What have we found?

Our research over the past 20 years has resulted in countless publications, book chapters, and student theses. This page is a collation of short summaries of everything we have found to date.

Student Theses: 2015 | 2014 | 2013 | 2012 | 2011 | 2010

2015

Student Name, Degree, Supervisor

Title

Abstract

David Parrick

Masters of Applied Psychology (Clinical)

 

Supervisor:

Corinne Reid

Cognitive and Behavioural Aspects of Executive Function in Children Born Extremely Preterm

 

Cognitive and Behavioural Aspects of Executive Function in Children Born Extremely Preterm

Survival rates for children born extremely preterm (EP) have improved significantly over the last two decades. At the same time, there has been a corresponding increase in interest in the developmental sequelae associated with premature birth. This review examined one aspect of these developmental sequelae, executive function (EF). The review briefly examines the construct of EF, elements that are thought to comprise the construct and their inter-relationships. The developmental sequelae of prematurity are then examine focussing on a range of educational, developmental and mental health issues. Subsequently, the review then looks at the intersection of prematurity and EG. A critical aspect of the review is the examination of differences in the measurement of EG, with measures focussing on either cognitive or behavioural EF with little evidence of overlap between the measurement techniques. The review concludes by noting that much of the research into the effect of premature birth on EG is potentially confounded by the inclusion of low birth weight participants in studies of EG in preterm children, and that there is a dearth of longitudinal studies focussing on the developmental trajectory of EG. Future research could profitably focus on excluding low birth weight participants and further examining the apparent lack of inter-correlations between cognitive and behavioural measures of EF.

Melissa Trindall

Masters of Applied Psychology (Professional)

 

Supervisor:

Gareth Roberts

The effect of prematurity on cognitive control abilities and complex task demands in 7-year-old children

The start of middle childhood is characterised as critical developmental period of the prefrontal cortex and related cognitive control abilities. IN this ERP study we investigate response control processes in a large sample of preterm (n = 98) and typically developing children (n =98). To meausure response control processes we administered a chid friendly flanker task containing congruent, incongruent, and reversed trails and used mass univariate analysis to compare N2 and P3 ERP amplitudes. Preterm children showed poorer performance on behavioural measures of accuracy and reaction time compared to full term peers, which was further supported electrophysiologically through decreased P3 amplitude on the reversed trial. This finding provides evidence of a specific deficit in efficient attentional and cognitive control processes in preterm children.

Lori Gardiner

Masters of Applied Psychology (Professional)

 

Supervisor:

Corinne Reid

The Impact of Working Memory and Inhibition on the Development of Empathy in Children Born Preterm

The aim of this study was to examine the relationship between empathic competence and executive dysfunction in school-aged children born vey preterm (VP, 28-32 weeks) and extremely preterm (EP, 23-27 weeks). Of particular interest was the role of inhibition and working memory as mediators of empathic development. Seventy-two EP and seventy four VP seven year-old children and forty-four full term children participated in the Project KIDS neurodevelopmental research program. As expected, children born extremely preterm and very preterm showed poorer performance on the Wechsler Intelligence Scale for Children (WISC-IV), Kid’s Empathy Development Scale (KEDS), multiple scales of the Behaviour Rating Inventory of Executive Function (BRIEF), and the Conners-3 ADHD Index (Parent Form). No differences were found on the Fruit Stroop task, BRIEF Inhibition, or the Strengths and Difficulties Questionnaire (SDQ). As predicted, the EP and VP group showed weaker empathic development when compared to typically developing children. They also showed poorer working memory abilities. However, the effect of preterm birth on empathy was not mediated by executive level of parental reports of inhibition or working memory. As such, the cognitive mechanisms underpinning poor empath competence in preterm children remains unclear. Future research may wish to examine the role of perceptual reasoning and emotion recognition.

Fiona Mann

Master of Applied Psychology (Clinical)

 

Supervisor:

Corinne Reid

Predictors and nature of parenting stress in mothers of very preterm children at three years of age.

Objective: The aim of the current study was to examine the nature, sources and predictors of parenting stress in mothers of three year old children born very preterm (VP; ie. <32 weeks gestation). Study design: 492 mothers of 566 children from a regional cohort of VP infants born between 1990 and 1992 were included. Correlations and regression analysis were used to identify predictors of maternal stress, and independent samples t-tests examined group differences between this group and the general population, and between VP mothers who showed ‘clinically concerning’ levels of parenting stress and those who did not. Results: Mothers of three-year-olds born VP report higher levels of parenting stress than is typically expected in the general population, predominantly accounted for by stress relating to child characteristics. A range of parent and child factors are implicated, confirmed by their prevalence in the clinical stress groups. The primary predictors of parenting stress were: maternal social support; internalising and externalising behaviours in the child; difficulty managing behaviour; child mood, sensitivity, and persistence. Post-hoc discriminant functions analysis confirmed the suitability of the Parenting Stress Index as a screening tool for services. Conclusions: Parenting stress remains elevated three years after VP birth. Intervention may focus on supporting mothers to develop and utilise their social support networks, as well as to understand and respond effectively to their child’s behaviour.

 

Helen Hoi Lam Ko

Doctor of Psychology

 

Supervisor:

Corinne Reid

Children born prematurely: Cognitive outcomes and preliminary findings for subsequent intervention.

