Before starting LLLL data collection, it is important to specify which specific population of older adults is to be studied. The term ‘older adults’ is often used as an umbrella term for anyone over the age of 65 (including in this paper), but this population is incredibly heterogeneous. Older adults, for example, do not only show larger variability in task-performance as a group compared to younger adults (Hultsch, MacDonald, and Dixon 2002), but they also show larger intra-individual variability having had a lifetime to uniquely develop (Dykiert et al. 2012), which is further influenced by health-status (Strauss et al. 2002). Furthermore, older adults also display significant intra-individual fluctuations in cognitive performance from day to day (Allaire and Marsiske 2005). Although this lies beyond the control of the researcher, it is important to be mindful of these fluctuations, which are more substantial in older as compared to younger populations.
Practical considerations
This section provides some practical considerations regarding inclusion criteria.
Screen participants for factors that may affect cognition or learning outcomes. These include, but are not limited to, potential cognitive impairment and use of commonly prescribed psychoactive medication (e.g., benzodiazepines). Not specific to older adults, but important for replicability, is to additionally screen for presence of traumatic brain injury, the presence of psychiatric or neurological illness, or (past) addiction to alcohol or other drugs.
fMRI and MRI contraindications. Participants with pacemakers, implantable cardioverter-defibrillators, cochlear implants, or other implants containing metal cannot be placed in an MRI scanner.
Eye-tracking. Participants whose pupils are (partially) obscured (e.g., due to ptsosis) or who cannot see without bifocal/varifocal glasses cannot be tested because it is not possible to get a good eye-tracking signal (see also the page on eye-tracking).