Object and observer motion in the perception of objects by infants

Sixteen-week-old human infants distinguish optical displacements given by their own motion from displacements given by moving objects, and they use only the latter to perceive the unity of partly occluded objects. Optical changes produced by moving the observer around a stationary object produced attentional levels characteristic of stationary observers viewing stationary displays and much lower than those shown by stationary observers viewing moving displays. Real displacements of an object with no subject-relative displacement, produced by moving an object so as to maintain a constant relation to the moving observer, evoked attentional levels that were higher than with stationary displays and more characteristic of attention to moving displays, a finding suggesting detection of the real motion. Previously reported abilities of infants to perceive the unity of partly occluded objects from motion information were found to depend on real object motion rather than on optical displacements in general. The results suggest that object perception depends on registration of the motions of surfaces in the three-dimensional layout.     

BUCK-PASSING AND THE RIGHT KIND OF REASONS

The 'buck-passing' account equates the value of an object with the existence of reasons to favour it. As we argued in an earlier paper, this analysis faces the 'wrong kind of reasons' problem: there may be reasons for pro-attitudes towards worthless objects, in particular if it is the pro-attitudes, rather than their objects, that are valuable. Jonas Olson has recently suggested how to resolve this difficulty: a reason to favour an object is of the right kind only if its formulation does not involve any reference to the attitudes for which it provides a reason. We argue that despite its merits, Olson's solution is unsatisfactory. We go on to suggest that the buck-passing account might be acceptable even if the problem in question turns out to be insoluble.     

Self-sacrifice

The paper discusses the problem of self-sacrifice as posed by Derrida in Foi et Savior and by Schiller in the Theosophie des Julius. Whereas Derrida understands self-sacrifice as an act of violence against oneself in order not to subject others to violence, Schiller rightly insists that one must distinguish between egotistical and altruistic self-sacrifice. But even this doesn’t go far enough: Altruistic self-sacrifice is different from suffering death as the consequence of an entirely unselfish love. Whoever loses his life out of love does not give it up for others, whether selfishly or unselfishly. He loves the other—to death. Such a death is not a (self-)sacrifice. It results from a passion of love, not an act of violence against oneself.     

Kontexteffekte und Routenwissen

Knowledge about how to go from one location to another one is called route knowledge. The paper presents two experiments that examine how memories of objects along a route are activated. We tested especially for a context effect regarding memory performance. In two further experiments, the hypothesis was put to test whether the combined influence of cues is over-additive.     

Vagueness as a Modality

I present a modal conception of vagueness and vague objects, according to which a vague object is a transworld object which coincides with one precise object in one world and with another precise object in another world. Such worlds are called precisifications; they are modal, worldly counterparts of the precisifications postulated in supervaluationism. I criticize Evans' argument against vague objects, admitting the validity of the argument, but rejecting its basic assumption that if there are vague objects, certain identity statements must be indefinite in truth value. I distinguish identity from coincidence, and claim that if there are vague objects, some statements of coincidence will be indefinite in truth-value, not statements of identity. To establish this point, I compare vagueness with temporal modality.     

Shape from shading in pigeons

Light is the origin of vision. The pattern of shading reflected from object surfaces is one of several optical features that provide fundamental information about shape and surface orientation. To understand how surface and object shading is processed by birds, six pigeons were tested with differentially illuminated convex and concave curved surfaces in five experiments using a go/no-go procedure. We found that pigeons rapidly learned this type of visual discrimination independent of lighting direction, surface coloration and camera perspective. Subsequent experiments varying the pattern of the lighting on these surfaces through changes in camera perspective, surface height, contrast, material specularity, surface shape, light motion, and perspective movement were consistent with the hypothesis that the pigeons were perceiving these illuminated surfaces as three-dimensional surfaces containing curved shapes. The results suggest that the use of relative shading for objects in a visual scene creates highly salient features for shape processing in birds.     

Are there developmental differences in reality-monitoring?

The question addressed by the present experiment is whether the ability to distinguish between veridical and imaginal memory representations changes with age. Second-grade, fourth-grade, and sixth grade children (8, 10, and 12 years old) and college students were shown pictures of familiar objects. Each picture was presented one, two, or three times and, interspersed with these presentations, subjects were asked to imagine each picture zero, one, or three times. Subsequently they were asked to judge the presentation frequency of each picture. For all groups, imagining the pictures resulted in inflated estimates of event frequency. However, contrary to the idea that children have a particularly difficult time discriminating externally generated from internally generated memories, one analysis indicated adults were actually somewhat more affected than children by the imagination trials.     

