A shift of the perceptual attributes of color due to the manifestation of the simultaneous contrast effect on a display

This research shows the effect of simultaneous contrast on a design solution that generates it, and it also shows how its manifestation affects the shift of perception attributes of the observer's color. In the conducted research, 55 subjects had to harmonize the primary stimuli from the reproduction obtained with the help of digital printing technology, with the primary stimuli presented on two computer screens. As a visual harmonization technique, simultaneous binocular harmonization was used. The primary stimuli were made achromatic, with a 50% Raster Tone value (RTV), and are surrounded by achromatic secondary stimuli whose values increase in steps from 10% RTV up to 100% RTV. A shift in the perceptual attributes of color has been shown with the help of the CIEDE2000 system. Using ANOVA with repeated-measures and Fisher's post hoc analysis, statistically significant differences were found between the perceived means of shift in the ΔC₀₀ chroma and ΔL₀₀ lightness on defined samples on both computer screens, while in the case of the ΔH₀₀ hue, no statistically significant differences were observed. The research also determined colorimetric differences in the ΔE₀₀ color difference. Moreover, the student's t test was used to determine that the effect is stronger when manifested on the Lenovo computer than on the Asus computer screen (P < .05).     

Manual patient transfers: factors that influence decisions and kinematic strategies employed by nursing aides

While extensive literature has characterised factors that influence the acceptable mass of ‘boxes’ during MMH tasks, less is known about these factors when moving ‘people’ in healthcare settings. This study examined factors that influence decisions/approaches employed during manual patient transfers. Sixteen nursing aides manually-transferred a standardised ‘patient’; patient mass was adjusted (using a weight vest) to determine a maximum acceptable patient mass for this task (mass_max). Grip strength was the only worker characteristic significantly associated with mass_max (r?=?0.48). Older worker age was associated with smaller peak trunk flexion (r?= ?0.58) and shoulder abduction (r?= ?0.59), and greater trunk axial twist (r?=?0.52). Workers emphasised that patient characteristics (e.g. physical/cognitive status) influenced their decisions when performing transfers. These findings extend previous literature by suggesting that grip strength is a useful predictor of perceived work capacity, older workers adapt protective postural strategies during patient transfers and worker-patient dynamics are crucial during this high-risk occupational task.

Practitioner Summary: This study examined manual patient transfers performed by nursing aides. Worker grip strength (but not age or size) was associated with perceptions of maximum acceptable patient mass. Kinematic changes suggested more conservative strategies used by older workers. Workers emphasised that patient characteristics substantially influenced their decisions when performing transfer tasks.     

Disentangling the adult attention-deficit hyperactivity disorder endophenotype: Parametric measurement of attention.

Attention deficit hyperactivity disorder (ADHD) persists frequently into adulthood. The decomposition of endophenotypes by means of experimental neuro-cognitive assessment has the potential to improve diagnostic assessment, evaluation of treatment response, and disentanglement of genetic and environmental influences. We assessed four parameters of attentional capacity and selectivity derived from simple psychophysical tasks (verbal report of briefly presented letter displays) and based on a “theory of visual attention.” These parameters are mathematically independent, quantitative measures, and previous studies have shown that they are highly sensitive for subtle attention deficits. Potential reductions of attentional capacity, that is, of perceptual processing speed and working memory storage capacity, were assessed with a whole report paradigm. Furthermore, possible pathologies of attentional selectivity, that is, selection of task-relevant information and bias in the spatial distribution of attention, were measured with a partial report paradigm. A group of 30 unmedicated adult ADHD patients and a group of 30 demographically matched healthy controls were tested. ADHD patients showed significant reductions of working memory storage capacity of a moderate to large effect size. Perceptual processing speed, task-based, and spatial selection were unaffected. The results imply a working memory deficit as an important source of behavioral impairments. The theory of visual attention parameter working memory storage capacity might constitute a quantifiable and testable endophenotype of ADHD. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Gustav Fechner: 150 years of Elemente der Psychophysik.

