Background: Although recent cross-sectional findings indicate that markers of biological age (BA) mediate chronological age (CA) differences in cognitive performance, little is known about their influence on actual cognitive changes. Objective: The purpose of this investigation is to examine CA and BA as predictors of 12-year cognitive change in a longitudinal sample of older adults. Methods: Data from the Victoria Longitudinal Study (VLS) were examined for 125 adults between 67 and 95 years of age. Biomarkers, including visual and auditory acuity, grip strength, peak expiratory flow, blood pressure, and body mass index, were submitted to a factor analysis and a composite BA variable was computed based on factor loadings. Intraindividual change across 5 waves of measurement (3-year intervals) was examined as a function of CA and BA for 5 cognitive domains: verbal processing speed, working memory, reasoning, episodic memory, and semantic memory. Results: The latent structure of biomarkers was consistent with previous investigations of functional age and a common factor view of biological aging. Results of hierarchical linear modeling showed that BA predicted actual cognitive change (decline) independent of CA. Conclusions: As a predictor of cognitive performance in late life, CA is a proxy for biological and environmental influences. We have shown that biological influences are independent predictors of actual cognitive change in older adults. This supports the view that cognitive decline is not due to aging per se, but rather is likely due to causal factors that operate along the age continuum.

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In young adults, intentions have been shown to be more accessible (e.g. faster reaction times and higher accuracy) compared to other sorts of to-be-remembered information, a result termed an 'intention superiority effect' (Goschke & Kuhl, 1993). In the current study, we assessed whether older adults also demonstrate this superiority of intention-related material and we used a new interference paradigm to examine performance. On each trial, participants performed a Stroop-like colour-naming task on a short series of words, including words related to an intention that they encoded at the beginning of the trial. In Experiment 1, results revealed an 'intention interference effect' for both young and older adults in which performance was slower for words belonging to an intention that participants intended to carry out versus an intention that did not have to be executed.In Experiment 2, we tested the effect that completing an intention had on the representation of intentions. For both groups, completing an intention led to a decrease in interference in Stroop task performance.

In two experiments, the effect of perceptual distinctiveness of cues on prospective memory performance was examined. Young and older adults completed a visual search task with embedded prospective memory instructions. On each trial, participants were asked to indicate the position of a target letter in a letter string, unless either of two letters previously identified as prospective memory cues was presented. Each prospective cue was associated with a specific response. Perceptual distinctiveness was manipulated by spatially displacing a single letter. The prospective component (successful detection of the cue) and the retrospective memory component (recalling the correct response when a cue is detected) were measured separately. Perceptual displacement of cues modulated performance of the prospective component but not the retrospective component. Young adults successfully detected a larger proportion of cues (prospective component) than older adults. However, there were minimal effects of age and no effect of cue displacement on participants' ability to recall the intention once they detected a cue (retrospective component performance). Results are discussed within the context of current theoretical models of prospective memory.

In the current study, participants performed an ongoing lexical decision task (LDT) in which they had to classify letter strings as words or non-words. In intention conditions, they also had to encode a postponed intention to remember to make a different response if a pre-specified cue appeared. Attempting to replicate an important finding from Cohen et al. (2008), the interest was in examining how varying cognitive load associated with an intention influences attention to the ongoing task (measured by reaction times). Typically, disengaging from a primary task is perceived as negative as it can lead to performance decrements, however, if disengaging from a primary task helps one to accomplish a desired future goal, then these attentional shifts may in fact be constructive. Results replicated those of Cohen et al. (2008) and showed that participants were very flexible in how they managed attention in the ongoing LDT. Reaction time costs emerged when cognitive load was high and solely for word trials (i.e., not for non-word trials). The implications for mind wandering are that, while our attention may wander when stimuli are present that trigger a suspended or unfulfilled goal, we are better able to stay on task when the stimuli are less goal relevant. Therefore, the decoupling process (e.g., Schooler et al., 2011) might be initiated when postponed goals are accompanied by a high degree of cognitive load and when external stimuli are present that relate to that goal.