Recognition memory for complex visual discriminations is influenced by stimulus interference in rodents with perirhinal cortex damage

Rats with perirhinal cortex (PRC), hippocampal, or sham lesions were trained on a successive discrimination go/no-go task to examine recognition memory for an array of visual objects with varying interference among the objects in the array. Rats were trained to recognize a target array consisting of four particular objects that could be presented in any one of four possible configurations to cover baited food wells. If the four target objects were presented, the rat should displace each object to receive food. However, if a novel object replaced any one or more of the target objects, then the rat should withhold its response. The number of novel objects presented on nonrewarded trials varied from one to four. The fewer the number of novel objects in the array, the more interference the array shared with the target array, therefore increasing task difficulty. An increased number of novel objects should result in less interference with the target array and decreased task difficulty. Although accuracy was slightly lower in rats with hippocampal lesions compared with controls, the learning of the groups was not statistically different. In contrast, rats with PRC lesions were significantly impaired in learning compared with both control and hippocampal-lesioned rats. The results suggest that recognition memory for complex visual discriminations is affected by stimulus interference in rodents with PRC damage.     

Kant on Construction,Apriority, and the Moral Relevance of Universalization

This paper introduces a referential reading of Kant’s practical project, according to which maxims are made morally permissible by their correspondence to objects, though not the ontic objects of Kant’s theoretical project but deontic objects (what ought to be). It illustrates this model by showing how the content of the Formula of Universal Law might be determined by what our capacity of practical reason can stand in a referential relation to, rather than by facts about what kind of beings we are (viz., uncaused causes). This solves the neglected puzzle of why there are passages in Kant’s works suggesting robust analogies between mathematics and ethics, since to universalize a maxim is to test a priori whether a practical object with that particular content can be constructed. An apparent problem with this hypothesis is that the medium of practical sensibility (feeling) does not play a role analogous to the medium of theoretical sensibility (intuition). In response I distinguish two separate Kantian accounts of mathematical apriority. The thesis that maxim universalization is a species of construction, and thus a priori, turns out to be consistent with the account of apriority that informs Kant’s understanding of actual mathematical practice.     

MORAL AND EPISTEMIC LUCK

Abstract: It is maintained that the arguments put forward by Bernard Williams and Thomas Nagel in their widely influential exchange on the problem of moral luck are marred by a failure to (i) present a coherent understanding of what is involved in the notion of luck, and (ii) adequately distinguish between the problem of moral luck and the analogue problem of epistemic luck, especially that version of the problem that is traditionally presented by the epistemological sceptic. It is further claimed that once one offers a more developed notion of luck and disambiguates the problem of moral luck from the problem of epistemic luck (especially in its sceptical guise), neither of these papers is able to offer unambiguous grounds for thinking that there is a problem of moral luck. Indeed, it is shown that in so far as these papers succeed in making a prima facie case for the existence of epistemic luck, it is only the familiar sceptical variant of this problem that they identify.     

Impossible shadows and the shadow correspondence problem

Shadows cast by objects contain potentially useful information about the location of these objects in the scene as well as their surface reflectance. However, before the visual system can use this information, it has to solve the shadow correspondence problem, that is to match the objects with their respective shadows. In the first experiment, it is shown that the estimate of the light source position is affected by a gradual luminance ramp added to the image. In the second experiment, it is shown that observers process impossible shadow images as if they ignored the local features of the objects. All together, the results suggest that the visual system solves the shadow correspondence problem by relying on a coarse representation of the scene.     

Individualism versus interactionism about social understanding

In the debate about the nature of social cognition we see a shift towards theories that explain social understanding through interaction. This paper discusses autopoietic enactivism and the we-mode approach in the light of such developments. We argue that a problem seems to arise for these theories: an interactionist account of social cognition makes the capacity of shared intentionality a presupposition of social understanding, while the capacity of engaging in scenes of shared intentionality in turn presupposes exactly the kind of social understanding that it is intended to explain. The social capacity in question that is presupposed by these accounts is then analyzed in the second section via a discussion and further development of Searle’s ‘sense of us’ and ‘sense of the other’ as a precondition for social cognition and joint action. After a critical discussion of Schmid’s recent proposal to analyze this in terms of plural pre-reflective selfawareness, we develop an alternative account. Starting from the idea that infants distinguish in perception between physical objects and other agents we distinguish between affordances and social affordances and cash out the notion of a social affordance in terms of “interaction-oriented representations”, parallel to the analysis of object affordances in terms of “action-oriented representations”. By characterizing their respective features we demonstrate how this approach can solve the problem formulated in the first part.     

