Searching for signs, symbols, and icons: effects of time of day, visual complexity, and grouping

Searching for icons, symbols, or signs is an integral part of tasks involving computer or radar displays, head-up displays in aircraft, or attending to road traffic signs. Icons therefore need to be designed to optimize search times, taking into account the factors likely to slow down visual search. Three factors likely to adversely affect visual search were examined: the time of day at which search was carried out, the visual complexity of the icons, and the extent to which information features in the icon were grouped together. The speed with which participants searched icon arrays for a target was slower early in the afternoon, when icons were visually complex and when information features in icons were not grouped together to form a single object. Theories of attention that account for both feature-based and object-based search best explain these findings and are used to form the basis for ways of improving icon design.     

The standard of care in suicide risk assessment: An elusive concept

Suicide risk assessment is now a core competency requirement in the residency training of psychiatrists. The purpose of suicide risk assessment is to identify modifiable or treatable acute, high-risk suicide factors, and available protective factors that inform patient treatment and safety management. The standard of care varies according to state statutory definitions. Heretofore, most states adopted an average physician or "ordinarily employed standard." Currently, more states are adopting a "reasonable, prudent physician" standard. No single source or authority defines the standard of care for suicide risk assessment. Evidence-based psychiatry can inform clinicians' suicide risk assessments. Carefully documented risk assessments will assist the courts in evaluating clinicians' decision-making process.     

Binocular coordination of the eyes during reading: word frequency and case alternation affect fixation duration but not fixation disparity

This experiment investigated whether properties of the text being read affect binocular coordination of the eyes during reading. Readers' binocular eye movements were recorded while they read sentences that contained high- and low-frequency words. In addition, half of the sentences were presented in normal case, and half were presented in alternating case (i.e., AlTeRnAtInG cAsE). Past research has suggested that the visual system tolerates less binocular fixation disparity with alternating than with normal case (Heller & Radach, 1999). While both word frequency and alternating case produced large effects on fixation durations on the target word, neither manipulation affected the magnitude of fixation disparity. It is concluded that linguistic and visual properties of the text being read do not influence binocular coordination of the eyes during reading. Additional analyses also showed no difference in fixation disparity between reading and a nonlinguistic task. Implications of these results for split-fovea models of reading are discussed.