Common or separate summary statistical processes for representing average and variance?

Recent findings have demonstrated the significance of ensemble perception as summarizing visual information to bypass the capacity limitations of working memory and attention. They have focused on representations of visual ensembles using summary statistics (i.e mean and variance). The goal of this study is to determine if mean and variance representations of orientation are encoded together or separately in the visual working memory. An odd-one-out search task was conducted to investigate this. 36 undergraduates in the University of Iceland took part in the experiment. At first they saw 36 stimuli, which were lines arranged in a 6x6 matrix for around three to four visual search trials and searched for a target which was an oddly oriented line compared to the other distractors. Next the observers were exposed to two new sets simultaneously, featuring only distractors. One set was a comparison set and the other had the same summary statistic as the previous distractor set. This task is called the 2 alternative-forced choice task (2AFC task). Observers had to choose which of the two sets were more similar to the distractors previously presented with. Our results from this study suggest that mean and variance representations are to some extent encoded together in the visual system