The emergence of kind-based object individuation in infancy

Four experiments investigated whether 12-month-old infants use perceptual property information in a complex object individuation task, using the violation-of-expectancy looking time method (Xu, 2002; Xu & Carey, 1996). Infants were shown two objects with different properties emerge and return behind an occluder, one at a time. The occluder was then removed, revealing either two objects (expected outcome, if property differences support individuation) or one object (unexpected outcome). In Experiments 1-3, infants failed to use color, size, or a combination of color, size, and pattern differences to establish a representation of two distinct objects behind an occluder. In Experiment 4, infants succeeded in using cross-basic-level-kind shape differences to establish a representation of two objects but failed to do so using within-basic-level-kind shape differences. Control conditions found that the methods were sensitive. Infants succeeded when provided unambiguous spatiotemporal information for two objects, and they encoded the property differences during these experiments. These findings suggest that by 12 months, different properties play different roles in a complex object individuation task. Certain salient shape differences enter into the computation of numerical distinctness of objects before other property differences such as color or size. Since shape differences are often correlated with object kind differences, these results converge with others in the literature that suggest that by the end of the first year of life, infants' representational systems begin to distinguish kinds and properties.     

How context influences predominance during binocular rivalry

Variations in the predominance of an object engaged in binocular rivalry may arise from variations in the durations of dominance phases, suppression phases, or both. Earlier work has shown that the predominance of a binocular rival target is enhanced if that target fits well-via common color, orientation, or motion-with its surrounding objects. In the present experiments, the global context outside of the region of rivalry was changed during rivalry, to learn whether contextual information alters the ability to detect changes in a suppressed target itself. Results indicate that context will maintain the dominance of a rival target, but will not encourage a suppressed target to escape from suppression. Evidently, the fate of the suppressed stimulus is determined by neural events distinct from those responsible for global organization during dominance. To reconcile diverse findings concerning rivalry, it may be important to distinguish between processes responsible for selection of one eye's input for dominance from processes responsible for the implementation and maintenance of suppression.     

Can rhesus monkeys spontaneously subtract?

Animals, including pigeons, parrots, raccoons, ferrets, rats, New and Old World monkeys, and apes are capable of numerical computations. Much of the evidence for such capacities is based on the use of techniques that require training. Recently, however, several studies conducted under both laboratory and field conditions have employed methods that tap spontaneous numerical representations in animals, including human infants. In this paper, we present the results of 11 experiments exploring the capacity of semi-free-ranging adult rhesus monkeys to spontaneously compute (i.e. single trial, no training) the outcome of subtraction events. In the basic design, we present one quantity of objects on one stage, a second quantity on a second stage, occlude both stages, and then remove one or no objects from each stage. Having watched these events, a subject is then allowed to approach one stage and eat the food objects behind the occluder. Results show that rhesus monkeys correctly compute the outcome of subtraction events involving three or less objects on each stage, even when the identity of the objects is different. Specifically, when presented with two food quantities, rhesus monkeys select the larger quantity following subtractions of one piece of food from two or three; this preference is maintained when subjects must distinguish food from non-food subtractions, and when food is subtracted from either one or both initial quantities. Furthermore, rhesus monkeys are capable of representing zero as well as equality when two identical quantities are contrasted. Results are discussed in light of recent attempts to determine how number is represented in the brains of animals lacking language.     

Phases of learning: How skill acquisition impacts cognitive processing

This fMRI study examines the changes in participants’ information processing as they repeatedly solve the same mathematical problem. We show that the majority of practice-related speedup is produced by discrete changes in cognitive processing. Because the points at which these changes take place vary from problem to problem, and the underlying information processing steps vary in duration, the existence of such discrete changes can be hard to detect. Using two converging approaches, we establish the existence of three learning phases. When solving a problem in one of these learning phases, participants can go through three cognitive stages: Encoding, Solving, and Responding. Each cognitive stage is associated with a unique brain signature. Using a bottom-up approach combining multi-voxel pattern analysis and hidden semi-Markov modeling, we identify the duration of that stage on any particular trial from participants brain activation patterns. For our top-down approach we developed an ACT-R model of these cognitive stages and simulated how they change over the course of learning. The Solving stage of the first learning phase is long and involves a sequence of arithmetic computations. Participants transition to the second learning phase when they can retrieve the answer, thereby drastically reducing the duration of the Solving stage. With continued practice, participants then transition to the third learning phase when they recognize the problem as a single unit and produce the answer as an automatic response. The duration of this third learning phase is dominated by the Responding stage.     