The year 2010 marks the 150th anniversary of Elements of Psychophysics [Elemente der Psychophysik] by Gustav Theodor Fechner (1801–1887) in Leipzig, Germany. It is near consensus among historians of psychology that this two-volume work was the first major publication to demonstrate that psychological phenomena could be studied experimentally and quantitatively. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fechner's "inner psychophysics."

Though psychologists are generally aware that Gustav Fechner introduced psychophysics and set down its essential methodology, most of them only know about the part that Fechner called “outer psychophysics.” In his classic publication of 1860, Fechner insisted that “inner psychophysics” was more important, yet this aspect of Fechner's work failed to receive any attention. The article reviews Fechner's presentation of inner psychophysics and suggests reasons why that part of his work was neglected and has been forgotten. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Speed limits: Orientation and semantic context interactions constrain natural scene discrimination dynamics.

The visual system rapidly extracts information about objects from the cluttered natural environment. In 5 experiments, the authors quantified the influence of orientation and semantics on the classification speed of objects in natural scenes, particularly with regard to object-context interactions. Natural scene photographs were presented in an object-discrimination task and pattern masked with various scene-to-mask stimulus-onset asynchronies (SOAs). Full psychometric functions and reaction times (RTs) were measured. The authors found that (a) rotating the full scenes increased threshold SOA at intermediate rotation angles but not for inversion; (b) rotating object or context degraded classification performance in a similar manner; (c) semantically congruent contexts had negligible facilitatory effects on object classification compared with meaningless baseline contexts with a matching contrast structure, but incongruent contexts severely degraded performance; (d) any object-context incongruence (orientation or semantic) increased RTs at longer SOAs, indicating dependent processing of object and context; and (e) facilitatory effects of context emerged only when the context shortly preceded the object. The authors conclude that the effects of natural scene context on object classification are primarily inhibitory and discuss possible reasons. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A comparison of constant stimuli and gray‐scale methods of color difference scaling

Two psychophysical techniques, the method of constant stimuli and the gray‐scale comparison method, were used to determine color tolerances for three different color centers in the hue, chroma, and lightness directions in CIELAB color space. The same color‐difference pairs were used as the stimuli in both experiments. Although the results followed the same trends, they were different for the two techniques. Based on comparison of the validity and precision of the results, as well as the ease of implementation, use, and analysis, the method of constant stimuli is the preferable method. © 2002 Wiley Periodicals, Inc. Col Res Appl, 28, 36–44, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.     

Obituary: J. P. Guilford (1897–1987).

Joy Paul Guilford, known to his friends as J.P., died of natural causes on November 26, 1987, at the UCLA Medical Center. He was 90 years old. He is survived by his wife, Ruth, his daughter, Joan S. MeGuire, three grandchildren, and three great grandchildren. In 1924, Guilford entered the PhD program at Cornell University, where he studied with such giants in the history of psychology as E. B. Titchener, Kurt Kottka, Harry Helson, and Karl Dallenbach. Guilford immersed himself in psychophysics and other classical topics in the experimental psychology of the times, publishing 5 articles before earning a PhD degree in 1927. His doctoral thesis showed that variations in reported sensory experience with weak stimuli should not be attributed to fluctuations in attention as was commonly supposed at the time. A list of honors and awards are stated. He had a profound impact on psychology as a teacher, scientist, and writer. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The psyche in psychophysics: A sensory-decision theory analysis of the effect of instructions on flicker sensitivity and response bias.

Instruction-induced changes in flicker thresholds, measured by traditional psychophysical procedures, may reflect changes in sensory sensitivity or in response bias. In 16 psychiatric patients, a facilitating set, in contrast to an inhibiting set, increased the proportion of flicker responses to both a physically intermittent light ("hits," p     

Illumination control system for adaptive dynamic range control

Abstract— We have developed an illumination control system for adaptive dynamic range control. This system satisfies several performance requirements for image quality and reliability. A projection system using the illumination control system can reproduce images with optimum brightness for each image.