School of Psychology - Recently Published Research

Cavanagh, P., Holcombe, A.O. and Chou, W-L. (2008) Mobile computation: Spatiotemporal integration of the properties of objects in motion. Journal of Vision, 8(12): 1 - 23.

ABSTRACT
We demonstrate that, as an object moves, color and motion signals from successive, widely spaced locations are integrated, but letter and digit shapes are not. The features that integrate as an object moves match those that integrate when the eyes move but the object is stationary (spatiotopic integration). We suggest that this integration is mediated by large receptive fields gated by attention and that it occurs for surface features (motion and color) that can be summed without precise alignment but not shape features (letters or digits) that require such alignment. Rapidly alternating pairs of colors and motions were presented at several locations around a circle centered at fixation. The same two stimuli alternated at each location with the phase of the alternation reversing from one location to the next. When observers attended to only one location, the stimuli alternated in both retinal coordinates and in the attended stream: feature identification was poor. When the observer's attention shifted around the circle in synchrony with the alternation, the stimuli still alternated at each location in retinal coordinates, but now attention always selected the same color and motion, with the stimulus appearing as a single unchanging object stepping across the locations. The maximum presentation rate at which the color and motion could be reported was twice that for stationary attention, suggesting (as control experiments confirmed) object-based integration of these features. In contrast, the identification of a letter or digit alternating with a mask showed no advantage for moving attention despite the fact that moving attention accessed (within the limits of precision for attentional selection) only the target and never the mask. The masking apparently leaves partial information that cannot be integrated across locations, and we speculate that for spatially defined patterns like letters, integration across large shifts in location may be limited by problems in aligning successive samples. Our results also suggest that as attention moves, the selection of any given location (dwell time) can be as short as 50 ms, far shorter than the typical dwell time for stationary attention. Moving attention can therefore sample a brief instant of a rapidly changing stream if it passes quickly through, giving access to events that are otherwise not seen.

Colagiuri B, Roscoe J.A., Morro G.R., Atikins J.N., Giguere J.K. and Colman L.K. (2008) How do patient expectancies, quality of life, and postchemotherapy nausea interrelate?. Cancer, 113, 654 - 661.

ABSTRACT
Background: Increasing evidence suggests a relation between patient expectancies and chemotherapy-induced nausea. However, this research has often failed to adequately control for other possible contributing factors. In the current study, the contribution of patient expectancies to the occurrence and severity of postchemotherapy nausea was examined using more stringent statistical techniques (namely hierarchical regression) than other similar studies that have relied on bivariate correlations, chi-square tests, and stepwise regression, and further extended upon previous research by including quality of life (QoL) in the analysis.

Methods: In all, 671 first-time chemotherapy patients taking part in a trial comparing antiemetic regimens answered questions regarding their expectancies for experiencing nausea. Patients then completed a diary assessing both the occurrence and severity of their nausea in the 4 days after their first infusion.

Results: Stronger expectancies for nausea corresponded with greater average and peak nausea after chemotherapy and this was after controlling for age, sex, susceptibility to motion sickness, diagnosis, and QoL. Interestingly, patients classified as highly expectant (first quartile) experienced significantly greater average and peak nausea than those classified as somewhat expectant, slightly expectant, and not expectant (second, third, and fourth quartiles, respectively), whereas there were no significant differences between these lower levels of expectancy. Furthermore, increases in average nausea led to a significant reduction in QoL after chemotherapy.

Conclusions: Patient expectancies appear to contribute to postchemotherapy nausea and patients that are highly expectant of experiencing nausea appear to be at particular risk. Interventions that target these patients should reduce the burden of nausea and may also improve QoL.

Juraskova, I., Butow, P., Lopez A., Seccombe, M., Coates, A., Boyle, F., McCarthy, N., Reaby, L., and Forbes, JF. (2008) Improving informed consent: pilot of a decision aid for women invited to participate in a breast cancer prevention trial (IBIS-II DCIS). Health Expectations, 11, 252-262.

ABSTRACT

Background: Patients and clinicians report difficulties with the process of informed consent to clinical trials and audiotape audits show that critical information is often omitted or poorly presented. Decision aids (DAs) may assist in improving consent.

Aims: This study piloted a DA booklet for a high priority breast cancer prevention trial, IBIS-II DCIS, which compares the efficacy of an aromatase inhibitor (anastrozole) with tamoxifen in women who have had surgery for ductal carcinoma in situ (DCIS).

Method: Thirty-one Australian women participating in the IBIS-I breast cancer prevention trial and who are currently in follow-up agreed to read the IBIS-II DCIS participant information sheet and the DCIS DA booklet, complete a set of standardized questionnaires, and provide feedback on the DA via a semi-structured phone interview.

Results: Women found the DA helpful in deciding about trial participation, reporting that it aided their understanding over and above the approved IBIS-II DCIS participant information sheet and was not anxiety provoking. Women's understanding of the rationale and methods of clinical trials and the IBIS-II DCIS trial was very good; with more than 80% of items answered correctly. The only areas that were not understood well were the concepts of randomization and blinding.

Conclusions: This study suggests that the DA will be acceptable to and valued by potential participants in the IBIS-II DCIS study. The revised DA is currently being evaluated prospectively in a randomized controlled trial. If successful, such DAs could transform the consent process to large clinical trials and may also reduce dropout rates.