The visual world is cluttered, and adaptive behavior often demands attention to multiple objects. Unfortunately, compared with young adults, older adults seem to show more difficulty in dividing attention across the visual field (e.g. Ball et al., 1988), an effect often interpreted as an age-related constriction of the attentional visual field (AVF). As yet, the mechanisms underlying progressive shrinking of the AVF across lifespan remain unclear. The current work directly gauged workload capacity, C(t), calculated based on response time distributions (Townsend & Nozawa, 1995), to isolate the effects of attention and sensory limits across the visual field in young and older adults. Young and older adults made a speeded discrimination of one or two colored target letter(s) presented at varying levels of retinal eccentricity with or without the presence of clutter. In Experiment 1, surprisingly, workload capacity increased with retinal eccentricity and in the presence of clutter, and these effects were larger for older than young adults. Experiment 2 and 3 examined the influence of intertarget contingencies (Mordkoff & Yantis, 1991) on workload capacity under varying levels of clutter and target eccentricity. Data failed to find evidence of an age-related capacity gain either in the absence of intertarget contingencies or under conditions of moderate intertarget contingencies.. Experiment 4 attempted to replicate the age-related benefit found in Experiment 1, but found similarities in attentional performance across young and older adults. Meta-analysis of mean capacity scores across all four experiments indicates general age-related benefit in visual divided capacity. Meta-analyses of effects of eccentricity and clutter indicate the age-related similarities at various eccentricity and benefit in cluttered environments. The findings argue against the suggestion that peripheral visual losses in older adults are strictly attentional, and suggest instead that they are sensory or perceptual in basis
