Spacing effects in cued-memory tasks for unfamiliar faces and nonwords

Memory for repeated items improves as the interval between repetitions in a list increases (the spacing effect). This study investigated the spacing effect in recognition memory and in a frequency judgment task for unfamiliar target faces that were repeated in the same or in a different pose during incidental learning. Changing the pose between prime and probe trials reduced perceptual repetition priming in a structural discrimination task and also reduced the spacing effect in a subsequent unexpected recognition memory task. Three further experiments confirmed that the spacing effect inrecognition memory (Experiments 2 and 4) or frequency judgment (Experiment 3) was reduced when the pose was changed between repeated presentations at study. Similarly, with nonwords as targets (Experiment 5), changing the font between repeated occurrences of targets at study removed the spacing effect in a subsequent unexpected recognition memory test. These results are interpreted to support the view that short-term perceptual repetition priming underlies the spacing effect in explicit cued-memory tasks for unfamiliar nonsense material.     

Facial Expressions of Emotion: Are Angry Faces Detected More Efficiently?

The rapid detection of facial expressions of anger or threat has obvious adaptive value. In this study, we examined the efficiency of facial processing by means of a visual search task. Participants searched displays of schematic faces and were required to determine whether the faces displayed were all the same or whether one was different. Four main results were found: (1) When displays contained the same faces, people were slower in detecting the absence of a discrepant face when the faces displayed angry (or sad/angry) rather than happy expressions. (2) When displays contained a discrepant face people were faster in detecting this when the discrepant face displayed an angry rather than a happy expression. (3) Neither of these patterns for same and different displays was apparent when face displays were inverted, or when just the mouth was presented in isolation. (4) The search slopes for angry targets were significantly lower than for happy targets. These results suggest that detection of angry facial expressions is fast and efficient, although does not "pop-out" in the traditional sense.     

Neubewertung kognitiver Leistungen im Lichte der F?higkeiten einzelliger Lebewesen

A closer look at unicellular organisms and their behavior as autonomous and social beings sheds new light on the nature of cognition. This allows, at the same time, a search for minimal conditions that help to identify the yet unknown appearance of cognition during evolution. Positive results might also serve as principles for the construction of intelligent artefacts as striven for in artificial intelligence and cognitive robotics research. Analyzing the abilities of prokaryotes and unicellular eukaryotes and comparing them to the abilities of "higher" organisms, we conclude that common definitions of cognition are not specific enough. The attempt to define cognition by focusing on the coupling between stimulus and response and asserting that (to have cognition) it has to be indirect and modifiable fails, simply because in all organisms every reaction to a stimulus is indirect and modifiable. A definition of cognition based on such a distinction cannot hold unless one is willing to ascribe cognitive capacities also to Escherichia coli bacteria, for instance. Viewing cognition as the sum of abilities necessary for coping with a complex physical and social environment is also highly questionable, i.e. unspecific. We show that functions comparable to the cognitive functions "perception" and "memory" in higher organisms can well be identified in unicellular beings. The "architecture" of the bacterial (prokaryotic) sensorimotor apparatus is also in some structures, but particularly at the functional level, comparable with that of higher organisms and should be, as a consequence, indicative of cognition. Furthermore, we discuss other, somewhat more delimitable, phenomena like detection of identity, counting, adaptation, habituation and learning in ethological categories and compare them to findings from the microorganismic world. In this context, we argue that so-called "true learning" and the appearance of nervous systems are not break-points in the evolution of cognition. The presence of nervous systems means only a huge amplification of the recognition power of individual organisms. The molecular net that realizes the regulation and transduction of signals in unicellular beings is comparable to the processes within a neural net, and a population of unicellular organisms can be viewed as an individual, multicellular net with amplified recognition power. Finally, we show that sophisticated forms of cooperation and competition developed also in populations of unicellular organisms. This seems not to be true for the phenomena imagination (rehearsal) and introspection, also to be seen as stemming from social problem-solving needs. As for these aspects, further research is needed, however, to put them on firm scientific grounds. Zusammenfassung. Eine genaue Betrachtung einzelliger Lebewesen und ihres Verhaltens als autonome und soziale Wesen wirft neues Licht auf die Natur von Kognition. Das erlaubt gleichzeitig eine Suche nach minimalen Bedingungen, die bei der Bestimmung des Erscheinens von Kognition in der Evolution helfen. Positive Ergebnisse könnten auch als Prinzipien für die Konstruktion intelligenter Artefakte dienen, wie sie in der Künstlichen Intelligenz und der kognitiven Robotikforschung angestrebt werden. Ein Vergleich der Fähigkeiten von Einzellern mit denen von "höheren" Organismen führt uns zu dem Schluß, daß gängige Definitionen von Kognition nicht spezifisch genug sind. Der Versuch, Kognition über die Indirektheit und Modifizierbarkeit der Kopplung zwischen Reiz und Reaktion zu definieren, scheitert, weil in allen Organismen Reiz-Reaktionsverbindungen indirekt und modifizierbar sind. Eine solche Definition ist nicht haltbar, es sei denn, man ist bereit, z.B. auch Escherichia coli-Bakterien kognitive Eigenschaften zuzubilligen. Die Definition von Kognition als Summe der Eigenschaften, die notwendig sind, um in einer komplexen physikalischen und sozialen Umgebung zu bestehen, ist ebenfalls hinterfragbar und unspezifisch. Wir zeigen, daß Leistungen, die mit den Kognitionsleistungen "Wahrnehmung" und "Gedächtnis" in höheren Organismen vergleichbar sind, in Einzellern nachweisbar sind. Die sensomotorische Komplexität von Einzellern ist auch in vieler Hinsicht strukturell, vor allem aber funktionell vergleichbar mit derjenigen höherer Organismen und kann deshalb als ein Hinweis auf Kognition gewertet werden. Darüber hinaus diskutieren wir andere, abgrenzbare Phänomene, wie Erfassung von Identität, Zählen, Adaptation, Habituation und Lernen, aus der Sicht der Verhaltensforschung und vergleichen sie mit Befunden aus der Welt der Mikroorganismen. In diesem Zusammenhang bestreiten wir, daß sogenanntes "echtes Lernen" und das Erscheinen von Nervensystemen Bruchstellen in der Evolution von Kognition sind. Die Anwesenheit von Nervensystemen bedeutet nur den Übergang von Systemen mit einem relativ begrenzten (Erkennungs-) Potential zu solchen mit einem riesigen Potential. Das molekulare Netz, das die Regulation und Transduktion von Signalen in Einzellern realisiert, ist vergleichbar mit den Prozessen innerhalb eines Nervennetzes. Eine Population von einzelligen Organismen kann als individuelles, multizelluläres Netz mit erhöhtem Erkennungspotential angesehen werden. Schließlich zeigen wir, daß raffinierte Formen von Kooperations- und Konkurrenzverhalten auch in Einzellerpopulationen vorhanden sind. Eine ähnliche Aussage scheint nicht für Phänomene wie Imagination (Probehandeln) und Introspektion möglich zu sein, die auch im Zusammenhang mit der Bewältigung sozialer Probleme zu sehen sind. Eine genaue naturwissenschaftliche Erfassung solcher Aspekte, die erst einen Vergleich zwischen Mehrzellern und Einzellern erlauben würde, ist allerdings noch zu leisten.     

