Roles of familiarity and novelty in visual preference judgments are segregated across object categories

Understanding preference decision making is a challenging problem because the underlying process is often implicit and dependent on context, including past experience. There is evidence for both familiarity and novelty as critical factors for preference in adults and infants. To resolve this puzzling contradiction, we examined the cumulative effects of visual exposure in different object categories, including faces, natural scenes, and geometric figures, in a two-alternative preference task. The results show a clear segregation of preference across object categories, with familiarity preference dominant in faces and novelty preference dominant in natural scenes. No strong bias was observed in geometric figures. The effects were replicated even when images were converted to line drawings, inverted, or presented only briefly, and also when spatial frequency and contour distribution were controlled. The effects of exposure were reset by a blank of 1 wk or 3 wk. Thus, the category-specific segregation of familiarity and novelty preferences is based on quick visual categorization and cannot be caused by the difference in low-level visual features between object categories. Instead, it could be due either to different biological significances/attractiveness criteria across these categories, or to some other factors, such as differences in within-category variance and adaptive tuning of the perceptual system

Interrupting the cascade: Orienting contributes to decision making even in the absence of visual stimulation

Most systematic studies of human decision making approach the subject from a cost analysis point of view and assume that people make the highest utility choice. Very few articles investigate subjective decision making, such as that involving preference, although such decisions are very important for our daily functioning. We have argued (Shimojo, Simion, Shimojo, & Scheier, 2003) that an orienting bias effectively leads to the preference decision by means of a positive feedback loop involving mere exposure and preferential looking. The illustration of this process is a continually increasing gaze bias toward the eventual choice, which we call the gaze cascade effect. In the present study, we interrupt the natural process of preference selection, but we show that gaze behavior does not change even when the stimuli are removed from observers’ visual field. This demonstrates that once started, the involvement of orienting in decision making cannot be stopped and that orienting acts independently of the presence of visual stimuli. We also show that the cascade effect is intrinsically linked to the decision itself and is not triggered simply by a tendency to look at preferred targets

Signal strength determines the nature of the relationship between perception and working memory

Neurophysiological and behavioral studies have shown that perception and memory share neural substrates and functional properties. But are perception and the active working memory of a stimulus one and the same? To address this question in the spatial domain, we compared the percept and the working memory of the position of a target stimulus embedded within a surround of moving dots. Motion in a particular direction after the target's offset biased the memory of target location in the same direction. However, motion simultaneous with a high-contrast, perceptually strong target biased the percept of target location in the opposite direction. Thus, perception and working memory can be modified by motion in qualitatively different ways. Manipulations to strengthen the memory trace had no effect on the direction of the memory bias, indicating that memory signal strength can never equal that of the percept of a strong stimulus. However, the percept of a weak stimulus was biased in the direction of motion. Thus, although perception and working memory are not inherently different, they can differ behaviorally depending on the strength of the perceptual signal. Understanding how a changing surround biases neural representations in general, and postsensory processes in particular, can help one understand past reports of spatial mislocalization

Postdiction: its implications on visual awareness, hindsight, and sense of agency

There are a few postdictive perceptual phenomena known, in which a stimulus presented later seems causally to affect the percept of another stimulus presented earlier. While backward masking provides a classical example, the flash lag effect stimulates theorists with a variety of intriguing findings. The TMS-triggered scotoma together with “backward filling-in” of it offer a unique neuroscientific case. Findings suggest that various visual attributes are reorganized in a postdictive fashion to be consistent with each other, or to be consistent in a causality framework. In terms of the underlying mechanisms, four prototypical models have been considered: the “catch up,” the “reentry,” the “different pathway” and the “memory revision” models. By extending the list of postdictive phenomena to memory, sensory-motor and higher-level cognition, one may note that such a postdictive reconstruction may be a general principle of neural computation, ranging from milliseconds to months in a time scale, from local neuronal interactions to long-range connectivity, in the complex brain. The operational definition of the “postdictive phenomenon” can be applicable to such a wide range of sensory/cognitive effects across a wide range of time scale, even though the underlying neural mechanisms may vary across them. This has significant implications in interpreting “free will” and “sense of agency” in functional, psychophysical and neuroscientific terms

