Effects of stress on defensive aggression and dominance in a water competition test

Water-deprived rats in a pair competing for a single source of water quickly establish a firm relationship during which one rat drinks consistently more (dominant) than the other (submissive) animal. This relationship is formed during the first competition and is very stable during subsequent tests. Exposure of dominant rats to a severe (18 hrs immobilization), but not a mild (2 hrs immobilization), stressor reduced markedly aggressive behavior and inverted transiently the dominant submissive relationship of the pairs. Exposure of submissive rats to the severe stressor resulted in only minor reductions of aggressive behavior in these animals. Prestress anxiety predicted stress effects in the dominant animals in that high-anxious animals lost more dominant behavior and weight during stress as compared with low-anxious rats. Thus, severe stress can transiently reduce dominant but not submissive behavior during water competition and high-anxious rats are more prone to lose their aggressive behavior.     

Rigid and non-rigid kinetic depth effect with rotating discrete helices

Summary To examine the conditions in which human observers fail to recover the rigid structure of a three-dimensional object in motion we used simulations of discrete helices with various pitches undergoing either pure rotation in depth (rigid stimuli) or rotation plus stretching (non-rigid stimuli). Subjects had either to rate stimuli on a rigidity scale (Experiments 1 and 2) or to judge the amount of rotation of the helices (Experiments 3 and 4). We found that perceived rigidity depended on the pitch of the helix rather than on objective non-rigidity. Furthermore, we found that helices with a large pitch/radius ratio were perceived as highly non-rigid and that their rotation was underestimated. Experiment 5 showed that the detection of a pair of dots rigidly related (located on. the helix) against a background of randomly moving dots is easier at small phases in which the change of orientation across frames is also small. We suggest that this is because at small phases the grouping of dots in virtual lines does occur and that this may be an important factor in the perceived nonrigidity of the helices.This research was supported by MPI 60% (1987, 1988) and CNR (1986), 1987, 1988) grants to Clara Casco and Sergio Roncato and Grant CNR 90.01603.PS93 to Giorgio Ganis.     

Decision problems for classes of diagonalizable algebras

We make use of a Theorem of Burris-McKenzie to prove that the only decidable variety of diagonalizable algebras is that defined by 0=1. Any variety containing an algebra in which 01 is hereditarily undecidable. Moreover, any variety of intuitionistic diagonalizable algebras is undecidable.     

Change in Attachment Dimensions and Reflective Functioning Following Emotionally Focused Group Therapy for Binge Eating Disorder

The current study examines change in attachment variables from pre- to six months post-emotionally focused group therapy (EFGT) for binge eating disorder (BED). A clinical sample of 118 women and men with BED attended 20 sessions of EFGT and completed the Adult Attachment Interview pre- and six months post-treatment. There was a significant increase in secure attachment style classification, significant increases in Coherence of Mind and Reflective Functioning scores, and significant decreases in both unresolved/disorganized attachment style classification and scale scores from pre- to six months post-treatment. Interventions specific to EFGT, common therapeutic factors and group process interventions may have contributed to changes in these attachment variables. The current study demonstrated that EFGT is a promising treatment for facilitating change in attachment in women and men with BED.     

Neophobia is negatively related to reversal learning ability in females of a generalist bird of prey,the Chimango Caracara, <Emphasis Type="Italic">Milvago chimango</Emphasis>

In an ever-changing environment, the ability to adapt choices to new conditions is essential for daily living and ultimately, for survival. Behavioural flexibility allows animals to maximise survival and reproduction in novel settings by adjusting their behaviour based on specific information and feedback acquired in their current environments. However, a growing body of evidence indicates that an individual’s personality type can limit the extent to which the individual might behave flexibly, by influencing the way an individual pays attention to novelty and how much information it collects and stores, which in turn affects the individual’s decision-making and learning process. In this study, the behavioural flexibility of a generalist predator, the Chimango Caracara, Milvago chimango, was analysed using the reversal learning paradigm, focusing on the comparison between age classes, and the relation of learning flexibility with a personality trait, the level of neophobia. Due to the low number of male individuals captured, this study was carried out only with female birds. The results showed that age had no significant effect either on the acquisition of a stimulus-reward association, or on the capacity of reversing this previously learned association. Reversal of the response was a harder task for these birds in comparison with the initial acquisition process. The individual’s performances in the learning tasks seemed to be uncorrelated with each other, suggesting that they involve different neural mechanisms. Contrary to the general pattern observed in the majority of previous work on personality and cognition in non-human animals, the level of neophobia did not correlate with the initial associative learning performance in both adults and juveniles, yet it showed a significant negative relationship with reversal learning ability, mainly in the regressive phase of this task, for the two age classes. Our results suggest that the predatory and generalist lifestyle of female individuals of M. chimango along with the selective pressures of the environment of the individuals studied might play a critical role in the degree and direction of the linkage between novelty response and learning flexibility observed in this study.     

