Nonadditive integration of visual information in ensemble processing

Neural responses to global and local visual information processing provide neural signatures of ADHD symptoms

Individuals with ADHD are thought to exhibit a reduced "global bias" in perceptual processing. This bias, found in typically developed individuals, characterizes the tendency to prioritize global over local information processing. However, the relationship between specific ADHD symptoms and global or local processing remains unclear. This study addresses this gap by employing an ensemble perception task with a large sample (N = 465). EEG recordings allowed for the isolation of neural responses to individual and global stimuli using linear regression modeling. The adult ADHD self-report scale was used to assess ADHD symptoms. The results showed a significant association between ensemble perception and early responses to global stimuli. Furthermore, inattention symptoms were associated with early responses to global stimuli, suggesting a reduced global prioritization in individuals with higher inattention scores. Moreover, inattention symptom was associated with later responses to local stimuli, as shown by attenuated neural responses to local stimuli in individuals with more severe symptoms. These findings provide insights that ADHD includes deficits in both global and local processing, challenging earlier theories that focused solely on global processing impairments.

Pupil responds spontaneously to visuospatial regularity

Beyond the light reflex, the pupil responds to various high-level cognitive processes. Multiple statistical regularities of stimuli have been found to modulate the pupillary response. However, most studies have used auditory or visual temporal sequences as stimuli, and it is unknown whether the pupil size is modulated by statistical regularity in the spatial arrangement of stimuli. In three experiments, we created perceived regular and irregular stimuli, matching physical regularity, to investigate the effect of spatial regularity on pupillary responses during passive viewing. Experiments using orientation (Experiments 1 and 2) and size (Experiment 3) as stimuli consistently showed that perceived irregular stimuli elicited more pupil constriction than regular stimuli. Furthermore, this effect was independent of the luminance of the stimuli. In conclusion, our study revealed that the pupil responds spontaneously to perceived visuospatial regularity, extending the stimulus regularity that influences the pupillary response into the visuospatial domain.

Perception of visual variance is mediated by subcortical mechanisms

Variance characterizes the structure of the environment. This statistical concept plays a critical role in evaluating the reliability of evidence for human decision-making. The present study examined the involvement of subcortical structures in the processing of visual variance. To this end, we used a stereoscope to sequentially present two circle arrays in a dichoptic or monocular fashion while participants compared the perceived variance of the two arrays. In Experiment 1, two arrays were presented monocularly to the same eye, dichopticly to different eyes, or binocularly to both eyes. The variance judgment was less accurate in different-eye condition than the other conditions. In Experiment 2, the first circle array was split into a large-variance and a small-variance set, with either the large-variance or small-variance set preceding the presentation of the second circle array in the same eye. The variance of the first array was judged larger when the second array was preceded by the large-variance set in the same eye, showing that the perception of variance was modulated by the visual variance processed in the same eye. Taken together, these findings provide evidence for monocular processing of visual variance, suggesting that subcortical structures capture the statistical structure of the visual world.