Well-established evidence shows that children born preterm/low birth weight (LBW) are at increased risk of academic difficulties (Lee, Yeatman, Luna, & Feldman, 2011; Pritchard et al., 2009) and, despite global IQ scores within the normal range, nonetheless display lower academic performance than their same age peers (Bhutta, Cleves, Casey, Cradock, & Anand, 2002; Kerr-Wilson, Mackay, Smith, & Pell, 2011). This is not fully understood and previous attempts to improve these circumstances through means of cognitive intervention have met with little success. Therefore, the current thesis investigates possible underlying mechanisms of this intellectual disparity and tests the effectiveness of one potential intervention. In doing so, the studies presented focus specifically on fluid intelligence (Taub, 2002). The investigation through fluid intelligence is relatively novel in the current literature and therefore worthy of further exploration. Normal individual differences in fluid intelligence have been explained with reference to information processing parameters. Previous studies have shown that children born preterm/LBW have impairments in basic processes identified with executive function (Aarnoudse-Moens, Smidts, Oosterlaan, Duivenvoorden, & Weisglas-Kuperus, 2009; Mulder, Pitchford, Hagger, & Marlow, 2009). However, the current study is the first to test whether differences in fluid intelligence, as measured by the Cattell Culture Fair Tests, between preterm (n = 217) and typically developing children (n = 145) could be accounted for by differences in working memory and cognitive flexibility, as measured by the digit span tasks and the Wisconsin Card Sorting Test respectively. Results indicate that the seven to nine years old preterm cohort performed less well on measures of fluid intelligence than their peers across all age groups and their differences were partially mediated by both working memory and cognitive flexibility in a multiple mediation analysis. It also identified at least one year of developmental delay in fluid intelligence between the clinical group and their peers.

Provided with evidence from Study 1 and parallel research suggesting that computerized working memory training may enhance working memory and fluid intelligence in non-clinical groups (Jaeggi, Buschkuehl, Jonides, & Perrig, 2008; Klingberg, Forssberg, & Westerberg, 2002; Studer et al., 2009), the second goal of this thesis was to conduct a preliminary study to investigate the feasibility of cognitive training for children born preterm/LBW. Therefore, in the second study, the utility of a brief adaptive working memory span training program (Buschkuehl, Jaeggi, Kobel, & Perrig, 2008) was tested in typically developing children. Sixty-three children, aged seven to nine years, were randomly assigned to one of three groups: Intervention, active control and passive control. The intervention group was trained in the adaptive version of the working memory span task and the active control group was trained in the non-adaptive version. Both groups trained for 15 minutes each day for a duration of 20 days. Participants in the passive control group participated only in pre and post assessments. All participants were assessed using the digit span and spatial span tasks for measuring working memory, the Stroop task for measuring executive control, a reaction time task for measuring processing speed and the Raven’s Standard Progressive Matrices for measuring fluid intelligence. Results indicate that children in the intervention group improved on their trained task and demonstrated significant far transfer effects on the assessment of fluid intelligence compared to both control groups. However, no near transfer to other measures was found. The reason behind the occurrence of far transfer effect without evidence of near transfer effects was unclear. However, given that the adaptive complex working memory training task was not in any way similar to the fluid intelligence measure, significant differences in fluid intelligence gains were unlikely to have been a consequence of practice or general familiarity effects but, rather, a consequence of the training.

Although Study 1 identified that working memory and cognitive flexibility partially mediate birth status-related differences in Gf, the impact of these variables on academic performance in children born preterm is still unknown. Nonetheless, current evidence of far transfer to fluid intelligence after adaptive complex working memory span training provides support for the utility of WM training and modifiability in Gf. This in turn provides a preliminary evidence-base approach for psychologists to work toward providing neuro-remediation treatment options to targeted clinical groups, such as those born preterm with fluid intelligence deficiencies. In combination, the outcomes of these two studies provide both a theoretical contribution to our understanding of the deficits observed in children born preterm and an applied contribution to beginning the process of developing appropriate intervention programmes suitable for this clinical group in the future, with hopeful prospects for improving cognitive outcomes.

 

Chris Brydges

Doctor of Philosophy

 

Supervisor: Mike Anderson

The Development of Executive Functions: Evidence from Behavioural and Electrophysiological Perspectives

Background: Executive functions are cognitive processes associated with higher-order levels of behaviour. Previous research has suggested that between the ages of 7 and 11 years, executive functions change from a unitary structure, where specific abilities are indistinguishable from each other, to displaying ‘unity and diversity’, where specific executive functions are separate constructs, yet related to each other. During the same developmental period, large-scale neural changes also occur within the brain. This thesis tests the hypothesis that electrophysiological development occurs before, and is related to, the development of behavioural abilities specific to single executive functions. It is further hypothesised that this development of executive functions through mid- to late-childhood may be a sequential process – neural changes occurring during this time are known to affect the amplitude and latency of event-related potential (ERP) peaks, which may then lead to the development of behavioural abilities specific to single executive functions. This process changes the structure of executive functions from unitary to displaying both unity and diversity. Methods: In chapter 2 of this thesis (published in Intelligence; Brydges, Reid, Fox, & Anderson, 2012), latent variable analyses were reported in order to determine the structure of executive functions in children aged 7-9 years (N = 215). A range of psychometric tasks designed to measure shifting, working memory, and inhibition were administered to attempt to replicate the ‘unity and diversity’ model of executive functions. In chapter 3, 14 young adults were administered a hybrid Go/Nogo flanker task whilst EEG data were recorded, in order to examine the manifestation of the N2 difference waveform elicited during two inhibitory subprocesses of cognitive control: response inhibition and interference suppression (published in PLoS ONE; Brydges, Clunies-Ross et al., 2012). The same task was administered to both children aged 8-11 3 years and young adults (both groups n = 13) to examine changes in the manifestation of the N2 difference waveform between childhood and adulthood (chapter 4, published in PLoS ONE; Brydges, Anderson, Reid, & Fox, 2013). Chapter 5 (published in Frontiers in Human Neuroscience; Brydges, Fox, Reid, & Anderson, 2014) expanded upon the findings of the preceding chapters by adding analysis of N2 and P3b ERP components, electrophysiological correlates of cognitive control/inhibition and updating of working memory, respectively, extracted from a modified flanker task. These components were added as predictors of the executive function model reported in chapter 2. Results: As reported in chapter 2, performance on all executive function measures between the ages of 7 and 9 years increased. Measurement invariance in the structure of executive functions was also observed between these two groups, and a unitary executive function factor was the best fit of the data. Differences in the manifestation of the N2 difference waveform, in terms of topography and peak latency, when response inhibition and interference suppression were required were reported in chapter 3. Furthermore, the results reported in chapter 4 show different developmental trajectories of the N2 peaks associated with these two cognitive control subprocesses. Specifically, site, latency, and amplitude differences in the N2 difference waveform elicited during response inhibition were reported between children and adults, and no significant interference suppression N2 was observed in the children. Structural equation modelling in chapter 5 showed that the mean amplitudes of the N2 difference waveform and the P3b ERP deflection were both significantly predictive of the unitary executive function factor. Conclusions: The measurement invariance and subsequent unitary executive function factor observed in chapter 2 implies that executive functions are indistinguishable until at least the age of 9 years, and that a general executive ability is developing during this 4 time period, whereas specific executive function abilities have not developed to an observable degree. The ERP deflections commonly associated with cognitive control/inhibition and updating of working memory were observed, even though the behavioural manifestations were not distinguishable from other executive functions. However, amplitude, latency, and topography differences between children and adults clearly showed that much neural development occurs between childhood and adulthood, with respect to these ERP components. Nonetheless, the results are consistent with maturation of these electrophysiological indices waveform leading to the development of specific executive functions, which result in the increased differentiation of inhibition from other executive functions.

