Absence of age effects on spontaneous past and future thinking in daily life
Previous research on voluntary mental time travel (i.e., deliberately thinking about the past or future) has resulted in negative age effects. In contrast, studies on spontaneous past thoughts (i.e., involuntary autobiographical memories) have reported small or no age effects. The aim of the present research was to investigate the effects of age on the nature and frequency of spontaneous future thoughts in everyday life. In two studies, we examined whether older adults reported spontaneous future thoughts as often as younger adults, and whether these thoughts were predominantly goal-oriented and less dependent on incidental cues than thoughts about the past. In Study 1, young and old participants kept a diary of spontaneous thoughts of upcoming prospective memory tasks and involuntary autobiographical memories for 2 weeks. In Study 2, a 1-day experience sampling method was used to investigate spontaneous and deliberate task-unrelated future and past thoughts, by having young and old participants complete a questionnaire in response to 30 random signals. In both studies, no age effects were found in the frequency of spontaneous future thoughts, which were reported as frequently as thoughts about the past (Study 2) and referred predominantly to upcoming tasks and goals rather than future events or hypothetical events (Study 2). Results concerning the triggers of reported thoughts provide initial support for the idea that representations of future thoughts may be more activated than memories of past events. Taken together, these results have important implications for research on cognitive ageing, mind-wandering, prospective memory and involuntary autobiographical memories.