Logics of Synonymy

Journal of Philosophical Logic - We investigate synonymy in the strong sense of content identity (and not just meaning similarity). This notion is central in the philosophy of language and in...     

The comparative psychology of same-different judgments by humans (Homo sapiens) and monkeys (Macaca mulatta)

The authors compared the performance of humans and monkeys in a Same-Different task. They evaluated the hypothesis that for humans the Same-Different concept is qualitative, categorical, and rule-based, so that humans distinguish 0-disparity pairs (i.e., same) from pairs with any discernible disparity (i.e., different); whereas for monkeys the Same-Different concept is quantitative, continuous, and similarity-based, so that monkeys distinguish small-disparity pairs (i.e., similar) from pairs with a large disparity (i.e., dissimilar). The results supported the hypothesis. Monkeys, more than humans, showed a gradual transition from same to different categories and an inclusive criterion for responding Same. The results have implications for comparing Same-Different performances across species--different species may not always construe or perform even identical tasks in the same way. In particular, humans may especially apply qualitative, rule-based frameworks to cognitive tasks like Same-Different.     

Evidence for adaptive shoulder-elbow control in cyclical movements with different amplitudes, frequencies, and orientations

The evolution of joint dynamics and muscle patterning in the shoulder and elbow was studied for cyclical line drawing tasks at different frequencies, amplitudes, and orientations in the horizontal plane. Three main modes of control were identified: elbow-centered, shoulder-centered, and elbow-shoulder, each referring to the principal joints or joint combinations that were used to achieve the behavioral goals. The contribution of the shoulder joint was most prominent across the majority of movement orientations and largely paralleled changes in the dynamic (inertial) forces in the end effector (shoulder-centered control). The two joints either exchanged roles during the performance of the right diagonal movement (elbow-centered control) or shifted from a single-joint strategy to a dual-joint strategy during the performance of large amplitudes with low or medium cycling frequencies (shoulder-elbow control). These behavioral results support the existence of a modular control mode that allows the central nervous system to effectively tune motor commands to meet a broad variety of orientations, amplitudes, and frequencies. This refers to the emergence of a context-dependent control mode for the shoulder and elbow that optimizes the implementation of the underlying motor goals under a rich combination of spatial and temporal manipulations.     

Learning reward expectations in honeybees

The aim of this study was to test whether honeybees develop reward expectations. In our experiment, bees first learned to associate colors with a sugar reward in a setting closely resembling a natural foraging situation. We then evaluated whether and how the sequence of the animals’ experiences with different reward magnitudes changed their later behavior in the absence of reinforcement and within an otherwise similar context. We found that the bees that had experienced increasing reward magnitudes during training assigned more time to flower inspection 24 and 48 h after training. Our design and behavioral measurements allowed us to uncouple the signal learning and the nutritional aspects of foraging from the effects of subjective reward values. We thus found that the animals behaved differently neither because they had more strongly associated the related predicting signals nor because they were fed more or faster. Our results document for the first time that honeybees develop long-term expectations of reward; these expectations can guide their foraging behavior after a relatively long pause and in the absence of reinforcement, and further experiments will aim toward an elucidation of the neural mechanisms involved in this form of learning.     

Gettier Cases without False Lemmas?

Examples cited by Feldman, Lehrer and others of true beliefs that are justified, but not by false lemmas, turn out under scrutiny to involve false lemmas after all. In each case there is an EG inference whose conclusion is unwarranted unless its base instance is false. A shift to non-deductive justification does not avert the difficulty. The relation of this result to non-inferential Gettier cases is suggested.     

Moderating effect of emotional intelligence on the role of negative affect in the motivation to drink in alcohol-dependent subjects undergoing protracted withdrawal

In order to understand how emotional aspects evolve and are related to craving for alcohol, different emotion-related variables were examined in relationship to craving during a protracted withdrawal. To this end state affectivity (PANAS), emotional intelligence (EI) (TEIQue), and craving (OCDS) were assessed at the onset (T1: day 1 or 2) and at the end (T2: day 14 to 18) of three-week protracted withdrawal among alcohol-dependent inpatients (DSM-IV, N = 41). A significant decrease in craving and negative affectivity (NA) was observed from T1 to T2 while EI scores remained low. At both baseline and follow-up, there was a significant moderation effect of EI on the link between NA and craving for alcohol. Negative mood at the onset of the cure was linked to craving at the end of the withdrawal period but only among patients with low trait EI scores. The merits of using psychotherapeutic approaches were discussed in the treatment of alcohol addiction.     

Question-asking strategies after severe closed head injury.

This investigation examined problem solving behaviors in survivors of severe closed head injury. Fourteen patients and 10 neurologically intact controls were administered the Twenty Questions procedure, requiring them to guess items the examiner was thinking of in a picture array. Relative to controls, survivors required more trials to guess the items and utilized a strategy characterized by attention to the individual pictures rather than to their shared conceptual features. The importance of problem solving impairments to neurobehavioral outcome after head injury is discussed.