When Imagining Yourself in Pain, Visual Perspective Matters : The Neural and Behavioral Correlates of Simulated Sensory Experiences

© 2015 Massachusetts Institute of TechnologyPeer reviewedPublisher PD

Pupil Dilation Dynamics Track Attention to High-Level Information

It has long been thought that the eyes index the inner workings of the mind. Consistent with this intuition, empirical research has demonstrated that pupils dilate as a consequence of attentional effort. Recently, Smallwood et al. (2011) demonstrated that pupil dilations not only provide an index of overall attentional effort, but are time-locked to stimulus changes during attention (but not during mind-wandering). This finding suggests that pupil dilations afford a dynamic readout of conscious information processing. However, because stimulus onsets in their study involved shifts in luminance as well as information, they could not determine whether this coupling of stimulus and pupillary dynamics reflected attention to low-level (luminance) or high-level (information) changes. Here, we replicated the methodology and findings of Smallwood et al. (2011) while controlling for luminance changes. When presented with isoluminant digit sequences, participants\u27 pupillary dilations were synchronized with stimulus onsets when attending, but not when mind-wandering. This replicates Smallwood et al. (2011) and clarifies their finding by demonstrating that stimulus-pupil coupling reflects online cognitive processing beyond sensory gain

Mind Perception: Real but Not Artificial Faces Sustain Neural Activity beyond the N170/VPP

Faces are visual objects that hold special significance as the icons of other minds. Previous researchers using event-related potentials (ERPs) have found that faces are uniquely associated with an increased N170/vertex positive potential (VPP) and a more sustained frontal positivity. Here, we examined the processing of faces as objects vs. faces as cues to minds by contrasting images of faces possessing minds (human faces), faces lacking minds (doll faces), and non-face objects (i.e., clocks). Although both doll and human faces were associated with an increased N170/VPP from 175–200 ms following stimulus onset, only human faces were associated with a sustained positivity beyond 400 ms. Our data suggest that the N170/VPP reflects the object-based processing of faces, whether of dolls or humans; on the other hand, the later positivity appears to uniquely index the processing of human faces—which are more salient and convey information about identity and the presence of other minds

Attentional pulse strengths of non-probe stimuli differ as a function of attention.

<p>Wierda and colleagues' automated pupil dilation deconvolution algorithm <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0102463#pone.0102463-Wierda1" target="_blank">[36]</a> was used to derive the attentional pulse strengths associated with non-probe stimuli in WM and CR conditions. This attentional pulse was significantly stronger in the WM condition (<i>M1</i> = .254, <i>SD1</i> = .28) than in the CR condition (<i>M2</i> = .064, <i>SD2</i> = .11), <i>t</i>(15) = 2.333, <i>p</i> = .03. The deconvolved pupillary responses to non-probes are displayed above, with error bars indicating one standard error of the mean.</p

A schematic of experimental tasks used in Smallwood et al. [25] and the current paradigm.

<p>The current paradigm conducted an isoluminant replication of the design used in Smallwood et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0102463#pone.0102463-Smallwood1" target="_blank">[25]</a>. Participants completed both Choice Reaction and Working Memory tasks. In both conditions, they viewed and sporadically assessed the parity of numbers presented on the computer monitor. The Choice Reaction task only demanded attention to colored numbers; the Working Memory condition demanded attention to all presented numbers.</p

Effects of attention on visual experience during monocular rivalry

AbstractThere is a long-running debate over the extent to which volitional attention can modulate the appearance of visual stimuli. Here we use monocular rivalry between afterimages to explore the effects of attention on the contents of visual experience. In three experiments, we demonstrate that attended afterimages are seen for longer periods, on average, than unattended afterimages. This occurs both when a feature of the afterimage is attended directly and when a frame surrounding the afterimage is attended. The results of these experiments show that volitional attention can dramatically influence the contents of visual experience