Influences of Affect and Naming on Children's Drawings

Positive and negative affective characterisations have been shown to influence children’s use of size in human figure drawings. Inconsistency in the literature regarding this influence and methodological issues makes the robustness of the findings uncertain. Furthermore theoretical debate continues over the underlying mechanisms, acquired pictorial convention (APC) or an appetitive defensive mechanism (ADM), causing a differential expression of size. The first two studies were designed to improve upon past methodology in examining the relationship between size and affect in children’s drawings: a novel model figure was developed, independent measures of affect taken and children took part in drawing production and perception tasks. The first two studies examined the influence of affect on children’s drawings of nice and nasty human figures and the role of APC and ADM. The results indicated that affectively labelling a model figure to be drawn did not reliably influence the size of children’s drawings. However, consistency in the effects of labelling on drawing perception tasks was found. This led to an examination of the features, other than size, that different children displayed in their free drawings. There was consistency shown in terms of the core features children drew for concrete objects and children appeared to be using a set of shared conventions for representing objects. This consistency of use of features was not as robust for less concrete more descriptive topics (such as nice and nasty figures). The use of a word label was also shown to influence children’s drawings when copying from a model. Children were significantly more likely to include core features from the labelled object despite these being absent in the model. Furthermore children would draw core features prior to more periphery features, supporting the core-to-periphery progression principle

Automatic age progression and estimation from faces

Recently, automatic age progression has gained popularity due to its numerous applications. Among these is the frequent search for missing people, in the UK alone up to 300,000 people are reported missing every year. Although many algorithms have been proposed, most of the methods are affected by image noise, illumination variations, and facial expressions. Furthermore, most of the algorithms use a pattern caricaturing approach which infers ages by manipulating the target image and a template face formed by averaging faces at the intended age. To this end, this thesis investigates the problem with a view to tackling the most prominent issues associated with the existing algorithms. Initially using active appearance models (AAM), facial features are extracted and mapped to people’s ages, afterward a formula is derived which allows the convenient generation of age progressed images irrespective of whether the intended age exists in the training database or not. In order to handle image noise as well as varying facial expressions, a nonlinear appearance model called kernel appearance model (KAM) is derived. To illustrate the real application of automatic age progression, both AAM and KAM based algorithms are then used to synthesise faces of two popular long missing British and Irish kids; Ben Needham and Mary Boyle. However, both statistical techniques exhibit image rendering artefacts such as low-resolution output and the generation of inconsistent skin tone. To circumvent this problem, a hybrid texture enhancement pipeline is developed. To further ensure that the progressed images preserve people’s identities while at the same time attaining the intended age, rigorous human and machine based tests are conducted; part of this tests resulted to the development of a robust age estimation algorithm. Eventually, the results of the rigorous assessment reveal that the hybrid technique is able to handle all existing problems of age progression with minimal error.National Information Technology Development Agency of Nigeria (NITDA

Understanding video through the lens of language

The increasing abundance of video data online necessitates the development of systems capable of understanding such content. However, building these systems poses significant challenges, including the absence of scalable and robust supervision signals, computational complexity, and multimodal modelling. To address these issues, this thesis explores the role of language as a complementary learning signal for video, drawing inspiration from the success of self-supervised Large Language Models (LLMs) and image-language models. First, joint video-language representations are examined under the text-to-video retrieval task. This includes the study of pre-extracted multimodal features, the influence of contextual information, joint end-to-end learning of both image and video representations, and various frame aggregation methods for long-form videos. In doing so, state-of-the-art performance is achieved across a range of established video-text benchmarks. Second, this work explores the automatic generation of audio description (AD) – narrations describing the visual happenings in a video, for the benefit of visually impaired audiences. An LLM, prompted with multimodal information, including past predictions, and pretrained with partial data sources, is employed for the task. In the process, substantial advancements are achieved in the following areas: efficient speech transcription, long-form visual storytelling, referencing character names, and AD time-point prediction. Finally, audiovisual behaviour recognition is applied to the field of wildlife conservation and ethology. The approach is used to analyse vast video archives of wild primates, revealing insights into individual and group behaviour variations, with the potential for monitoring the effects of human pressures on animal habitats

Assessment of cognitive development in four to eight year old children by means of drawing tasks

The present thesis explores the link between children's drawings and cognitive development. The aim of this study is to investigate the intellectual abilities of the child draughtsman with good depiction skills and to evaluate the merit of the drawing technique in the assessment of conceptual maturity. The standardised Goodenough-Harris Drawing Test (GHDT) of intellectual maturity was administered to 115 children between 4 to 8 years of age against criterion ability measures (Wechsler scales). Its psychometric properties are examined in respect to its norms and scales, its reliability and validity at different age levels and ranges of intelligence. Early theories in the area of pictorial representation were directed towards identifying features characteristic of different developmental periods (Kerschensteiner, 1905; Luquet, 1927/1977). At the same time Piaget and Inhelder (1948/1967) incorporated these stage theories into their model of spatial intelligence. Yet, the recent experimental study of children's drawings has disclosed a number of variables which interfere during the course of production, challenging the view that drawings can be seen as the royal route to access children's concepts. Stage theories are re-evaluated by means of fourteen experimental drawing tasks with various degree of difficulty. The tasks - administered to the same children tested with the standardised instruments -are spatial in nature and have been sampled from two widely researched areas related to the pictorial representation of partial occlusion and of spatial axes (horizontal/vertical). The acquisition of the pertinent spatial concepts by means of drawings is examined, considering competence-deficiency and competence-utilisation accounts of children's performance at different ages. Finally, overall perfomance on spatial tasks is compared with performance on conventional (Wechsler scales) and non-verbal (GHDT) measures of intellectual functioning, considering the optimum method to assess children's abilities by means of drawings. In general, drawing performance is reasonably sensitive to children's level of intelligence, yet the significance of drawing varies at different ages and ranges of IQ. Finally, the establishment of steadfast developmental trajectories falls short in the field of pictorial representation. The variable performance, particularly from the children at intermediate ages, suggests that the stages of intellectual or visual realism should be seen as relative and not as absolute

Exploring spatial memory in children with autism and ADHD

The study investigates spatial memory in neurotypicals, ASD and ADHD children. In a reaction-time accuracy task, children (N = 117) were presented with a grid containing twenty-five individual places. In the presentation phase, children saw different categories of object-in-places which varied from technical to social role play toys. An interference object which was either the same or a different-object exemplar filled the delay between the presentation and test. At test, children were required to recall the location occupied by the object. Among the clinical and matched control groups tested, comparatively better place memory accuracy was evident in ASD children; however this was accompanied by longer place memory reaction times. Same-object presentation in the delay was improving place memory accuracy and speeding up reaction times of children, in comparison to a different-object exemplar. Technical objects were better remembered by the mainly male sample than roleplay and neutral objects, but this particular category of objects had the slowest reaction times. When the binding strategies as per Common Region Test (CRT) were included in the analyses, place memory accuracy was more accurate among systematic coders than unsystematic coders. Interestingly, place memory accuracy and reaction times of those who adopted systematic binding benefitted more from repetition (same-object delay) than those who coded unsystematically - a pattern found across most object categories. Thus, one could say that the repetition was helping to reinforce the object-place binding among systematic coders