Abstract

The present diary study examined everyday PM tasks in 20 younger and 19 older adults and explored the role of personal task importance, use of reminders, and everyday stress as possible correlates of age-related PM performance in everyday life. Results revealed an age benefit in everyday PM tasks. In addition, task importance was identified as a critical moderator of age-related PM performance. More frequent use of reminders and lower levels of stress were associated with better PM performance in general but did not contribute to age-related PM performance. Exploring further possible correlates of PM revealed that the strategy to reprioritize initially planned intentions was associated with age benefits in everyday PM. Results suggest that the age-related benefit observed in experimenter-given tasks transfers to everyday PM and varies in dependence of motivational and cognitive factors. Implications for theoretical models of PM and aging are discussed.¹

4.2 Introduction

Remembering to implement planned intentions is referred to as PM (Zeintl, Kliegel, &

Hofer, 2007). Everyday examples of PM are remembering to switch off the stove after cooking, paying utility bills in time, or remembering to take medication according to schedule.

The vast majority of studies on age-related PM performance has been carried out in the laboratory (see Kliegel, Jäger, & Phillips, 2008c, for a recent meta-analysis) and used tasks like remembering to stop a clock seven minutes after the beginning of a trial (Rendell &

1 Concerning the reproduction of the three study articles, in some few cases, minor changes were made to the original language to maintain a coherent wording across the present thesis.

Thomson, 1999) or remembering to press a pre-specified key when the PM target cue appears on the computer screen (Einstein & McDaniel, 1990). In their meta-analytic review, Henry, MacLeod, Phillips, and Crawford (2004) concluded that younger adults generally perform better than older adults in those laboratory-type PM tasks.

There are also - much fewer - studies applying PM tasks in a naturalistic setting (i.e., in the everyday life of the participant), such as asking participants to telephone the

experimenter at a specific time over two weeks (Moscovitch, 1982), to mail postcards to the experimenter (Patton & Meit, 1993), or to periodically log the time on an electronic organizer (Rendell & Thomson, 1993, 1999). For those naturalistic settings, Henry et al. (2004) showed that - somewhat surprisingly - older adults tend to outperform younger adults. Reviewing the evidence on this age benefit, Phillips, Henry, and Martin (2008) have recently stressed the urgent need for research on naturalistic PM tasks with high ecological validity. They differentiate between “real” naturalistic PM tasks which occur in everyday life without

interference of an experimenter (i.e., actual intentions participants make, try to remember, and fulfill at specific times or events) and more or less artificial tasks externally provided by an experimenter like calling or posting messages at pre-specified times. So far, studies exploring age benefits in naturalistic PM tasks have focused on the second task type and there is

surprisingly little known about age-related PM in the “real” naturalistic task type. Therefore, the first aim of the present study was to explore whether the age benefit found in previous naturalistic PM studies using experimenter-given PM tasks generalizes to “real” PM tasks occurring in the everyday life of the participants. For this purpose, in terms of methodology, the present study adopted a diary procedure.

Furthermore, the second aim of the present study was to go beyond the description of possible age differences in real life PM tasks and test for mechanisms underlying the

performance. As outlined above, there is little evidence concerning age-related PM in real life tasks. Thus, we revert to mechanisms that have been suggested to underlie the age benefit in

naturalistic PM tasks. Further, a mechanism suggested as influential for real life PM performance in a study from Marsh, Hicks, and Landau (1998) focusing on younger adults only will be taken up.

Specifically, Marsh et al.’s (1998) data suggest that younger adults implemented more important real life intentions more frequently than less important ones. If one assumes that important tasks raise the motivation for correct fulfillment, this finding is in line with research on the role of motivation for the age benefit in naturalistic PM tasks. In a first study directly examining the motivational angle in experimenter-given naturalistic PM tasks in younger and older adults, Aberle, Rendell, Rose, McDaniel, and Kliegel (2010) used a monetary incentive to manipulate motivation. Results show that providing a monetary incentive improved only younger adults, who then reached the level of performance of older adults. Further evidence comes from a recent study showing that higher a priori ratings of motivation to perform an experimenter-given naturalistic PM task in the older adults were correlated to their subsequent higher PM performance (Schnitzspahn, Ihle, Henry, Rendell, & Kliegel, 2011).

