B − A − 2C within the brain, it is not unreasonable to assume that the specific neural connections which are active during a water-jar problem-state and those that are active when one thinks “take the second term, subtract the first term, then subtract two of the third term” tend to increase in the amount of overlap as more and more instances where B − A − 2C works are presented. Other Einstellung research Psychological stress The following experiments were designed to gauge the effect of different stressful situations on the Einstellung effect. Overall, these experiments show that stressful situations increase the prevalence of the Einstellung effect. The speed test Luchins gave an elementary-school class a set of water jar problems. In order to create a stressful situation, experimenters told the students that the test would be timed, that the speed and accuracy of the test would be reviewed by their principal and teachers, and that the test would affect their grades. To further agitate the students during the test, experimenters were instructed to comment on how much slower the children were compared to children in lower grades. The experimenters observed anxious, stressed, and sometimes tearful faces during the experiment. The results of the experiment indicated that the stressful speed test situation increased rigidity. Luchins found that only three of the ninety-eight students tested were able to solve the extinction problem, and only two students used the direct method for the critical problems. The same experiment conducted under non-stress conditions showed 70% rigidity during the test problems and 58% failure of the extinction problem, while the anxiety-inducing situation showed 98% and 97% respectively. The speed test was performed with college students as well, which yielded similar results. Even when college students were told ahead of time to use the direct method in order to avoid mistakes made by children, the college students continued to exhibit rigidity under time pressure. The results of these studies showed that the emphasis on speed increased the Einstellung effect on the water jar problems. Maze tracing Luchins also instructed subjects to draw a solution through a maze without crossing any of the maze's lines. The maze was either traced normally or traced using the mirror reflection of the maze. If the subject drew over the lines of the figure, they had to start at the beginning, which was disadvantageous since the subject was told that