Task Decomposition Through Competition in a Modular Connectionist Architecture: The What and Where Vision Tasks

A novel modular connectionist architecture is presented in which the networks composing the architecture compete to learn the training patterns. An outcome of the competition is that different networks learn different training patterns and, thus, learn to compute different functions. The architecture performs task decomposition in the sense that it learns to partition a task into two or more functionally independent tasks and allocates distinct networks to learn each task. In addition, the architecture tends to allocate to each task the network whose topology is most appropriate to that task. The architecture's performance on “what” and “where” vision tasks is presented and compared with the performance of two multilayer networks. Finally, it is noted that function decomposition is an underconstrained problem, and, thus, different modular architectures may decompose a function in different ways. A desirable decomposition can be achieved if the architecture is suitably restricted in the types of functions that it can compute. Finding appropriate restrictions is possible through the application of domain knowledge. A strength of the modular architecture is that its structure is well suited for incorporating domain knowledge.     

Are Reaching Movements Planned to be Straight and Invariant in the Extrinsic Space? Kinematic Comparison Between Compliant and Unconstrained Motions

Two main questions were addressed in the present study. First, does the existence of kinematic regularities in the extrinsic space represent a general rule? Second, can the existence of extrinsic regularities be related to specific experimental situations implying, for instance, the generation of compliant motion (i.e. a motion constrained by external contact)? To address these two questions we studied the spatio-temporal characteristics of unconstrained and compliant movements. Five major differences were observed between these two types of movement: (1) the movement latency and movement duration were significantly longer in the compliant than in the unconstrained condition; (2) whereas the hand path was curved and variable according to movement direction for the unconstrained movements, it was straight and invariant for the compliant movements; (3) whereas the movement end-point distribution was roughly circular for the unconstrained movements, it was consistently elongated and typically oriented in the movement direction for the compliant movements; (4) whereas constant errors varied as a function of target eccentricity for the unconstrained movements, they were independent of this factor for the compliant movements; (5) the instruction to move the final effector along a straight line path influenced the characteristics of the unconstrained movements but not the characteristics of the compliant movements. When considered together, the previous observations suggest that compliant and unconstrained movements involve different planning strategies. Our data support the hypothesis that unconstrained motions, unlike compliant motions, are not programmed to follow a straight line path in the extrinsic space. This observation provides a theoretical frame of reference within which some apparently contradictory results reported in the movement generation literature may be explained.     

The Social Psychology of Black–White Interracial Interactions: Implications for Culturally Competent Clinical Practice

Social psychological research suggests that because of concerns about being perceived in stereotypical ways, people may experience negative affect and diminished attention and cognitive capacity during interracial interactions. The authors discuss this research in relation to therapy and assessment and also offer practical suggestions for ensuring culturally competent professional practice. La investigación en el campo de la psicología social sugiere que, debido a la preocupación por ser percibida de forma estereotipada, la gente puede experimentar sentimientos negativos y un nivel reducido de atención y capacidad cognitiva durante interacciones interraciales. Los autores discuten esta investigación en relación a la terapia y evaluación, y también ofrecen sugerencias prácticas para asegurar una práctica profesional culturalmente competente.     

Zebra finches and Dutch adults exhibit the same cue weighting bias in vowel perception

Vocal tract resonances, called formants, are the most important parameters in human speech production and perception. They encode linguistic meaning and have been shown to be perceived by a wide range of species. Songbirds are also sensitive to different formant patterns in human speech. They can categorize words differing only in their vowels based on the formant patterns independent of speaker identity in a way comparable to humans. These results indicate that speech perception mechanisms are more similar between songbirds and humans than realized before. One of the major questions regarding formant perception concerns the weighting of different formants in the speech signal (“acoustic cue weighting”) and whether this process is unique to humans. Using an operant Go/NoGo design, we trained zebra finches to discriminate syllables, whose vowels differed in their first three formants. When subsequently tested with novel vowels, similar in either their first formant or their second and third formants to the familiar vowels, similarity in the higher formants was weighted much more strongly than similarity in the lower formant. Thus, zebra finches indeed exhibit a cue weighting bias. Interestingly, we also found that Dutch speakers when tested with the same paradigm exhibit the same cue weighting bias. This, together with earlier findings, supports the hypothesis that human speech evolution might have exploited general properties of the vertebrate auditory system.     

Ethical Assurance Statements in Political Science Journals

Many journals in the physical sciences require authors to submit assurances of compliance with human subjects and other research ethics standards. These requirements do not cover all disciplines equally, however. In this paper we report on the findings of a survey of perceptions of ethical and managerial problems from journal editors in political science and related disciplines. Our results show that few journals in political science require assurance statements common to journals for other scientific disciplines. We offer some reasons for this as well as some recommendations for implementing ethical assurance safeguards for political science.