This volume is divided into three parts. Part 1 presents a review of the literature regarding the predictive validity of the Adult Attachment Interview (George, Kaplan & Main, 1985) since van IJzendoorn's (1995) meta-analysis on the subject. The review replicates van Ijzendoorn's, confirming the prediction of infant attachment by the AAI and to a lesser extent maternal behaviour. The literature reviewed highlights a move in research since 1995, away from focusing exclusively on maternal sensitivity in understanding the transmission of attachment from parent to child, to consider other potential mediators and moderators of attachment transmission. Part 2 presents an empirical paper investigating the relationship between maternal reflective functioning and emotional availability in two high-risk samples of mothers and their infants. The samples were drawn from two projects investigating the effectiveness of clinical interventions, one in a community sample and the other in a prison population. Two research psychologists undertook data collection (M.S. & J.N.), whilst the author (J.G.) undertook the majority of data coding. One of the research psychologists plans to submit a PhD thesis (M. Sleed 2009) based on some of the data used in the current empirical paper. An association was found between maternal reflective functioning and emotional availability in the prison sample but not the community sample. However, reflective functioning could account for some of the variance in emotional availability identified between the two samples. Within the community sample, associations between emotional availability and parenting stress as well as emotional availability and aspects of maternal psychopathology were identified. Maternal IQ, which has been neglected in past research regarding maternal representations and mother-infant interaction, was found to be strongly associated with maternal representations and emotional availability. Clinical implications and directions for future research are discussed. Part 3 contains a critical analysis of the research process. Methodological choices are discussed and building on the discussion contained within the empirical paper, the clinical implications and directions for research are expanded upon. Part 3 ends with some personal reflections on the research conducted.

Many development trajectories leading to maladaptive outcomes begin in infancy and toddlerhood. With more fathers caring for their children from a younger age there is a need to understand the associations between paternal behaviour and child development. This thesis will explore the relationship between father-child interaction and child outcomes in the early years. Part one is a review of the literature looking at the association between father-child interaction in the preschool years and child outcomes across social, behavioural, cognitive and linguistic domains. The key question addressed is, ‘Do father-child interactions in the preschool years predict later child outcomes?’ Part two of the thesis reports findings from a longitudinal cohort study looking at the associations between father-child interactions and child behaviour across the first two years. Specifically, it examines cross-sectional and longitudinal correlations between father-child interaction, infant temperament and externalizing behaviours, including exploring the direction of effects between fathers and their children. Part three is a critical appraisal of the research process which considers the issues that arise in translating complex family dynamics into quantifiable variables, including issues of measurement and researcher subjectivity.

This research investigates the opportunities provided in different play contexts, both indoor and outdoor, for three-year-old children to play, talk and listen with peers. The analysis draws on data from an ethnographic study of boys’ and girls’ play in two family centres, two college creches and a nursery class. Observations of naturally occurring informal talk between three-year-olds were documented via note-taking, audio and video recordings and verbatim descriptions of events. One hundred and sixteen recordings of naturally occurring informal talk between three-year-olds were transcribed. Whilst analysing the linguistic strategies of questioning, repetition and appropriation within the children’s discourse it became clear that they were simultaneously learning the language system, learning in an intellectual sense and learning to communicate effectively. The study demonstrates the gendered nature of children’s peer talk as well as illustrating how peers can provide a scaffold and model for children with language delay. Various excerpts show how the transition from solitary/parallel play to collaborative play is discursively managed and expressed. The research results suggest that outdoor play facilities can be particularly beneficial for children’s conceptual, linguistic and communicative development.

