model parameterization and verification; and (3) couple landscape fraction maps to an ecosystem simulation model to observe biogeochemical dynamics under changing landscape structure and climatological forcings

Spatial Displays and Spatial Instruments

The conference proceedings topics are divided into two main areas: (1) issues of spatial and picture perception raised by graphical electronic displays of spatial information; and (2) design questions raised by the practical experience of designers actually defining new spatial instruments for use in new aircraft and spacecraft. Each topic is considered from both a theoretical and an applied direction. Emphasis is placed on discussion of phenomena and determination of design principles

Dependence of perceptual choice on number of response alternatives and fidelity of evidence

The study of perceptual decisions has been developed as a substitute for investigating more complex multiple attribute decisions. However, little attention has been paid to the similarity of results between the two literatures. Four separate behavioral experiments and a secondary trial- by-trial analysis investigated the sensitivity of perceptual decisions. Results were compared to both previous perceptual decision research and that of multiple attribute decisions in an effort to bridge the divide. The first experiment examined the effect of increasing the similarity of available response alternatives on accuracy and reaction time. The results suggest that high levels of similarity can begin to degrade the decision process by lowering accuracy and slowing reaction time; however these changes may be dependent on the extent to which the alternatives use overlapping neuronal pools. The second experiment examined the effect of increasing the number of response alternatives available for a single decision. The results suggest that increasing the number of alternatives may not affect performance until some critical point (in this case, eight alternatives). The third experiment examined how delay in the presentation of evidence compared to the start of the decision process affects the overall accuracy and reaction time once information is given. The results demonstrate that as the decision process extends in time, decisions are made faster and less accurately. Finally, the fourth experiment examined how the interrupting the incoming stream of information with either highly informative or highly misleading evidence would affect the decision. The results illustrated a complicated picture in which highly informative evidence accelerated decisions but misleading evidence failed to slow decisions. In addition to the individual aims, a secondary analysis investigated potential trial-by- trial variation in performance. There was some evidence that participants made ongoing adjustments to their strategy dependent on performance, but only when feedback was available; previous trial status (e.g., highly informative vs. highly misleading evidence) did not affect current trial performance. In sum the results demonstrate that perceptual decisions do show high levels of sensitivity to a variety of manipulations, but fail to replicate many of the results from more complicated multiple attribute decisions