Overestimation of the projected size of objects on the surface of mirrors and windows

Four experiments investigated judgments of the size of projections of objects on the glass surface of mirrors and windows. The authors tested different ways of explaining the task to overcome the difficulty that people had in understanding what the projection was, and they varied the distance of the observer and the object to the mirror or window and varied the size of the mirror. The authors compared estimations of projected size with estimations of the physical size of the object that produced the projection. For both mirrors and windows, observers accurately judged the physical size of objects but greatly overestimated the projected size of the same objects. Indeed, judgments of projected size were more similar to physical than to projected size. People were also questioned verbally about their knowledge of projected size relative to physical size. The errors produced for these conceptual questions were similar to those found in the perceptual estimation tasks. Together, these results suggest that projections of objects on mirrors and windows are treated in the same way and that observers cannot perceive such projections as distal objects.     

Perceived distance of targets in convex mirrors

We investigated the perceived distance of targets in convex and plane mirrors. In Experiment 1, 20 subjects matched the distance of targets in a real scene to the distance of a virtual target in different mirrors. The matched distances were much larger for convex mirrors than for a plane mirror. In Experiment 2, 20 subjects viewed two targets in a mirror and adjusted their own positions so that the distance to the closer target was perceived to equal the distance between the targets. The mean distance to the closer target was smaller for the convex mirrors than for the plane mirror. In Experiment 3, 20 subjects adjusted the position of a target so that the distance to it in a mirror was perceived to equal the distance designated by the experimenter. The best-fitting power functions showed that the scaling factors were larger for the convex mirrors than for the plane mirror, but the exponents were smaller for the convex mirrors than for the plane mirror. It is suggested that distance in the convex mirrors was perceived to be larger than in the plane mirror, and that the growth of perceived distance in the convex mirrors was slower than in the plane mirror.     

Context specificity of inhibitory control in dogs

Across three experiments, we explored whether a dog’s capacity for inhibitory control is stable or variable across decision-making contexts. In the social task, dogs were first exposed to the reputations of a stingy experimenter that never shared food and a generous experimenter who always shared food. In subsequent test trials, dogs were required to avoid approaching the stingy experimenter when this individual offered (but withheld) a higher-value reward than the generous experimenter did. In the A-not-B task, dogs were required to inhibit searching for food in a previously rewarded location after witnessing the food being moved from this location to a novel hiding place. In the cylinder task, dogs were required to resist approaching visible food directly (because it was behind a transparent barrier), in favor of a detour reaching response. Overall, dogs exhibited inhibitory control in all three tasks. However, individual scores were not correlated between tasks, suggesting that context has a large effect on dogs’ behavior. This result mirrors studies of humans, which have highlighted intra-individual variation in inhibitory control as a function of the decision-making context. Lastly, we observed a correlation between a subject’s age and performance on the cylinder task, corroborating previous observations of age-related decline in dogs’ executive function.     

Naïve predictions of motion and orientation in mirrors: From what we see to what we expect reflections to do

The study aimed to investigate naïve beliefs regarding the dynamic and static behavior of reflections. In the first three experiments, participants in the study made predictions about the correspondence between real and reflected movements or about the orientation of the reflection of a static object placed in front of a mirror. In Experiments 1 and 2, paper-and-pencil tasks were used and in Experiment 3 participants were asked to make their predictions while imagining that they were facing a mirror. Results revealed that a percentage of undergraduates (ranging from 25% to 35%) were unable to make correct predictions. We classified the errors into types and found that responses either conform to the belief that reflections do the same or that they do the opposite. This suggests an oversimplification of the geometry of mirror reflections in two directions: participants either generalize what they see when movements are parallel to the mirror or what they see when movements are orthogonal to the mirror. Findings from Experiment 4 confirmed that these two expectations fit in with what people perceive in mirrors. Findings from Experiment 5 confirmed that this is also in agreement with the relationship perceived when looking at similar movements and orientations “outside” mirrors.     

Naive optics: Predicting and perceiving reflections in mirrors

Undergraduate students predicted what would be made visible by a planar mirror. A paper-and-pencil task confirmed previous findings that when approaching a mirror from the side, participants expected to see their reflection in the mirror earlier than they actually would. This early response was found for all mirrors when the observer moved horizontally--even when the mirror was placed on the floor or the ceiling--but not when the observer moved vertically (in a lift). The data support the hypothesis that many people imagine the world in the mirror as rotated around the vertical axis. When participants had to judge manipulated mirror reflections according to their naturalness, a high degree of tolerance was found. In contrast to the prediction task, a rotation around the vertical axis was judged to be less natural than other distortions. The authors conclude that perceptual knowledge and predictive knowledge lead to different patterns of errors. ((c) 2003 APA, all rights reserved)     

