Perceptual similarity of mirror images in infancy

Perception of mirror images by three-to four-month infants was studied in five experiments using habituation paradigms. In the first experiment, babies discriminated right profiles of two different faces but not the left and right profile of the same face. In the second, babies discriminated a 45° oblique from a vertical line, but not the oblique from its mirror image. In the third, babies discriminated oblique lines that differed by 50° and were not mirror images. In the final experiments. 90° rotations of a ?-shape were discriminated but not 180° rotations that formed lateral or vertical mirror images. These results demonstrated that although babies were able to discriminate differences in orientation (even among obliques) they tended to view mirror images, especially lateral mirror images, as equivalent stimuli. We propose that the perceptual equivalence of mirror images reflects an adaptive mode of visual processing; mirror images in nature are almost always aspects of the same object, and they usually need not be discriminated. The relations of the perceptual similarity of mirror images to the ontogeny of the object concept and to the development of reading are discussed.     

Self-awareness and physical aggression

A theory of self-awareness was applied to aggression. In Experiment I, men were given an opportunity to aggress against women in the presence of a mirror, an audience, or neither. The mirror significantly inhibited aggression, but the audience did not. In Experiment II, an audience inhibited aggression, but only when there was frequent eye contact between the aggressor and the audience. These results were consistent with the predictions derived from the theory.     

A device for the computer processed analysis of video frames

This article briefly describes a system of analyzing movement sequences extracted from video images. The system uses an IBM-PC or compatible computer, equipped with a CGA screen and a mouse, and a videotape recorder and monitor. The coordinates of the points selected from the images with the mouse are stored in an ASCII-format file by a computer program. The principle behind this system is that it projects video images on a computer screen through a one-way mirror while avoiding parallax effects.     

Mirror-reading in right- and left-handers

In mirror-reading, words are read from right to left and letters are read in a reverse right-to-left orientation. In one experiment we compared the ability of normal right- and left-handed subjects to mirror-read and found that the left-handers made fewer errors and could read mirror print more rapidly. In a second experiment we attempted to learn whether there is a hemifield superiority for reading mirror words and whether there are any differences between left- and right-handers in a hemifield. We found that although both right- and left-handers more rapidly detected mirror words projected to the left visual half-field, there were no differences between groups. However, in the right visual half-field, the performance of left-handers was superior to that of the right-handers. The results of the hemifield study suggest that left-handers may be superior at reading mirror words because they can more easily reverse their scanning pattern.     

Effects of the one-way mirror on family therapy

The one-way screen often used in family therapy is usually a mirror and may have unsuspected effects, ensuring that clients' behaviour in therapy reflects social acceptability and personal values, rather than their usual interactions.     

Self-focused attention and reactions to fear

Two studies were conducted to study the effect of self-focused attention on behavioral responses to fear. In Experiment 1, phobics and nonphobics were asked to approach and hold a snake either in the presence of a mirror or with no mirror. In Experiment 2, high and low private self-conscious subjects were asked to submit to a series of either mild or strong electric shock for humanitarian reasons. In each case, self-directed attention caused increased responsivity to the fearful affect and made subjects more likely to withdraw from the situation, regardless of the fact that a behavioral standard existed which called for an opposite response. The theoretical and behavioral implications of the findings were discussed.     

Functional significance of stimulus orientation: effects on orientation discrimination.

Children (6- and 9-year-olds) and adults were required to discriminate identical pairs of visual stimuli from mirror images. It was hypothesized that a key factor in performance would be the extent to which orientation was a functionally significant attribute of the stimuli. Two variables were manipulated, type of orientation discrimination and stimulus class. The first variable refers to the fact that the mirror images could be produced by either left/right or top/bottom reversals. Three classes of stimuli, varying in the extent to which a particular orientation was emphasized, were used: mobile objects (for which left/right orientation is assumed to be important); stationary objects (which lack comparable relevance for left/right orientation); and novel, abstract forms. The prediction was that if the discrimination task involved left/right reversals, as contrasted with top/bottom reversals, subjects would show an advantage for mobile objects, producing an interaction between stimulus class and orientation discrimination. In the first study, the subjects were children and performance was measured in terms of error rates. In the second study adults were tested, and reaction times were measured. Both studies manifested the predicted interaction. Results are discussed in terms of an information-processing framework, in which the incorporation of orientation-related features in the code representing a stimulus varies with the functional significance of the orientation to the stimulus class.     

Two Improvements for the Econo-Cage #110 metabolism unit

The Econo-Cage metabolism unit is improved by replacing a breakable plastic rod which holds the feeder screen in place and by collecting feces on a removable screen instead of from the urine contaminated base.     

On the choice between eating and aggressive display in the Siamese fighting fish (Betta splendens)

In Expt 1, male Betta splendens were given a choice between food and a mirror image in a T-maze. All fish consistently preferred food. In Expt 2, the choice of fish that lived in the T-maze for the duration of the experiment was compared with the choice of fish that were transferred to the T-maze for each experimental session. Fish that lived in the T-maze consistently preferred food, but fish that were transferred showed a shift in preference toward mirror image. Differential inhibition of hunger and aggression by fear is suggested as the cause of the preference shift.     

