Research on thinking in adults has suggested that there is what has been termed a “future-oriented” or “prospective” bias (Grant & Walsh,
2016; Smallwood, Nind, & O’Connor,
2009). Experience sampling techniques in the laboratory and in the context of daily life have indicated that adults typically report future-oriented thoughts more frequently than past-oriented thoughts (e.g., Grant & Walsh,
2016; Smallwood et al.,
2009; Smallwood et al.,
2011; Spronken, Holland, Figner, & Dijksterhuis,
2016; Stawarczyk, Cassol, & D’Argembeau,
2013; Stawarczyk, Majerus, Maj, Van der Linden, & D’Argembeau,
2011; Song & Wang,
2012). Adults attach greater value to future events than past events, feel greater emotions when considering future events compared to past events, and judge the future to feel closer than the past (Caouette, Wohl, & Peetz,
2012; Caruso,
2010, Caruso, Gilbert, & Wilson,
2008; Caruso, Van Boven, Chin, & Ward,
2013; Van Boven & Ashworth,
2007); such findings can also be interpreted as evidence of a future-oriented bias in judgments and attitudes (Suhler & Callender,
2012; Sullivan,
2018).
Numerous authors have emphasized the adaptive nature of future-oriented cognition in allowing us to prepare for a future that is as yet undetermined, in comparison to merely dwelling on past events that cannot be changed (e.g., Parfit,
1984; Schacter, Addis, & Buckner,
2007; Suddendorf & Corballis,
2007; Suhler & Callender,
2012). On such an approach, a future-oriented bias can be seen as an evolutionary adaptation. What is not clear, though, is the developmental origins of such a bias (though see Burns, McCormack, Jaroslawska, Fitzpatrick, McGourty, & Caruso,
2018). In particular, very little is known about the salience of the future in the mental lives of children. Children begin to use and understand the future tense in language at the early stages of language acquisition (Harner,
1982; Weist,
1989), and research on the development of episodic future thinking suggests that when prompted, children can reliably begin to describe specific future events around 3–4 years of age (Busby & Suddendorf,
2005; Hayne, Gross, McNamee, Fitzgibbon, & Tustin,
2011; Quon & Atance,
2010; Richmond & Pan,
2013). However, although it has been suggested that episodic future and past thinking develop in tandem in the preschool years (Busby & Suddendorf,
2005; Richmond & Pan,
2013), studies of middle childhood indicate that the ability to episodically remember the past develops more quickly than the ability to episodically imagine the future (Coughlin, Lyons, & Ghetti,
2014; Wang, Capous, Koh, & Hou,
2014). If children do have particular difficulty episodically imaging the future, this might translate into future thoughts playing
less of a role in their mental lives.
The aims of the current study are to examine whether children show future-oriented bias, as operationalized by a tendency to think about the future rather than the past, and whether there are developmental changes in the magnitude of such a bias across childhood, adolescence, and into adulthood. We measured the tendency to think about the future versus the past in two ways: using a mind-wandering task and a word-cueing task that prompted episodic thinking.
Mind-wandering
Adult studies have examined spontaneous future and past thoughts using experience sampling methods, and in particular by looking at the temporal focus of mind-wandering in laboratory-based testing (e.g., Baird, Smallwood, & Schooler,
2011; Smallwood et al.,
2009,
2011). Given the educational significance of mind-wandering (Smallwood, Fishman, & Schooler,
2007), it is perhaps surprising that there are extremely few developmental studies, and no existing data that we are aware of that examine whether there are developmental changes in the temporal focus of mind-wandering. In a recent developmental study, Van den Driessche et al. (
2017) examined mind-wandering (and relatedly, “mind-blanking”) in children of a mean age of 8 years using a paradigm similar to that typically used with adults. The focus of their study was actually on the effects of ADHD, and they did not examine developmental change and also did not report the temporal focus of mind-wandering in their child samples. Stawarczyk, Majerus, Catale, and D’Argembeau (
2014) compared levels of mind-wandering in adolescents and adults but did not ask participants to report whether mind-wandering was to the past or future. Two earlier studies of mind-wandering in late childhood, however, did report temporal focus. Zhang, Song, Ye, and Wang (
2015) examined mind-wandering in 9- to 11-year-olds who were performing a Go-NoGo task and found that children reported more future-oriented episodes of mind-wandering than past-oriented episodes. In Ye, Song, Zhang, and Wang’s (
2014) study, children aged 9–14 (mean age of 11 years) reported on mind-wandering while performing a choice reaction time task or a 1-back working memory task. For both tasks, children reported thinking about the future around 25% of the time, whereas they reporting thinking about the past 11–14% of the time. The findings of both Ye, Song, Zhang, & Wang (
2014) and Zhang et al.’s (
2015) studies suggest that by late childhood, a future-oriented bias is apparent. However, developmental changes have not been examined, and it is not known if such a bias exists in younger children.
