Research Topics
| R J SnowdenSummaryAffiliation: Cardiff University Country: UK Publications
| Collaborators |
Detail Information
Publications
Impulsivity and psychopathy: associations between the barrett impulsivity scale and the psychopathy checklist revisedRobert J Snowden
Cardiff University, UK
Psychiatry Res 187:414-7. 2011..Thus, our results show that only some psychopaths show increased impulsivity and that not all forms of impulsivity are raised...- Assessing risk of future violence among forensic psychiatric inpatients with the Classification of Violence Risk (COVR)Robert J Snowden
School of Psychology, Cardiff University, Park Place, Cardiff, Wales, United Kingdom
Psychiatr Serv 60:1522-6. 2009..The purpose of this study was to provide an independent validation of the COVR in a sample of forensic psychiatric inpatients in the United Kingdom... 
Actuarial prediction of violent recidivism in mentally disordered offendersRobert J Snowden
School of Psychology, Cardiff University, Cardiff, UK
Psychol Med 37:1539-49. 2007..We compared two instruments that differ in terms of what they are designed to predict (general versus violent recividism) and the inclusion of stable mental health variables...- Implicit and explicit measurements of sexual preference in gay and heterosexual men: a comparison of priming techniques and the implicit association taskRobert J Snowden
School of Psychology, Cardiff University, Cardiff CF10 3AT, Wales, United Kingdom
Arch Sex Behav 37:558-65. 2008.... - Motion perception in the ageing visual system: minimum motion, motion coherence, and speed discrimination thresholdsRobert J Snowden
School of Psychology, Cardiff University, Wales, UK
Perception 35:9-24. 2006..It is concluded that these hypotheses do not provide an adequate account of the data, and therefore that the losses occurring with age are complex and probably are a result of the loss of several types of cell... - The visual perception of motionRobert J Snowden
School of Psychology, Cardiff University, Cardiff CF10 3YG, UK
Curr Biol 14:R828-31. 2004 - Indirect behavioral measures of cognition among sexual offendersRobert J Snowden
School of Psychology, Cardiff University, United Kingdom
J Sex Res 48:192-217. 2011.... - Visual attention to color: parvocellular guidance of attentional resources?Robert J Snowden
School of Psychology, Cardiff University, Wales, United Kingdom
Psychol Sci 13:180-4. 2002..Hence, color vision not only aids target identification but also is a strong aid for target detection and localization... - Visuospatial attention: the role of target contrast and task difficulty when assessing the effects of cuesR J Snowden
School of Psychology, Cardiff University, Wales, UK
Perception 30:983-91. 2001..The results suggest that manipulation of target contrast changes the attention cueing effect at a stage of attracting attention to a location of the target (the 'move' stage), rather than at a later processing stage... - Spatial frequency adaptation: threshold elevation and perceived contrastR J Snowden
School of Psychology, University of Wales College of Cardiff, UK
Vision Res 36:1797-809. 1996.... - Stereoscopic depth cues can segment motion informationR J Snowden
School of Psychology, Cardiff University, UK
Perception 28:193-201. 1999..We conclude that stereo disparity can be used as a segmentation cue by the motion system... - Shifts in perceived position following adaptation to visual motionR J Snowden
School of Psychology Cardiff University Cardiff CF1 9EB Wales UK
Curr Biol 8:1343-5. 1998..As the pattern is stationary, one cannot account for this result via the notion of perceptual lags... - The effects of surround contrast on contrast thresholds, perceived contrast and contrast discriminationR J Snowden
Vision Research Unit, School of Psychology, Cardiff University, UK
Vision Res 38:1935-45. 1998.... - Colour and polarity contributions to global motion perceptionR J Snowden
School of Psychology, Cardiff University, UK
Vision Res 39:1813-22. 1999..When this strategy was eliminated by presenting the stimuli in the near-periphery or very briefly the effect of the colour or polarity information disappears... - Texture segregation and visual search: a comparison of the effects of random variations along irrelevant dimensionsR J Snowden
School of Psychology, Cardiff University, USA
J Exp Psychol Hum Percept Perform 24:1354-67. 1998..This notion was examined in 3 additional experiments that manipulated grouping processes through task demands and stimulus design. The data provide tentative support for this notion... - Can one pay attention to a particular color?P Brawn
School of Psychology, Cardiff University, Wales
Percept Psychophys 61:860-73. 1999..We conclude that subjects can selectively attend to items on the basis of color given the appropriate task and stimulus dynamics... - Contrast gain mechanism or transient channel? Why the effects of a background pattern alter over timeR J Snowden
School of Psychology, Cardiff University, CF1 3YG, Cardiff, UK
Vision Res 41:1879-83. 2001..We find similar masking at pedestal offset, when the pedestal is continually flickered, or when pedestal and test have a high spatial frequency. These results were all predicted on the basis of sustained and transient channels... - Identification of visual stimuli is improved by accompanying auditory stimuli: the role of eye movements and sound locationM C Doyle
School of Psychology, Cardiff University, UK
Perception 30:795-810. 2001.... 
