| The present study tested the hypothesis that three visual pathways (i.e. parvocellular, magnocellular, and koniocellular pathways) may influence the degree of dual-task interference using dual-task methodology. The magnocellular pathway consists of feature-coding mechanisms that are sensitive to transients and motion, and is thought to process information about the locations and movements of objects. The parvocellular pathway consists of feature-coding mechanisms that are sensitive to red-green and brightness information, while the koniocellular pathway consists of feature-coding mechanisms that are sensitive to blue-yellow chromatic information. Both the parvocellular and the koniocellular pathway are thought to process information useful for identifying objects. The hypothesis predicted that engaging in two search tasks that were mediated by feature-coding mechanisms in two different pathways would result in less dual-task interference in performance than two tasks that were mediated by feature-coding mechanisms in the same pathway. Magnocellular stimuli were defined by brief luminance transients and motion, and parvocellular and koniocellular stimuli were defined by color. The most interference was observed for task pairs that were different in nature and mediated in one pathway. Two tasks mediated by the two different pathways resulted in a small interference, while two identical task pairs mediated by one pathway resulted in no dual-task interference. No significant negative contingency was observed in any task pair. Dual-task interference consistent with a sampling model (e.g. Bonnel et al., 1992) and an independence model (e.g. Morrone et al., 2002 & 2004) were observed. No task pairs produced dual-task interference consistent with the prediction of a switching model (e.g. Duncan, 1996). |
