Effects of 3-D complexity on the perception of 2-D depictions of objects

In a recent study, Pelli (1999 Science 285 844-846) performed a set of perceptual experiments using portrait paintings by Chuck Close. Close's work is similar to the 'Lincoln' portraits of Harmon and Julesz (1973 Science 180 1194-1197) in that they are composite images consisting of coarsely sampled, individually painted, mostly homogeneous cells. Pelli showed that perceived shape was dependent on size, refuting findings that perception of this type is scale-invariant. In an attempt to broaden this finding we designed a series of experiments to investigate the interaction of 2-D scale and 3-D structure on our perception of 3-D shape. We present a series of experiments where field of view, 3-D object complexity, 2-D image resolution, viewing orientation, and subject matter of the stimulus are manipulated. On each trial, observers indicated if the depicted objects appeared to be 2-D or 3-D. Results for face stimuli are similar to Pelli's, while more geometrically complex stimuli show a further interaction of the 3-D information with distance and image information. Complex objects need more image information to be seen as 3-D when close; however, as they are moved further away from the observer, there is a bias for seeing them as 3-D objects rather than 2-D images. Finally, image orientation, relative to the observer, shows little effect, suggesting the participation of higher-level processes in the determination of the 'solidness' of the depicted object. Thus, we show that the critical image resolution depends systematically on the geometric complexity of the object depicted.     

Something from nothing: exploring dimensions of children's knowing through the repeated reading of favourite books

Witte‐Townsend and DiGiulio explore some of the dimensions of knowing that children, teachers and parents may engage together during story‐time. They reflect on some of their own long‐term relationships with children and children's books, especially Phoebe Gilman's Gilman P 1992 Something from nothing (New York, NY, Scholastic Inc)  [Google Scholar] Something from nothing (published in 1992) and Simms Taback's Taback S 1999 Joseph had a little overcoat (New York, NY, Viking‐Penguin)  [Google Scholar] Joseph had a little overcoat, published in 1999. The authors probe issues such as why children ask to hear a favourite story over and over and why they suddenly abandon all interest and move on to a new book. They explore the meaning of the silences that sometimes arise during story‐time, pooling around the young listeners as the last words of the book are read. Witte‐Townsend and DiGiulio remind us of the value of literature in the lives of children and they affirm that the reading and re‐reading of favourite stories enables the understanding of complex human issues and contributes significantly to social, emotional and spiritual growth.     

Adjustment to chronic low back pain--the relative influence of fear-avoidance beliefs, catastrophizing, and appraisals of control

The present study investigated the relative extent to which patients' adjustment to chronic low back pain (CLBP) was influenced by their fear-avoidance beliefs, their tendency to catastrophize, and their appraisals of control. Eighty-three CLBP patients completed a series of self-report measures before participating in a physical therapist-led intervention. Hierarchical multiple regression analyses revealed that patients' perceptions of their ability to decrease pain explained a small, but statistically significant, proportion of the variance in pain intensity. In addition, patients' levels of catastrophizing, as well as their fear-avoidance beliefs about both work and physical activity, were independently associated with levels of disability. Interestingly, however, when exploring the relative predictive utility of these three psychological factors, it became evident that fear-avoidance beliefs about physical activity (FABs-PA) were the only significant predictor of patients' disability. Specifically, those patients who exhibited higher levels of FABs-PA tended to report greater levels of disability, even after adjusting for age, sex and pain intensity.     

Relating distinctive orthographic and phonological processes to episodic memory performance

Three experiments examined the role of three distinctive perceptual factors in recognition and recall memory. Using a subject-paced presentation rate, the first two experiments (recognition and recall) examined (1) the number of phonological-to-orthographic neighbors, (2) phonological-to-orthographic consistency, and (3) orthographic-to-phonological consistency. The third experiment (recall) reexamined the number of phonological-to-orthographic neighbors, using an experimenter-paced presentation rate of 2 sec per item. In both recognition and recall memory tasks, the number of phonological-to-orthographic neighbors influenced memory performance, whereas the two types of consistency did not. The results indicate that having fewer phonological-to-orthographic neighbors (i.e., having distinct mappings between orthography and phonology, and between phonology and orthography, e.g., pulp) relieve words from interference in episodic memory tests for such words. Furthermore, words that are indistinct in terms of these mappings (e.g., tuck) are subject to interference from words with similar representations (e.g., luck, buck, stuck), and this weakens the memory trace for a particular word.     