Psychophysical characterisation of early functional loss in glaucoma and ocular hypertensionE A Ansari
Department of Ophthalmology, University of Wales College of Medicine, Cardiff, UK
Br J Ophthalmol 86:1131-5. 2002..These findings are not consistent with the hypothesis that the magnocellular pathway is selectively damaged in early glaucoma...- An implicit test of the associations between children and sex in pedophilesNicola S Gray
School of Psychology, Cardiff University, Cardiff, United Kingdom
J Abnorm Psychol 114:304-8. 2005..The task can therefore identify a core cognitive abnormality that may underpin some pedophilic deviant sexual behavior... - The relevance of irrelevance to schizophreniaNicola S Gray
School of Psychology, Cardiff University, Cardiff CF10 3YG, UK
Neurosci Biobehav Rev 29:989-99. 2005.... - A new continuous within-participants latent inhibition task: examining associations with schizotypy dimensions, smoking status and genderLisa H Evans
School of Psychology, Cardiff University, Cardiff CF10 3AT, UK
Biol Psychol 74:365-73. 2007..These findings indicate that the task may have sufficient sensitivity to be used in patients with schizophrenia... - Implicit measurement of sexual associations in child sex abusers: role of victim type and denialAnthony S Brown
Cardiff University, UK
Sex Abuse 21:166-80. 2009.... - Do we have direct access to retinal image motion during smooth pursuit eye movements?Tom C A Freeman
School of Psychology, Cardiff University, UK
J Vis 9:33.1-11. 2009..Nevertheless, sequential relative motion still provided the best account of the data. The results suggest that observers do not have direct access to retinal motion when making perceptual judgements about movement during pursuit... - Reduced P50 suppression is associated with the cognitive disorganisation dimension of schizotypyLisa H Evans
School of Psychology, Cardiff University, Cardiff, CF10 3AT, UK
Schizophr Res 97:152-62. 2007..This research supports the view that there is a link between poor P50 suppression and certain symptom clusters in schizophrenia... - Predicting future reconviction in offenders with intellectual disabilities: the predictive efficacy of VRAG, PCL-SV, and the HCR-20Nicola S Gray
School of Psychology, Cardiff University, Cardiff, UK
Psychol Assess 19:474-9. 2007..Hart, 1997) were all significant predictors of violent and general reconviction in this sample, and in many cases, their efficacy was greater than in a control sample of mentally disordered offenders without an intellectual disability... - Predicting violent reconvictions using the HCR-20Nicola S Gray
School of Psychology, Cardiff University, Cardiff, UK
Br J Psychiatry 192:384-7. 2008..Risk assessment of future violent acts is of great importance for both public protection and care planning. Structured clinical assessments offer a method by which accurate assessments could be achieved... - Prepulse inhibition of startle and its moderation by schizotypy and smokingLisa H Evans
School of Psychology, Cardiff University, Cardiff, South Wales, UK
Psychophysiology 42:223-31. 2005..The results suggest that PPI is altered differentially in psychosis-prone populations who display different symptom profiles, and that these relationships are moderated by smoking status... - Which schizotypal dimensions abolish latent inhibition?Nicola S Gray
School of Psychology, Cardiff University, UK
Br J Clin Psychol 41:271-84. 2002..To evaluate which dimensions of schizotypy are associated with a reduction in latent inhibition (LI), akin to that seen in schizophrenia... - A demonstration of within-subjects latent inhibition in the human: limitations and advantagesNicola S Gray
School of Psychology, Cardiff University, PO Box 901, Park Place, Cardiff, CF10 3YG, South Wales, UK
Behav Brain Res 138:1-8. 2003..However, the limited range of pre-exposure scores in the current within-subject paradigm may severely limit it is use as an indicator of subtle performance changes... - The partial reinforcement extinction effect in humans: effects of schizophrenia, schizotypy and low doses of amphetamineNicola S Gray
School of Psychology, Cardiff University, PO Box 901, Park Place, South Wales, UK
Behav Brain Res 133:333-42. 2002..The results of these experiments on human PREE provide no support that PREE is a valid paradigm with which to explore the cognitive dysfunction underlying schizophrenia... - Forensic psychology: Violence viewed by psychopathic murderersNicola S Gray
School of Psychology, Cardiff University, Cardiff CF10 3YG, UK
Nature 423:497-8. 2003 - Prediction of violence and self-harm in mentally disordered offenders: a prospective study of the efficacy of HCR-20, PCL-R, and psychiatric symptomatologyNicola S Gray
