Clues for dominance in female chamois: Age,weight, or horn size?

A study of social interactions among female Apennine chamois Rupicapra pyrenaica ornata was made in Abruzzo National Park, central Italy, between 1981 and 1982. A linear hierarchy among females was observed, rank order being highly correlated with age, weight, and horn size. An analysis of which physical clues are used by females to assess dominance suggests that body weight may be the most important attribute. The percentages of threats and dominance displays decrease beyond 7–8 years of age when females usually start to lose weight, whereas horns keep growing throughout life. Furthermore, the greater effect of weight compared to that of horn size on the rank/age correlation supports our conclusion.     

The number–weight illusion

Psychonomic Bulletin & Review - When objects are manually lifted to compare their weight, then smaller objects are judged to be heavier than larger objects of the same physical weights: the...     

When is a weight not illusory?

Weight illusions occur whenever some aspect of an object--such as its size, material or colour--arouses the expectation that its weight will be heavier or lighter than it actually is. The direction of the illusion normally contrasts with the expected weight. When objects are hidden from sight and lifted by strings they can provide no misleading cues, and a correct weight-expectation should be achieved after one or two trials. When a visible object has the same physical and apparent weight as a hidden object, it can be defined as non-illusory. Weighted tins and polystyrene blocks of various sizes were compared with hidden weights. Tins were found to be non-illusory when their density was about 1.7, and polystyrene blocks when their density was about 0.14.

Weight illusions may be due to a central scaling process which enables a wide range of weights to be estimated, different ranges being selected according to the expected value of the weight. If the selected range is inappropriate an illusion occurs. Changes in expected value could also allow for the operation of “weight-constancy” during changes in proprioceptive stimulation.     

The locus of “memory displacement” is at least partially perceptual: Effects of velocity, expectation, friction, memory averaging, and weight

When observers are asked to localize the final position of a moving target, the judged position is usually displaced from the actual position. It has been suggested that mental processes derived from a number of invariant and noninvariant principles produce the mislocalization in memory. In this study, the effects of velocity, expectation, friction, memory averaging, and weight were reconsidered, and evidence was accumulated that supports the alternative view that the distortions arise to a large degree at a perceptual level. Effects of velocity and expectation were present when observers still perceived a persisting image of the target. It is suggested that the active reorienting of the perceptual organs explains the distortions. Furthermoremore, distortions of the perceived center of a visible stimulus may explain effects that have previously been attributed to memory averaging and mental analogues of weight. Thus, the locus of memory displacement is at least partially perceptual.     

Weightlifting exercise and the size–weight illusion

In the size–weight illusion (SWI), large objects feel lighter than equally weighted small objects. In the present study, we investigated whether this powerful weight illusion could influence real-lift behavior—namely, whether individuals would perform more bicep curls with a dumbbell that felt subjectively lighter than with an identically weighted, but heavier-feeling, dumbbell. Participants performed bicep curls until they were unable to continue with both a large, light-feeling 5-lb dumbbell and a smaller, heavy-feeling 5-lb dumbbell. No differences emerged in the amounts of exercise that participants performed with each dumbbell, even though they felt that the large dumbbell was lighter than the small dumbbell. Furthermore, in a second experiment, we found no differences in how subjectively tired participants felt after exercising for a set time with either dumbbell. We did find, however, differences in the lifting dynamics, such that the small dumbbell was moved at a higher average velocity and peak acceleration. These results suggest that the SWI does not appear to influence exercise outcomes, suggesting that perceptual illusions are unlikely to affect one’s ability to persevere with lifting weights.     

Are inaccuracies in self-reported weight motivated distortions?

The accuracy of self-reported weight and the motivation of distorted reporting were studied among 169 female and 101 male college students. Although subjects were moderately accurate in their weight estimates, errors reflected women's underreporting, men's overreporting, and heavier persons' underreporting. With body mass controlled, most motivational variables had little explanatory value.     

Self-perceived weight in adolescents: Over-estimation or under-estimation?

