The role of preparatory muscular tension in the size-weight illusion

Muscle action potentials were recorded from lifting muscles during the foreperiod before lifts of large and small objects when the size-weight illusion occurred. There were increases in tension throughout the foreperiod of both lifts, culminating in a large increase following the instruction to lift. The increases were greater before lifts of the large can, supporting the peripheral theory of comparative weight judgment. The “set to lift” effect was shown to exist in the action potentials before the foreperiod of the second lift when compared to those just prior to the lift of the first can.     

The role of haptic versus visual volume cues in the size-weight illusion

Three experiments establish the size-weight illusion as a primarily haptic phenomenon, despite its having been more traditionally considered an example of vision influencing haptic processing. Experiment 1 documents, across a broad range of stimulus weights and volumes, the existence of a purely haptic size-weight illusion, equal in strength to the traditional illusion. Experiment 2 demonstrates that haptic volume cues are both sufficient and necessary-for a full-strength illusion. In contrast, visual volume cues are merely sufficient, and produce a relatively weaker effect. Experiment 3 establishes that congenitally blind subjects experience an effect as powerful as that Of blindfolded sighted observers, thus demonstrating that visual imagery is also unnecessary for a robust size-weight illusion. The results are discussed in terms of their implications for both sensory and cognitive theories of the size-weight illusion. Applications of this work to a human factors design and to sensor-based systems for robotic manipulation are also briefly considered.     

A new explanation for the Poggendorff illusion

Kanizsa (1972, 1974) has observed that the surface upon which a figure is amodally completed undergoes shrinkage. That observation is investigated here as a possible explanation of the Poggendorff illusion, on the assumption that the shrinkage of the surface behind the surface defined by the two vertical parallel lines results in displacement of the two visible segments of the oblique line. The first two experiments attempted to quantify the shrinkage of the amodal surface by measuring the enlargement of the vertical strip required to achieve perceived collinearity; the oblique lines intercepted the vertical strip at 45- and 30-deg angles. In both cases, the enlargement required to counterbalance the assumed amodal shrinkage was approximately 30%. In the third experiment, the oblique line was rotated to the horizontal, and again the perceived shrinkage of the amodal surface was approximately 30%. The application of this explanation to the Poggendorff illusion is discussed, as well as the relevance of this explanation to the common experimental finding that magnitude of the illusion is dependent upon the slope of the oblique line.     

Psychophysical scales of apparent heaviness and the size-weight illusion

The apparent heaviness of a set of 40 cylindrical objects was scaled by the method of magnitude estimation. The objects varied in weight, volume. and density. There were three main conclusions: (1) For any constant volume, heaviness grows as a power function of weight; the larger the volume. the larger the exponent of the power function. The family of such power functions converge at a common point in the vicinity of the heaviest weight that can be lifted. (2) For any constant density (i:e., weight proportional to volume), heaviness does not grow as a power function of weight. (3) For any constant weight, heaviness decreases approximately as a logarithmic function of volume; the constants of the log function depend systematically on the weight of the object. The outcome furnishes a broad quantitative picture of apparent heaviness and of the size-weight illusion (Charpentier’s illusion).     

Forgiveness: a review of the theoretical and empirical literature

This paper reviews the published literature addressing forgiveness as a therapeutic issue. The review revealed four major themes. These included: diverse attempts in the literature to define forgiveness; the presentation of models of intervention; resistance among theoreticians and therapists to examine forgiveness as a therapeutic construct, and empirical evidence of forgiveness intervention applied to clinical settings. These theoretical and empirical publications are described and critiqued. An evaluation is made as to the current state of the research, and suggestions for future directions.     

Independence and separability of volume and mass in the size-weight illusion

Numerous size-weight illusion models were classified in the present article according to general recognition theory (Ashby & Townsend, 1986), wherein the illusion results from a lack of perceptual separability, perceptual independence, decisional separability, or a combination of the three. These options were tested in two experiments in which a feature-complete factorial design and multidimensional signal detection analysis were used (Kadlec & Townsend, 1992a, 1992b). With haptic touch alone, the illusion was associated with a lack of perceptual and decisional separability. When the participant viewed the stimulus in his or her hand, the illusion was associated only with a lack of decisional separability. Visual input appeared to improve the discrimination of mass, leaving only the response bias due to expectation.     

A review of theoretical and empirical advancements

In this article, we review both theoretical and empirical advancements in retirement adjustment research. After reviewing and integrating current theories about retirement adjustment, we propose a resource-based dynamic perspective to apply to the understanding of retirement adjustment. We then review empirical findings that are associated with the key research questions in this literature: (a) What is the general impact of retirement on the individual? and (b) What are the factors that influence retirement adjustment quality? We also highlight important future research directions that may be fruitful for psychologists to pursue in this area.     

The illusion of group productivity: a reduction of failures explanation

It has consistently been found that people produce more ideas when working alone as compared to when working in a group. Yet, people generally believe that group brainstorming is more effective than individual brainstorming. Further, group members are more satisfied with their performance than individuals, whereas they have generated fewer ideas. We argue that this ‘illusion of group productivity’ is partly due to a reduction of cognitive failures (instances in which someone is unable to generate ideas) in a group setting. Three studies support that explanation, showing that: (1) group interaction leads to a reduction of experienced failures and that failures mediate the effect of setting on satisfaction; and (2) manipulations that affect failures also affect satisfaction ratings. Implications for group work are discussed. Copyright © 2005 John Wiley & Sons, Ltd.     

