Ideal Epistemic Situations and the Accessibility of Realist Truth

There is a widespread opinion that the realist idea that whether a proposition is true or false typically depends on how things are independently of ourselves is bound to turn truth, in Davidson's words, into something to which humans can never legitimately aspire. This opinion accounts for the ongoing popularity of epistemic theories of truth, that is, of those theories that explain what it is for a proposition (or statement, or sentence, or what have you) to be true or false in terms of some epistemic notion, such as provability, justifiability, verifiability, rational acceptability, warranted assertibility, and so forth, in some suitably characterized epistemic situation. My aim in this paper is to show that the widespread opinion is erroneous and that the (legitimate) epistemological preoccupation with the accessibility of truth does not warrant the rejection of the realist intuition that truth is, at least for certain types of propositions, radically nonepistemic.     

Preference for symmetry is experience dependent in newborn chicks (Gallus gallus)

Spontaneous pecking preferences toward symmetric or asymmetric stimuli were tested in newborn chicks (Gallus gallus). A preference for asymmetric patterns was found in na?ve chicks (either 24 or 48 hours old), although a preference for symmetry appeared at retest after chicks had experienced standard rearing conditions (Experiments 1 and 2). Only food-experienced chicks preferred symmetric patterns; food-deprived and hand-fed chicks did not show any preference (Experiment 3). A key factor that allowed for the emergence of a preference for symmetry may relate to the improving of pecking sensorimotor skills occurring during active food manipulation. Possible explanations are discussed for the late emergence of the preference for symmetry and for the preference for asymmetry found in na?ve chicks.     

Piagetian object permanence and its development in Eurasian jays (<Emphasis Type="Italic">Garrulus glandarius</Emphasis>)

Object permanence in Eurasian jays (Garrulus glandarius) was investigated using a complete version of the Uzgiris and Hunt scale 1. Nine hand-raised jays were studied, divided into two groups according to their different developmental stages (experiment 1, older jays: 2–3 months old, n = 4; experiment 2, younger jays: 15 days old, n = 5). In the first experiment, we investigated whether older jays could achieve piagetian stage 6 of object permanence. Tasks were administered in a fixed sequence (1–15) according to the protocols used in other avian species. The aim of the second experiment was to check whether testing very young jays before their development of “neophobia” could influence the achievement times of piagetian stages. Furthermore, in this experiment tasks were administered randomly to investigate whether the jays’ achievement of stage 6 follows a fixed sequence related to the development of specific cognitive abilities. All jays tested in experiments 1 and 2 fully achieved piagetian stage 6 and no “A not B” errors were observed. Performance on visible displacement tasks was better than performance on invisible ones. The results of experiment 2 show that “neophobia” affected the response of jays in terms of achievement times; the older jays in experiment 1 took longer to pass all the tasks when compared with the younger, less neophobic, jays in experiment 2. With regard to the achieving order, jays followed a fixed sequence of acquisition in experiment 2, even if tasks were administered randomly, with the exception of one subject. The results of these experiments support the idea that piagetian stages of cognitive development exist in avian species and that they progress through relatively fixed sequences. Electronic Supplementary Material Supplementary material is available in the online version of this article at and is accessible for authorized users.     

Perception of the stereokinetic illusion by the common marmoset (<Emphasis Type="Italic">Callithrix jacchus</Emphasis>)

Stereokinetic illusions have never been investigated in non-human primates, nor in other mammalian species. These illusions consist in the perception of a 3D solid object when certain 2D stimuli are rotated slowly in the plane perpendicular to the line of sight. The ability to perceive the stereokinetic illusion was investigated in the common marmoset (Callithrix jacchus). Four adult marmosets were trained to discriminate between a solid cylinder and a solid cone for food reward. Once learning criterion was reached, the marmosets were tested in sets of eight probe trials in which the two solid objects used at training were replaced by two rotating 2D stimuli. Only one of these stimuli produced, at least to the human observer, the stereokinetic illusion corresponding to the solid object previously reinforced. At test, the general behaviour and the total time spent by the marmosets observing each stimulus were recorded. The subjects stayed longer near the stimulus producing the stereokinetic illusion corresponding to the solid object reinforced at training than they did near the illusion corresponding to the previously non-rewarded stimulus. Hence, the common marmosets behaved as if they could perceive stereokinetic illusions.     

Infinite Forcing and the Generic Multiverse

Studia Logica - In this article we present a technique for selecting models of set theory that are complete in a model-theoretic sense. Specifically, we will apply Robinson infinite forcing to the...     

The use of spatial and local cues for orientation in domestic chicks (Gallus gallus)

Animal Cognition - Birds have been widely used to study spatial orientation. However, since different birds rely on different types of visual information to find goal locations (such as spatial...     

Face detection in complex visual displays: an eye-tracking study with 3- and 6-month-old infants and adults

The ability to detect and prefer a face when embedded in complex visual displays was investigated in 3- and 6-month-old infants, as well as in adults, through a modified version of the visual search paradigm and the recording of eye movements. Participants (N=43) were shown 32 visual displays that comprised a target face among 3 or 5 heterogeneous objects as distractors. Results demonstrated that faces captured and maintained adults' and 6-month-olds' attention, but not 3-month-olds' attention. Overall, the current study contributes to knowledge of the capacity of social stimuli to attract and maintain visual attention over other complex objects in young infants as well as in adults.     

Use of the gait deviation index for the evaluation of patients with Parkinson's disease

The authors aimed to determine whether the Gait Deviation Index (GDI) could be feasible to characterize gait in patients with Parkinson's disease (PD) and evaluate outcomes of levodopa treatment. Twenty-two PD participants were evaluated with clinical examination and 3-D quantitative gait analysis (GDI was calculated from gait analysis) in 2 states (OFF and ON) after taking levodopa. Twenty age-matched healthy participants (CG) were included as controls. The GDI value in the OFF state was 83.4 ± 11.5 (statistically different from CG) while clinical scales demonstrated a moderate-severe gait impairment of these patients. Significant improvements are evident from clinical scores and by GDI values in the ON state. The mean GDI for the ON state (GDI(ON): 87.9 ± 10.4) was significantly higher than in for the OFF state (GDI(OFF): 83.4 ± 11.5), indicating a global gait improvement after the treatment. The results show that GDI has lower value as an indicator of pathology in PD patients than in quantifying the effects of levodopa treatment in PD state.     

Internalization of the thin and muscular body ideal and disordered eating in adolescence: the mediation effects of body esteem

This study investigates body esteem factors (weight-esteem and appearance-esteem) as mediators of the relationship between ‘internalization of the ideal body figure’ and disordered eating behaviors (restrained, emotional and external eating) in a community sample of adolescent males (n = 810) and females (n = 1137) from the Ontario Research on Eating and Adolescent Lifestyles (REAL) study. Mediation models were examined using a bootstrapping approach to test indirect effects and indirect contrasts. In males, weight-esteem partially mediated the relationship between muscular ideal and restrained eating; appearance-esteem partially mediated effects in the emotional and external eating regressions. In females, both weight-esteem and appearance-esteem partially mediated the relationship between thin ideal and all three forms of disordered eating; weight-esteem was a stronger mediator for restrained eating, and appearance-esteem a stronger mediator for emotional and external eating. Body esteem is important to consider for prevention and treatment of disordered eating in both genders.