Tufted capuchin monkeys (<Emphasis Type="Italic">Cebus apella</Emphasis>) show understanding of human attentional states when requesting food held by a human

Researchers have investigated to what extent non-human primates understand others’ attentional states, as this ability is considered an important prerequisite for theory of mind. However, previous studies using food requesting tasks have failed to show that non-human primates attribute perception to others as a function of their attentional states. One possible reason is that food requesting tasks may require subjects not only to take into account an experimenter’s attentional state but also to direct it toward the food. The present study tested tufted capuchin monkeys’ (Cebus apella) understanding of others’ attentional states in a food requesting task. In the first situation, monkeys were required only to attract an experimenter’s attention. In the second situation, the monkeys were required to both attract the experimenter’s attention and direct it toward food on a table. The results revealed that capuchin monkeys showed evidence of understanding the experimenter’s attentional variations only in the former condition. This suggests that previous tasks, requiring referential gestures, lacking in most non-human primates, failed to reveal sensitivity to human attentional states because the subjects might not have understood the requesting situation. In conclusion, capuchin monkeys can understand variations in others’ attentional states, although this ability appears limited compared to what is seen in humans.     

Chimpanzees (Pan troglodytes) remember the location of a hidden food item after altering their orientation to a spatial array

Two chimpanzees (Pan troglodytes) had a direct view of an experimenter placing a food item beneath one of several cups within a horizontal spatial array. The chimpanzees then were required to move around the spatial array, shifting their orientation to the array by 180 degrees . Both chimpanzees remembered the location of the food item. In the next experiment, a visual barrier was placed between the chimpanzees and the spatial array after the food item had been hidden to prevent visual tracking of the location of the object during the chimpanzees' movement. One chimpanzee remembered the location of the hidden item in this variation. These results demonstrate another capacity for spatial memory in this species that complements data indicating chimpanzee spatial memory for invisible displacements, array rotations, and array transpositions.     

Interacting with objects compresses environmental representations in spatial memory

People perceive individual objects as being closer when they have the ability to interact with the objects than when they do not. We asked how interaction with multiple objects impacts representations of the environment. Participants studied multiple-object layouts, by manually exploring or simply observing each object, and then drew a scaled version of the environment (Exp. 1) or reconstructed a copy of the environment and its boundaries (Exp. 2) from memory. The participants who interacted with multiple objects remembered these objects as being closer together and reconstructed smaller environment boundaries than did the participants who looked without touching. These findings provide evidence that action-based perceptual distortions endure in memory over a moving observer’s multiple interactions, compressing not only representations between touched objects, but also untouched environmental boundaries.     

Beyond the politics of reception: Jacques Rancière and the politics of art

Jacques Rancière’s work has become a major reference point for discussions of art and politics. However, while Rancière’s negative theses (about what “political art” is not) are becoming widespread and well understood, his positive thesis is still poorly understood, owing partly to Rancière’s own formulation of the issue. I first clarify Rancière’s account of the links between politics and art. I then explore a gap in this account; Rancière has stuck too closely to a politics of art’s reception. I argue for a politics of art production, which would expand the possible engagement between politics and art.     

Nine-month-old infants learn about a physical event in a single session: Implications for infants' understanding of physical phenomena

Infants' ability to learn about physical phenomena after only brief training was observed. During training, infants first observed and handled a weighted ball or an identical-looking empty ball, then watched an experimenter place a ball in the bottom of a tube connected to a paddle. When infants pressed the paddle, the empty ball ascended the tube while the weighted ball stayed down. During test trials infants experienced trials that were consistent and inconsistent (i.e., heavy ball ascended and empty ball did not) with training trials. Infants pressed and looked longer at the inconsistent events. A second experiment replicated the findings and ensured that infants were not using prior knowledge about gravity and weight. Infants formed a representation of what was inside the balls, remembered what each ball did during training, and detected a violation of expectations about the ball's movement.     

Knowing when you don't know enough: Children's judgements about ambiguous information

Two experiments were carried out to find out whether young children's failure to realise when messages are ambiguous is specific to verbally transmitted information about a person's intended meaning. In Experiment 1, children judged whether they had been told/shown enough to identify which one of a set of cards the experimenter had chosen. In one game the experimenter gave verbal messages about her chosen cards, and in a second game, she gave visual messages. With ambiguous visual messages, relevant parts of cards were physically covered. We expected that this would make it more obvious that the speaker's intended meaning was not being fully conveyed. No difference was found between verbal and visual conditions: correct judgements about message ambiguity occured with the same frequency in both.In Experiment 2, children judged in one game whether they had been told enough about the experimenter's chosen card, as in Experiment 1. In a second game, visual information about a card was not conveyed by the experimenter, Rather, the child operated a pointer, set in a disc with windows, beneath which lay cards. The child judged whether the window showed enough for him/her to tell which card the pointer indicated. Again, correct judgments about ambiguity occured with the same frequency in both games.The results implied that children's failure to realise when verbal messages are ambiguous is but one aspect of a more general failure to realise when one has insufficient information at one's disposal to guarantee a correct interpretation of what the world is like.     

