Psychology - Theses, Dissertations, and other Required Graduate Degree Essays

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Mechanisms of attentional processing during visual search: how distraction is handled by the brain

Author: 
Date created: 
2016-11-23
Abstract: 

In order to effectively search the visual environment, an observer must continually locate objects of interest amid an abundance of irrelevant and distracting stimuli. These visual distractors can sometimes inadvertently attract attention to their locations, even when an observer is attempting to search for an entirely different object. To deal with visual distractors, it has been well established that the visual system can implement a suppression mechanism to filter out irrelevant stimuli. Within the past decade, event-related potential (ERP) recordings have isolated an attentional component that is thought to reflect this suppressive processing. This ERP component—termed the distractor positivity (PD)—has been used to demonstrate that the sensory processing of irrelevant information can be strongly modulated in line with the visual search goals of an observer. Here, four electrophysiological studies of attention are presented which focus on yielding insight into how the visual system deals with irrelevant information during visual search and seeks to further our understanding of the PD component. Chapter 2 tests the stimulus conditions necessary to elicit the distractor suppression indexed by the PD by examining how differences in the salience of an irrelevant stimuli affect visual search. Chapter 3 explores how individual differences in target and distractor processing are associated with variations in visual working memory (vWM) capacity. Chapter 4 asks how distractor processing is altered during a disruption of attentional control by examining how visual search is affected during the attentional blink (AB). Chapter 5 explores how high levels of trait anxiety alter inhibitory control and the ability to ignore distracting information. In the final chapter, future directions are discussed and a model for attentional processing is proposed.

Document type: 
Thesis
File(s): 
Supervisor(s): 
John McDonald
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Dissertation) Ph.D.

Revisiting itemmetrics: Do psychologists need to watch their language?

Date created: 
2016-12-13
Abstract: 

Despite a long tradition of studying psychometric properties of self-report questionnaires in psychology, the literature identifying specific linguistic features of questionnaire items is sparse. Moreover, it is unclear whether linguistic features affect all individuals similarly, or interact with individual characteristics. The present study offers a novel methodological contribution whereby a variety of linguistic features, based on the domains typically studied by linguists (i.e., morphology, syntax, semantics), are proposed. To demonstrate how these itemmetrics can be used empirically, we analyzed data from the Center for Epidemiological Studies-Depression (CES-D) scale. Additionally, we probed interactions between sex and English fluency and each of the features to examine whether there were differential effects depending on the individual. Our results suggest that certain features may impact responding and interact with individual characteristics. We argue that our findings necessitate a stronger focus on this area of research.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Rachel T. Fouladi
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Thesis) M.A.

An Examination of the Interrater Reliability and Concurrent Validity of the Spousal Assault Risk Assessment Guide – Version 3 (SARA-V3)

Author: 
Date created: 
2016-12-08
Abstract: 

The Spousal Assault Risk Assessment Guide-Version 2 (SARA-V2; Kropp, Hart, Webster, & Eaves, 1995, 1999, 2008) is one of the most widely used Intimate Partner Violence (IPV) risk assessment tools in the world. After over 20 years, the SARA has been updated to reflect advances in research related to IPV and risk assessment more generally. The purpose of this thesis is to examine the interrater reliability and concurrent validity of the most recent version of the Spousal Assault Risk Assessment-Version 3 (SARA-V3). A total of N = 97 closed IPV cases were used to rate SARA-V3. To examine interrater reliability, a second rater coded n = 30 of the same files using SARA-V3. Interrater reliability for individual risk factors, SARA-V3 numerical total scores, and summary risk ratings fell primarily in the moderate range and consistent with prior research. Other raters had previously coded the same files with SARA-V2 and a number of other IPV risk assessment tools, and these tools served as the basis for evaluating the concurrent validity of the SARA-V3. ICCs were mostly in the fair to good range indicating adequate interrater reliability. Correlations between SARA-V3 and other IPV risk assessments were medium to large indicating good concurrent validity. Overall, the interrater reliability and concurrent validity findings were in line with previous research on SARA-V2 and the other assessments of IPV risk. Limitations of this study and implications for future research and practice are discussed.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Stephen D. Hart
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Thesis) M.A.

