Natural scenes contain a rich variety of contours that the visual system extracts to segregate the retinal image into perceptually coherent regions. Covert spatial attention helps extract contours by enhancing contrast sensitivity for 1st-order, luminance-defined patterns at attended locations, while reducing sensitivity at unattended locations, relative to neutral attention allocation. However...

Cortical visual neurons in the cat and monkey are inhibited by stimuli surrounding their receptive fields (surround suppression) or presented within their receptive fields (cross-orientation or overlay suppression). We show that human contrast sensitivity is similarly affected by two distinct suppression mechanisms. In agreement with the animal studies, human surround suppression is tightly tun...

Photopic contrast sensitivity of air-breathing scuba divers was measured with a translucent test pattern at depths up to 40 m. The pattern was composed of sine wave gratings with spatial frequency and contrast changing logarithmically. The spatial transfer characteristics were measured at various depths under controlled optical conditions in seawater and in fresh water. Analysis indicates that ...

In order to investigate the mechanisms underlying green/red equiluminance matches in human observers and their relationship to mechanisms subserving luminance and/or chromatic (green/red) contrast sensitivity, we tested 21 human subjects along these dimensions at 16 different spatial and temporal frequencies (spatial frequency, 0.25-2 c/deg; temporal frequency, 2-16 Hz) and applied factor analy...

Despite the emerging scientific and clinical importance of measuring human contrast sensitivity (CS), developmental data are sparse, especially those obtained with a single methodology. We used a new, time-efficient, psychophysical card procedure to evaluate binocular CS in groups of 20 4- to 9-yr-olds and 10 adults. Combined with data from infants and toddlers obtained previously with the same...

In four studies, the authors show that consumers’ savings can be increased or decreased merely by changing the way consumers think about their saving goals. Consumers can (1) either specify or not specify an exact amount to save (goal specificity) and (2) focus on either how to save or why to save (construal level). The results illustrate that specific goals help consumers save more when the sa...

The proposed work deals with highly complex, multi-dimensional systems/processes that cannot be described using low-level details. This is due to the complexity and uncertainty inherent in their nature of functionality, behaviour, interaction, hierarchy and geometry. To keep pace with such complexity and uncertainty, abstract modelling would be useful in predicting the level and nature of the e...

The goal of this study was to investigate the role of inferred parvocellular (PC) and magnocellular (MC) pathways in spatial contrast sensitivity. Localized, spatially narrow-band patterns (sixth derivatives of Gaussians, D6s) were presented at various peak spatial frequencies. When the D6 appeared on a pulsed luminance pedestal (Pulsed-Pedestal Paradigm), the spatial contrast sensitivity showe...

coastal area sensitivity assessment is in fact, the assessment of an extraordinary ecological rich region, in spite of existing environmental polluting factors. this study has been based on established criteria and values. the aim of this sensitivity assessment has been to give objectivity to the boushehr province coastline region, so as to be able to pinpoint areas requiring ecological conserv...