Object pose: perceiving 3-d shape as sticks and slabs

Estimating the pose (three-dimensional orientation) of objects is an important aspect of 3-D shape perception. We studied the ability of observers to match the pose of the principal axes of an object with the pose of a cross consisting of three perpendicular axes. For objects, we used a long and a flat spheroid and eight symmetric objects with aspect ratios of dimensions of approximately 4:2:1. Stimulus cues were the contour and stereo for the spheroids, and contour, stereo, and shading for the symmetric objects. In addition, the spheroids were shown with or without surface texture and with or without active motion. Results show that observers can perform the task with standard deviations of a few degrees, though biases could be as large as 30 degrees. The results can be naturally decomposed in viewer-centered coordinates, and it turns out that the estimation of orientation in the frontoparallel plane (tilt) is more precise than estimation of orientation in depth (slant, roll). A comparison of long and flat spheroids shows that sticks lead to better performance than do slabs. This can even be the case within the same object; the pose of the stick-like aspect is seen with more precision than is the pose of the slab-like aspect. The largest biases occurred when the spheroids were displayed with the binocular contour as the only cue. We can explain these biases by assuming that subjects' settings are influenced by the orientation of the rim.     

Parsing silhouettes: the short-cut rule.

Many researchers have proposed that, for the purpose of recognition, human vision parses shapes into component parts. Precisely how is not yet known. The minima rule for silhouettes (Hoffman & Richards, 1984) defines boundary points at which to parse but does not tell how to use these points to cut silhouettes and, therefore, does not tell what the parts are. In this paper, we propose the short-cut rule, which states that, other things being equal, human vision prefers to use the shortest possible cuts to parse silhouettes. We motivate this rule, and the well-known Petter's rule for modal completion, by the principle of transversality. We present five psychophysical experiments that test the short-cut rule, show that it successfully predicts part cuts that connect boundary points given by the minima rule, and show that it can also create new boundary points.     

烧香皈太上 稽首礼虚皇——谈谈道教的烧香与磕头

礼虚皇”,词作得很文雅,其实说白了,这两句话说的就是“烧香磕头”而己。记得我刚出家之时,有好长一段时间对这“小事”有点“不屑一顾”,好像有点感觉那是俗家人为了求这求那才去干的,出家人身超物外,心香奉神,没必要做这些形式。当时恩师已年逾八旬,每天早上起来必定到每个殿堂每位祖师像前焚香跪拜,一年下来从不间断。我那时也就在一旁陪着、看着。四年前恩师羽化登真了,出于对他老人家的怀念,我也学着每天早上去烧香磕头。渐渐地,却让我悟出少许道理来,别看烧香磕头是小事,这里面的学问还大着哩。懂得这些学问,对于我们修行是大有帮助的…     

Seeing through eyes,mirrors, shadows and pictures

I argue that we can see in a great many cases that run counter to common sense. We can literally see through mirrors, in just the same way that we (literally) see through our eyes. We can, likewise, literally see through photographs, shadows, and (some) paintings. Rather than starting with an analysis of seeing, I present a series of evolving thought experiments, arguing that in each case there is no relevant difference between it and the previous case regarding whether we see. In a sense, my arguments can be thought of as akin to the Extended Mind Hypothesis (Clark and Chalmers 1998). But instead of arguing that our minds can extend into the world, I argue that our sensory organs can extend into the world. Among the things that emerge from this discussion are (1) that—contrary to Currie (1995) and Carroll (1996)—seeing an object O doesn’t require being able to locate O with respect to yourself, (2) that—contrary to Sorensen (2008)—we can see objects by seeing their shadows, and (3) that—contrary to Walton (1984)—it doesn’t matter whether the causal relation between O and yourself is mediated by beliefs.     

Seeing black: race, crime, and visual processing

Using police officers and undergraduates as participants, the authors investigated the influence of stereotypic associations on visual processing in 5 studies. Study 1 demonstrates that Black faces influence participants' ability to spontaneously detect degraded images of crime-relevant objects. Conversely, Studies 2-4 demonstrate that activating abstract concepts (i.e., crime and basketball) induces attentional biases toward Black male faces. Moreover, these processing biases may be related to the degree to which a social group member is physically representative of the social group (Studies 4-5). These studies, taken together, suggest that some associations between social groups and concepts are bidirectional and operate as visual tuning devices--producing shifts in perception and attention of a sort likely to influence decision making and behavior.     

Understanding and Simple Seeing in Husserl

Husserl’s Logical Investigations has undergone explicitly conceptualist and non-conceptualist interpretations. For Richard Cobb-Stevens, he has extended understanding into the domain of sensuous intuition, leaving no simple perceptions that are actually separated from higher-level understanding. According to Kevin Mulligan, Husserl does in fact sunder nominal and propositional seeing from the simple or straightforward—and yet interpretative—seeing of particulars. To see simply is not to exercise an individual meaning or a general concept. Arguing that Logical Investigations provides evidence for both views, I endeavour to show that the account of perceptual consciousness in Husserl’s subsequent work is far more clear and consistent. It is one of growing beyond the situation portrayed by Mulligan and into the one explicated by Cobb-Stevens. Though they are notionally separable, pre-conceptual syntheses at the passive and noematic levels are inevitably interwoven with conceptual and categorial articulations in a developed consciousness.     

Seeing by Feeling: Virtues,Skills, and Moral Perception

Champions of virtue ethics frequently appeal to moral perception: the notion that virtuous people can “see” what to do. According to a traditional account of virtue, the cultivation of proper feeling through imitation and habituation issues in a sensitivity to reasons to act. Thus, we learn to see what to do by coming to feel the demands of courage, kindness, and the like. But virtue ethics also claims superiority over other theories that adopt a perceptual moral epistemology, such as intuitionism – which John McDowell criticizes for illicitly “borrow[ing] the epistemological credentials” of perception. In this paper, I suggest that the most promising way for virtue ethics to use perceptual metaphors innocuously is by adopting a skill model of virtue, on which the virtues are modeled on forms of practical know-how. Yet I contend that this model is double-edged for virtue ethics. The skill model belies some central ambitions and dogmas of the traditional view, especially its most idealized claims about virtue and the virtuous. While this may be a cost that its champions are unprepared to pay, I suggest that virtue ethics would do well to embrace a more realistic moral psychology and a correspondingly less sublime conception of virtue.     

Seeing, acting, understanding: motor resonance in language comprehension

Observing actions and understanding sentences about actions activates corresponding motor processes in the observer-comprehender. In 5 experiments, the authors addressed 2 novel questions regarding language-based motor resonance. The 1st question asks whether visual motion that is associated with an action produces motor resonance in sentence comprehension. The 2nd question asks whether motor resonance is modulated during sentence comprehension. The authors' experiments provide an affirmative response to both questions. A rotating visual stimulus affects both actual manual rotation and the comprehension of manual rotation sentences. Motor resonance is modulated by the linguistic input and is a rather immediate and localized phenomenon. The results are discussed in the context of theories of action observation and mental simulation.     

Seeing mind in action

Much recent work on social cognition and empathy in philosophy of mind and cognitive science has been guided by the assumption that minds are composed of intracranial phenomena, perceptually inaccessible and thus unobservable to everyone but their owners. I challenge this claim. I defend the view that at least some mental states and processes??or at least some parts of some mental states and processes??are at times visible, capable of being directly perceived by others. I further argue that, despite its initial implausibility, this view receives robust support from several strands of empirical research.