Risk Assessment with the HCR-20v3 across Genders, Subsamples, and Time-Frames

Author: 
Date created: 
2016-11-24
Abstract: 

One of the most well-established violence risk assessment schemes, the HCR-20: Assessing Risk for Violence Manual, Version 2 (HCR-20v2; Historical/Clinical/Risk Management-20), has recently been revised. The present study evaluated the performance of the new HCR-20v3 in a sample of 119 participants on probation or recently discharged into the community (i.e., from incarceration or short-term psychiatric hospitalization). The HCR-20v3 demonstrated concurrent validity with the HCR-20v2 and was predictive, prospectively, of whether, and how rapidly, participants engaged in violence. The SRRs added incrementally to the presence and relevance scores. Generally, no moderation effects of subsample type were noted, with the exception of the impact of subsample on the ability of the C subscale to predict the likelihood of verbal violence, as well as its impact on the SRRs, which might more strongly predict violence for the participants who were receiving short-term psychiatric inpatient care. As pertains to gender, some moderation effects were observed at 6 weeks for violence and physical violence, but this was no longer the case at 8 months. However, the H relevance rating may be more strongly predictive of time to physical violence in women, than it is in men.Moreover, the HCR-20v3 components generally demonstrated a relationship to violent victimization, whereas they did not do so for suicide. Some ratings might exhibit a relationship to self-harm. There was no moderation effect of subsample type on the ability of HCR-20v3 to forecast violent victimization. The HCR-20v3 components were not predictive of violent victimization, suicide, or self-harm in men at 6 weeks, but some demonstrated a relationship with violent victimization at 8 months. For women, some of HCR-20v3 components were predictive of violent victimization and self-harm for both time-frames. The H presence score was more predictive of violent victimization in women. Generally, the higher the scores on all HCR-20v3 presence ratings, the sooner participants were violently victimized and there was no moderation effect of subsample type. However, there was a moderation effect of gender on the ability of the C subscale to forecast the imminence of this outcome, and this may also the case for the total presence score.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Kevin S. Douglas
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Dissertation) Ph.D.

Predictors of Medication Adherence in Renal Transplant Recipients: Self-Efficacy, Depressive Symptomatology, and Neurocognitive Abilities.

Date created: 
2016-12-12
Abstract: 

Background: Estimates indicate 20-70% of renal transplant recipients (RTR) are medication non-adherent, significantly increasing the risk of organ rejection. Medication adherence decreases in relation to everyday problem solving (EPS), and associations between depressive symptoms, self-efficacy (SE), and adherence are reported in RTR. Nonetheless, to date, these individual associations have not been examined concurrently and comprehensively. To increase our understanding of adherence in RTR, we computed an omnibus model examining relationships among neurocognitive abilities, depressive symptoms, SE, and medication adherence. Methods: RTR (N= 211) underwent transplant at least 6-months prior to participation. Adherence was measured via self-report, medication possession ratio, and immunosuppressant blood-level. Traditionally-measured neurocognitive and everyday problem-solving abilities were assessed. Depressed and positive affect, somatic, and interpersonal symptoms of depression were measured via self-report, as were general and medication adherence related SE. Structural equation modeling was used to assess the fit of the model to available data. Results: For our final model, the fit indices examined indicated a good fit between the model and the data (CFI =.97; SRMR =.072; RMSEA =.031). EPS and SE had direct positive effects on adherence. Depressive symptoms were negatively associated with SE. Traditionally-measured neurocognitive abilities were positively associated with SE, and negatively associated with depressive symptoms. Conclusions: This study presents a comprehensive investigation of relationships between neurocognitive and psychosocial factors and adherence in RTR. Findings confirm the importance of EPS and SE in predicting adherence within a causal model, and suggest that influences of depressive symptoms and neurocognitive abilities are indirect. Findings have important implications for future development of interventions to improve medication adherence in RTR.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Wendy Thornton
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Dissertation) Ph.D.