Not your mother's view: the dynamics of toddler visual experience

Human toddlers learn about objects through second-by-second, minute-by-minute sensory-motor interactions. In an effort to understand how toddlers' bodily actions structure the visual learning environment, mini-video cameras were placed low on the foreheads of toddlers, and for comparison also on the foreheads of their parents, as they jointly played with toys. Analyses of the head camera views indicate visual experiences with profoundly different dynamic structures. The toddler view often consists of a single dominating object that is close to the sensors and thus that blocks the view of other objects such that individual objects go in and out of view. The adult view, in contrast, is broad and stable, with all potential targets continually in view. These differences may arise for several developmentally relevant reasons, including the small visuo-motor workspace of the toddler (short arms) and the engagement of the whole body when actively handling objects.     

Consequences of schematism

In his (2001a) and in some related papers, Tim Crane has maintained that intentional objects are schematic entities, in the sense that, insofar as being an intentional object is not a genuine metaphysical category, qua objects of thought intentional objects have no particular nature. This approach to intentionalia is the metaphysical counterpart of the later Husserl's ontological approach to the same entities, according to which qua objects of thought intentionalia are indifferent to existence. But to buy a metaphysically deflationary approach does not mean to buy an ontologically deflationary approach, according to which we have to accept all the intentional objects there apparently are. Being metaphysically deflationary on intentionalia rather means that from the ontological point of view one must really allow only for those intentionalia for which one is entitled to say that there are such things; typically, for which an ontological proof is available. From metaphysical schematism plus conditional, or partial, ontological committment to intentionalia, further interesting consequences follow. First, this theoretical combination allows one to deal with the ‘too-many entities’ problem (may one fail to accept an ontological proof for an entity of a given kind if she thinks that the entity we would have to be committed to is an entity of another kind?). Second, it allows one to deal with the ‘genuinely true report’ problem (how is it that if we exercise mindreading with respect to a somehow deluded person, we want our reports to come out as really, not merely fictionally, true?).     

Waiting by mistake: Symbolic representation of rewards modulates intertemporal choice in capuchin monkeys,preschool children and adult humans

In the Delay choice task subjects choose between a smaller immediate option and a larger delayed option. This paradigm, also known as intertemporal choice task, is frequently used to assess delay tolerance, interpreting a preference for the larger delayed option as willingness to wait. However, in the Delay choice task subjects face a dilemma between two preferred responses: “go for more” (i.e., selecting the larger, but delayed, option) vs. “go for sooner” (i.e., selecting the immediate, but smaller, option). When the options consist of visible food amounts, at least some of the choices of the larger delayed option might be due to a failure to inhibit a prepotent response towards the larger option rather than to a sustained delay tolerance. To disentangle this issue, we tested 10 capuchin monkeys, 101 preschool children, and 88 adult humans in a Delay choice task with food, low-symbolic tokens (objects that can be exchanged with food and have a one-to-one correspondence with food items), and high-symbolic tokens (objects that can be exchanged with food and have a one-to-many correspondence with food items). This allows evaluating how different methods of representing rewards modulate the relative contribution of the “go for more” and “go for sooner” responses. Consistently with the idea that choices for the delayed option are sometimes due to a failure at inhibiting the prepotent response for the larger quantity, we expected high-symbolic tokens to decrease the salience of the larger option, thus reducing “go for more” responses. In fact, previous findings have shown that inhibiting prepotent responses for quantity is easier when the problem is framed in a symbolic context. Overall, opting for the larger delayed option in the visible-food version of the Delay choice task seems to partially result from an impulsive preference for quantity, rather than from a sustained delay tolerance. In capuchins and children high-symbolic stimuli decreased the individual’s preference for the larger reward by distancing from its appetitive features. Conversely, the sophisticated symbolic skills of adult humans prevented the distancing effect of high-symbolic stimuli in this population, although this result may be due to methodological differences between adult humans and the other two populations under study. Our data extend the knowledge concerning the influence of symbols on both human and non-human primate behavior and add a new element to the interpretation of the Delay choice task. Since high-symbolic stimuli decrease the individual’s preference for the larger reward by eliminating those choices due to prepotent responses towards the larger quantity, they allow to better discriminate responses based on genuine delay aversion. Thus, these findings invite greater caution in interpreting the results obtained with the visible-food version of the Delay choice task, which may overestimate delay tolerance.