Detecting infant facial cues is a necessary precursor for effective parenting responses. The question arises whether infant faces elicit preferential allocation of attention in order to facilitate such detection. This thesis employed variations of an existing behavioural attentional paradigm (Hodsoll, Viding, & Lavie, 2011) in first-time parents and non-parents. Individual differences in attentional engagement to infant faces were investigated in relation to: parental status; sex; current symptoms of depression; parenting stress; and childhood experience of maltreatment. Mothers and fathers, and women without children, were found to show greater attentional engagement with infant faces compared to adult, adolescent, and pre- adolescent faces (Chapters 2-4). Parents as compared to non-parents showed the greatest level of attentional engagement with infant faces, and mothers and fathers showed a similar pattern of response (Chapter 4). However, pre-adolescent child faces receive enhanced attentional engagement as compared to older faces, but only when displaying negative affect (Chapters 3 and 4). Emotion was found to play an important role, with parents and non-parents showing enhanced attentional engagement with infant faces when they displayed emotional expressions (Chapters 2-4). Current parenting stress and experience of childhood maltreatment were found to be associated with individual differences in attention to infant compared to adult faces; by contrast, current symptoms of depression were not associated with performance on the attention task (Chapters 1 and 5). These findings suggest that infant faces are inherently salient stimuli, especially for parents of infants. Increased attention to infant faces may reflect part of a wider set of adaptive behavioural changes associated with becoming a parent. However, these changes appear to be modulated by early or current adverse life experience, which may affect normative attention processes involved in detecting infant facial cues, with possible implications for parenting behaviour.

This thesis addresses whether children with severe behavioural problems lack emotional competence in key areas and, if so, whether this is reflected in their ability to appraise emotions in others. Self-rated and objectively rated emotional competence of children in mainstream schooling was compared with 20 children aged seven to 11 excluded for severe social, emotional and behavioural difficulties. In Study 1 self-report questionnaires measured affect perception, empathy and expressivity in typically developing (N=203), special educational needs (N=36) and socially, emotionally and behaviourally disordered (N=30) children in mainstream schooling. Younger children were less perceptive of affect than older children and scored lower for cognitive empathy. Boys scored lower in cognitive and affective empathy than girls and were less intimate, and more covert, in their expression of emotion. Special educational needs children appeared less emotionally perceptive than their peers. In Studies 2a and 2b, affect appraisal and the ability to describe emotional change were examined using a new measure employing pictorial representations of children in ambiguous postures and facial representations of emotion. Typical patterns of appraisal of possibly threatening, depressive and innocuous postures were established (N=242). A developmental progression in reasons given for emotional change was seen with older children providing more socially based and mentalising answers than younger children. Study 3 developed an interactive computerised measure to examine the point at which children recognise the emergence of emotion from an interpolation of photographic facial expressions. Eighty-five typically developing children manipulated 26 emotional changes, including emotion/emotion and emotion/neutral transitions and chose a point of uncertainty in the transformation. A significant effect was found for facial representations of fear and anger, indicating a threat detection mechanism in response to emergent emotion. In Study 4 children with severe behavioural problems were compared across all measures with typically developing children from the first three studies. Behaviourally challenged children were deficient in cognitive and affective empathy and exhibited a hostile appraisal bias when assessing ambiguous postures of other children. No deficit was found in the ability to evaluate emotional change and provide age-appropriate reasons. However, anger was dominant in the perception even over fear stimuli when assessing emotional transition. Overall, children excluded from mainstream schooling with severe behavioural problems showed a very different profile to mainstream children with behavioural problems, suggesting a qualitative difference in cognitive functioning that could have a predictive function. This thesis not only supports the premise that severe SEBD children exhibit altered emotional functioning but has developed a series of tests that will have ongoing value in applied research.

