Fig. 1: Experimental task.
From: Emotions and individual differences shape human foraging under threat
a, In the task, participants could freely choose to forage (a(i)) to gain points, check for predator threats (a(ii)) or hide (a(iii)) from threat. Predators (differing in three levels of approach speed) appeared at a randomized location at the edge of the game area after a variable delay and moved toward the fish until either catching it or retreating. When arriving in the center, the predator caught the fish if it was not hidden. Being caught decreased participants’ life counter by one. b, Study outline. The task comprised 20 blocks of 90 s varying in the type of predator (slow, medium or fast) and the number of check areas (one to four). Within a block, there were several predator epochs (see c for example), which varied in average reward rate. Between blocks, participants used sliding scales to rate their level of excitement and stress during the previous block. c, Epochs lasted from the disappearance of the previous predator (or the beginning of a block) until the arrival of a predator in the center of the screen. In red are highlighted some aggregate behavioral measures that we computed (Supplementary Table 5). d,e, The data were analyzed using different types of regression models: using behavioral measures averaged across epochs (d(i)) or blocks (d(ii)–d(iv)) or using non-averaged (that is ‘single’) choices (e). Taking advantage of the interleaved nature of mood ratings and task blocks, we could establish directionality in the impacts of the task on mood (d(ii)), of mood on behavior (d(iii)) and of behavior on mood (d(iv)).
