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A conspiracy theory is defined as the conviction that a group of actors secretly meets for a malevolent purpose. Based on the conceptual overlap between cheating and conspiracy (both involving intentional and deceptive behaviors), Aubert-Teillaud and Vaidis (2024) redefined conspiracy as the coordinated action of several cheaters. Drawing on error management theory (an adaptive extension of signal detection theory), they argue that certain social cues from social environment (e.g. past cheating, power asymmetry, etc) may modulate the probability of detecting cheaters, either by influencing perceptual sensitivity or by affecting the decision bias, thereby producing conspiracy inferences. According to their model, a liberal decision bias strongly oriented towards false positives is likely to generate more conspiracy theories than it really exists. However, this theoretical model has not yet been tested empirically. The present study aims to experimentally examine the relationship between cheating detection bias and correlates of conspiracist thinking. In a face discrimination task and after a memorization phase (to prevent stereotype expression), participants will identify morphed faces as ”cheaters” or ”non-cheaters”. We will manipulate the decision bias through asymmetric monetary incentives depending on error types (e.g. a bonus for hits and correct rejections, a malus for misses and false alarms). We will then assess established proxies of conspiracist thinking: the Snowy Pictures Task (illusory pattern perception) and causal interpretation of spurious correlations. We will examine whether inducing a liberal decision bias would increase correlates of conspiracist thinking, while a conservative bias would decrease them.

Preparing an eye movement is known to enhance perception at its goal location, improving the processing of target features such as orientation, contrast, and spatial resolution. In previous work (Laaboudi et al., 2025), we demonstrated that preparing an ocular saccade (a rapid eye movement) can also reduce our natural tendency to underestimate the size of objects seen in peripheral vision. We observed this improvement in size perception about 200 ms after the peripheral object’s disappearance, and before the eyes moved. In the present study, we investigated the temporal dynamics of this size perception enhancement. Fifteen participants compared a briefly presented peripheral disk of variable size with a reference disk shown at the saccade landing position. By manipulating the timing of an auditory go signal, we varied the delay between stimulus offset and saccade onset from 50 to 550 ms. Size estimation of the peripheral disk was estimated for five temporal bins. In separate fixation trials, we assessed peripheral size perception without saccade preparation. Peripheral size underestimation was reliably reduced when participants prepared and executed a saccade compared to when they maintained fixation. However, this improvement did not depend on the timing of the saccade onset. These surprising results cannot be explained by pre-saccadic attention alone (known to increase progressively from 150 ms onwards before the saccade is made) and should be clarified by further research. To this aim, a followup study (for which preliminary data may also be presented) compares voluntary and stimulusdriven attentional mechanisms.

Across the lifespan, we learn associations between our actions and their sensory consequences. Such sensorimotor couplings are considered as strong when they are overlearned (e.g., keypress → tone) and weak when they are novel (e.g., ocular saccade → tone). These couplings may affect perception differently. Indeed, we recently observed (Paire et al., 2025) that keypress-generated tones were perceived as less intense than passively presented tones, replicating the classical sensory attenuation effect. In contrast, perceptual responses to saccade-generated tones depended on tone expectancy (estimated through prediction errors derived from a reinforcement learning model). These findings are consistent with the hybrid prediction model proposed by Dogge et al. (2019), which states that sensorimotor predictions derived from motor-based forward models dominate under overlearned coupling, whereas general predictive mechanisms may operate under weak coupling. However, in our 2025 study, the strength of action-outcome coupling was not directly manipulated. The present study aims at testing this model by progressively strengthening an initially novel association between saccades and tones across four daily sessions. The perceived intensity of tones following saccades, keypresses or cues (without action) are compared, as well as the influence of tone expectancy. A key prediction of Dogge et al.’s model is that, following training, perceptual responses to saccade-generated tones should resemble those to keypress-generated tones (i.e., presence of sensory attenuation and reduced influence of tone expectancy). Such results would suggest a transition between different predictive mechanisms in saccade-tone coupling. Preliminary results will be presented and discussed within the hybrid prediction framework.

Sensory attenuation refers to reduced neural and perceptual responses to self-generated tones compared to tones triggered externally. Our previous study showed that the strength of action-outcome coupling (SAOC) influences the perceptual biases for sound intensity. Indeed, we observed that the overall perceived intensity of tones triggered by keypresses (strong coupling) was attenuated, in contrast to tones triggered by ocular saccades (weak coupling). Building on this earlier study, we investigated the influence of SAOC on perceptual attenuation for auditory pitch. Indeed, to date, no behavioral study has demonstrated any sensory attenuation effect regarding pitch perception, although it has been suggested that attenuation may manifest in this case as a change in the ability to perceive pitch differences (discrimination sensitivity). A total of 140 participants were divided into three groups. They performed a pitch discrimination task in which test tones of varying frequency were triggered either by an ocular saccade, a keypress, or played after a cue (no action required, or “passive” group). Test tones were presented 150 ms or 1500 ms after the action (or cue). Results revealed lower discrimination sensitivity in the keypress group compared to the passive group (Cohen's d = 0.66). In contrast, no significant difference was found between the saccade and passive groups. Also, in the keypress group only, we observed a small effect of delay (Cohen's d = 0.14), with reduced sensitivity at the shorter action-outcome interval. This reduced perceptual sensitivity for keypress-triggered tones may reflect sensory attenuation (sounds are more difficult to differentiate), possibly due to predictive mechanisms. Importantly, the absence of a significant difference between the saccade and passive groups, together with the small size of the delay effect, suggests that this reduction in sensitivity cannot be explained by dual-task interference alone. These results align with our previous findings suggesting that a strong action-outcome coupling is necessary to observe perceptual attenuation.

Preparing an eye movement is known to enhance visual perception at its goal location, improving the processing of several stimulus features. Previous findings indicate that saccade preparation also reduces the Size-Eccentricity Effect, i.e. the classic underestimation of object size in peripheral vision (Laaboudi et al., 2025). Importantly, this perceptual enhancement was observed about 200 ms before saccade onset, earlier than the typical time window reported for pre-saccadic enhancement. We therefore sought to clarify the temporal profile of this effect. In a first experiment, 15 participants compared a briefly presented peripheral disk with a reference disk shown at the saccade landing position. By manipulating the timing of an auditory go-signal, we varied the delay between stimulus offset and saccade onset from 50 to 550 ms. Separate fixation trials assessed peripheral size perception without saccade preparation. Replicating our previous findings, perceived size in the periphery was more accurate in saccade than in fixation trials. However, this perceptual enhancement did not depend on saccade timing. Because the effect remained stable, in a second experiment, we tested whether it reflected other, cue-driven attentional mechanisms. In particular, endogenous attention is generally more sustained over time than exogenous and pre-saccadic attention. To explore this, we extended our paradigm from a single peripheral location to four possible locations. In an exogenous condition, cues validly or invalidly indicated the test disk location with equal probability, whereas in an endogenous condition one location was favored (75%). Preliminary results revealed no reliable cueing effect, but a systematic perceptual enhancement associated with saccade preparation. Together, these findings indicate that the increase in peripheral perceived size is robust across a broader temporal window than expected for typical pre-saccadic enhancement and is more specifically linked to oculomotor preparation than to the covert cueing manipulations tested here.