This thesis investigated whether 18-36 month olds understand humour and humorous intentions. Also investigated was whether parents use vocal acoustic and verbal cues to indicate that a joke was intended. 1. Unambiguous physical jokes and mistakes accompanied by intentional cues (laughter, Woops!) were demonstrated to 19-36 month olds. Toddlers of all ages distinguished unambiguous jokes and mistakes by copying jokes and correcting mistakes. Ambiguous physical actions interpretable either as jokes or mistakes were demonstrated. Toddlers saw half of these actions with a humorous intentional marker (laughter), and the other half with an accidental marker (Woops!). Only 25-30 and 31-36 month olds differentiated humorous intentions and mistakes by copying actions marked with laughter and correcting actions marked with Woops! 2. In a two-part study, parents read storybooks with humorous, sweet, and neutral pages to their 18-26 month olds. Target book sentences were measured for speech rate, intonation contours, and mean, standard deviation, and range of both fundamental frequency and amplitude. Humorous sentences displayed unique vocal acoustic patterns (versus neutral and sweet sentences). 3. Parents read a book containing humorous and non-humorous pages to their 19-26 month olds. Parents used significantly more high abstraction extra-textual utterances (ETUs) and significantly less low abstraction ETUs when reading the humorous pages. Parents read either a humorous or non-humorous book to their 18-24 month olds. Parents reading the funny book made significantly more ETUs encouraging disbelief of prior utterances. These findings indicate that toddlers understand humour by at least 19 months, and humorous intentions by 25 months. This is the earliest known age at which children understand that other can intend to do the wrong thing (versus pretense, lying, metaphor, etc.) The acoustic and verbal cues given by parents could help toddlers, (1) notice that a joke was said, and (2) understand what the joke was.

A large proportion of recent research on the development of numerical cognition has focused on the foundational role of approximate number sense, yet number sense alone cannot fully explain how young children acquire numeracy skills. This thesis aims to investigate how other domain-specific processes and domain-general cognitive processes relate to numeracy in early childhood and whether they play a role in learning about mathematics. The experiments presented in Chapter 2 explored how domain-general processes relate to young children's attention to discrete number in non-symbolic representations through a correlational approach. Results supported the role for inhibitory control in selecting numerosity as the relevant stimulus dimension. In order to investigate causal relationships in emerging maths performance, Chapter 3 reports a cognitive training study aimed at contrasting transfer effects of domain-general and domain-specific training in pre- schoolers. Findings suggested caution in interpreting published transfer effects without the highest level of control. The latter chapters targeted learning mechanisms by tackling a specific process in mathematical cognition: acquiring the meaning of numerical symbols. Specifically, the experiments presented in Chapter 4 employed an artificial learning paradigm to test factors influencing adults' and children's formation of novel symbolic numerical representations. Congruency between discrete and continuous non-symbolic quantity influenced novel representations and numerical order information facilitated learning, especially in children. In order to explore symbolic representations of real numbers, Chapter 5 focuses on associations between different representational formats of real numbers in young children and how this relates to both domain-specific and domain-general factors. Children had stronger mappings between symbols and precise non-symbolic representations for numbers smaller than four, than between larger numbers and approximate non-symbolic representations. Taken together, results from the experiments presented in this thesis highlight the need to incorporate factors beyond number sense in theories of numeracy development.

The relationship between sleep and language during infancy has not attracted a great deal of scrutiny despite its theoretical importance in the function of sleep and the practical implications to which resulting findings could contribute. With this in mind, the current thesis aims to investigate this question with a focus on word learning, generalisation of word meanings and vocabulary development. A cross-sectional design in 16 month old infants was used as one of the main approaches to test the potential effects of naps on word learning and generalisation. In both experiments, infants were randomly assigned to nap or wake conditions. After teaching two novel object-pairs to them, their initial performance was tested with an intermodal preferential looking task. An increase in target preference indicated the recognition of the auditory label-looking behaviour being monitored with an automatic eye-tracker. In the case of word learning, the same objects were shown in the test trials as in the training trials, whereas the test objects were different in colour in the generalisation experiment. In both experiments target preference increased only after a nap, while there was no change in the performance of the wake groups. These results indicate that daytime napping facilitates both the consolidation of novel words and the generalisation of novel word meanings in infancy. The relationship between sleep and vocabulary development was studied in a longitudinal questionnaire based design, in which vocabulary questionnaires and sleep diaries were employed, with a cohort of 246 children between the ages of 7 and 38 months being analysed. Sleep measures were used as predictors in a multi-level growth curve analysis of vocabulary development. The length of daytime naps was positively correlated with both expressive and receptive vocabulary growth, whereas the length of night-time sleep was negatively associated with rate of expressive vocabulary growth. To conclude, the results of the present thesis highlight the importance of daytime naps in early childhood.