Self-report and performance-based measures of impulsivity in justice-involved youths: Predictive validity and dynamic change

Date created: 
2016-08-18
Abstract: 

Impulsivity is a multi-faceted construct comprised of lack of premeditation, urgency related to negative affect, sensation seeking and lack of perseverance with difficult tasks (Whiteside & Lynam, 2001). Impulsivity is also a key risk factor for recidivism (Andrews & Bonta, 2010), and particularly relevant to adolescent behaviour (Hirschi & Gottfredson, 1983; Steinberg, 2007). An understanding of dynamic risk factors that are amenable to change, such as impulsivity, is important for risk management and intervention (Douglas & Skeem, 2005). Prior research has typically relied upon self-report questionnaires, but performance-based measures that focus on completing a specific task may provide unique information on impulse control (Reynolds, Penfold, & Patak, 2008), and conduct problems (Mathias, Marsh-Richard, & Dougherty, 2008). Minimal research has compared different measures of impulsivity in adolescent populations, or examined whether dynamic change relates to outcomes. The purpose of this study was to examine whether self-report (Eysenck Junior Impulsiveness Scale; EJIS; Eysenck, Easting & Pearson, 1984) and performance-based (GoStop Impulsivity Paradigm; GoStop; Dougherty, Mathias, & Marsh, 2003b) measures of impulsivity related to each other, changed over time, and whether change differentially predicted reoffending and violence. Participants were 107 adolescents (35 females) between ages 12 and 18 who were supervised on community probation orders. Youths completed questionnaires during semi-structured interviews with a 6-month interval. Recidivism was measured through self-report and official records. Results indicated that the two impulsivity measures were not associated, but both predicted prospective outcomes of reoffending, aggression and violence. GoStop scores significantly contributed to the prediction of recidivism, even after controlling for EJIS and age of first arrest, supporting the notion that performance-based impulsivity measures provide complementary information to self-report. Group-level changes were non-significant, but intra-individual changes were observed for a small group of youths over the 6-month follow up period. Lower reported physical victimization, substance use, and negative affective states, including anger and depression/anxiety, were associated with gains in impulse control. Change scores predicted self-report and official records of general and violent reoffending at 6- and 12-month follow ups. Thus, both self-reported and performance-based impulsivity are relevant to outcomes of reoffending and violence among justice-involved youths.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Jodi Viljoen
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Dissertation) Ph.D.

Perspective-taking and hindsight bias

Author: 
Date created: 
2016-07-26
Abstract: 

Participants read a vignette about a woman and man from a self (first-person) or other (third-person) perspective and predicted the likelihood of several outcomes. Later, they learned positive (marriage proposal), negative (rape), or no outcome information before recalling their original predictions and completing a memory questionnaire designed to investigate whether they misremembered details stereotypical of the outcome they learned. Perspective did not affect memory. Alternatively, outcome information did affect memory; however, only participants who learned negative outcome information exhibited hindsight bias, misremembering their initial likelihood ratings as being more consistent with the outcome than their original ratings actually were. Furthermore, performance on the vignette task did not correlate with performance on a standard paradigm for measuring hindsight bias. While taking another’s perspective rather than one’s own perspective may not make an outcome seem more or less predictable, learning negative outcome information likely makes an outcome seem more predictable in hindsight.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Deborah Connolly
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Thesis) M.A.

