Figure 1: Task and behavior.

a. Sequence of events within a trial. A monkey holds down a button, then fixates and views one of 4 familiar fractal images. A delay interval ensues, during which the operant response must be indicated (release or continue to hold the button, H and R). After a trace period, a liquid reward is delivered for correct responses for 2 of the 4 stimuli. Correct responses to the other 2 stimuli result in no reward, but avoids a timeout and trial repetition. b. Task scheme, SRO mappings for conditions in the 2 contexts. A-D, stimuli. +/−, reward/no reward for correct choices. Operant and reinforcement contingencies are orthogonal. After 50–70 trials in one context, context switches; experiments contain many context switches. c. Monkeys utilize inference to adjust behavior. Average percent correct plotted for the first presentation of the last image appearing before a context switch (”Last”) and for the first instance of each image after a context switch (1–4). For image numbers 2–4, monkeys adjusted performed at above chance despite not having experienced these trials in the current context (inference). Binomial parameter estimate, bars are 95% Clopper-Pearson confidence intervals d. Average percent correct performance plotted vs. trial number aligned on the first correct trial where the monkey used inference (red circle, defined as the first correct trial among the first presentations of the 2nd, 3rd or 4th image type appearing after a context switch). So if Image 1 is the first image after a context switch, and the first presentation of image 2 is performed correctly, it is the first correct inference trial. If it is performed incorrectly, the first correct inference trial could occur on the first presentation of image 3 or 4.