This study reports the results of a meta-analysis of empirical studies on Internet addiction published in academic journals for the period 1996-2006. The analysis showed that previous studies have utilized inconsistent criteria to define Internet addicts, applied recruiting methods that may cause serious sampling bias, and examined data using primarily exploratory rather than confirmatory data analysis techniques to investigate the degree of association rather than causal relationships among variables. Recommendations are provided on how researchers can strengthen this growing field of research.

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This study used meta-analysis to investigate the relationships between career decision self-efficacy (CDSE) and its relevant variables. The authors aimed to integrate the mixed results reported by previous empirical studies and obtain a clearer understanding of CDSE's role within the framework of social cognitive career theory (SCCT). For purposes of this study, the authors searched and selected nine relevant variables (gender, age, race, self-esteem, vocational identity, career barriers, peer support, vocational outcome expectation, and career indecision). While some variables (i.e., gender, race, and career barriers) did not have a significant effect on CDSE, in accordance with the SCCT model, CDSE correlated significantly to self-esteem, vocational identity, peer support, vocational outcome expectation, and career indecision variables. The authors discuss these results in the context of the SCCT.

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Melanopsin is expressed in distinct types of intrinsically photosensitive retinal ganglion cells (ipRGCs), which drive behaviors from circadian photoentrainment to contrast detection. A major unanswered question is how the same photopigment, melanopsin, influences such vastly different functions. Here we show that melanopsin's role in contrast detection begins in the retina, via direct effects on M4 ipRGC (ON alpha RGC) signaling. This influence persists across an unexpectedly wide range of environmental light levels ranging from starlight to sunlight, which considerably expands the functional reach of melanopsin on visual processing. Moreover, melanopsin increases the excitability of M4 ipRGCs via closure of potassium leak channels, a previously unidentified target of the melanopsin phototransduction cascade. Strikingly, this mechanism is selective for image-forming circuits, as M1 ipRGCs (involved in non-image forming behaviors), exhibit a melanopsin-mediated decrease in excitability. Thus, melanopsin signaling is repurposed by ipRGC subtypes to shape distinct visual behaviors.