Fig. 2: Monkeys were efficient foragers choosing targets in descending order of their value.

a Scan path of the 91st trial in a representative experiment. This trial is shown in Supplementary Movie 1 along with audio of a simultaneously recorded SC neuron. The white line represents the eye trace and the numbers indicate the order of successfully harvested targets. The start and end of the trial is denoted with triangle and asterisk, respectively. In some instances, such as the fixation between eye position 12 and 13, the monkey did not hold fixation long enough to successfully harvest the target. These instances were not included in subsequent analyses. The colored numbers in the legend correspond with the value of the associated target colors. This particular trial/experiment is denoted by larger data points in subsequent panels. For illustration purposes, purple is used to represent red color in task paradigm. b Calculating the rank value of target colors. Each dot represents the value based on the order in which a particular class of colored targets was selected within a given trial. The colored lines represent the sliding average of rank value over five trials. The dashed line represents the time to behavioral acquisition (see “Methods”) when a stable value ranking was established as determined. The right colored numbers indicate the value ranking of each color which is measured from the order of median rank value across the block. c Same format as panel b except an unsignaled change in the target color-value relationship occurred at the solid line. Only the trials before the rule changes were included in population analyses. d The monkey’s efficiency at harvesting water for the representative experiment shown in (b). The black line represents the sliding average of efficiency over five trials. The horizontal line represents 95% confidence interval of chance efficiency by simulating random selection for 5000 trials. e Foraging efficiencies across all blocks plotted against their corresponding chance efficiencies. Only experiments that displayed significantly efficient and stable preference (black filled dots) were included in further analyses whereas inefficient (gray filled dots) and unstable blocks (unfilled black dots) were excluded. f Choice preferences of blocks in population neuronal analyses as menu transitioned from 3-values to 2-values, and to 1-value targets remaining. Source data are provided as a Source data file. For the boxplots, on each box, the central mark is the median, the edges of the box are the 25th and 75th percentiles, and the whiskers extend to the most extreme data points that the algorithm considers not to be outliers. Outliers are data points that are larger than Q3 + 1.5 × (Q3 − Q1) or smaller than Q1 – 1.5 × (Q3 − Q1), where Q1 and Q3 are the 25th and 75th percentiles, respectively (N.B.: The association between target color and value ranking was randomized between each experiment. However, for display purposes, purple, green, and blue will indicate the number 1, 2, and 3 value rankings, respectively, throughout the remainder of the paper.).