Visual symmetry recognition by pigeons

Summary Pigeons learned to discriminate a large number of bilateral symmetric and asymmetric visual patterns successively projected on the pecking-key of an operant conditioning chamber. Responses to the positive stimuli were reinforced according to a variable interval schedule. Once acquisition was complete generalization trials, involving sets of new stimuli, were instituted under extinction. The birds classified these novel test stimuli with high accuracy throughout, according to their symmetry or asymmetry. Their performance was not disturbed by sets of test stimuli whose geometrical style differed considerably from the training stimuli. Pigeons were even able to discriminate when only allowed the use of one eye. The generalization series were partly designed to test some classical symmetry recognition theories. None was found to be adequate. Subsidiary experiments suggested that most pigeons have a slight spontaneous preference for asymmetric patterns and that symmetry/asymmetry differences can aid pattern discrimination learning at an early stage. It is concluded that pigeons, much like humans, can discriminate bilaterally symmetric from non-symmetric visual forms in a concept-like, generalizing way. The ontogenetic and phylogenetic development of this competence is considered. A novel symmetry recognition hypothesis based on spatial frequency analysis and neuronal feature-detector considerations is proposed.     

Shared lesion correlates of semantic and letter fluency in post-stroke aphasia

Lesion–symptom mapping studies have reported a temporal versus frontal dissociation between semantic and letter fluency, and mixed evidence regarding the role of white matter. Mass-univariate and multivariate lesion–symptom mapping was used to identify regions associated with semantic and letter fluency deficits in post-stroke aphasia. Multivariate LSM revealed broad networks including underlying white matter, and substantial overlap between both types of fluency, suggesting that semantic fluency and letter fluency largely rely on the same neural system. All data are available on OSF.     

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Do Existential Variables Mediate Between Religious-Spiritual Facets of Functionality and Psychological Wellbeing

Religiosity has been related to psychological wellbeing outcomes. Although this relationship is primarily based on studies of church attendance or prayer and wellbeing, more recent work has focused on the potential mechanisms that may mediate the religion-wellbeing findings. One of the major function of religion is finding of meaning of life and improving hope. Recent studies have indicated that hope and meaning of life are the potential variables mediate between religion and wellbeing. It was hypothesized that one pathway through which religiosity may exert its positive influence on psychological wellbeing is through finding meaning of life and improving hope. One study was conducted examining the relationships among spiritual experiences, hope, meaning of life and psychological wellbeing operationalized as satisfaction with life, positive affect and negative affect. The following research tools were used: Daily Spiritual Experiences Scale, Purpose in Life Test, Hearth Hope Index, Cantril Ladder, Positive and Negative Affect Schedule. Meaning of life and hope were noticed to mediate between spiritual experiences and satisfaction with life as well as between spiritual experiences and positive affect. Spiritual experiences were not related to negative affect. Both meaning of life and hope predicted negative affect. This study found meaning of life and hope to be an important factors in the religion-wellbeing relationship and related to positive psychological outcomes, including improved satisfaction with life and positive affect as well as reduced negative affect.     

On Some Generalizations of the Concept of Partition

There are well-known isomorphisms between the complete lattice of all partitions of a given set A and the lattice of all equivalence relations on A. In the paper the notion of partition is generalized in order to work correctly for wider classes of binary relations than equivalence ones such as quasiorders or tolerance relations. Some others classes of binary relations and corresponding counterparts of partitions are considered.