On Hierarchical Propositions

Journal of Philosophical Logic - There is an apparent dilemma for hierarchical accounts of propositions, raised by Bruno Whittle (Journal of Philosophical Logic, 46, 215–231, 2017): either...     

Methodological evolution and clinical application of C.G. Jung's Word Association Experiment: a follow-up study

We became interested in the clinical application of the Word Association Experiment (AE) when we decided to use Jung's theory of complexes in the psycho-diagnostic evaluation and treatment of patients applying to our Psychotherapy Out-patients Unit (Psychiatric Clinic, Milan University). In psychopathological situations, complexes with a particularly high emotional charge become autonomous and disturbing, inhibiting the ego's functions. The representations and affective states corresponding to these complexes become dominant, conditioning the expression of symptoms and the subject's relational modes. In this experimental study we started out from the basic theory that our psycho-therapeutic work should lead to a progressive change in the patient's initial complex set up. Jung's Word Association Experiment allows us to identify those words which indicate and stimulate a specific activation of the complexes for each subject via specific markers of complexes. We therefore decided to determine whether AE, administered during the first phase of clinical-diagnostic evaluation and after one year of treatment, revealed any changes occurring in the patients' set up of complexes.     

Brain, emotion and decision making: the paradigmatic example of regret

Human decisions cannot be explained solely by rational imperatives but are strongly influenced by emotion. Theoretical and behavioral studies provide a sound empirical basis to the impact of the emotion of regret in guiding choice behavior. Recent neuropsychological and neuroimaging data have stressed the fundamental role of the orbitofrontal cortex in mediating the experience of regret. Functional magnetic resonance imaging data indicate that reactivation of activity within the orbitofrontal cortex and amygdala occurring during the phase of choice, when the brain is anticipating possible future consequences of decisions, characterizes the anticipation of regret. In turn, these patterns reflect learning based on cumulative emotional experience. Moreover, affective consequences can induce specific mechanisms of cognitive control of the choice processes, involving reinforcement or avoidance of the experienced behavior.     

Spatial reorientation: the effects of space size on the encoding of landmark and geometry information

The effects of the size of the environment on animals’ spatial reorientation was investigated. Domestic chicks were trained to find food in a corner of either a small or a large rectangular enclosure. A distinctive panel was located at each of the four corners of the enclosures. After removal of the panels, chicks tested in the small enclosure showed better retention of geometrical information than chicks tested in the large enclosure. In contrast, after changing the enclosure from a rectangular-shaped to a square-shaped one, chicks tested in the large enclosure showed better retention of landmark (panels) information than chicks tested in the small enclosure. No differences in the encoding of the overall arrangement of landmarks were apparent when chicks were tested for generalisation in an enclosure differing from that of training in size together with a transformation (affine transformation) that altered the geometric relations between the target and the shape of the environment. These findings suggest that primacy of geometric or landmark information in reorientation tasks depends on the size of the experimental space, likely reflecting a preferential use of the most reliable source of information available during visual exploration of the environment.     

Inexperienced newborn chicks use geometry to spontaneously reorient to an artificial social partner

A fundamental process underlying navigation behaviour, shown to occur in every species tested, uses geometric properties of the environment for location memory and orientation. Here we employ a new method to ask whether this basic geometric orientation ability is innately predisposed in the brain or depends on specific experiences navigating in a geometrically rich environment. Using the newborn domestic chick as a model system, we present a working memory task testing reorientation towards a filial imprinting object under rigorous controlled rearing conditions. In the absence of any previous exposure to a geometrically rich environment, newly hatched chicks spontaneously recovered their bearings by making use of distances and directional relations to reorient themselves to an artificial social partner. These findings provide evidence for an innate capacity to navigate by the geometric structure of the environment.