Final answer:
The 'area of bars' is not an elementary perceptual task used for extracting quantitative information from bar charts; instead, we use the length, position, and direction of the bars for such purposes.
Step-by-step explanation:
The elementary perceptual task not used to extract quantitative information from a bar chart is area of bars. In bar charts, we typically use length of bars to represent numerical values. The position of bars along a common scale helps to compare these lengths against a quantitative scale, often placed on the y-axis.
Additionally, we note the direction of the bars (vertical or horizontal), although this doesn't convey quantitative information directly. But, the area of bars is not typically used for extracting quantitative information, as it can be misleading in the context of bar charts where only the length and height of the bars are significant.