1979: the age of mental arithmetic
Apparently people could carry out mental arithmetic problems much better back in 1979. In a recent study, these Standford researchers found people could only correctly answer problems in the easy category, while those in 1979 could perform mental arithmetic in the medium and difficult categories. I think it all went down hill after the calculator watch was released in the mid 1970s.
Figure 1: Pupillary response during the mental multiplication task. There is a small (0.1 mm) increase in pupil size as the multiplicand is committed to short term memory and a larger, longer-lasting increase after the subjects hear the multiplier and begin computing the product. The graph on the left is from Ahern and Beatty [1979], reprinted with permission from AAAS. The graph on the right shows the results from our replication of their experiment. The two graphs are aligned and plotted at the same scale. Although we gave problems at all three difficulties, the easy level was the only one for which we collected sufficient correct responses for analysis. The pupillary response we observed for these easy problems resembles the prior result for medium and difficult problems. We speculate that students in 1979 had more practice with mental arithmetic.
