Fig 7.

Mean SPFs for rhesus monkeys, capuchin monkeys, pigeons, and humans on four-item visual list-memory tests. One group of rhesus monkeys (squares, right error bars) was trained and tested with Carousel projectors and a lever response, and another rhesus group (circles, left error bars) was trained with digitized pictures, video monitors, and touch screens. Serial position 1 was the first list item. Open triangles (diff) show performance on trials (different) where the test item did not match any of the list items. Delay was the retention interval (in s) between the last list item (position 4) and the test. Error bars are the average standard error of the mean for the four serial positions of each function.