Presented research deals with biphasal model of working memory search and the relationship between the sequential position of memorized stimuli and the focus of attention in working memory. The experiment applied modified Sternberg's procedure within which participants had to memorize sequentially presented set of stimuli (either verbal or non-verbal) and jugde whether the test stimulus was, or was not previously presented. The manipulation concerned the set size, type of required response (Yes or No), and stimuli presentation pace. The position of test stimulus in a previously presented set was controlled. The results confirmed the main hypothesis about negative relationship between stimulus postion in a set and accuracy of its identification, i.e. the earlier it occured in a sequence, the less accurate participants identified it. This effect was especially salient with non-verbal stimuli and faster presentation pace. Moreover, it occured that the capacity of focal attention is significantly less when participants had to memorize non-verbal stimuli than the verbal ones.