The aim of this dissertation was to develop a novel behavioural method to assess young children’s capacity for episodic foresight. Specifically, I developed a marble game paradigm to assess whether 3-, 4-, and 5-year-old children would save marbles for future enjoyment. Study 1 demonstrated that preschoolers will save more spontaneously when they can draw on a recent past experience compared to when the context is completely novel. Results from study 1 also suggest that preschoolers are sensitive to the relative value of future rewards. Study 2 revealed that providing children with a verbal prompt alerting them to their possible courses of action (i.e., saving or spending) facilitated saving, that 5-year-olds saved more than 3-year-olds, and that children’s performance on this behavioural (i.e., nonverbal) measure of saving was independent of their language proficiency. Children’s saving was not associated with other capacities hypothesized to relate to episodic foresight (theory of mind, inhibitory control, and working memory). Implications for children's saving, the development of episodic foresight, and future research are discussed.

Mental time travel (MTT) refers to an individual’s ability to mentally travel through subjective time, autonoetically re-experiencing past events under the form of autobiographical memories (past MTT), and pre-experiencing events as future autobiographical representations (future MTT). MTT can occur voluntarily, whereby a past/future autobiographical event is subjectively experienced as an intended occurrence, or involuntarily, wherein such an event is subjectively experienced as an unintended outcome of which the individual is aware. Studies investigating MTT’s characteristics in dysphoria and depression show that dysphoric and depressed individuals produce more overgeneral and negative MTT events when compared to control groups. However, existing research has been limited to past and voluntary MTT events, with few studies investigating involuntary MTT and future MTT in dysphoria and depression. The overarching aim of the present research was to compare the phenomenological characteristics of MTT in dysphoric individuals vs. normal mood individuals (Study 1), and in clinically depressed individuals vs. never-depressed individuals (Study 2), with the purpose of furthering existing knowledge on MTT and its relation with dysphoria and Major Depressive Disorder. This aim was addressed by conducting two studies, using a 2 x (2 x 2) mixed-factorial design, with temporality (past vs. future events) and type of retrieval (voluntary vs. involuntary events) as within-subjects independent variables, and participant group as a between-subjects variable. In Study 1, Portuguese university students were categorised into a dysphoric (n=17) or a normal mood group (n=39) depending on their score on the Beck Depression Inventory (BDI-IA) – cutoff point (≥ 10). In Study 2, clinically diagnosed depressed patients (n=32) were recruited from a Portuguese hospital and matched for age and gender with never-depressed control participants (n=32) recruited from the community. The dependent variables tested were: level of spatiotemporal specificity, self-relevance, mood and physical impact, valence, and visual perspective of the MTT events produced. A diary methodology was used in both studies, with an open-ended time period that lasted for a minimum of two weeks, for participants to record their MTT events and grade them on the above mentioned variables using Likert-type ratings. Between seven and fourteen MTT events were produced for each of the four MTT conditions (past voluntary, past involuntary, future voluntary, future involuntary). Results showed that when compared to their respective control groups, depressed, but not dysphoric participants, exhibited a clear influence of mood on several of the phenomenological characteristics of MTT. In Study 1 there were no statistically significant differences in the specificity, negative valence, and mood/physical impact of the MTT events produced by dysphoric and normal mood participants. On the contrary, in Study 2, results partially supported a lower specificity and fully supported a greater negativity and mood/physical impact of MTT events in depressed individuals compared with never-depressed participants. Both studies supported the greater self-relevance of voluntary MTT events and partially supported the hypothesised effect of type of retrieval in specificity. These were the first studies to directly compare past and future, voluntary and involuntary MTT events in dysphoric and depressed individuals, addressing existing gaps in the literature. The key limitation is the relatively small sample size of both studies, however each participant was comprehensively assessed for at least two weeks, providing a rich set of reliable data. Despite limitations, this thesis provides novel pilot findings that help understand the similarities and differences between involuntary and voluntary, past and future MTT, as well as providing new information regarding the possible role of MTT in dysphoria and depression.

The capacity to mentally project the self into the future or, what has recently been termed “episodic foresight” is an emerging topic of study in developmental psychology. The aim of this dissertation was to review available research on this topic and explore its development in two groups of children: typically-developing preschoolers and children with autism spectrum disorder (ASD). This dissertation had two main goals. The first goal was to explore whether tasks thought to measure episodic foresight in children are related and whether, as has been hypothesized, they were related to theory of mind (ToM) and executive function (EF). Study 1 showed that after controlling for age and language ability, episodic foresight tasks were not intercorrelated, nor were they individually related to ToM or EF tasks. Importantly, however, an episodic foresight composite score was related to several EF tasks. Specifically, the results suggested a significant relation between episodic foresight and inhibitory control. The second goal of this dissertation was to explore the development of episodic foresight in children with ASD. Specifically, I tested whether children with ASD would perform more poorly on a series of episodic foresight tasks than a mental-age matched group of typically-developing children. Study 2 revealed significant group differences on several episodic foresight tasks, suggesting that children with ASD showed impairments in thinking about themselves in the future. These results are a timely contribution to the research on episodic foresight and will hopefully aid in the further development of tasks that adequately measure this important cognitive ability in children.

The aim of this dissertation was to explore whether preschoolers understand that preferences differ over time and between people. The first goal was to determine if 3-, 4-, and 5-year-olds could appreciate that their future or “grown-up” preferences may differ from their current ones (self-future condition). This understanding was compared to children’s understanding of the preferences of a grown-up (adult-now condition), or the grown-up preferences of a same-aged peer (peer-future condition). Results from 3 experiments (N = 240) suggest that these types of reasoning develop substantially over the preschool years, and that children are generally proficient by 5 years of age. Results also indicate that thinking about one’s own future preferences is more difficult than thinking about the (future) preferences of others. The second goal of this dissertation was to explore the relations between reasoning about preferences and theory of mind (ToM) and executive function (EF) abilities. Correlational analyses revealed that children’s reasoning about their future preferences and those of others was associated with EF skills, but not with ToM. These findings provide a timely contribution to the expanding research on children’s future-oriented cognition. Implications for theories about perspective-taking abilities, more broadly, and future research are also discussed.

The capacity to mentally project the self into the future or, what has recently been termed “episodic foresight” is an emerging topic of study in developmental psychology. The aim of this dissertation was to review available research on this topic and explore its development in two groups of children: typically-developing preschoolers and children with autism spectrum disorder (ASD). This dissertation had two main goals. The first goal was to explore whether tasks thought to measure episodic foresight in children are related and whether, as has been hypothesized, they were related to theory of mind (ToM) and executive function (EF). Study 1 showed that after controlling for age and language ability, episodic foresight tasks were not intercorrelated, nor were they individually related to ToM or EF tasks. Importantly, however, an episodic foresight composite score was related to several EF tasks. Specifically, the results suggested a significant relation between episodic foresight and inhibitory control. The second goal of this dissertation was to explore the development of episodic foresight in children with ASD. Specifically, I tested whether children with ASD would perform more poorly on a series of episodic foresight tasks than a mental-age matched group of typically-developing children. Study 2 revealed significant group differences on several episodic foresight tasks, suggesting that children with ASD showed impairments in thinking about themselves in the future. These results are a timely contribution to the research on episodic foresight and will hopefully aid in the further development of tasks that adequately measure this important cognitive ability in children.