Do chimpanzees anticipate an object’s weight? A field experiment on the kinematics of hammer-lifting movements in the nut-cracking Taï chimpanzees

When humans are about to manipulate an object, our brains use visual cues to recall an internal representation to predict its weight and scale the lifting force accordingly. Such a long-term force profile, formed through repeated experiences with similar objects, has been proposed to improve manipulative performance. Skillful object manipulation is crucial for many animals, particularly those that rely on tools for foraging. However, despite enduring interest in tool use in non-human animals, there has been very little investigation of their ability to form an expectation about an object’s weight. In this study, we tested whether wild chimpanzees use long-term force profiles to anticipate the weight of a nut-cracking hammer from its size. To this end, we conducted a field experiment presenting chimpanzees with natural wooden hammers and artificially hollowed, lighter hammers of the same size and external appearance. We used calibrated videos from camera traps to extract kinematic parameters of lifting movements. We found that, when lacking previous experience, chimpanzees lifted hollowed hammers with a higher acceleration than natural hammers (overshoot effect). After using a hammer to crack open one nut, chimpanzees tuned down the lifting acceleration for the hollowed hammers, but continued lifting natural hammers with the same acceleration. Our results show that chimpanzees anticipate the weight of an object using long-term force profiles and suggest that, similarly to humans, they use internal representations of weight to plan their lifting movements.     

Communication of Genetic Risk Information to Daughters in Families with Fragile X Syndrome: The Parent’s Perspective

Parental approaches to communicating information about genetic disorders to their children may be an important determinant in how the children manage stress as well as their adjustment and adaptation to that information. We explored communication patterns through structured interviews with 46 parents of daughters who learned about their genetic risk status as minors. Three different levels of knowledge about fragile X syndrome were explored: 1) informing that it has been diagnosed in the family and is an inherited disorder, 2) informing about the possibility of a daughter being a carrier, and 3) if testing had been done, informing the daughter of her actual carrier status. Additionally, parental perceptions of their daughter’s understanding of the information were explored along with frequency of discussions. We found that communication about genetic risk was initiated by the parents. Five disclosure patterns were identified with variations in style, content, and frequency of communication related to the information that was being disclosed. Aspects of resilient communication were present for all levels of disclosure; however, as the information became more personally relevant for the daughter such as disclosure about the possibility of “being a carrier” for fragile X syndrome and there was uncertainty regarding potential outcomes, the conversations included fewer resilient characteristics. Uncertainty about what and how to present information may negatively affect a parent’s ability to include elements of resilient communication when disclosing genetic risk information.     

Spatial navigation in complex and radial mazes in APP23 animals and neurotrophin signaling as a biological marker of early impairment

Impairment of hippocampal function precedes frontal and parietal cortex impairment in human Alzheimer's disease (AD). Neurotrophins are critical for behavioral performance and neuronal survival in AD. We used complex and radial mazes to assess spatial orientation and learning in wild-type and B6-Tg(ThylAPP)23Sdz (APP23) animals, a transgenic mouse model of AD. We also assessed brain content of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3). Performance was alike in wild-type and APP23 animals in the radial maze. In contrast, performance in the complex maze was better in wild-type than APP23 animals. Contrary to the wild-type, hippocampal BDNF levels decreased on training in APP23 animals. Hippocampal and frontal cortex NGF levels in APP23 animals correlated with the time to solve the complex maze, but correlated inversely with escape time in wild-type animals. NT-3 levels were alike in wild-type and APP23 animals and were unchanged even after training. Both types of mazes depend on hippocampal integrity to some extent. However, according to the cognitive mapping theory of spatial learning, the complex maze because of the increased complexity of the environment most likely depends more strongly on preserved hippocampal function than the radial maze in the working memory configuration applied here. Greater impairment in complex maze performance than in radial maze performance thus resembles the predominant affliction of the loss of hippocampal function in human AD. NGF and BDNF levels on maze learning are different in wild-type and transgenic animals, indicating that biological markers of AD may be altered on challenge even though equilibrium levels are alike.     

Adaptation of panic-related psychopathology measures to Russian

The study reports results of adaptation of panic-related psychopathology measures to Russian, including the Anxiety Sensitivity Index (ASI), the Agoraphobic Cognitions Questionnaire (ACQ), and the Mobility Inventory for Agoraphobia (MIA). Psychometric properties (e.g., reliability, factor structure, endorsement) and external validity of the adaptations were evaluated in a representative sample of Moscow residents (N = 390) and Ukrainian undergraduates (N = 492). The adapted ASI was generally equivalent to the original English-language version. The ACQ showed structural equivalency but did not exhibit expected specificity to panic. Finally, the MIA displayed notable structural discrepancies but had external validity comparable to the original.     

Diathesis stress model for panic-related distress: a test in a Russian epidemiological sample

To investigate a cognitive diathesis-stress model, the present study evaluated the main and interactive effects of anxiety sensitivity (AS) and exposure to aversive conditions (past month) in predicting theoretically relevant panic vulnerability variables in an epidemiologically defined sample from Russia (N = 390). Consistent with expectation, findings suggested that the combination of high levels of exposure to aversive conditions and high AS physical concerns predicted panic attacks (past week) and agoraphobic avoidance above and beyond the variance accounted for by negative affect. These findings are discussed in relation to biopsychosocial theories of panic disorder, which emphasize the importance of both a cognitive diathesis and stress component in the pathogenesis of the disorder.     

The “Incompatible Idea” Revisited: The Oft-Invisible Ego-Ideal and Shame Dynamics

The observation that incompatibility with conscience initiates deployment of defense goes back to Freud's conceptualization of the "incompatible idea" put forward in Studies on Hysteria. In this view, consciousness itself, insofar as it gives rise to painful affect resulting from conflict with the conscience, is the cornerstone for dynamic thinking, first as regards repression of traumatic memory and later for dynamic thinking generally. Subsequent discoveries about the conscience tended to give rise to pars pro toto thinking in which the new discovery replaced rather than added to the basic notion of conscience. Such pars pro toto imbalance exists in full force in psychoanalytic thinking today: Modern conflict theory privileges the postoedipal retaliative aspect of the conscience, as Kleinian thinking does for the preoedipal projective aspects of retaliation. Neither conceptualizes shame adequately. Kohut appreciated the role of shame, but discarded the notion of incompatibility with the ego-ideal. The incompatible idea model still provides an all-inclusive model for conceptualizing the conscience in the context of intrapsychic conflict.     

Abortion attitudes and personality

Attitudes toward abortion were predicted by age, sex, and religiosity but not personality in a sample of 99 college students.