2014

Student Name, Degree, and Supervisor

Title

Abstract

Amy Grace,

Lori Gardiner,

Lauren Ticehurst,

Jeanne Burger,

Matthew Hill,

Aishvarya Rajalingam,

Tanja Vasev,

Nicole Baradziej

Bachelor of Psychology

 

Supervisor: Corinne Reid

 

The Role of Inhibition and Working Memory on Socio-emotional Vulnerabilities in Preterm Children

 

Author: Amy Grace

 

This study examined the empathy in children born preterm in comparison to their typically developing peers. Two core executive functions, inhibition and working memory, were concurrently examined. The aim of the study was to investigate whether preterm children performed more poorly than their typically developing peers on measures of empathy and if differences in inhibition and working memory could account for this difference in empathy. Seven year old participants (N=124) were divided into gestational groups of extremely preterm (<28 weeks), very preterm (28-32 weeks) and typically developing (>32 weeks) children. Participants completed the Kids’ Empathic Development Scale (KEDS), the Fruit Stroop measure of inhibition the Working Memory Index (WMI) subtest of Wechsler Intelligence Scale for Children (WISC_IV), the Behavioural Rating Index of Executive Functioning (BRIEF) and the WISC-IV Full Scale IQ (FSIQ) or Wechsler Abbreviated Scale of Intelligence (WASI-II). Children Born extremely and very preterm had significant poorer performance on measures of empathy, IW, and working memory, when compared to typically developing children. Extremely preterm children displayed poorer overall executive functioning than their full term peers. Correlational analysis did not support inhibition or working memory as predictors of empathy. Multiple regression did not show any significant relationship between empathy and inhibition or working memory, rejecting the hypothesis that executive functioning level inhibition and working memory mediate empathy development.

Alyssa Cunanne

Honours

 

Supervisor: Corinne Reid

 

Cognitive Deficits in School-Age Children Born Preterm: Specific or Global?

A debate exists within the literature as to whether the deficits in cognitive functioning amount children born preterm are best described as specific or global. My primary aim is to contribute to this debate using Crawford, Blackmore, Lamb and Simpsons’s (2000) technique of testing for a differential deficit, which provides an empirical solution to several problems that commonly arise when studying the issue. I further aim to explore whether a differential deficit is consistent from ages 7 to 9 years. The present study tested 139 preterm and 91 typically developing children, aged either 7 or 9 years, on measures of executive function and general intelligence to explore the nature of the cognitive deficits among children born preterm. While deficits were found for the 7 year old preterm children on measures of general intelligence and some measures of executive function, these deficits did not meet Crawford et al.’s criteria for differential deficit. However, analyses revealed that only one of the differences observed between the two age groups could be attributed to a differential effect of preterm birth. It was concluded that children born preterm experience both specific and global deficits in cognitive functioning, with a global deficit providing the best description. In addition, it was concluded that the deficits associated with preterm birth are generally stable across children aged 7

 

Greg Chaine

Master of Applied Psychology (Clinical)

 

Supervisor: Corinne Reid

 

Effects and mechanisms of potential treatments for executive function deficits: Comparing Cogmed and Uberbrain

With the move towards transdiagnostic symptom-based intervention, there has been a focus on the executive function (EF) deficits underlying social, emotional, and behavioural dysregulation in children and adolescents. Evidence of adaptive plasticity has provided support for neurorehabilitation programs such as Cogmed. This review outlines research showing promising results in clinical populations and evidence that cognitive training successfully improves EF in order to alleviate associated symptoms. Recommendations are made for the future based on studies where adaptive plasticity has been observed in response to environment demands and methodological limitations of past studies are discussed.

Linda Tanner

Master of Applied Psychology (Clinical)

 

Supervisor: Corinne Reid

 

What’s the Risk? Assessing the Developmental Trajectories of Aboriginal Children in a Remote Northern Territory Community

An archival dataset collected with 89 Australian Aboriginal children living in a very remote area of the Northern Territory (NT) was analysed in order to profile performance on mainstream measures of cognitive ability, phonological awareness (PA) and literacy. Performance on the cognitive assessment indicated a diversity of developmental need which is not commensurately matched to mainstream curricular expectations a school entry. Performance on the measures of phonological awareness and literacy indicated progress in pre-literacy skills over a 12 month period, however, the pattern of development showed at least a two year delay in fundamental skills. This findings suggest that a poor fit between developmental need and school expectations put a majority of the children at risk across developmental outcomes. Implications for intervention are discussed in relation to the multi-risk developmental context.

Nikita A. Sutrisno

Honours

 

Supervisor: Corinne Reid

 

The Role of Executive Functioning and Processing Speed in Determining Fluid Intelligence Difference in Pre- and Full-term Born Children

There is a lack of theoretical understanding on the underlying constructs of fluid intelligence (gF) and how premature birth affects it. A study was carried out to test the developmental cascade model (Fry & Hale, 1996) in explaining the role of executive functioning (EF) and processing speed (PS) in determining fluid intelligence (gF) in pre- (n = 147) and full-term born children (n = 97). In general, preterms had significantly poorer performance than fullterms on EF and gF. Premature burth was suggested to compromise cognitive ability by two years. Confirmatory factor analysis showed that EF and processing speed are unitary with a one-factor model providing an excellent fit for pre- and full-term’s data. Possible explanations for these findings are discussed and implications towards the understanding of gF are provided. This study sheds light to the nature of constructs underlying gF and suggested that improvementon general intelligence may be possible through brain training program that targests EF.

