Experimental effects and individual differences in linear mixed models: estimating the relationship between spatial, object, and attraction effects in visual attention
- 1 Department of Psychology, University of Potsdam, Potsdam, Germany
- 2 Beijing Key Laboratory of Learning and Cognition and Department of Psychology, Capital Normal University, Beijing, China
- 3 Center for Brain and Cognitive Sciences and Department of Psychology, Peking University, Beijing, China
- 4 Key Laboratory of Machine Perception (Ministry of Education), Peking University, Beijing, China
Linear mixed models (LMMs) provide a still underused methodological perspective on combining experimental and individual-differences research. Here we illustrate this approach with two-rectangle cueing in visual attention (Egly et al., 1994). We replicated previous experimental cue-validity effects relating to a spatial shift of attention within an object (spatial effect), to attention switch between objects (object effect), and to the attraction of attention toward the display centroid (attraction effect), also taking into account the design-inherent imbalance of valid and other trials. We simultaneously estimated variance/covariance components of subject-related random effects for these spatial, object, and attraction effects in addition to their mean reaction times (RTs). The spatial effect showed a strong positive correlation with mean RT and a strong negative correlation with the attraction effect. The analysis of individual differences suggests that slow subjects engage attention more strongly at the cued location than fast subjects. We compare this joint LMM analysis of experimental effects and associated subject-related variances and correlations with two frequently used alternative statistical procedures.
Keywords: linear mixed model, individual differences, visual attention, spatial attention, object-based attention
Citation: Kliegl R, Wei P, Dambacher M, Yan M and Zhou X (2011) Experimental effects and individual differences in linear mixed models: estimating the relationship between spatial, object, and attraction effects in visual attention. Front. Psychology 1:238. doi: 10.3389/fpsyg.2010.00238
Received: 21 June 2010;
Accepted: 15 December 2010;
Published online: 05 January 2011.
Moon-Ho R. Ho
, Nanyang Technological University, Singapore
Copyright: © 2011 Kliegl, Wei, Dambacher, Yan and Zhou. This is an open-access article subject to an exclusive license agreement between the authors and the Frontiers Research Foundation, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are credited.
*Correspondence: Reinhold Kliegl, Department of Psychology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany. e-mail: firstname.lastname@example.org; Xiaolin Zhou, Center for Brain and Cognitive Sciences and Department of Psychology, Peking University, Beijing 100871, China. e-mail: email@example.com