Self-awareness and cigarette-smoking behavior

According to the theory of objective self-awareness (Duval & Wicklund, 1972), the concept of generalized drive is unnecessary, its explanatory function having been replaced by the concepts of self-evaluation and desire to be “correct”. An experiment was designed to compare alternative predictions from the drive and self-awarencess theories. Subjects listened to music in the presence of a mirror and, at another time, not in the presence of a mirror. The effect of self-consciousness on several habitual behaviors related to smoking was assessed. It was known that the subjects believed the number of cigarettes one should smoke “ideally” was significantly less than the number they actually smoked. Hence, the theory of objective self-awarencess predicts decreased smoking in the presence of the mirror, while a drive theory interpretation of self-consciousness predicts the opposite. Results generally supported the drive theory.     

Mirror reversal: Empirical tests of competing accounts

In a mirror, left and right are said to look reversed. Surprisingly, this very familiar phenomenon, mirror reversal, has still no agreed-upon account to date. This study compared a variety of accounts in the light of empirical data. In Experiment 1, 102 students judged whether the mirror image of a person or a character looked reversed or not in 15 settings and also judged the directional relation between its components. In Experiment 2, 52 students made the reversal judgements in 13 settings. It was found for the first time that a substantial proportion of people denied the left–right mirror reversal of a person, whereas virtually all of them did recognize that of a character. This discrepancy strongly suggested that these two kinds of mirror reversal are produced by different processes, respectively. A number of findings including this discrepancy clearly contradicted two accounts that are currently active: the one based on the priority of the up–down and front–back axes over the left–right axis, and the one based on the physical rotation of an object. All the findings were consistent with an account that considered mirror reversal a complex of three different phenomena produced by three different processes, respectively.     

Mirror reversal: empirical tests of competing accounts

In a mirror, left and right are said to look reversed. Surprisingly, this very familiar phenomenon, mirror reversal, has still no agreed-upon account to date. This study compared a variety of accounts in the light of empirical data. In Experiment 1, 102 students judged whether the mirror image of a person or a character looked reversed or not in 15 settings and also judged the directional relation between its components. In Experiment 2, 52 students made the reversal judgements in 13 settings. It was found for the first time that a substantial proportion of people denied the left-right mirror reversal of a person, whereas virtually all of them did recognize that of a character. This discrepancy strongly suggested that these two kinds of mirror reversal are produced by different processes, respectively. A number of findings including this discrepancy clearly contradicted two accounts that are currently active: the one based on the priority of the up-down and front-back axes over the left-right axis, and the one based on the physical rotation of an object. All the findings were consistent with an account that considered mirror reversal a complex of three different phenomena produced by three different processes, respectively.     

Objective self-awareness,standards of evaluation,and moral behavior

In a performance setting, subjects were given an opportunity to cheat without fear of detection on puzzle problems. Subjects were led to believe that successful performance was due to ability in some conditions, but to luck in other conditions. In fact, most of the problems were insolvable, so that success was impossible without cheating. Self-awareness was induced in half the subjects by having them sit in front of a mirror and listen to a tape recording of their own voice as they worked on the puzzle problems; the remaining subjects were not exposed to a mirror and listened to a tape of someone else's voice as they worked on the problems. It was predicted that cheating frequency would be higher under ability attribution conditions than under luck attribution conditions, and that this effect of performance attribution would be greater among self-aware subjects than among non-self-aware subjects. Results confirmed these hypotheses. Discussion centered on the differential use of morality and competence standards for behavior when in a state of self-awareness.     

The self-attention-induced feedback loop and social facilitation

It has been proposed that self-directed attention leads to the engagement of a cybernetic feedback loop, by which discrepancies between present behavior and a standard of comparison are reduced. This analysis is applied to performance facilitation effects, which are more typically explained in terms of drive theories. Though these two approaches to motivation make similar behavioral predictions in this context, they assume different mediating states. Support is noted for the assumptions that mirror presence and audience presence induce self-focus, and that they lead to comparison with salient behavioral standards. Support for the assumption that these manipulations increase arousal is also reviewed, and is challenged on methodological grounds. The attentional analysis is used to derive predictions regarding changes in physiological state over the course of a typical social facilitation procedure. An experiment is reported which confirmed these predictions. Discussion centers on how to interpret physiological changes in terms that are compatible with control theory, how to account for social impairment phenomena in terms of the present model, and the conceptual relationship between mirror presence and audience presence as experimental manipulations.     