Chris Brydges

Doctor of Philosophy

 

Supervisor: Mike Anderson

 

The Development of Executive Functions: Evidence from Behavioural and Electrophysiological Perspectives

Background: Executive functions are cognitive processes associated with higher-order levels of behaviour. Previous research has suggested that between the ages of 7 and 11 years, executive functions change from a unitary structure, where specific abilities are indistinguishable from each other, to displaying ‘unity and diversity’, where specific executive functions are separate constructs, yet related to each other. During the same developmental period, large-scale neural changes also occur within the brain. This thesis tests the hypothesis that electrophysiological development occurs before, and is related to, the development of behavioural abilities specific to single executive functions. It is further hypothesised that this development of executive functions through mid- to late-childhood may be a sequential process – neural changes occurring during this time are known to affect the amplitude and latency of event-related potential (ERP) peaks, which may then lead to the development of behavioural abilities specific to single executive functions. This process changes the structure of executive functions from unitary to displaying both unity and diversity. Methods: In chapter 2 of this thesis (published in Intelligence; Brydges, Reid, Fox, & Anderson, 2012), latent variable analyses were reported in order to determine the structure of executive functions in children aged 7-9 years (N = 215). A range of psychometric tasks designed to measure shifting, working memory, and inhibition were administered to attempt to replicate the ‘unity and diversity’ model of executive functions. In chapter 3, 14 young adults were administered a hybrid Go/Nogo flanker task whilst EEG data were recorded, in order to examine the manifestation of the N2 difference waveform elicited during two inhibitory subprocesses of cognitive control: response inhibition and interference suppression (published in PLoS ONE; Brydges, Clunies-Ross et al., 2012). The same task was administered to both children aged 8-11 3 years and young adults (both groups n = 13) to examine changes in the manifestation of the N2 difference waveform between childhood and adulthood (chapter 4, published in PLoS ONE; Brydges, Anderson, Reid, & Fox, 2013). Chapter 5 (published in Frontiers in Human Neuroscience; Brydges, Fox, Reid, & Anderson, 2014) expanded upon the findings of the preceding chapters by adding analysis of N2 and P3b ERP components, electrophysiological correlates of cognitive control/inhibition and updating of working memory, respectively, extracted from a modified flanker task. These components were added as predictors of the executive function model reported in chapter 2. Results: As reported in chapter 2, performance on all executive function measures between the ages of 7 and 9 years increased. Measurement invariance in the structure of executive functions was also observed between these two groups, and a unitary executive function factor was the best fit of the data. Differences in the manifestation of the N2 difference waveform, in terms of topography and peak latency, when response inhibition and interference suppression were required were reported in chapter 3. Furthermore, the results reported in chapter 4 show different developmental trajectories of the N2 peaks associated with these two cognitive control subprocesses. Specifically, site, latency, and amplitude differences in the N2 difference waveform elicited during response inhibition were reported between children and adults, and no significant interference suppression N2 was observed in the children. Structural equation modelling in chapter 5 showed that the mean amplitudes of the N2 difference waveform and the P3b ERP deflection were both significantly predictive of the unitary executive function factor. Conclusions: The measurement invariance and subsequent unitary executive function factor observed in chapter 2 implies that executive functions are indistinguishable until at least the age of 9 years, and that a general executive ability is developing during this 4 time period, whereas specific executive function abilities have not developed to an observable degree. The ERP deflections commonly associated with cognitive control/inhibition and updating of working memory were observed, even though the behavioural manifestations were not distinguishable from other executive functions. However, amplitude, latency, and topography differences between children and adults clearly showed that much neural development occurs between childhood and adulthood, with respect to these ERP components. Nonetheless, the results are consistent with maturation of these electrophysiological indices waveform leading to the development of specific executive functions, which result in the increased differentiation of inhibition from other executive functions.

Marissa-Lynn Chia

 

BPsych(Hons)

 

Supervisor: Gareth Roberts

 

The Effects of Type 1 Diabetes on Executive Functioning in Children Aged 6 to 10: An Event-Related Potential Study

The relationship between Type 1 Diabetes Mellitus (T1DM) and cognition has received considerable attention and remains a controversial topic due to inconsistent findings regarding the effect T1DM has on cognition, including the domain of executive functioning. The current study aimed at examining the effect of T1DM on executive functioning in children using event-related potentials (ERPs) to determine if deficits in executive functioning are associated with the disease. Two ERP components associated with executive functioning – the N2 and P3b – were observed for differences between Type 1 diabetics and controls. A total of 97 children – 48 T1DM and 49 controls – between the ages of 6 and 10 participated in the current study. Participants performed a modified visual Flanker task while electroencephalograms (EEGs) were recorded. Both groups did not differ significantly in behavioral performance on the Flanker task. Significant differences were found posteriorly in an ERP component known as the late Positive Slow Wave (PSW), which is associated with sustaining attention in a task, between the T1DM and control groups in the incongruous and switch trials of the Flanker task. No significant differences were found in the N2 and P3b components. These results highlight that there are minimal differences in sustained attention between children with Type 1 diabetes compared to their healthy counterparts, but not in other domains of executive functioning. Directions for future research were discussed including the need to conduct a follow-up study on this sample of children, possibly in adulthood, to determine if longer disease duration has effects on executive functioning.

Melissa Trindall

 

BPsych(Hons)

 

Supervisor: Chris Brydges

 

An examination of the differences in performance of typically developing children to those born pre-term in measures of executive functioning and ERP

Executive functions are considered a fundamental component of cognitive functioning. Children aged 6–10 years born preterm (N = 163) or typically developing controls (N = 105) completed nine measures of inhibition, working memory and shifting and EEG data was recorded during a modified Flanker task. The aim of this study was to test the hypotheses that event-related potentials (ERPs) associated with specific executive functioning would be predictive of behavioural measures in the typical group but would not be predictive in the preterm group due to neurodevelopmental delay. The N2 difference waveform associated with response inhibition and the P3b peak associated with working memory were analysed as latent variables in confirmatory factor analysis and structural equation models with a unitary executive functioning factor. The N2 difference waveform was found to be predictive of executive functioning in typically developing controls, but neither ERP component was predictive of executive functioning in the preterm group. These results provide evidence of a developmental delay in the differentiation of executive functions in children born preterm.

