Previous studies report that monitoring the passing of time by checking a clock either frequently or strategically (immediately before a target time) improves the likelihood of remembering to perform a planned intention at a specific time (i.e., time-based prospective memory [TBPM]). Critically, strategicness of clock-checking is usually measured as the number of clock-checks during the last time interval before the target time—an operationalization where strategicness actually intertwines with absolute frequency of clock-checking and may not properly account for age effects in TBPM performance. To disentangle the respective contribution of frequent versus strategic clock-checking to the age-related decrease in TBPM performance, we propose a new, more fine-grained indicator of strategicness (i.e., relative clock-checking), which accounts for interindividual differences in the total frequency of clock-checking (i.e., absolute clock-checking). In this study, 223 participants from an adult lifespan sample (age range = 19–86, M = 45.61, SD = 17.24; 70% women) had to remember to push the ENTER key every 60 s while performing a two-back picture decision task. Together, relative and absolute clock-checking fully mediated the negative age effect on TBPM and explained 53.6% of the variance of TBPM performance. Complementary analyses revealed that both indicators were needed to fully mediate the effect of age on TBPM, but that strategic (i.e., relative) clock-checking was a stronger predictor of TBPM performance than absolute clock-checking. These results stress the importance of considering both aspects of clock-checking to investigate time monitoring in laboratory TBPM tasks and age effects therein, and provide avenues of intervention for improving older adults’ TBPM.

While objective memory performance in older adults was primarily shown to be affected by education as indicator of life course socioeconomic conditions, other life course socioeconomic conditions seem to relate to subjective memory complaints. However, studies differ in which life course stages were investigated. Moreover, studies have explored these effects in an isolated way, but have not yet investigated their unique effect when considering several stages of the life course simultaneously. This study, therefore, examined the respective influence of socioeconomic conditions from childhood up to late-life on prospective memory (PM) performance as an objective indicator of everyday memory as well as on subjective memory complaints (SMC) in older age using structural equation modeling. Data came from two waves of the Vivre-Leben-Vivere aging study (n=993, Mage=80.56). The results indicate that only socioeconomic conditions in adulthood significantly predicted late-life PM performance. PM performance was also predicted by age and self-rated health. In contrast, SMC in older age were not predicted by socioeconomic conditions at any stage of the life course but were predicted by level of depression. In line with the cognitive reserve hypothesis, present results highlight the significance of education and occupation (adulthood socioeconomic conditions) for cognitive functioning in later life.

Successful prospective memory (PM) performance relies on executive functions, including inhibition. However, PM and inhibition are usually assessed in separate tasks, and analytically the focus is either on group differences or at most on interindividual differences. Conjoint measures of PM and inhibition performance that take into account intraindividual variability (IIV) are thus missing. In the present study, we assessed healthy older adults’ level of performance and IIV in both inhibition and PM using a classical Go/NoGo task. We also created a prospective Go/NoGo version that embeds a PM component into the task. Using dynamic structural equation modeling, we assessed the joint effects of mean level ( ), an indicator of amplitude of fluctuations in IIV (or net IIV; intraindividual standard deviation, iSD ), and an indicator of time dependency in IIV (the autoregressive parameter ) in reaction times (RTs) on inhibition and PM performance. Results indicate that higher inhibition failure, but not IIV, predicted PM errors, corroborating the current literature on the involvement of prepotent response inhibition in PM processes. In turn, fastest RT latency ( ) and increased net IIV ( iSD ) were consistently associated with prepotent response inhibition failure, while coherence in RT pattern ( ) was beneficial to inhibition performance when the task was novel. Time-dependent IIV ( ) appears to reflect an adaptive exploration of strategies to attain optimal performance, whereas increased net IIV ( iSD) may indicate inefficient sustained cognitive processes when performance is high. We discuss trade-off processes between competing tasks.