School of Psychology, Cardiff University, Glanrhyd Hospital, Mid Glamorgan, Wales, United Kingdom
J Consult Clin Psychol 71:443-51. 2003..BHS was the only variable predictive of self-harm. Although risk assessment measures were successful at predicting in-patient violence, a clinical measure of mental state was at least as effective in these mentally disordered offenders... - The extra-retinal motion aftereffectTom C A Freeman
School of Psychology, Cardiff University, Cardiff, UK
J Vis 3:771-9. 2003..In an explicit test of the nystagmus-suppression hypothesis, we find extra-retinal MAE fails to store over a 30s delay between adaptation and test. Implications for our understanding of motion aftereffects are discussed... - Relative efficacy of criminological, clinical, and personality measures of future risk of offending in mentally disordered offenders: a comparative study of HCR-20, PCL:SV, and OGRSNicola S Gray
School of Psychology, Cardiff University, United Kingdom
J Consult Clin Psychol 72:523-30. 2004..The authors suggest that for maximum efficacy clinical risk should be rated at a time of active symptoms rather than at discharge when symptoms are minimal... - Spatial shifts in visual attention in normal ageing and dementia of the Alzheimer typeAndrea Tales
School of Psychology, Cardiff University, Wales, UK
Neuropsychologia 40:2000-12. 2002..We conclude that patients with Alzheimer's disease have an abnormality in automatic, but not controlled visuospatial attention... - Glaucoma: squaring the psychophysics and neurobiologyE A Ansari
Department of Ophthalmology, University Hospital of Wales, Cardiff, UK
Br J Ophthalmol 86:823-6. 2002..These exciting new findings may help us develop psychophysical tests to monitor early retinal ganglion cell damage, possibly before neurons are committed to the process of cell death... - Phasic visual alertness in Alzheimer's disease and ageingAndrea Tales
School of Psychology, Cardiff University, Cardiff CF11 3YG, Wales, UK
Neuroreport 13:2557-60. 2002..This marked inability to increase phasic alertness in AD may contribute to the everyday problems faced by these patients, and may provide a simple tool to aid diagnosis and disease progression... - Optokinetic potential and the perception of head-centred speedJane H Sumnall
School of Psychology, Cardiff University, P.O. Box 901, Cardiff, Wales CF10 3YG, UK
Vision Res 43:1709-18. 2003..The results cast doubt on the idea that changing contrast or spatial frequency affects perceived head-centred speed by altering optokinetic potential... - The effects of saliency and task difficulty on visual search performance in ageing and Alzheimer's diseaseAndrea Tales
School of Psychology, Cardiff University, Cardiff CF11 3YG, Wales, UK
Neuropsychologia 42:335-45. 2004..We conclude that inefficiency in visual search tasks in AD probably represents the product of both attention shifting and target processing factors... - Context dependent latent inhibition in adult humansN S Gray
School of Psychology, Cardiff University, Cardiff, CF10 3YG, UK
Q J Exp Psychol B 54:233-45. 2001..In two experiments we manipulated context in either the real world or a virtual world, and showed that LI is abolished by a change of context in adult humans... - Alerting and orienting in Alzheimer's diseaseAndrea Tales
Clinical Sciences, Department of Care of the Elderly, University of Bristol, The BRACE Centre, Blackberry Hill Hospital, Bristol, United Kingdom
Neuropsychology 20:752-6. 2006..In this further study examining exogenous spatial orienting and phasic alerting, the authors present evidence to suggest that the increased spatial orienting effect in AD is not the result of a decreased phasic alerting effect... - Abnormal spatial and non-spatial cueing effects in mild cognitive impairment and Alzheimer's diseaseAndrea Tales
Department of Care of the Elderly University of Bristol, Clinical Research Centre and Memory Disorders Clinic, The BRACE Centre, Blackberry Hill Hospital, Bristol, UK
Neurocase 11:85-92. 2005.... - Abnormal visual search in mild cognitive impairment and Alzheimer's diseaseAndrea Tales
Department of Care of the Elderly University of Bristol, Clinical Research Centre and Memory Disorders Clinic, The BRACE Centre, Blackberry Hill Hospital, Bristol, UK
Neurocase 11:80-4. 2005.... - A taxometric analysis of the Psychopathy Checklist: Screening Version (PCL:SV): further evidence of dimensionalityGlenn D Walters
Psychology Services, Federal Correctional Institute Schuylkill, Minersville, PA 17954, USA
Psychol Assess 19:330-9. 2007..It is concluded that scores on the PCL:SV differ quantitatively as points on a dimension (high vs. low psychopathy) rather than partitioning into qualitatively distinct categories of behavior (psychopath vs. nonpsychopath)...