Prevalence of obesity has increased worldwide in the past 20 years, but it is not known whether this has resulted in increased numbers of young adults feeling overweight. This study evaluated weight self-perception in a large, multi-ethnic sample of 14-15 years old (n=4167) in London, UK as part of a longitudinal, school-based study of health behaviours. Weight perceptions were recorded on a simple scale from 'too thin' to 'too fat'. Results indicated that under-estimation was more common than over-estimation, with more than a quarter of overweight or obese adolescents unaware of their excess weight. Under-estimation was greatest among boys and ethnic minorities. It may be timely to reassess weight control advice given to adolescents.     

The material–weight illusion induced by expectations alone

In the material-weight illusion (MWI), equally weighted objects that appear to be made from different materials are incorrectly perceived as having different weights when they are lifted one after the other. Here, we show that continuous visual experience of the lift is not a prerequisite for this compelling misperception of weight; merely priming the lifters' expectations of heaviness is sufficient for them to experience a robust MWI. Furthermore, these expectations continued to influence the load force used to lift MWI-inducing stimuli trial after trial, supporting the notion that vision plays an important role in the skillful lifting of objects.     

Should medicare reimburse providers for weight loss interventions?

This issue of the American Psychologist (April 2007) includes two reviews of the literature on the effects of behavioral programs to reduce body weight. One review (T. Mann et al., 2007) concentrates on dietary interventions and finds little evidence that diets are of benefit. The second review (L. H. Powell, J. E. Calvin III, & J. E. Calvin Jr., 2007) concentrates on multicomponent interventions and reports some significant achievements of behavioral interventions. Although the reviews come to different conclusions about the value of supporting weight loss interventions, there appears to be agreement that diet alone results in little or no long-term benefit. Evidence-based multicomponent behavioral interventions or interventions that combine behavioral with medical or surgical treatments may offer better chances of long-term weight control. Evidence-based studies are needed to inform policy on provider reimbursement for weight loss programs.     

Positive fantasies or negative contrasts: The effect of media body ideals on restrained eaters’ mood,weight satisfaction,and food intake

Although viewing media body ideals promotes body dissatisfaction and problematic eating among women (e.g., extreme restraint/overeating), some argue that women only report such negative effects because they think that they are meant to (i.e., demand characteristics). Because restrained eaters are trying to lose weight, they might be vulnerable to such media exposure. However, because of demand characteristics, evidence is mixed. Therefore, we minimized demand characteristics and explored whether media body ideals would trigger restrained eaters to report negative (negative mood, weight dissatisfaction) or positive (positive mood, weight satisfaction) effects. We also hypothesized that this change (negative or positive) would encourage food intake. Restrained and unrestrained eaters (n = 107) memorized media or control images. Restrained eaters exposed to media images reported decreased weight satisfaction and increased negative mood, but their food intake was not significantly affected. Perhaps paying advertent attention to the images caused goal-related negative affect, which triggered restraint.     

Effects of massage intervention on discharged premature infants’ weight,parental stress,and parent–child attachment: A randomized controlled trial

Infant massage enhances the growth and development of premature infants and promotes parent–child bonding. However, its effects on parental stress and parent–child attachment in premature infants, as well as gender differences thereof, remain unclear. In this randomized controlled trial, we used a repeated-measures design and included 61 premature infants (mean gestational age: 35.1 ± 1.5 weeks). Weight, parental stress, and parent–child attachment were measured at multiple time points: before massage and 1, 4, 8, and 12 weeks after commencing infant massage. The results revealed that the massage group infants had significantly higher weight gain than the control (no massage) group infants at all four time points. Moreover, parents in the massage group reported notably lower levels of stress than those in the control group, particularly in the parental distress and difficult children subscales. No significant between-group differences were observed in parent–child attachment. Furthermore, no significant differences were observed between fathers and mothers in parental stress and parent–child attachment. However, fathers reported higher levels of distress than mothers at 4 and 12 weeks. In conclusion, infant massage led to increased infant weight and reduced parental stress over time, and differences between fathers and mothers were not significant, except fathers exhibiting higher levels of distress than mothers over time. Healthcare professionals should educate and support parents on infant massage before discharge of premature infants.     