The Impact of Traumatic Brain injury and Aggregate Comorbidities on Cognitive Functioning in a Marginally Housed Sample

Date created: 
2016-06-28
Abstract: 

Individuals living in marginal urban housing face numerous health risks that impair cognition and produce burden in these individuals that may differentially attenuate capacity to tolerate further brain insult. We investigated the effect of self-reported traumatic brain injury (TBI) on cognition in persons with differential levels of neurocognitive burden. Two hundred and twenty participants (age: 23-68; 170 M, 50 F), recruited from single-room occupancy hotels underwent neurocognitive testing. A statistically weighted neurocognitive burden index was created reflecting the aggregate extent to which non-TBI comorbidities (vascular health, mental health, substance use, viral infection, neurological illness) and demographics (age, education, premorbid IQ) were associated with overall cognition. This index was investigated for its moderating influence on the relationship between self-reported TBI history (loss of consciousness of 30 minutes or more) and neurocognition. Hierarchical linear regression revealed that the burden index accounted for 31.4% of the total variance in cognition (F(1, 212) = 97.052, p < .001). TBI itself did not account for additional variance in cognition; nor did burden moderate the effect of TBI. Self-reported TBI history, as defined in the present study, has minimal value in signifying cognitive dysfunction in multimorbid marginally housed individuals.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Allen Thornton
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Thesis) M.A.

Predictors of one-year cognitive decline in a marginally housed, multimorbid sample

Date created: 
2016-08-25
Abstract: 

Marginal housing is associated with high prevalence of several morbidities, including viral infection, psychiatric diagnosis and substance use, each of which is known to compromise cognition. The nature or course of cognition in marginally housed persons is understudied, and the impact of comorbidity on cognition is often unaddressed in the literature. Over a period of one year, participants recruited from the Downtown Eastside of Vancouver evidenced generally stable cognitive performance, except for a slight improvement in sustained attention and a slight decline in cognitive flexibility. HIV seropositive individuals showed declines in memory and response inhibition, while cannabis dependence was marginally associated with decline in memory. Given the negative impact of cognitive impairment on functioning, these results can inform prioritization of treatment targets in multimorbid populations.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Allen Thornton
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Thesis) M.A.

Validation of the Risk for Sexual Violence Protocol in Adult Sexual Offenders

Date created: 
2016-08-10
Abstract: 

Sexual violence is a serious societal issue that is associated with victims experiencing a wide range of psychological difficulties. The proper assessment of risk for future sexual violence is critical to the treatment and management of sexual offenders. The Risk for Sexual Violence Protocol (RSVP; Hart et al., 2003) is a set of structured professional guidelines for assessing risk for sexual violence that provides a framework for estimating future risk as well as clinical formulation for treatment and management needs. To date, there has been very little research published on the RSVP even though it is currently being used by forensic professionals (Judge, Quayle, O'Rourke, Russell, & Darjee, 2014). This study examined the psychometric properties of the RSVP vis-à-vis the Sexual Violence Risk-20 (SVR-20; Boer, Hart, Kropp, & Webster, 1997), which is considered a parallel form of the RSVP given the similarity in content between these two sets of structured professional judgement guidelines. This study also examined the psychometric properties of the RSVP vis-à-vis a number of actuarial risk assessment instruments: the Static-99R (Helmus, Thornton, Hanson, & Babchishin, 2012), the Static- 2002R (Helmus et al., 2012), and the Sexual Offender Risk Appraisal Guide (SORAG; Quinsey, Harris, Rice, & Cormier, 1998, 2006; Harris, Rice, Quinsey, & Cormier, 2015). The sample consisted of 100 adult male sexual offenders who had participated in a sex offender treatment program. Sexual recidivism was coded over the follow-up period of approximately 10 years. Overall, the RSVP performed well in terms of interrater reliability, concurrent validity, and predictive validity. The interrater reliability of RSVP total scores and Summary Risk ratings was excellent (ICC2 range = .85 to .96) and was comparable with the interrater reliability of the SVR-20 and actuarial instruments. The RSVP total scores and Case Prioritization ratings demonstrated good concurrent validity with respect to SVR-20 total and domain scores and with the actuarial instruments’ total scores and risk categories, correlations all significant at p < .001. The RSVP total scores and Case Prioritization ratings were moderately and significantly associated with sexual recidivism, as were the SVR-20 total scores and the actuarial instruments’ total scores and risk categories.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Stephen D. Hart
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Dissertation) Ph.D.