Debora Valcan

 

BPsych (Hons)

 

Supervisor: Helen Davis

 

Updating but not inhibition predicts empathy, as well as fluid intelligence in children

Empathy and fluid intelligence are of fundamental importance in everyday life, as processes related to these constructs are associated with life outcomes. However, little is known about the relation between empathy and fluid intelligence, and their underlying functions. This study examined the relations of empathy and fluid intelligence to two separable executive functions: inhibition and updating, in 214 typically developing children aged between 7 years and 10 years. Updating was highly correlated with empathy, and updating and inhibition were highly correlated with fluid intelligence. In structural equation modeling, whilst controlling for the inter-executive functioning correlations, updating strongly predicted empathy and fluid intelligence, but the relations of inhibition to fluid intelligence and empathy were small and not significant. Furthermore, mediation analysis revealed that fluid intelligence fully mediated the relationship between updating and empathy. The results indicate that of the executive functions assessed, updating is a key factor underpinning both empathy and fluid intelligence. The mediation effect indicates that empathy may be best understood as an application of fluid intelligence.

Amy Pollock

 

BPsych (Hons)

 

Supervisor: Helen Davis

 

Fluid Intelligence: The Differential Contributions of Processing Speed, Inhibition, Shifting, Updating, at Ages Seven and Nine.

 

Several uni-dimensional information-processing parameters are postulated to account for the developmental change that occurs in fluid intelligence including, Processing Speed, Inhibition, Shifting and Updating. However, our understanding of how these information- processing parameters contribute to developmental change with age is limited and remains ambiguous. The objective of this study was to examine whether the information processing parameters that predict fluid intelligence (e.g. Processing Speed, Inhibition, Shifting and Updating) make significantly different contributions to fluid intelligence in children aged 7- and 9-years old. With the data of 239 typically developing children and a total of 12 measures, three for each information-processing parameter and one for fluid intelligence, the present study investigated this aim. Results using Structural Equation Modelling were inconclusive and, therefore, regression analysis was relied upon. Regression analysis revealed that two measures of shifting and two measures of updating significantly predicted the Cattell Culture Fair Test (CCFIT) in 7-year-olds. In contrast, one measure of processing speed and one measure of shifting in 9-year-olds predicted CCFIT; these results were not in-line with postulations. However, these results provide preliminary support for the assumption the developmental change of fluid intelligence is driven by multiple constructs and these constructs make differential contributions across age. Although there are several limitations emanating from the present study that should be kept in mind when drawing conclusions. It is suggested that future research needs to employ multidimensional models when examining the developmental change of fluid intelligence in order to bolster our understanding.

 2013

Student Name, Degree, and Supervisor

Title

Abstract

Gareth Roberts

Doctor of Philosophy

 

Supervisor:

Mike Anderson

Intelligence and Task Structure Complexity: A Neurocognitive Investigation of Goal Neglect in Children and Adults

 

The PhD investigates the hypothesis that individual differences in intelligence (more specifically, fluid g) is intimately related to the construction of mental programs, during problem solving or action planning (Duncan, 2010) – termed the mental program hypothesis. A series of experiments explores the cognitive and electrophysiological mechanisms behind goal neglect—a disregard of task requirements that while understood and remembered, fail to guide behaviour at real-time execution. This PhD takes an interdisciplinary approach to the study of goal-directed behaviour and its relationship with intelligence – drawing on the fields of developmental psychology, cognitive psychology, electrophysiology, artificial intelligence, and individual differences research. The PhD uses two main approaches: the investigation of goal neglect in typically developing children using new experimental paradigms, and the investigation of goal neglect using modern Electroencephalographic (EEG) analysis methods. Both approaches investigate how task structure complexity can be increased by manipulations of the task instructions presented to participants. All studies found that task structure complexity causes poorer task performance and increases goal neglect. Moreover, experimental conditions that cause participants to maintain a more complex task structure, increase the relationship between goal neglect and fluid g. EEG analysis reveals task structure complexity disrupts two processes: an early (~200 ms) evaluation process of stimuli for task relevance, and later occurring phasic interactions between theta, alpha and beta oscillatory activities.

Jasmin Fyfe,

Nicola Birkelund,

Rashna Patel,

Renee Goldspink,

Bachelor of Psychology

 

Supervisor: Corinne Reid

The Long and the Short of IT: Validation of a New IPad Inspection Time Task

(author: Nicola Birkelund)

Inspection time provides a measure of cognitive speed that has long been reported to significantly correlate with measures of intelligence. Computer programs that measure inspection time can provide a quick and engaging way to administer assessment of children’s speed of processing. The present research is designed to assess a new iPad format for measuring inspection time The new iPad task and traditional computer inspection time task were administers to 80 children, along with the Institute of Personality and Ability Testing (IPAT) Culture Fair Intelligence Test as a psychometric measure of fluid intelligence. The iPad inspection time score correlates with fluid intelligence in much the same way as other computer-based inspect time measures. Although acceptable to children and moderately correlated with the existing computer task, the correlation is not strong enough to completely support the validity of the iPad task, in its current form, as an equivalent measure. There is a strong correlation between the tasks with the preterm children in the study, however no correlation for the typically developing children. There is, however, reason to believe that with some further adjustments, the iPad task could become a reliable and valid measure of inspection time. This would be an improvement to existing measures as it makes the task more portable and therefore accessible to a variety of hard-to-access communities.