A number of findings suggest the hypothesis that the temporal focus of mind-wandering may shift developmentally towards becoming more future-biased. First, developmental changes in executive functioning, which are well-documented to occur over a long developmental period (Best & Miller,
2010), might result in changes in temporal focus. Baird et al. (
2011) found that adults with higher working memory capacity showed a greater future-oriented bias in mind-wandering (though see McVay, Unsworth, McMillan, & Kane,
2013; Robison & Unsworth,
2017); moreover, increasing the demands of the primary task on working memory capacity reduces the future-oriented bias (Smallwood et al.,
2009,
2011). Both of these findings suggest that the future-oriented bias in mind-wandering may be linked to available working memory capacity, which in turn suggests that as working memory capacity increases, a future-oriented bias may emerge or become more pronounced.
Second, there is some evidence that brain regions which are known to develop across childhood and into adolescence (Blakemore & Choudhury,
2006; Hooper, Luciana, Conklin, Yarger,
2004) are critical for the future-oriented bias in mind-wandering. Bertossi and Ciaramelli (
2016) reported that patients with ventromedial prefrontal damage not only showed reduced overall levels of mind-wandering, but most strikingly, reported no future-oriented mind-wandering at all. These authors argue that this pattern stems from impairments in episodic thinking (Bertossi, Tesini, Cappelli, & Ciaramelli,
2016) which may be particularly pronounced for episodic future thinking (Bertossi, Candela, Ciaramelli, & De Luca,
2017). Although it is difficult to straightforwardly extrapolate developmental predictions from studies of neuropsychological patients, these findings indicate that the future-oriented bias in mind-wandering may depend on brain regions and associated cognitive functions that develop gradually.
In our study, we used a simplified mind-wandering paradigm in which participants reported when probed as to whether they were thinking about the past, present, or future while they completed another task. Because we were concerned about young children’s potential difficulties in reporting on mind-wandering while simultaneously completing a cognitively demanding task, and because we wanted to match task difficulty as closely as possible across age groups, we asked participants to do some coloring-in rather than the more standard type of cognitive task typically used in mind-wandering studies with adults. They were then probed at intervals to report, by pressing one of three buttons on a touch-screen, whether they were thinking about the past, the here-and-now, or the future. We note that the “here-and-now” category of response does not distinguish between whether children were thinking about the coloring-in task or other aspects of their present environment. However, we wanted to keep the response options simple for young children, and our primary focus was on the relative proportions of past versus future responses.
Cued episodic thinking
Our participants also completed an episodic thinking task using a cue word technique. Cue word studies of episodic thinking and its development have been conducted previously (e.g., Coughlin et al.,
2014; Quon & Atance,
2010); what was distinctive about our task was that participants were free to generate either a past or a future episode in response to the cue, whereas in previous studies, participants were explicitly directed to describe only either past or future events. We were interested in the relative proportions of past and future episodes that participants generated in response to the cues and specifically if these proportions changed developmentally. In addition, we asked for participants to make ratings about the clarity of the events in their minds, how quickly the event came to mind, and the valence of the event. For these additional measures, we were interested in past–future differences, and also whether these showed a developmental pattern.