In the light of these results, the present study explored personal importance of real life intentions as one possible moderator of age-related performance in those tasks. Our

predictions were based on considerations of Aberle et al.’s (2010) and Schnitzspahn et al.’s (2011) results on experimenter-given naturalistic PM performance in younger and older adults as well as Marsh et al.’s (1998) data on younger adults’ real life PM performance. Therefore, we predicted generally high levels of PM accuracy for very important intentions in both age groups and that age benefits should only or more pronouncedly occur in less important intentions.

Another explanation for age benefits in naturalistic PM tasks that was adopted and tested for age-related PM performance in real life tasks in the present study is that older adults use more reminders to cue PM retrieval (Phillips et al., 2008). Available results concerning the use of reminders in younger and older adults in naturalistic PM tasks are however mixed

(Maylor, 1996b; Patton & Meit, 1993): In some studies older adults reported using more reminders (e.g., Jackson, Bogers, & Kerstholt, 1988), whereas in other studies younger adults reported more frequent use of reminders (e.g., Dobbs & Rule, 1987; Rendell & Thompson, 1999). Rendell and Craik (2000) instructed participants not to use reminders in a naturalistic PM task. In a post-task debriefing interview, both younger and older participants reported generally low use of reminder strategies, whereas an age benefit in PM performance was still present. Moreover, Rendell and Thompson (1999) found that providing both age groups an alarm in one condition and in another condition with instructions and the opportunity to link cues from their environment to the prospective action did not reduce the magnitude of the older adults’ superiority compared to younger adults on a naturalistic PM task. In line with these results Phillips et al. (2008) concluded there is remarkably little evidence supporting the popular idea that age-related benefits on PM in daily lives are caused by increased use of reminders. On the other hand, so far, PM tasks used in naturalistic studies mostly were artificial, experimenter-generated tasks and not intentions occurring in participants’ real life.

Thus, up to now, it is in fact unclear as to whether an effect of reminder use may emerge in everyday life intentions. Here, participants, especially older adults, may be more aware of their need for using reminders. Conceptually, such knowledge of successfully using supportive strategies can be considered as one component of metacognitive awareness.

Importantly, in a recent study, Schnitzspahn et al. (2011) revealed better metacognitive performance predictions in older adults regarding their naturalistic PM performance in an experimenter-given PM task. Moreover, an association of metacognitive judgments with age benefits in the naturalistic PM task was observed. The present study set out to further explore this issue, but given the heterogeneity of previous results on reminder and age-related PM performance, no straightforward predictions were formed.

A third explanation for age benefits in naturalistic PM performance that was tested in the current study with regard to its validity for real life PM tasks is that older adults may be

less stressed than younger adults and may therefore implement delayed intentions more accurately. This hypothesis was developed by Phillips et al. (2008) considering that most studies have compared younger adult university students with retired older adults. So far, this possibility has not been directly tested for real life intentions but available evidence on stress effects, again, is inconclusive. On one hand, Rendell and Thompson (1999) found no

difference in naturalistic PM performance between working and retired older adults. On the other hand, Schnitzspahn et al. (2011) observed that younger adults reported significantly more perceived everyday stress than older adults and everyday stress mediated age-related variance in a naturalistic, experimenter-provided PM task. Again, given the heterogeneity of previous results on everyday stress and age-related PM performance, no straightforward predictions were formed.

To sum up, the first aim of the present study was to examine if age benefits also occur in real life everyday PM tasks. The second aim was to explore three possible moderators of age-related PM performance in naturally occurring PM tasks (i.e., personal importance, use of reminders, and everyday stress).

4.3 Method