Page 156 - Emotions through the eyes of our closest living relatives- Exploring attentional and behavioral mechanisms

Chapter 7
Figure 1. Block design of the PIAT. Here, the adult version of the PIAT is shown. Block 1 and 2 always consisted of trials in which participants had to categorize faces and positive and negative images (in random order). Block 3 is the first critical block in which concepts and attributes are combined. In Block 4, the position of the faces is reversed. Block 5 is the last critical block.
Practice blocks consisted of 20 trials, and critical blocks included 40 trials. Before the start of each trial, a “fixation” dot appeared in the lower-middle part of the screen, which had to be touched in order to start or continue the task (Figure 2A, I). The dot functioned as a fixation cross that directed the participants’ gaze and hand towards it, thereby preventing an attentional bias to the left or right side of the screen.
In the first practice block, participants learned to categorize images into superordinate categories (i.e., faces were categorized into the superordinate “Moroccan”and “Dutch”categories, each represented by one exemplar image of a man of Moroccan or Dutch descent). These concepts were presented on the top left and right side of the screen, while the images that had to be categorized were presented in the lower-middle part of the screen. Correct categories could be indicated by pressing on the exemplar image on the screen (Figure 2A, II), and feedback was given in the form of a thumbs-up or -down image2 (2s), indicating a correct or incorrect answer (Figure 2A, III). Next, a dot appeared that had to be touched to start the next trial (Figure 2A, IV-V). In the second practice block of the PIAT, participants again categorized images into two categories, but this time the images represented a positive or negative attribute dimension. In block three (the first critical block), the
2 Populations unfamiliar to this sign will in a separate learning phase need to learn that thumbs up means ‘good’ and down, ‘bad’. Alternatively, different culture-specific signs can be implemented instead.
154