Video S1: Procedure demonstrations and monkey response

The video shows the lottery machine task used in all three studies. The first clip shows the Fruit Preference Validation procedure from Study 1 from the monkey's perspective. Here, E1 uses a stick (out of the monkey's view) to rotate the lottery machine; in this study the population of fruit is occluded in this phase. E1 then releases a lemon from the machine to the clear cup below, and says “now” to mark the start of the trial. Each trial then lasts 10 s, and the looking time of the monkey is recorded. The second clip shows the Probability Inference procedure from Study 2. Here, E1 open the curtains and reveals a lemon machine containing a population with a probable likelihood distribution (3:1 distribution of lemons and apples). Then, after rotating the machine, she releases the expected outcome (a lemon). The third clip shows the Non-causal control procedure from Study 3. E1 opens the curtains and reveals again a lemon machine, but this time it contains a population with a possible likelihood distribution (only one type of fruit is present). After rotating the cube, E1 visibly pulls the impossible (unexpected) outcome (an apple) from her pocket and then places it into the container above the cube. The final clip shows an example of the monkey's looking response in the task.本视频展示了三项研究共同采用的摇奖机任务（lottery machine task）。第一段视频以猕猴视角呈现了研究1中的水果偏好验证流程（Fruit Preference Validation procedure）：主试1（E1）借助一根处于猕猴视野外的木棍转动摇奖机；本研究此阶段中，摇奖机内的水果总体视觉信息被遮挡。随后主试1将一颗柠檬从摇奖机中释放至下方的透明杯内，并说出"now"以标记试次开始。每个试次持续10秒，同时记录猕猴的注视时长。第二段视频展示了研究2中的概率推断流程（Probability Inference procedure）：主试1拉开帷幕，露出一台装有符合概率分布（柠檬与苹果比例为3:1）的水果总体的摇奖机。转动摇奖机后，她释放出预期结果（一颗柠檬）。第三段视频展示了研究3中的非因果对照流程（Non-causal control procedure）：主试1再次拉开帷幕，露出一台摇奖机，但本次摇奖机内的水果总体仅包含单一品类，符合随机分布设定。转动该立方体摇奖机后，主试1从口袋中取出本不可能出现的（非预期）结果（一颗苹果），并将其放置在立方体上方的容器中。最后一段视频展示了猕猴在该任务中的注视反应示例。