370 research outputs found
Nakayama, Shimojo, and Ramachandran’s 1990 paper
No full textThe target paper reviewed in this article was titled "Transparency: relation to depth, subjective contours, luminance, and neon colour spreading" coauthored by K Nakayama, S Shimojo, and V S Ramachandran, published in 1990. This paper, one of the first in a series on surface perception, examined how in untextured stereograms, local disparity and luminance contrast can drastically change surface quality, subjective contours, and the effect of neon colour spreading. When we began to conceive this and related work, the ascendant view on visual perception was derived from the pioneering studies of the response properties of visual neurons with microelectrodes, including those of Barlow (1953), Lettvin et al (1959), and Hubel and Wiesel (1959, 1962). All suggested that there are remarkable operations on the image by earliest stages of the visual pathway, which bestowed selectivity to colour, orientation, motion direction, spatial frequency, binocular disparity, etc. As such, it would seem that an understanding of vision would come through more systematic description of the properties of single neuron selectivities. This viewpoint was well summarised by Horace Barlow in his famous neuron doctrine paper (Barlow 1972), which emphasised the importance of analysing the image in successive stages of processing by neurons with specific classes of receptive fields. Later work altered this conception somewhat by seeing receptive fields as linear filters. Rather than detecting the presence of edges, bars, or otherwise perceptually identifiable elements in a scene, cells were seen as making measurements of an image. It was an 'image based' approach to vision, treating the basic operations of vision with no particular regard as to what aspects of scenes were being coded, whether a given cell's response corresponded to something about surfaces, edges, or objects in the real world
Interrupting the cascade: Orienting contributes to decision making even in the absence of visual stimulation
Get PDFMost 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
Response to H.C. Howland, “Orbital orientation is not visual orientation”
No full textWe have hypothesized that the size of the binocular field among mammals has been selected to maximize the visually surveyable region around the animal (Changizi and Shimojo, 2008). At first glance it may seem that this hypothesis should always predict lateral pointing eyes, and a consequently small binocular field width. However, the hypothesis does not predict lateral pointing eyes in cases where the environment is filled with leafy occlusions and the animal's interpupillary distance surpasses the typical widths of the leaves (when both of these apply, we call the environment “cluttered”). In such cases, within an animal's binocular region the eyes tend to sample the scene independently. Laterally directed eyes also sample the scene independently, but the binocular region benefits from a variety of binocular summation, lowering the threshold for the recognition of objects in the binocular field. Our hypothesis predicts that mammals outside of leafy environments should have small binocular fields, independent of the size of the animal; but it predicts that for animals in leafy environments, whereas small animals should have small binocular fields (because their interpupillary distance is small compared to the typical occlusion width), large animals should have large binocular fields (because the binocular region begins to become more powerful at object recognition). Our paper provided evidence consistent with these predictions
深層学習を用いたパレイドリア誘発刺激の系統的な生成に関する研究
Get PDF岩手大学博士（工学）原著論文
Systematic Face Pareidolia Generation Method using Cycle-Consistent Adversarial Networks, Yoshitaka Endo, Rinka Asanuma, Shinsuke Shimojo, Takuya Akashi, IEEJ Transactions on Electrical and Electronic Engineering 19 (4), 535-541, 2024doctoral thesi
Novelty vs. familiarity principles in preference decisions: Task-context of past experience matters
No full textOur preferences are shaped by past experience in many ways, but a systematic understanding of the factors is yet to be achieved. For example, studies of the mere exposure effect show that experience with an item leads to increased liking (familiarity preference), but the exact opposite tendency is found in other studies utilizing dishabituation (novelty preference). Recently, it has been found that image category affects whether familiarity or novelty preference emerges from repeated stimulus exposure (Park, Shimojo, and Shimojo, PNAS 2010). Faces elicited familiarity preference, but natural scenes elicited novelty preference. In their task, preference judgments were made throughout all exposures, raising the question of whether the task-context during exposure was involved. We adapt their paradigm, testing if passive exposure or objective judgment task-contexts lead to different results. Results showed that after passive viewing, familiar faces were preferred, but no preference bias in either direction was found with natural scenes, or with geometric figures (control). After exposure during the objective judgment task, familiar faces were preferred, novel natural scenes were preferred, and no preference bias was found with geometric figures. The overall results replicate the segregation of preference biases across object categories and suggest that the preference for familiar faces and novel natural scenes are modulated by task-context memory at different processing levels or selection involvement. Possible underlying mechanisms of the two types of preferences are discussed
Behavioral and neural correlates of visual preference decision
Get PDFThree 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")
Correspondence should be addressed to R.K.