Development of young children's understanding that the recent past is causally bound to the present

The results of 6 studies (involving 304 children) suggested that 4- and 5-year-olds, but not 3-year-olds, understand that very recent past events determine the present. In Studies 1-3, 3- and 4-year-old children were introduced to 2 empty hiding locations. With children's backs to these locations, a camera recorded an experimenter secretly hiding a puppet in one of them. Children then viewed the videotape of what had just happened, along with another tape that depicted identical events except with a different child and with the puppet hidden in the other location. Only 4-year-olds were subsequently able to locate the puppet, even though 3-year-olds remembered the contents of the tapes and understood the equivalence between the video events and the real world. In Study 4, similar effects were obtained when a verbal analog of the test was presented to 3-5-year-olds. Studies 5 and 6 showed that when children observed 2 events in which they had just participated, only 5-year-olds understood that the most recent events were relevant.     

Why does a mirror image look left-right reversed? A hypothesis of multiple processes

This paper proposes a solution to the mirror reversal problem: Why does a mirror reverse left and right but not up and down? The paper first reviews past hypotheses and shows that none of them has succeeded in explaining all the related phenomena. It then proposes a multiprocess hypothesis based on the insight that what is called a mirror reversal is actually composed of three different types of reversal: The Type I reversal is produced by the discrepancy between an orientational framework that is aligned with a viewer’s body and the one that is assumed in the viewer’s mirror image; the Type II reversal is produced by the discrepancy between the mental representation of an object and its mirror image; and the Type III reversal is produced by a mirror’s optical transformation. The proposed hypothesis is shown to provide reasonable accounts for all the related phenomena disputed in the past literature.     

Precue effects in visual search: Data or resource limited?

Precuing an observer as to where a target is more likely to occur in a subsequent visual array can increase the detectability (d′) of a target at that location. This is often attributed to the observer’s increased allocation of some limited cognitive resource (“attention”) to the cued location. Two experiments are reported which are difficult to interpret in this way even though they involve similar cue effects. The first involves postcuing a location well after the array but before the observer responds, so that the cue can influence the response but not the observation. The second involves precuing, but with slow sequential presentation of array elements prior to the response, so the observer need not share any limited resource while processing each element in turn. Enhanced detectability similar to that produced with precues and simultaneous presentation of elements is shown to occur in each experiment. An alternative data-limited (rather than resource-limited) interpretation of these effects is provided by a mathematical model in which the observer integrates equally noisy or degraded internal representations of the array elements, but gives more weight to cued elements in selecting a response. Theoretical parameters of the model are shown to provide separate measures of both an observer’s overall sensitivity and precue effects in cost-benefit analyses of cuing data.     

Visual self-recognition in mirrors and live videos: Evidence for a developmental asynchrony

Three experiments (N = 123) investigated the development of live-video self-recognition using the traditional mark test. In Experiment 1, 24-, 30- and 36-month-old children saw a live video image of equal size and orientation as a control group saw in a mirror. The video version of the test was more difficult than the mirror version with only the oldest children's performance approaching ceiling. In Experiment 2, most 24-month-olds showed self-recognition when presented with a TV-set that featured a mirror in place of a screen. This finding does not substantiate the possibility that expectations about what appears on TV are responsible for the asynchrony. In Experiment 3, children were given a mark-test involving only their legs. Again, a video version was more difficult than previously reported performance with mirrors, suggesting that the impossibility of eye-contact in video cannot explain this developmental asynchrony. The findings suggest that self-recognition can be added to the growing list of contexts in which 2-year-olds display what has been called a “video deficit” [Anderson, D. R., & Pempek, T. A. (2005). Television and very young children. American Behavioral Scientist, 48, 505–532].     