2012

Student Name, Degree, and Supervisor

Title

Abstract

Amelia Stephens

Honours

 

Supervisor: Mike Anderson

Dual-Task Performance in early school aged children born very and extremely preterm

Dual-tasking is related to attention and executive functioning. There is evidence to suggest dual-task performance provides a particularly sensitive measure of ‘frontal’ dysfunction. The current study extends this research by examining whether children born preterm have a specific deficit in dual-tasking in addition to other well-documented executive deficiencies. Ninety-nine preterm and 55 typically developing 6 to 7 year-old children were tested, through Project K.I.D.S., on the TEA-Ch.  Results indicate that although preterm children obtain significantly greater Dual-task Decrement scores, it is unclear whether this remains significant after accounting for single-task performance.  This highlights the need to adjust single-tasks to account for individual ability.

Clara Kasahara

Honours

 

Supervisor: Mike Anderson

Investigating the relationship between processing speed and reading: rapid automatized naming (RAN) and phonological awareness as mediating factors.

Understanding the relationships among processing speed, rapid automatised naming (RAN), phonological awareness, and reading are essential to improve theory about the processes underlying reading ability. The current investigation sought to address the issue of inconsistencies in processing speed measures in relevant literature, by creating a latent variable of processing speed. One hundred typically developing children participated in this study through Project K.I.D.S. Structural equation modelling was used to investigate the relationships among variables. Consistent with the hypotheses, phonological awareness and RAN significantly predicted reading ability. Processing speed also significantly predicted phonological awareness and RAN. As expected, the effect of processing speed on reading appeared to be mediated by phonological awareness and RAN, but the results indicate this warrants further investigation.

Megan Bell

Honours

 

Supervisor: Mike Anderson

Evaluating a Cascade Model of Fluid Intelligence in Preterm Children Aged 6-7 Years: The Contributions of Working Memory, Processing Speed, and Attention.

Children born preterm generally have IQ scores 10 points lower than their term-born peers (Bayless & Stevenson, 2007). Rose et al. (2011) suggest that group differences can be explained by a cognitive cascade, whereby deficits in elementary cognitive abilities lead to deficits in complex abilities, and consequently IQ. This study evaluated whether a cascade model could also account for group differences in fluid intelligence (gF). Ninety-seven preterm children and 52 controls aged 6-7 years completed measures of gF, working memory (WM), processing speed and attention. It was found that preterm children’s lower gF scores could be accounted for by a cascade of effects, whereby poorer attention and slower processing speed were associated with poorer WM, resulting in lower gF.

2011

Name

Title

Abstract

Elizabeth Vuletich

Doctor of Philosophy

 

Supervisors: Allison Fox and Mike Anderson

 

 

The Neuropsychological sequelae of on and off pump coronary artery bypass graft surgery.

Post-operative neuropsychological decline is considered one of the major morbidity outcomes following Coronary Artery Bypass Graft (CABG) surgery. Traditional CABG uses the cardiopulmonary bypass machine to ensure a still operative field (on-pump technique), but introduces microemboli and decreases perfusion in the brain. These can potentially affect neurological integrity and compromise cognitive functioning. Alternatively, performing CABG on the beating heart (off-pump method) allows normal circulation to continue, which reduces cerebral emboli and hypoperfusion, and therefore the risk of neurological damage. On this basis, it is argued that off-pump CABG should be less detrimental to neuropsychological functioning than on-pump CABG. To date, research findings have been inconsistent, largely due to substantial disagreement about what constitutes meaningful post-CABG neuropsychological impairment. Consequently, the relationship between on-pump CABG and cognitive dysfunction remains controversial. Additionally, studies have not clearly established the candidate cognitive functions most at risk during CABG surgery, or whether the effects are transient or persisting. Methodological shortfalls, including differences in assessment times, use of control samples, and failure to account for practice effects, measurement error and regression to the mean, as well as varied and often arbitrary criteria used to define impairment, are likely to blame for the lack of clarity within the literature. Using a longitudinal study, this thesis aims to determine whether 1) pre-existing neuropsychological impairments occur in candidates for CABG surgery, 2) CABG surgery is associated with neurocognitive impairment, 3) neuropsychological function is differentially affected following on- versus off-pump CABG and, therefore, whether the CPB is responsible for neurologic injury that manifests as neuropsychological impairment.

Louise Delane

Honours

 

Supervisor: Mike Anderson

The contribution of executive functions and speed of processing to impaired fluid intelligence in early school aged children born very preterm.

Prematurity at birth is associated with lower performance on measures of intelligence, however the exact nature of this deficit remains unclear. Anderson’s (1992) Minimal Cognitive Architecture proposes two routes to intelligence – one through speed of processing and one through modules (executive functioning). The current study compared 66 very preterm children to 62 controls (six to seven year-olds) on measures of fluid intelligence, executive function and processing speed. It was hypothesised that lower fluid intelligence would be explained by lower executive functioning, not speed of processing. However, preterm children performed significantly lower on all three measures, and both impaired executive functioning and speed of processing fully mediated impaired fluid intelligence. These findings have important implications for practice, research and theory.

Rebecca Seward

Honours

 

Supervisor:

Donna Bayliss

Memory consolidation: a predictor of working memory?

Working memory is an ‘active’ memory system that is responsible for the processing and storage of information relevant to a specific cognitive task. One process thought to be necessary for successful encoding into working memory is consolidation- the process of transforming a fleeting perceptual representation into a durable representation in short-term memory.  However, the extent to which consolidation contributes to working memory performance is unknown. The purpose of this investigation was to determine whether memory consolidation is an important underlying process in working memory and whether it is distinct from storage capacity and processing speed. Sixty children with ages ranging from 6-11 years participated in the study as part of the Project K.I.D.S developmental research program. The results demonstrated that memory consolidation is not a unique predictor of working memory over and above storage capacity and processing speed. Implications and directions for future research are discussed.