Do children think that inheritance determines height and weight?

Three studies were conducted to investigate if children think that physical growth is determined by inheritance. All three studies employed the “switched‐at‐birth” task. Study 1 investigated if children and adults thought that height and weight were determined by parentage. Study 2 examined preschoolers and elementary school children's and adults' understanding of the role of parentage and nutrition in determining weight. Study 2a examined children's and adults' understanding of the role of parentage and nutrition in determining height. Results indicate that overall, preschoolers and third graders have more of an inheritance bias for height than for weight. However, when nutrition was introduced, apart from third graders, all other grades reasoned that nutrition played a greater role in determining weight. Overall, these results indicate that even young children have a rudimentary but differentiated theory of the role of inheritance in determining height and weight.

Highlights

• Participants were presented with switched‐at‐birth tasks to determine if they thought that parentage and/or nutrition influences height and weight.
• Young children viewed height as determined more by parentage than weight, suggesting that they have a differentiated and autonomous theory for the determination of height.

     

Great apes’ performance in discriminating weight and achromatic color

Much work has been done on visual discrimination in primates over the past decade. In contrast, very little is known about the relevance of non-visual information in discrimination learning. We investigated weight and achromatic color (color, henceforth) discrimination in bonobos, gorillas and orangutans, using the exchange paradigm in which subjects have to give objects to the experimenter in order to receive a reward. Unlike previous studies, subjects were not trained to lift objects because lifting the objects was an integral part of the exchange procedure. This methodology also allowed us a direct comparison between visual and weight discrimination. We presented 12 subjects (5 bonobos, 2 gorillas and 5 orangutans) with two sets of objects corresponding to two conditions. The objects in the color condition (white/black) differed only in color and those in the weight condition (light/heavy) differed only in weight. Five apes learned to discriminate weight and six to discriminate color. Subjects learned color discrimination faster than weight discrimination. Our results suggest that bonobos and orangutans are sensitive to differences in weight and able to learn discriminating objects that differ in this property.     

Charpentier (1891) on the size—weight illusion

This paper offers background for an English translation of an article originally published in 1891 by Augustin Charpentier (1852–1916), as well as a summary of it. The article is frequently described as providing the first experimental evidence for the size—weight illusion. A comparison of experiments on the judged heaviness of lifted weights carried out by Weber (1834) and by Charpentier (1891) supports the view that Charpentiers work deserves priority; review of other experimental studies on the size-weight illusion in the 1890s suggests that the idea that the illusion depended on “disappointed expectations,” especially with respect to speed of lift, became dominant almost immediately following the publication of Charpentiers paper. The fate of this and other ideas, including “motor energy,” in 20th-century research on the illusion is briefly described.     

‘It’s not a diet,it’s a lifestyle’: a longitudinal,data-prompted interview study of weight loss maintenance

Objective: To advance understanding of the individual and environmental factors underpinning weight loss maintenance. Design: Semi-structured, data-prompted interviews were conducted with twelve overweight adult participants (three men, nine women) who had lost over 5% of their body weight in the year before baseline. Participants gathered daily data through wireless scales, activity monitors (Fitbit?), ecological momentary assessment and experience sampling (taking photographs, writing notes). They were interviewed at 3- and 6-months post baseline. Interview stimuli included personal data of weight and activity graphs, correlations of psychological factors, and self-generated notes and photographs. Interview data were analysed using the Framework Method, applying pre-specified maintenance-relevant theoretical themes. Results: The theoretical Framework provided a good fit for the narratives, with five main themes underpinning successful weight loss maintenance: sustained motivation, effective self-regulation, plentiful resources, habit formation and a supportive environment. Additionally, participants reported an identity shift from being a dieter to accepting a new healthy lifestyle. Goal prioritising and allowing for occasional controlled lapses enhanced weight loss maintenance. Conclusions: This study successfully used the novel method of data-prompted interviews to explore weight loss maintenance experiences with new explanations emerging from the data. Future research should further develop behaviour change maintenance theory and data-prompted interview method.     