Evidence of heterospecific referential communication from domestic horses (<Emphasis Type="Italic">Equus caballus</Emphasis>) to humans

Referential communication occurs when a sender elaborates its gestures to direct the attention of a recipient to its role in pursuit of the desired goal, e.g. by pointing or showing an object, thereby informing the recipient what it wants. If the gesture is successful, the sender and the recipient focus their attention simultaneously on a third entity, the target. Here we investigated the ability of domestic horses (Equus caballus) to communicate referentially with a human observer about the location of a desired target, a bucket of food out of reach. In order to test six operational criteria of referential communication, we manipulated the recipient’s (experimenter) attentional state in four experimental conditions: frontally oriented, backward oriented, walking away from the arena and frontally oriented with other helpers present in the arena. The rate of gaze alternation was higher in the frontally oriented condition than in all the others. The horses appeared to use both indicative (pointing) and non-indicative (nods and shakes) head gestures in the relevant test conditions. Horses also elaborated their communication by switching from a visual to a tactile signal and demonstrated perseverance in their communication. The results of the tests revealed that horses used referential gestures to manipulate the attention of a human recipient so to obtain an unreachable resource. These are the first such findings in an ungulate species.     

TELESCOPE + MIRROR = REFLECTIONS ON THE COSMOS: UMBERTO ECO AND THE IMAGE OF RELIGION

Umberto Eco argues that a mirror image is not a sign. At best it is a double, a thing that ceases to be once the reflected object is removed. Harry Mulisch narratively suggests that mirror images function metaphorically as gateways between human suffering and the divine. And interestingly, science employs mirrors and mirror images both to turn our gaze upwards and to show us reflections of our place in the cosmos. Tying together Eco's notion of the double, Mulisch's insistence that mirror images reflect humanity's construction of the divine, and the Giant Magellan Telescope Project's cosmic images, it is my contention that modern, telescopic mirror images are much more than snapshots of the cosmos. They are constructions of human and divine meaning that—signifying—pose the question, what is reflected: the cosmos or humanity?     

Illusion and offense in <Emphasis Type="Italic">Philosophical Fragments</Emphasis>: Kierkegaard’s inversion of Feuerbach’s critique of Christianity

The article shows the “Appendix” to Søren Kierkegaard’s Philosophical Fragments to be a response to Ludwig Feuerbach’s critique of Christianity. While previous studies have detected some influence by Feuerbach on Kierkegaard, they have so far discovered little in the way of specific responses to Feuerbach’s ideas in Kierkegaard’s published works. The article first makes the historical argument that Kierkegaard was very likely reading Feuerbach’s Essence of Christianity while he was writing Philosophical Fragments, as several of Kierkegaard’s journal entries from that period discuss Feuerbach in relation to central ideas in Fragments. The article then shows how Kierkegaard’s pseudonym Johannes Climacus inverts Feuerbach’s projection theory, turning it against critics like Feuerbach. At the heart of Feuerbach’s critique of Christianity is the claim that religion is a conceptual illusion, whereby the individual projects his or her personal limits onto the species and then projects the unlimited onto a supposed divine being. Furthermore, Feuerbach sees Christianity as rife with absurdities that tell against its reasonableness. In exploring a hypothetical transcendent avenue toward the truth, Climacus inverts both of these philosophical moves. He argues that on the transcendent hypothesis, the immanentist critic is himself a victim of an “acoustical illusion”: the absolute paradox of the appearance of the god in time is in fact not judged by, but rather judges, the critic as absurd. In inverting and not repudiating Feuerbach’s critique, Climacus reveals the critic as a Socratic figure who displays the heights—and ultimately, the limits—of secular philosophy’s capabilities.     

Using mu rhythm desynchronization to measure mirror neuron activity in infants

The Mirror Neuron System hypothesis stating that observed actions are projected onto the observer’s own action system assigns an important role to development, because only actions mastered by the observer can be mirrored. The purpose of the present study was to investigate whether there is evidence of a functioning mirror neuron system (MNS) in 8-month-old infants. High-density EEG was used to assess the mu rhythm desynchronization in an action observation task where the infants observed a live model. To reduce noise, ICA decompositions were used. The results show a higher desynchronization of the mu rhythm when infants observed a goal-directed action than when they observed a spatially similar non-goal-directed movement. The localizations of the sources are in agreement with those proposed by the MNS hypothesis. This indicates that the MNS is functioning at this age.     

Building false memories without suggestions

People can come to remember doing things they have never done. The question we asked in this study is whether people can systematically come to remember performing actions they never really did, in the absence of any suggestion from the experimenter. People built LEGO vehicles, performing some steps but not others. For half the people, all the pieces needed to assemble each vehicle were laid out in order in front of them while they did the building; for the other half, the pieces were hidden from view. The next day, everyone returned for a surprise recognition test. People falsely and confidently remembered having carried out steps they did not; those who saw all the pieces while they built each vehicle were more likely to correctly remember performing steps they did perform but equally likely to falsely remember performing steps they did not. We explain our results using the source monitoring framework: People used the relationships between actions to internally generate the missing, related actions, later mistaking that information for genuine experience.