To the best of our knowledge, this was the first study to examine cued episodic thinking in which participants were free to report either past or future event descriptions. However, there are some existing findings that make it possible to speculate on the likely temporal focus, and on past–future differences regarding the additional measures. With regard to the former issue, it might be predicted that temporal focus would not show future-oriented bias even in adults. In the context of mind-wandering, thoughts that are cued by environmental stimuli tend to be past- rather than future-oriented. Maillet and Schacter (
2016) found that past rather than future thinking was more prevalent for episodes of mind-wandering that were triggered by presented stimuli, whereas this was not the case for thoughts unrelated to the stimuli. Similarly, Plimpton, Patel, and Kvavilashvili (
2015) reported that mind-wandering was dominated by past-oriented thoughts under circumstances in which unrelated verbal cues appeared the screen (see also Vannucci, Pelagatti, & Marchetti,
2017). All these authors suggest that verbal cueing is more likely to trigger memory retrieval than future thinking. Studies of involuntary mental time travel, in which participants report when mental time travel to either the past or future occurs spontaneously also indicate the absence of a future-oriented bias; in these studies, similar amounts of past and future thought occur (Berntsen, Rubin, & Salgado,
2015; Cole, Staugaard, & Berntsen,
2016; Finnbogadóttir & Berntsen,
2013).
Although our task was not a mind-wandering task, because participants were explicitly asked to generate event descriptions in response to word cues, these findings suggest that we are unlikely to find a future-oriented bias. Nevertheless, we thought it was possible that there would be a developmental shift in the relative proportions of past versus future event descriptions, with an age-related increase in future event descriptions. Such a prediction could be generated on the basis of previous findings indicating that children find episodic future thinking particularly difficult (Coughlin et al.,
2014; Wang et al.,
2014). It would be consistent with suggestions that episodic future thinking is more cognitively effortful than episodically remembering because of its greater demands on constructive processes (Addis, Wong, & Schacter,
2007; D’Argembeau, Ortoleva, Jumentier, & van der Linden,
2010; Schacter & Addis,
2007; though see Anderson, Dewhurst, & Nash,
2012; Jeunehomme & D’Argembeau,
2016). Thus, we speculated that the proportion of future events described might increase developmentally.
On the basis of previous findings, we were also able to make predictions about the other measures used in our task (clarity, how quickly the event came to mind, and valence). Studies with adults suggest that the rated clarity of remembered events might be greater than imagined future events (Berntsen & Bohn,
2010; D’Argembeau & Van der Linden,
2004, D’Argembeau & Van der Linden,
2006; Gamboz, Brandimonte, & De Vito,
2010), and one might predict that such a past–future difference may be even more marked in children (although we note that Coughlin et al.
2014, did not report past–future differences in clarity in any of their age groups). In terms of self-reported speed at which the event came to mind, Coughlin et al. found that child groups reported that future events took longer to come to mind than past events, but this was not true for their adult group. Coughlin et al. speculate that children’s self-reports on this measure reflect their greater difficulties with generating future event descriptions compared to past event descriptions, whereas adults do not struggle with future event generation to the same extent. We were interested in whether we could replicate Coughlin et al.’s developmental findings regarding self-reported speed at which an event came to mind in the context in which participants could freely choose to describe a past or a future event. One possibility is that past–future differences in speed may disappear even in children under circumstances in which participants can describe whichever type of event comes to mind first.
Finally, there is considerable evidence that suggests that imagined future events are more likely to be rated as having positive valence than remembered events, both in situations in which thought about events at other times is cued and when it occurs spontaneously (Berntsen & Bohn,
2010; Berntsen & Jacobsen,
2008; Cole et al.,
2016; Finnbogadóttir & Berntsen,
2013), i.e., that there is a marked future positivity bias (Cole et al.,
2016). This is in line with a variety of findings that suggest that people have a tendency to assume that their future will be rosy (e.g., Newby-Clark & Ross,
2003; Ross & Newby-Clark,
1998). There is some evidence to suggest that even relatively young children tend to be (over) optimistic about their future over long-time scales (Bohn & Berntsen,
2013; Lockhart, Chang, & Story,
2002), and in their developmental study of episodic thinking. Abram, Picard, Navarro, and Piolino (
2014) found a future positivity bias that did not interact with age. Thus, we anticipated that the future positivity bias might be present in all of our age groups.