The quality of affective relations within families and the peer group can influence psychological development in childhood and is implicated in the aetiology of childhood psychiatric disorders. Instruments currently available to assess children's emotional environment do so from an adult perspective and assess the environment shared by the child with siblings and peers rather than specifically focusing on the child's non-shared experiences. The aim of this research was to determine whether an instrument that assesses children's perceptions of their affective relations with other members of the family and peer group is feasible, is acceptable to them, valid and reliable. The literature is reviewed and an existing instrument that assesses the child's perception of family relations is re-examined. These findings informed the design of an innovative instrument to assess the child's report of the affective content of parallel dyadic relations, encompassing up to 20 emotions in five age groups from 3 and 15 years of age. Three types of phrasing were compared each designed to elicit categorical responses. A pilot study resulted in minor changes to a test-retest design to assess the reliability of these items. 97 children from a Child and Adolescent Mental Health Service participated in the subsequent main study, which found that children of 7 years and older were able to concentrate on the task, and found it acceptable. A form of phrasing that focused on each dyad sequentially was the most reliable the percentage agreement ranged 77-81% across three age groups, between 7-15 years. Future developments of the test are described, and include the use of a scale, its standardisation, assessment of desired as well as perceived affective relations, and its computerisation. Its place in clinical practice and research may include discriminating between populations, prediction of risk, outcome and preventive studies.

The goals of the thesis were to identify the development of 3- to 7-year-old children’s comprehension and production of two contrasting temporal connectives - before and after - that signal the order of events in two-clause sentences, and to establish the reasons for difficulties with these linguistic devices. Chapter 1 reviews the literature that is considered relevant to the experimental work. In the experimental work (Chapters 2 to 4), children’s comprehension and production of two-clause sentences containing before and after was examined in separate groups of children aged 3 to 7 years. The sentence structures differed in their memory and also language demands. Independent measures of memory and language were related to performance. The design enabled a contrast of traditional memory capacity accounts (e.g., Just & Carpenter, 1992) versus more recent language-based accounts (e.g., Van Dyke, Johns, & Kukona, 2014) of why working memory explains variance in the processing of complex sentences. A capacity account predicts a direct relation between memory and sentence processing: specifically, that some sentence structures are more difficult to process than others because they require more information to be held in working memory than others. Alternatively, a language-based account proposes an indirect relation between memory and sentence processing, such that good language skills modulate the influence of memory on sentence processing, by influencing the accurate representation of information in verbal working memory. Experiment 1 (Chapter 2) was a touch-screen comprehension paradigm. Children listened to two-clause sentences linked by a temporal connective, before or after, while viewing animations of the actions in each clause. After each sentence, they were asked to select the event that happened first to assess their understanding of the temporal connective. The pattern of results suggested that the memory demands of specific sentence structures limited children’s comprehension of sentences containing temporal connectives, supporting a memory capacity account. Experiment 2 (Chapter 3) further investigated comprehension of these sentences focusing on how memory and language influence the ease of processing. Children were trained to make speeded responses to the sentence structures investigated in Experiment 1. The findings support Experiment 1: memory capacity best predicted comprehension of these sentence structures. Experiments 3 and 4 (Chapter 4) examined production of the same sentence types. In two experiments (elicited production with blocked conditions, and sentence repetition), separate groups of children viewed an animated sequence of two actions, and were asked to describe the order of events. Instructions and practice trials were used to model the target sentence structures. In contrast to the comprehension experiments (Experiments 1 and 2), this work showed that children’s individual differences in the production of two-clause sentences linked by before or after were related to variability in language skills, rather than poor memory capacity. In Chapter 5, I conclude that Experiments 1-4 reveal a differential influence of working memory and language on children’s comprehension and production of two-clause sentences containing before and after. I argue that the existing theoretical accounts of the influence of memory and language on sentence processing (e.g., Just & Carpenter, 1992; Van Dyke et al., 2014) require much more detailed investigation within the sentence structures examined here, and across other complex sentences that are also considered to differ in their memory and language demands. I present several suggestions as to how this might be accomplished in future work.