No full textWhen our visual system is confronted with ambiguous stimuli, the perceptual interpretation spontaneously alternates between the competing incompatible interpretations. The timing of such perceptual alternations is highly stochastic and the underlying neural mechanisms are poorly understood. Here, we show that perceptual alternations can be triggered by a transient stimulus presented nearby. The induction was tested for four types of bistable stimuli: structure-from-motion, binocular rivalry, Necker cube, and ambiguous apparent motion. While underlying mechanisms may vary among them, a transient flash induced time-locked perceptual alternations in all cases. The effect showed a clear dependency on the adaptation to the dominant percept prior to the presentation of a flash. These perceptual alternations show many similarities to perceptual disappearances induced by transient stimuli (Kanai & Kamitani, 2003, Moradi & Shimojo, 2004). Mechanisms linking these two transient induced phenomena are discussed. 2 1
Mind reading: Discovering individual preferences from eye movements using switching hidden Markov models
No full textHere we used a hidden Markov model (HMM) based approach to infer individual choices from eye movements in preference decision-making. We assumed that during a decision making process, participants may switch between exploration and decision-making periods, and this behavior can be better captured with a Switching HMM (SHMM). Through clustering individual eye movement patterns described in SHMMs, we automatically discovered two groups of participants with different decision making behavior. One group showed a strong and early bias to look more often at the to-be chosen stimulus (i.e., the gaze cascade effect; Shimojo et al., 2003) with a short final decision-making period. The other group showed a weaker cascade effect with a longer final decision-making period. The SHMMs also showed capable of inferring participants' preference choice on each trial with high accuracy. Thus, our SHMM approach made it possible to reveal individual differences in decision making and discover individual preferences from eye movement data.</p
Postdiction : Its implications on visual awareness, hindsight, and sense of agency
Get PDFThere are a few postdictive perceptual phenomena known, in which a stimulus presented later seems to causally affect 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, and the TMS-triggered scotoma and its filling-in 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 underlying mechanisms, three prototypical models have been considered: the catch up, the reentry and the different pathway models. By extending the list of postdictive phenomena to memory, sensory-motor and higher-level cognition, one may note that such postdictive reconstruction may be a general principle of neural computation, ranged from milliseconds to months of time scale, from local neuronal interactions to long-range connectivity, in the complex brain. It has significant implications in interpreting free will and sense of agency in functional, psychophysical and neuroscientific terms
Recommended from our members
Mind reading: discovering individual preferences from eye movements using switching hidden Markov models
Get PDFHere we used a hidden Markov model (HMM) based approach to infer individual choices from eye movements in preference decision-making. We assumed that during a decision making process, participants may switch between exploration and decision-making periods, and this behavior can be better captured with a Switching HMM (SHMM). Through clustering individual eye movement patterns described in SHMMs, we automatically discovered two groups of participants with different decision making behavior. One group showed a strong and early bias to look more often at the to-be chosen stimulus (i.e., the gaze cascade effect; Shimojo et al., 2003) with a short final decision-making period. The other group showed a weaker cascade effect with a longer final decision- making period. The SHMMs also showed capable of inferring participants’ preference choice on each trial with high accuracy. Thus, our SHMM approach made it possible to reveal individual differences in decision making and discover individual preferences from eye movement data.postprin
- …