Do capuchin monkeys use weight to select hammer tools?

The extent to which tool-using animals take into account the properties of the tool is little explored. The use of percussors to crack open encapsulated fruit is a complex form of tool use, the choice of an adequate tool being a critical aspect in success. Several properties (e.g., material, resistance, friability, shape and weight) affect the suitability of an object to open a hard-shelled nut, with weight being amongst the most important factors. In general, heavier tools require fewer strikes to crack open a nut.     

The dopamine D4 receptor gene,birth weight,maternal depression,maternal attention,and the prediction of disorganized attachment at 36 months of age: A prospective gene × environment analysis

BackgroundEfforts to understand the developmental pathways for disorganized attachment reflect the importance of disorganized attachment on the prediction of future psychopathology. The inconsistent findings on the prediction of disorganized attachment from the dopamine D4 receptor (DRD4) gene, birth weight, and maternal depression as well as the evidence supporting the contribution of early maternal care, suggest the importance of exploring a gene by environment model.MethodsOur sample is from the Maternal Adversity, Vulnerability, and Neurodevelopment project; consisting of 655 mother–child dyads. Birth weight was cross-referenced with normative data to calculate birth weight percentile. Infant DRD4 genotype was obtained with buccal swabs and categorized according to the presence of the 7-repeat allele. Maternal depression was assessed with the Center for Epidemiologic Studies Depression Scale at the prenatal, 6-, 12-, and 24-month assessments. Maternal attention was measured at 6-months using a videotaped session of a 20-min non-feeding interaction. Attachment was assessed at 36-months using the Strange Situation Procedure.ResultsThe presence of the DRD4 7-repeat allele was associated with less disorganized attachment, β = −1.11, OR = 0.33, p = 0.0008. Maternal looking away frequency showed significant interactions with maternal depression at the prenatal assessment, β = 0.003, OR = 1.003, p = 0.023, and at 24 months, β = 0.004, OR = 1.004, p = 0.021, as at both time points, women suffering from depression and with frequent looking away behavior had an increased probability of disorganized attachment in their child, while those with less looking away behavior had a decreased probability of disorganized attachment in their child at 36 months.ConclusionsOur models support the contribution of biological and multiple environmental factors in the complex prediction of disorganized attachment at 36 months.     

How much weight do organizational personality inferences have on judgments of organizations?

Organizational personality inferences are the human-like attributes individuals ascribe to organizations. Extant research has shown that individuals reliably distinguish organizations on these traits and these inferences influence individuals’ judgments of organizations. Theory of Symbolic Attraction posits that the importance given to organizational personality when forming judgments depends on the needs of the person. This policy capturing study investigated how much weight individuals give to each personality factor when forming organizational judgments and tested propositions that social identity concerns moderate the weight given. Results were also compared to the aggregated effects from extant research. Organizational personality inferences directly affected organizational judgments, some of these effects were moderated by social identity concerns, and the pattern of results were different than past research.     

Maintenance of weight loss after obesity treatment: is continuous support necessary?

OBJECTIVE: This study examined outcome differences of 109 obese subjects, who participated in a 10-week cognitive-behavioral inpatient treatment followed by either a weight maintenance program or a follow-up period without professional support. METHODS: Self-rated weight loss, eating behaviors, and general psychopathology were assessed several months before treatment, when subjects were admitted, at discharge, and at the 6-, 12-, and 18-month follow-ups. Structured interviews for mental disorders and eating pathology were conducted additionally. RESULTS: The mean weight of the sample at baseline was 127 kg. Weight loss of the total sample amounted to 8.0 kg (6.3%) and was completely maintained during the follow-up period. Significant reductions of eating and general psychopathology were observed at the 18-month follow-up. The outcome in the maintenance condition did not significantly differ from the outcome in the control condition. CONCLUSIONS: Weight regain after obesity treatment is not inevitable, but continuous patient-therapist contacts do not distinctly improve treatment effects.