 

 

Student Name, Degree, Supervisor

Title

Abstract

David Parrick

Masters of Applied Psychology (Clinical)

 

Supervisor:

Corinne Reid

Cognitive and Behavioural Aspects of Executive Function in Children Born Extremely Preterm

 

Cognitive and Behavioural Aspects of Executive Function in Children Born Extremely Preterm

Survival rates for children born extremely preterm (EP) have improved significantly over the last two decades. At the same time, there has been a corresponding increase in interest in the developmental sequelae associated with premature birth. This review examined one aspect of these developmental sequelae, executive function (EF). The review briefly examines the construct of EF, elements that are thought to comprise the construct and their inter-relationships. The developmental sequelae of prematurity are then examine focussing on a range of educational, developmental and mental health issues. Subsequently, the review then looks at the intersection of prematurity and EG. A critical aspect of the review is the examination of differences in the measurement of EG, with measures focussing on either cognitive or behavioural EF with little evidence of overlap between the measurement techniques. The review concludes by noting that much of the research into the effect of premature birth on EG is potentially confounded by the inclusion of low birth weight participants in studies of EG in preterm children, and that there is a dearth of longitudinal studies focussing on the developmental trajectory of EG. Future research could profitably focus on excluding low birth weight participants and further examining the apparent lack of inter-correlations between cognitive and behavioural measures of EF.

Melissa Trindall

Masters of Applied Psychology (Professional)

 

Supervisor:

Gareth Roberts

The effect of prematurity on cognitive control abilities and complex task demands in 7-year-old children

The start of middle childhood is characterised as critical developmental period of the prefrontal cortex and related cognitive control abilities. IN this ERP study we investigate response control processes in a large sample of preterm (n = 98) and typically developing children (n =98). To meausure response control processes we administered a chid friendly flanker task containing congruent, incongruent, and reversed trails and used mass univariate analysis to compare N2 and P3 ERP amplitudes. Preterm children showed poorer performance on behavioural measures of accuracy and reaction time compared to full term peers, which was further supported electrophysiologically through decreased P3 amplitude on the reversed trial. This finding provides evidence of a specific deficit in efficient attentional and cognitive control processes in preterm children.

Lori Gardiner

Masters of Applied Psychology (Professional)

 

Supervisor:

Corinne Reid

The Impact of Working Memory and Inhibition on the Development of Empathy in Children Born Preterm

The aim of this study was to examine the relationship between empathic competence and executive dysfunction in school-aged children born vey preterm (VP, 28-32 weeks) and extremely preterm (EP, 23-27 weeks). Of particular interest was the role of inhibition and working memory as mediators of empathic development. Seventy-two EP and seventy four VP seven year-old children and forty-four full term children participated in the Project KIDS neurodevelopmental research program. As expected, children born extremely preterm and very preterm showed poorer performance on the Wechsler Intelligence Scale for Children (WISC-IV), Kid’s Empathy Development Scale (KEDS), multiple scales of the Behaviour Rating Inventory of Executive Function (BRIEF), and the Conners-3 ADHD Index (Parent Form). No differences were found on the Fruit Stroop task, BRIEF Inhibition, or the Strengths and Difficulties Questionnaire (SDQ). As predicted, the EP and VP group showed weaker empathic development when compared to typically developing children. They also showed poorer working memory abilities. However, the effect of preterm birth on empathy was not mediated by executive level of parental reports of inhibition or working memory. As such, the cognitive mechanisms underpinning poor empath competence in preterm children remains unclear. Future research may wish to examine the role of perceptual reasoning and emotion recognition.

Fiona Mann

Master of Applied Psychology (Clinical)

 

Supervisor:

Corinne Reid

Predictors and nature of parenting stress in mothers of very preterm children at three years of age.

Objective: The aim of the current study was to examine the nature, sources and predictors of parenting stress in mothers of three year old children born very preterm (VP; ie. <32 weeks gestation). Study design: 492 mothers of 566 children from a regional cohort of VP infants born between 1990 and 1992 were included. Correlations and regression analysis were used to identify predictors of maternal stress, and independent samples t-tests examined group differences between this group and the general population, and between VP mothers who showed ‘clinically concerning’ levels of parenting stress and those who did not. Results: Mothers of three-year-olds born VP report higher levels of parenting stress than is typically expected in the general population, predominantly accounted for by stress relating to child characteristics. A range of parent and child factors are implicated, confirmed by their prevalence in the clinical stress groups. The primary predictors of parenting stress were: maternal social support; internalising and externalising behaviours in the child; difficulty managing behaviour; child mood, sensitivity, and persistence. Post-hoc discriminant functions analysis confirmed the suitability of the Parenting Stress Index as a screening tool for services. Conclusions: Parenting stress remains elevated three years after VP birth. Intervention may focus on supporting mothers to develop and utilise their social support networks, as well as to understand and respond effectively to their child’s behaviour.

 

Helen Hoi Lam Ko

Doctor of Psychology

 

Supervisor:

Corinne Reid

Children born prematurely: Cognitive outcomes and preliminary findings for subsequent intervention.

Well-established evidence shows that children born preterm/low birth weight (LBW) are at increased risk of academic difficulties (Lee, Yeatman, Luna, & Feldman, 2011; Pritchard et al., 2009) and, despite global IQ scores within the normal range, nonetheless display lower academic performance than their same age peers (Bhutta, Cleves, Casey, Cradock, & Anand, 2002; Kerr-Wilson, Mackay, Smith, & Pell, 2011). This is not fully understood and previous attempts to improve these circumstances through means of cognitive intervention have met with little success. Therefore, the current thesis investigates possible underlying mechanisms of this intellectual disparity and tests the effectiveness of one potential intervention. In doing so, the studies presented focus specifically on fluid intelligence (Taub, 2002). The investigation through fluid intelligence is relatively novel in the current literature and therefore worthy of further exploration. Normal individual differences in fluid intelligence have been explained with reference to information processing parameters. Previous studies have shown that children born preterm/LBW have impairments in basic processes identified with executive function (Aarnoudse-Moens, Smidts, Oosterlaan, Duivenvoorden, & Weisglas-Kuperus, 2009; Mulder, Pitchford, Hagger, & Marlow, 2009). However, the current study is the first to test whether differences in fluid intelligence, as measured by the Cattell Culture Fair Tests, between preterm (n = 217) and typically developing children (n = 145) could be accounted for by differences in working memory and cognitive flexibility, as measured by the digit span tasks and the Wisconsin Card Sorting Test respectively. Results indicate that the seven to nine years old preterm cohort performed less well on measures of fluid intelligence than their peers across all age groups and their differences were partially mediated by both working memory and cognitive flexibility in a multiple mediation analysis. It also identified at least one year of developmental delay in fluid intelligence between the clinical group and their peers.

