Stimulus control of the pigeon's ability to peck a moving target.

Two pigeons were trained to peck whichever of eight keys displayed a white field (SD). The other seven keys displayed a white "X" on a black background (S delta). Each peck to SD produced three-second access to grain, a three-second intertrial interval (ITI), and the next trial. Pecks to S delta produced a three-second timeout (TO) and the same trial. During later sessions the key displaying SD changed every t seconds (t = 3, 2, 1, .5, and .25 sec), requiring the birds to track the position of the SD. Pecks on a ninth key increased t. Several sessions employed novel stimuli to ascertain the controlling stimulus dimensions. Both birds made few errors acquiring the original discrimination. During the tracking sessions, both birds made few errors when t = .5 sec. Only one reliably lengthened t. Data from sessions with novel stimuli indicate that color and form were important aspects of SD and S delta respectively; movement contributed to the final performance.     

Imitation and novelty in product development

A human stigmergy model of product development through a series of incremental novelties and imitations is obtained by observing the isomorphism between solution trees generated by groups of humans participating in online games like Foldit, self-organizing topics in online learning systems, product evolution through a combination of innovation and imitation in the cell phone industry, and social networks formed over the past 40 years in creation of the Boston biotech commons. The model incorporates two very simple rules: (1) preferential attachment, and (2) the combination of existing product designs into a single design. A computer model used to simulate the model produces product evolution networks isomorphic to observed solution trees and product evolution trees. Additionally, industries with a high degree of novelty produce a product evolution network with scale-free and betweenness centrality structure.     

Measuring concept semantic relatedness through common spatial pattern feature extraction on EEG signals

We study the semantic relationship between pairs of nouns of concrete objects such as “HORSE - SHEEP” and “SWING - MELON” and how this relationship activity is reflected in EEG signals. We collected 18 sets of EEG records; each set containing 150 events of stimulation. In this work we focus on feature extraction algorithms. Particularly, we highlight Common Spatial Pattern (CSP) as a method of feature extraction. Based on these latter, different classifiers were trained in order to associate a set of signals to a previously learned human answer, pertaining to two classes: semantically related, or not semantically related. The results of classification accuracy were evaluated comparing with other four methods of feature extraction, and using classification algorithms from five different families. In all cases, classification accuracy was benefited from using CSP instead of FDTW, LPC, PCA or ICA for feature extraction. Particularly with the combination CSP-Naïve Bayes we obtained the best average precision of 84.63%.     

Performed or observed keyboard actions affect pianists' judgements of relative pitch

Action can affect visual perception if the action's expected sensory effects resemble a concurrent unstable or deviant event. To determine whether action can also change auditory perception, participants were required to play pairs of octave-ambiguous tones by pressing successive keys on a piano or computer keyboard and to judge whether each pitch interval was rising or falling. Both pianists and nonpianist musicians gave significantly more “rising” responses when the order of key presses was left-to-right than when it was right-to-left, in accord with the pitch mapping of the piano. However, the effect was much larger in pianists. Pianists showed a similarly large effect when they passively observed the experimenter pressing keys on a piano keyboard, as long as the keyboard faced the participant. The results suggest that acquired action–effect associations can affect auditory perceptual judgement.     

Working with Families from the Indian Sub-Continent: An Indo-German Experience*

Whereas most Western European therapists and clients consider emotional distance and abstinence as desirable and conducive in the therapeutic process, this may not always be the case with clients from India. Cultural components such as the contrast between linear and cyclic world-views and the traditional view of the psychologist as an advisor in India present a challenge to professionals with a Western background. Some factors such as the situation of women in society and seemingly too close familiy ties can mean that a Western therapist fails to promote the changes an Indian client is desiring for his or her family. However, besides cultural awareness and caution, one of the most helpful tools in work across cultures is curiosity in its most positive sense and the readiness to be surprised by ones’ clients.I would like to thank all my Indian colleagues who supported and advised me in my work in India.     

Logic of Knowledge and Utterance and the Liar

We extend the ordinary logic of knowledge based on the operator K and the system of axioms S₅ by adding a new operator U, standing for the agent utters , and certain axioms and a rule for U, forming thus a new system KU. The main advantage of KU is that we can express in it intentions of the speaker concerning the truth or falsehood of the claims he utters and analyze them logically. Specifically we can express in the new language various notions of lying, as well as of telling the truth. Consequently, as long as lying or telling the truth about a fact is an intentional mode of the speaker, we can resolve the Liar paradox, or at least some of its variants, turning it into an ordinary (false or true) sentence. Also, using Kripke structures analogous to those employed by S. Kraus and D. Lehmann in [3] for modelling the logic of knowledge and belief, we offer a sound and complete semantics for KU.     

Are there True Contradictions? A Critical Discussion of Graham Priest's, Beyond the limits of thought

The present article critically examines three aspects of Graham Priest's dialetheic analysis of very important kinds of limitations (the limit of what can be expressed, described, conceived, known, or the limit of some operation or other). First, it is shown that Priest's considerations focusing on Hegel's account of the infinite cannot be sustained, mainly because Priest seems to rely on a too restrictive notion of object. Second, we discuss Priest's treatment of the paradoxes in Cantorian set-theory. It is shown that Priest does not address the issue in full generality; rather, he relies on a reading of Cantor which implicitly attributes a very strong principle concerning quantification over arbitrary domains to Cantor. Third, the main piece of Priest's work, the so-called “inclosure schema”, is investigated. This schema is supposed to formalize the core of many well-known paradoxes. We claim, however, that formally the schema is not sound. This revised version was published online in August 2006 with corrections to the Cover Date.     

Complex learning and information processing by pigeons: a critical analysis

Three models of conditional discrimination learning by pigeons are described: stimulus configuration learning, the multiple-rule model, and concept learning. A review of the literature reveals that true concept learning is not characteristic of the behavior of pigeons in matching-to-sample, oddity-from-sample, or symbolic matching studies. Instead, pigeons learn a set of sample-specific S^D rules. Transfer of the discrimination to novel stimuli, at least along the hue dimension, is predicted by a “coding hypothesis”, which holds that pigeons make a unique, but usually unobserved response, R₁, to each sample, and that the comparison stimulus chosen depends on which R₁ was emitted in the presence of the sample. Convincing evidence is found that pigeons do code sample hues, but there is little evidence that allows one to infer that the “coding event” must have behavioral properties. Parameters of the conditional discrimination paradigm are identified, and it is shown that by appropriate parametric manipulation, a variety of analogous tasks may be generated for both human and animal subjects. The tasks make possible the comparative study of complex learning, attention, memory, and information processing, with the added advantage that behavior processes may be compared systematically across tasks.