Behavioral and neural correlates of visual preference decision

Three sets of findings are reported here, all related to behavioral and neural correlates of preference decision. First, when one is engaged in a preference decision task with free observation, one's gaze is biased towards the to-be-chosen stimulus (eg. face) long before (s)he is consciously aware of the decision ("gaze cascade effect"). Second, an fMRI study suggested that implicit activity in a subcortical structure (the Nucleus Accumbens) precedes cognitive and conscious decision of preference. Finally, both novelty and familiarity causally contribute to attractiveness, but differently across object categories (such as faces and natural scenes). Taken together, these results point to dynamical and implicit processes both in short- and long-term, towards conscious preference decision. Finally, some discussion will be given on aesthetic decision (i.e. "beauty")

Implicit Processes are Dynamic and Interactive

Can the implicit level of mind execute only simple sensory/cognitive functions? And is the bottleneck to consciousness single, or multi-gated? These questions are elusive, especially considering examples such as implicit semantic priming, and implicit stroop effect (Hung talk in this symposium). I will aim for taxonomy and integration of related findings including my own, to have a clearer overview. First, there are multiple definitions of implicit processing on top of “subliminal”, as exemplified in causal misattribution in action (Wu talk), and attention vs. consciousness (Tsuchiya talk). Second, the implicit/ explicit distinction will NOT map onto the lower-/higher-levels of cognitive function (Hung talk). Rather, there are multiple gates to consciousness as indicated in the binocular rivalry debate (80s, up to now), and also quick interplays between implicit and explicit processes. Third, the implicit process may be dynamic spreading over time, operating predictively and postdictively. Auditory-visual “rabbit” effect would be a great example where implicit postdictive process leads to a conscious percept (Shimojo talk). The implicit process is also based on separate dynamic sampling frequencies. Some evidence comes from interpersonal bodily and neural synchrony (Shimojo talk), and dependence of perceptual changes upon allocation of attention relying on different temporal frequencies (Tsuchiya talk). Thus all together, we may need to abandon several simplistic ideas of implicit processes, and rather take a more dynamic and interactive view

Mirror Adaptation in Sensory-Motor Simultaneity

Background: When one watches a sports game, one may feel her/his own muscles moving in synchrony with the player's. Such parallels between observed actions of others and one's own has been well supported in the latest progress in neuroscience, and coined “mirror system.” It is likely that due to such phenomena, we are able to learn motor skills just by observing an expert's performance. Yet it is unknown whether such indirect learning occurs only at higher cognitive levels, or also at basic sensorimotor levels where sensorimotor delay is compensated and the timing of sensory feedback is constantly calibrated. Methodology/Principal Findings: Here, we show that the subject's passive observation of an actor manipulating a computer mouse with delayed auditory feedback led to shifts in subjective simultaneity of self mouse manipulation and auditory stimulus in the observing subjects. Likewise, self adaptation to the delayed feedback modulated the simultaneity judgment of the other subjects manipulating a mouse and an auditory stimulus. Meanwhile, subjective simultaneity of a simple visual disc and the auditory stimulus (flash test) was not affected by observation of an actor nor self-adaptation. Conclusions/Significance: The lack of shift in the flash test for both conditions indicates that the recalibration transfer is specific to the action domain, and is not due to a general sensory adaptation. This points to the involvement of a system for the temporal monitoring of actions, one that processes both one's own actions and those of others

Spatial contexts can inhibit a mislocalization of visual stimuli during smooth pursuit

The position of a flash presented during pursuit is mislocalized in the direction of the pursuit. Although this has been explained by a temporal mismatch between the slow visual processing of flash and fast efferent signals on eye positions, here we show that spatial contexts also play an important role in determining the flash position. We put various continuously lit objects (walls) between veridical and to-be-mislocalized positions of flash. Consequently, these walls significantly reduced the mislocalization of flash, preventing the flash from being mislocalized beyond the wall (Experiment 1). When the wall was shortened or had a hole in its center, the shape of the mislocalized flash was vertically shortened as if cutoff or funneled by the wall (Experiment 2). The wall also induced color interactions; a red wall made a green flash appear yellowish if it was in the path of mislocalization (Experiment 3). Finally, those flash–wall interactions could be induced even when the walls were presented after the disappearance of flash (Experiment 4). These results indicate that various features (position, shape, and color) of flash during pursuit are determined with an integration window that is spatially and temporally broad, providing a new insight for generating mechanisms of eye-movement mislocalizations