Self-focused attention and belief perseverance

The perseverance of an erroneous belief was investigated in the debriefing paradigm as a function of self-focused attention. Subjects were given either success or failure experiences via bogus performance feedback and received this feedback under high or low mirror self-focusing. All subjects were subsequently debriefed about the false nature of the feedback, and then, before answering questions about their estimated actual performance and ability, mirror self-focus was again manipulated. The results showed that self-focus prior to debriefing increased belief perseverance while self-focus after debriefing reduced the perseverance effects. Discussion of these findings emphasized the role of self-focus in information processing before and adherence to veridical standards after debriefing.     

A low-cost method for digitizing videotaped continuous movements on the Macintosh

We describe an inexpensive means of digitizing videotaped positions of moving points, such as the positions of the joints of a person who is performing an action. Single-frame video images and a Macintosh computer monitor are optically superimposed, using a half-silvered mirror, and the positions of reference points in the video image are manually clicked in by the operator, so that the screen coordinates of the reference points on each frame can be stored in a text file for later analysis. The digitizing program records comments and identifying information along with the position data.     

Self-esteem,anxiety, and the avoidance of self-focused attention

The present study was designed to provide converging support for the hypothesis that individuals with low self-esteem (low SEs) find self-focused attention more anxiety provoking, relative to people with high self-esteem (high SEs). Subjects were premeasured for their self-esteem and given a brief opportunity to “practice” two tasks that they believed they would be required to perform in a later part of the experiment. One task was practiced in front of a self-focusing stimulus—a large mirror (mirror task)—whereas the other was not (no-mirror task). Subjects evaluated the tasks after they had practiced each one. Consistent with the notion that self-focused attention is more anxiety provoking for individuals with lower self-esteem, it was observed that: (1) relative to high SEs, lowmedium SEs rated the mirror, but not the no-mirror, task as less enjoyable, and (b) low-medium, but not high, SEs preferred to avoid the mirror task for the alleged upcoming part of the experiment. Subjects high in dispositional private selfconsciousness also wanted to avoid the mirror task, particularly if they were also low in self-esteem. Contrary to prediction, success-failure feedback from a previous task had no effect on subjects' task preferences. Theoretical explanations and implications are discussed.     

The early development of human mirror mechanisms: evidence from electromyographic recordings at 3 and 6 months

In primates and adult humans direct understanding of others' action is provided by mirror mechanisms matching action observation and action execution (e.g. Casile, Caggiano & Ferrari, 2011). Despite the growing body of evidence detailing the existence of these mechanisms in the adult human brain, their origins and early development are largely unknown. In this study, for the first time, electromyographic (EMG) measures were used to shed light on the emergence of mirror motor mechanisms in infancy. EMG activity was recorded while 6‐ and 3‐month‐old infants watched two videos displaying an agent reaching for, grasping and bringing an object either to the mouth or to the head. Results indicate that the motor system of 6‐month‐olds, but not 3‐month‐olds, was recruited and selectively modulated during observation of the goal‐directed actions, favoring the idea that mirror mechanisms driving action understanding gradually emerge during early development.     

Laser-induced afterimages in humans

Afterimages induced by incoherent light sources have been studied as complex visual perceptions for over 200 years; however, individuals who have viewed a coherent source (a laser) on-axis have reported visual experiences unlike those observed for full-field flashes from incoherent sources. In the present study, 10 volunteers viewed all combinations of blue, green, and red laser light and background colors that matched the wavelengths of the laser sources (a total of 9 conditions). The bright focal (50 microm retinal irradiance diameter) 3-sec. exposures (approximately 9 log trolands-40% of the maximum permissible exposure level) given to the volunteers were administered as they performed a simulator tracking task. A 50/50 mirror (a mirror which reflected 50% of the laser beam into the optical pathway while allowing the 50% of the light from the visual scene to pass through the mirror) permitted simultaneous intrabeam viewing of the laser source and the scene. The volunteers were asked to report what they saw immediately after the laser was turned off and 1-min postexposure. The immediate reports indicated that the image they observed was the same color as the laser source and not the complementary color. Also, the images were of ten surrounded by well-defined borders and, regardless of laser's or background's col or, were generally red. One minute following presentation of the laser light the images seen were predominantly purple, dark or no longer present; however, the edge color when present generally appeared red. The immediate appearance of the images was inferred to be neural in nature and not photochemical. These results suggest the properties of the laser source, i.e., coherency, monochromaticity, and the laser's capacity to place an intense beam of light in a small retinal area, all contributed to the unique appearance of the postflash images.     

Naive optics: understanding the geometry of mirror reflections

Paper-and-pencil tasks showed that many university students believed that when laterally approaching a mirror, they would see a reflection in the mirror before it was geometrically possible. Participants failed to adequately factor in the observer's location in the room. However, when asked about the behavior of a ray of light, participants knew about the law of reflection. No differences between psychology and physics students were detected, suggesting that the phenomenon is widespread and refractory to training. The findings were replicated with observers making judgments about image locations in a real room using a pretend mirror. Possible heuristics about mirror reflection that might explain the data are discussed. Naive optics is a promising venue to further knowledge of how observers understand basic laws of physics.