Effects of absolute luminance and luminance contrast on visual search in low mesopic environments

Diverse adaptive visual processing mechanisms allow us to complete visual search tasks in a wide visual photopic range (>0.6 cd/m²). Whether search strategies or mechanisms known from this range extend below, in the mesopic and scotopic luminance spectra (<0.6 cd/m²), has yet to be addressed. Based on a study that addressed simple target discrimination in luminance environments using contrast-dependent behavioral efficiency functions, we assessed visual search in more complex-feature and conjunction-search paradigms. The results verify the previously reported deficiency windows defined by an interaction of base luminance and luminance contrast for more complex visual-search tasks. Based on significant regression analyses, a more precise definition of the magnitude of contribution of different contrast parameters. Characterized feature search patterns had approximately a 2.5:1 ratio of contribution from the Michelson contrast property relative to Weber contrast, whereas the ratio was approximately 1:1 in a serial-search condition. The results implicate near-complete magnocellular isolation in a visual-search paradigm that has yet to be demonstrated. Our analyses provide a new method of characterizing visual search and the first insight in its underlying mechanisms in luminance environments in the low mesopic and scotopic spectra.

     

Naturalist Political Realism and the First Political Question

Many political realists reject the idea that the first task for political philosophy is to justify the existence of coercive political institutions (CPIs). Instead, they say, we should begin with the factual existence of CPIs, and ask how they ought to be structured. In holding this view, they adopt a form of political naturalism that is broadly Aristotelian in character. In this article, I distinguish between two forms that this political naturalism might take ‐ what I call a ‘strong’ form, and a ‘weak’ form ‐ and argue that both ought to be rejected. 1     

A Phenomenological Inquiry of Identity Development,Same‐Sex Attraction,and Religious Upbringing

Growing up in religious/spiritual communities often creates identity issues for lesbian and gay individuals. In this phenomenological study, the authors investigated the experiences of 25 lesbian and gay individuals who self‐identified as having been raised within organized religious communities. Participants described that these communities were affirming, tolerant, or nonaffirming. Accordingly, emergent themes indicated that the current spiritual lives of participants varied greatly depending on their experiences of identity integration and affirmation. Implications for counselors and researchers are discussed.     

Intellectual Perfectionism about Schooling

In education, character education is a burgeoning field; however, it is also the target of considerable criticism. Amongst criticisms of character education, the political criticism that character education is a form of indoctrination stands out. In particular, the charge is made against character education that it breaches the principle of liberal neutrality about the good. In this article I discuss liberal approaches to character education. I outline the two most prominent liberal approaches to character education in school, liberal neutralism and liberal perfectionism, as we find it in the work of Clayton (neutralism) and Levinson (liberal perfectionism). I hold that the two standard liberal approaches do not distinguish carefully enough between two possible forms of character education – moral character education and intellectual character education. Drawing on recent work in virtue epistemology, I hold that the liberal position tacitly demands intellectual character education. Regarding moral character education, however, I hold that the picture appears different. In the final analysis, I advocate a new form of perfectionism regarding character education that I call ‘intellectual perfectionism’. According to intellectual perfectionism, schools should be perfectionist regarding children's intellects, but neutralist regarding their morals.