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Peripherally located objects are often perceived to be smaller than centrally located objects. This perceptual phenomenon, known as the Size-Eccentricity Effect (SEE), is mainly due to the structural properties of the visual system and is further modulated by covert attention. In this study, we evaluated whether pre-saccadic attention could also compensate for this effect. Participants performed a judgment task where they compared a test disk of varying size, briefly presented in peripheral vision, to a reference disk appearing 450 ms later in foveal vision. When no saccade was made toward the location of the test disk, the SEE was observed. However, when participants initiated saccades about 200 ms after the test disk extinction, points of subjective equality were close to objective equality. The second experiment aimed at excluding an explanation involving non-specific arousal mechanisms, also known to enhance visual perception. Participants executed a keypress or an antisaccade instead of a saccade. The size-eccentricity disappeared only in the saccade condition, confirming the crucial role of pre-saccadic attention shifts in this SEE compensation. Therefore, pre-saccadic attention improves not only the processing of orientation, contrast and spatial frequency (as previously demonstrated), but also the processing of peripheral object size.

Voluntary actions, such as pressing a button, can affect the loudness of the sounds produced. To date, the role of intentional motor-sensory coupling and the involvement of more general prediction mechanisms remain unclear. Asking participants to make ocular saccades (which do not naturally produce sounds: weak coupling) instead of pressing a button (which frequently produces sounds: strong coupling) allowed us to investigate this question. Two independent groups of participants performed either a saccade task (N=42) or a keypress task (N=43). In a short movement-sound delay condition, a tone of variable intensity was presented 150 ms after movement onset. In a long delay condition, the tone was presented 1500 ms after movement onset, in order to dissociate it from possible motor-based effects. We also manipulated motor-sensory coupling within each task by presenting the tones after every movement in one subgroup, whereas in another subgroup, tones were delivered randomly after 50% of the movements. A reference tone was presented 800-1200 ms after the variable tone, and participants indicated which of the two tones was louder. The only significant effect we observed on the psychometric functions was a larger JND in the 150-ms delay condition of the saccade task compared to all other experimental conditions. We found no significant effects of the movement-tone contingency. A reinforcement learning model was then used to compute a prediction error regarding tone occurrence for each trial (in the 50% movement-tone contingency). Prediction error affected the judgment of saccade generated tones (GLMM analysis, p = .005), but not the judgment of keypress generated tones (p = .285). These results suggest that motor-based effects on the perception of self-generated tones depend critically on the strength of the previously learned association between a movement and the sound it produces. This may explain the inconsistent results found in the literature.

Peripherally located objects are often perceived to be smaller than centrally located objects. This perceptual phenomenon, known as the Size-Eccentricity Effect (SEE), is mainly due to the structural properties of the visual system and is further modulated by covert attention. In this study, we evaluated whether pre-saccadic attention could also compensate for this effect. Participants performed a judgment task where they compared a test disk of varying size, briefly presented in peripheral vision, to a reference disk appearing 450 ms later in foveal vision. When no saccade was made towards the location of the test disk, the SEE was observed. However, when participants initiated saccades about 200 ms after the test disk extinction, points of subjective equality were close to objective equality. The second experiment aimed at excluding an explanation involving non-specific arousal mechanisms, also known to enhance visual perception. Participants executed a keypress or an antisaccade instead of a saccade. The SEE disappeared only in the saccade condition, confirming the crucial role of pre-saccadic attention shifts in this SEE compensation. Therefore, pre-saccadic attention improves not only the processing of orientation, contrast and spatial frequency (as previously demonstrated), but also the processing of peripheral object size.

The concealed information test (CIT) aims at identifying knowledge that a person wants to hide, by measuring physiological indices during the presentation of known versus unknown items. Recently, Lancry-Dayan et al. ( Journal of Applied Research in Memory and Cognition , 7 (2), 291–302, 2018) proposed a new version of this test that included a short-term memory task to maximize differences between responses to items. Participants were asked to memorize four pictures of faces that included one face of an acquaintance. The authors observed that participants looked at the familiar face during the first second and then tended to avoid it. This specific orientation-avoidance pattern occurred even in participants instructed to conceal their familiarity with the known faces (in a spontaneous or a guided manner). In a first experiment, we reproduced Lancry-Dayan et al.’s (2018) study using photos of famous faces. The pattern found by Lancry-Dayan et al. was observed in participants asked to perform the memory task only, participants asked to conceal their familiarity with the famous faces, and participants of a countermeasure group. In a second experiment, we tested the robustness of Lancry-Dayan et al.'s countermeasure. We modified the instructions by emphasizing the oculomotor task or giving feedback. While between-group differences in gaze-pattern appeared after feedback was provided, classification analyses were still able to distinguish between familiar and unfamiliar faces accurately, which revealed the good resistance of this new CIT protocol to countermeasures.