Attempting to avoid false memories in the Deese/Roediger—McDermott paradigm: Assessing the combined influence of practice and warnings in young and old adults

On each of five study-test trials, young and old adults attempted to memorize the same list of 60 words (e.g., bed, rest, awake), which were blocked according to their convergence on four corresponding associates. Half of the participants in each age group were given an explicit warning about the DRM paradigm prior to encoding and were asked to attempt to avoid recalling any associated but nonpresented words (e.g., sleep). Lists were presented auditorily at either a fast (1,250 msec/word) or a slow (2,500 msec/word) rate. Without a warning, the probability of veridical recall across trials increased for both age groups; however, the probability of false recall across trials decreased only for young adults. When a warning about false recall was provided, young adults virtually eliminated false recall by the second trial. Even though old adults also used warnings to reduce false recall on Trial 1, they were still unable to decrease false memories across the remaining four study-test trials. Old adults also reduced false recall more with slow than with fast presentation rates. Taken together, these findings suggest that old adults have a breakdown in spontaneous, self-initiated source monitoring as reflected by little change in false recall across study-test trials but a preserved ability to use experimenter-provided warnings or slow presentation rates to reduce false memories.     

Holography does not account for goodness: a critique of van der Helm and Leeuwenberg (1996)

P. A. van der Helm and E. L. J. Leeuwenberg (1996) outlined a holographic account of figural goodness of a perceptual stimulus. The theory is mathematically precise and can be applied to a broad spectrum of empirical data. The authors argue, however, that the account is inadequate on both theoretical and empirical grounds. The theoretical difficulties concern the internal consistency of the account and its reliance on unspecified auxiliary assumptions. The account also makes counterintuitive empirical predictions, which do not fit past data or the results of a series of new experimental studies.     

Verb deficits in Alzheimer's disease and agrammatism: implications for lexical organization

This study examined the nature of verb deficits in 14 individuals with probable Alzheimer's Disease (PrAD) and nine with agrammatic aphasia. Production was tested, controlling both semantic and syntactic features of verbs, using noun and verb naming, sentence completion, and narrative tasks. Noun and verb comprehension and a grammaticality judgment task also were administered. Results showed that while both PrAD and agrammatic subjects showed impaired verb naming, the syntactic features of verbs (i.e., argument structure) influenced agrammatic, but not Alzheimer's disease patients' verb production ability. That is, agrammatic patients showed progressively greater difficulty with verbs associated with more arguments, as has been shown in previous studies (e.g., Kim & Thompson, 2000; Thompson, 2003; Thompson, Lange, Schneider, & Shapiro, 1997), and suggest a syntactic basis for verb production deficits in agrammatism. Conversely, the semantic complexity of verbs affected PrAD, but not agrammatic, patients' performance, suggesting "bottom-up" breakdown in their verb lexicon, paralleling that of nouns, resulting from the degradation or loss of semantic features of verbs.     

Life and mind: From autopoiesis to neurophenomenology. A tribute to Francisco Varela

This talk, delivered at De l'autopoièse à la neurophénoménologie: un hommage à Francisco Varela; from autopoiesis to neurophenomenology: a tribute to Francisco Varela, June 18–20, at the Sorbonne in Paris, explicates several links between Varela's neurophenomenology and his biological concept of autopoiesis.     

The Physical Appearance Ambiguous Feedback Scale (PAAFS): a measure for indexing body image related cognitive bias

Recent conceptualizations of body image disturbance have included an information processing model that includes a focus on an interpretive information processing bias. Study 1 involved the development and validation of a measure of appearance-based cognitive bias, the Physical Appearance Ambiguous Feedback Scale (PAAFS). In Studies 2 and 3, two samples of college females (n=313) were tested and the psychometric characteristics of the PAAFS were evaluated. Reliability was acceptable and convergence with measures of body image and eating disturbance was moderate. In Study 4, 313 college females completed the PAAFS in the laboratory based on an instructional content designed to induce processing bias. Preliminary evidence indicates that the PAAFS appears to be sensitive to instructional set manipulations and dispositional level of body dissatisfaction.     

The effects of extinction,noncontingent reinforcement and differential reinforcement of other behavior as control procedures

Several techniques have been used in applied research as controls for the introduction of a reinforcement contingency, including extinction, noncontingent reinforcement (NCR), and differential reinforcement of other behavior (DRO). Little research, however, has examined the relative strengths and limitations of these "reversal" controls. We compared the effects of extinction with those of NCR and DRO in both multi-element and reversal designs, with respect to (a) rate and amount of response decrement, (b) rate of response recovery following reintroduction of reinforcement, and (c) any positive or negative side effects associated with transitions. Results indicated that extinction generally produced the most consistent and rapid reversal effects, with few observed negative side effects.