Decision Making as a Factor in the Ease of Using Numerical Tables

The speed and accuracy with which people could obtain information from numerical tables was examined for a variety of presentation formats. All tables contained 10 numerical coll values arranged either as a 4 × 4 matrix or as a 16 × 1 row. It was found that for both these arrangements people were slower and more error-prone when they had to make four successive binary decisions than when making two decisions each time selecting among four alternatives. People also made more errors when the presentation format required them to combine decisions along two different spatial dimensions (using both row and column headings) compared with u format for which the decisions could he made successively along a single dimension (nosted column headings). This latter format approximates a logical tree structure and the present findings support other evidence that such formats are particularly useful for problems having extraneous information.