Lexical ambiguity resolution across languages: a theoretical and empirical review

Words that involve completely different meanings across languages but possess significant overlap in form are referred to as homographic noncognates or interlexical homographs (e.g., red is a color word in English but means "net" in Spanish). An important question in the investigation of the processing of these words is whether or not both meaning and form are integral to their representation leading to language-specific processing of these items. In contrast, some theories have been put forth indicating that the processing of these words is nonselective with regards to language. Simply stated, when one of these words is encountered, all of the relevant meanings are accessed regardless of the specific demands of the task and the base language that is being used. In the present, critical review, evidence purported to favor each view is presented along with a discussion of the methodological and analytic constraints that moderate the reported findings. The data lead to the conclusion that there is a time course involved in the activation of multiple meanings such that a primary or dominant meaning (sometimes biased by frequency) is typically accessed more readily, followed by the opposite language meaning. These results indicated that studies should focus on manipulating the timing intervals between the presentation of these words and subsequent responses that are required by a particular task.     

The role of awareness in Pavlovian conditioning: empirical evidence and theoretical implications

This article reviews research over the past decade concerning the relationship between Pavlovian conditioning and conscious awareness. The review covers autonomic conditioning, conditioning with subliminal stimuli, eyeblink conditioning, conditioning in amnesia, evaluative conditioning, and conditioning under anesthesia. The bulk of the evidence is consistent with the position that awareness is necessary but not sufficient for conditioned performance, although studies suggestive of conditioning without awareness are identified as worthy of further investigation. Many studies have used inadequate measures of awareness, and strategies for increasing validity and sensitivity are discussed. It is concluded that conditioning may depend on the operation of a propositional system associated with consciousness rather than a separate, lower level system.     

The significance of occupations in work careers: An empirical and theoretical review

The central position of occupations in work careers has been a widely accepted position in the study of careers. Furthermore, it has also been commonly believed that most work careers follow the temporal sequence of occupational choice, occupational preparation and training, and occupational entry and retention. An analysis of research findings, however, shows that most individuals do not make stable occupational choices as the first step in their work careers, nor do they show a strong commitment to a particular occupation during their work careers. On the contrary, occupational mobility is far more characteristic of most work careers than occupational stability. One possible explanation of the high rates of occupational mobility is that individuals are responding to opportunities that develop during the course of their careers. As opportunities unfold during work careers, individuals use those opportunities to make future career and occupational choices. Thus, careers may be more accurately considered as a series of responses to a succession of opportunity situations than the effort to realize a predetermined occupational goal.     

Picture-word interference is a Stroop effect: A theoretical analysis and new empirical findings

The picture-word interference (PWI) paradigm and the Stroop color-word interference task are often assumed to reflect the same underlying processes. On the basis of a PRP study, Dell’Acqua et al. (Psychonomic Bulletin & Review, 14: 717-722, 2007) argued that this assumption is incorrect. In this article, we first discuss the definitions of Stroop- and picture-word interference. Next, we argue that both effects consist of at least four components that correspond to four characteristics of the distractor word: (1) response-set membership, (2) task relevance, (3) semantic relatedness, and (4) lexicality. On the basis of this theoretical analysis, we conclude that the typical Stroop effect and the typical PWI effect mainly differ in the relative contributions of these four components. Finally, the results of an interference task are reported in which only the nature of the target – color or picture – was manipulated and all other distractor task characteristics were kept constant. The results showed no difference between color and picture targets with respect to all behavioral measures examined. We conclude that the assumption that the same processes underlie verbal interference in color and picture naming is warranted.     

The fluttering-heart illusion: a new hypothesis

The fluttering-heart illusion is a perceived lagging behind of a colour target on a background of a different colour when the two are oscillated together. It has been proposed that the illusion is caused by a differential in the perceptual latencies of different colours (Helmholtz 1867/1962), a differential in rod-cone latencies (von Kries 1896) and rod-cone interactions (von Grünau 1975, 1976 Vision Research 15 431-436, 437-440; 16 397-401; see list of references there). The purpose of this experiment was to assess the hypothesis that the fluttering-heart illusion is caused by a differential in the perceived velocities of chromatic and achromatic motion. To evaluate this hypothesis, we tested observers possessing normal colour vision and deuteranopes. The perceived delay of a chromatic target relative to an achromatic target was measured as a function of background cone contrast and target colour. For observers with normal colour vision, the perceived delay of the chromatic target is greater in the L-S than the L-M testing conditions. The reverse is observed in deuteranope observers. We suggest that this is caused by the absence of an L-M opponent mechanism contributing to chromatic motion in deuteranopes. Greater background cone contrasts tended to yield smaller perceived delays in both normal and deuteranope observers, indicating that greater chromatic modulation decreases the perceived delay of the colour target. These results support the hypothesis that the fluttering-heart illusion can be explained by a differential in the perceived velocities of chromatic and achromatic motion.     

Scientific explanation,unifying mathematics,and indispensability arguments (A new Cicada MES)

Synthese - Indispensability arguments occupy a prominent role in discussions of mathematical realism. While different versions of these arguments are discussed in the literature, their general...     

A new dynamic visual illusion: The bending hourglass

Attention, Perception, & Psychophysics - A white hourglass moving laterally across a black surface appears to bend in such a way that the narrow portion lags behind its true position, but only...     

A test of the spatial-frequency explanation of the Müller-Lyer illusion

Previous investigations have shown that the response of spatial-frequency-specific channels in the human visual system is differentially affected by adaptation to gratings of distinct spatial frequencies and/or orientations. A study is reported of the effects of adaptation to vertical or horizontal gratings of a high or a low spatial frequency on the extent of the Brentano form of the Müller-Lyer illusion in human observers. It is shown that the illusion decreases after adaptation to vertical gratings of low spatial frequency, but seems unaffected otherwise. These results are consistent with the notion of visual channels that are spatial-frequency and orientation specific, and support the argument that the Müller-Lyer illusion may be due primarily to lower-spatial-frequency components in the Fourier spectra of the image.