Provided with evidence from Study 1 and parallel research suggesting that computerized working memory training may enhance working memory and fluid intelligence in non-clinical groups (Jaeggi, Buschkuehl, Jonides, & Perrig, 2008; Klingberg, Forssberg, & Westerberg, 2002; Studer et al., 2009), the second goal of this thesis was to conduct a preliminary study to investigate the feasibility of cognitive training for children born preterm/LBW. Therefore, in the second study, the utility of a brief adaptive working memory span training program (Buschkuehl, Jaeggi, Kobel, & Perrig, 2008) was tested in typically developing children. Sixty-three children, aged seven to nine years, were randomly assigned to one of three groups: Intervention, active control and passive control. The intervention group was trained in the adaptive version of the working memory span task and the active control group was trained in the non-adaptive version. Both groups trained for 15 minutes each day for a duration of 20 days. Participants in the passive control group participated only in pre and post assessments. All participants were assessed using the digit span and spatial span tasks for measuring working memory, the Stroop task for measuring executive control, a reaction time task for measuring processing speed and the Raven’s Standard Progressive Matrices for measuring fluid intelligence. Results indicate that children in the intervention group improved on their trained task and demonstrated significant far transfer effects on the assessment of fluid intelligence compared to both control groups. However, no near transfer to other measures was found. The reason behind the occurrence of far transfer effect without evidence of near transfer effects was unclear. However, given that the adaptive complex working memory training task was not in any way similar to the fluid intelligence measure, significant differences in fluid intelligence gains were unlikely to have been a consequence of practice or general familiarity effects but, rather, a consequence of the training.

Although Study 1 identified that working memory and cognitive flexibility partially mediate birth status-related differences in Gf, the impact of these variables on academic performance in children born preterm is still unknown. Nonetheless, current evidence of far transfer to fluid intelligence after adaptive complex working memory span training provides support for the utility of WM training and modifiability in Gf. This in turn provides a preliminary evidence-base approach for psychologists to work toward providing neuro-remediation treatment options to targeted clinical groups, such as those born preterm with fluid intelligence deficiencies. In combination, the outcomes of these two studies provide both a theoretical contribution to our understanding of the deficits observed in children born preterm and an applied contribution to beginning the process of developing appropriate intervention programmes suitable for this clinical group in the future, with hopeful prospects for improving cognitive outcomes.

 

Chris Brydges

Doctor of Philosophy

 

Supervisor: Mike Anderson

The Development of Executive Functions: Evidence from Behavioural and Electrophysiological Perspectives

Background: Executive functions are cognitive processes associated with higher-order levels of behaviour. Previous research has suggested that between the ages of 7 and 11 years, executive functions change from a unitary structure, where specific abilities are indistinguishable from each other, to displaying ‘unity and diversity’, where specific executive functions are separate constructs, yet related to each other. During the same developmental period, large-scale neural changes also occur within the brain. This thesis tests the hypothesis that electrophysiological development occurs before, and is related to, the development of behavioural abilities specific to single executive functions. It is further hypothesised that this development of executive functions through mid- to late-childhood may be a sequential process – neural changes occurring during this time are known to affect the amplitude and latency of event-related potential (ERP) peaks, which may then lead to the development of behavioural abilities specific to single executive functions. This process changes the structure of executive functions from unitary to displaying both unity and diversity. Methods: In chapter 2 of this thesis (published in Intelligence; Brydges, Reid, Fox, & Anderson, 2012), latent variable analyses were reported in order to determine the structure of executive functions in children aged 7-9 years (N = 215). A range of psychometric tasks designed to measure shifting, working memory, and inhibition were administered to attempt to replicate the ‘unity and diversity’ model of executive functions. In chapter 3, 14 young adults were administered a hybrid Go/Nogo flanker task whilst EEG data were recorded, in order to examine the manifestation of the N2 difference waveform elicited during two inhibitory subprocesses of cognitive control: response inhibition and interference suppression (published in PLoS ONE; Brydges, Clunies-Ross et al., 2012). The same task was administered to both children aged 8-11 3 years and young adults (both groups n = 13) to examine changes in the manifestation of the N2 difference waveform between childhood and adulthood (chapter 4, published in PLoS ONE; Brydges, Anderson, Reid, & Fox, 2013). Chapter 5 (published in Frontiers in Human Neuroscience; Brydges, Fox, Reid, & Anderson, 2014) expanded upon the findings of the preceding chapters by adding analysis of N2 and P3b ERP components, electrophysiological correlates of cognitive control/inhibition and updating of working memory, respectively, extracted from a modified flanker task. These components were added as predictors of the executive function model reported in chapter 2. Results: As reported in chapter 2, performance on all executive function measures between the ages of 7 and 9 years increased. Measurement invariance in the structure of executive functions was also observed between these two groups, and a unitary executive function factor was the best fit of the data. Differences in the manifestation of the N2 difference waveform, in terms of topography and peak latency, when response inhibition and interference suppression were required were reported in chapter 3. Furthermore, the results reported in chapter 4 show different developmental trajectories of the N2 peaks associated with these two cognitive control subprocesses. Specifically, site, latency, and amplitude differences in the N2 difference waveform elicited during response inhibition were reported between children and adults, and no significant interference suppression N2 was observed in the children. Structural equation modelling in chapter 5 showed that the mean amplitudes of the N2 difference waveform and the P3b ERP deflection were both significantly predictive of the unitary executive function factor. Conclusions: The measurement invariance and subsequent unitary executive function factor observed in chapter 2 implies that executive functions are indistinguishable until at least the age of 9 years, and that a general executive ability is developing during this 4 time period, whereas specific executive function abilities have not developed to an observable degree. The ERP deflections commonly associated with cognitive control/inhibition and updating of working memory were observed, even though the behavioural manifestations were not distinguishable from other executive functions. However, amplitude, latency, and topography differences between children and adults clearly showed that much neural development occurs between childhood and adulthood, with respect to these ERP components. Nonetheless, the results are consistent with maturation of these electrophysiological indices waveform leading to the development of specific executive functions, which result in the increased differentiation of inhibition from other executive functions.