Objective versus estimated age of word acquisition: A study of 202 Italian children

We provide objective data concerning the age of acquisition (AoA) of words from 202 Italian children 34–69 months of age. We investigated picture naming with 80 concrete words belonging to eight semantic categories that are included in a widely used battery for the study of naming and semantic memory. For each word, we calculated three different indices: two directly expressing the age at which a picture was given the correct name by at least 75% of the subjects, and one expressing the overall percentage of our children who were correct in the task. (For the latter index, we provide separate values for boys and girls.) The correlation between objective indices of AoA and adult estimates culled from the literature was not very high. Moreover, objective indices showed low correlations with frequency and familiarity, in contrast to adult ratings. We conclude that adult estimates of AoA present validity problems and should be used with caution. The full set of stimuli is available at www.psychonomic.org/archive.     

Writing errors by normal subjects

Writing is a complex process requiring visual memory, attention, phonological and semantic operations, and motor performance. For that reason, it can easily be disturbed by interfering with attention, memory, by interfering subvocalization, and so on. With 16 female third-year students (23.4 +/- 0.8 yr.) from the University of Trieste, we investigated the production of errors in three experimental conditions (control, articulatory suppression, and tapping). In the articulatory suppression condition, the participants produced significantly more linguistic impairments (such as agrammatism, unrelated substitutions, sentence omissions, and semantically deviant sentences), which are similar to linguistic impairments found in aphasia. On the tapping condition there were more perseverations, deletions, and substitutions of both letters and words. These data suggest that writing is not an automatic skill. Only after many years of experience and practice of processing information (through cortical to subcortical channels) can writing be considered an automatic skill. Limited experimental conditions can disrupt the writing system of normal subjects, probably interfering with the cortical to subcortical loops, and link normality to pathology.     

Effects of the Novel Acetylcholinesterase InhibitorN-Octyl-1,2,3,4-tetrahydro-9-aminoacridine on Locomotor Activity and Avoidance Learning in Mice

The acetylcholinesterase reversible inhibitorN-octyl-1,2,3,4-tetrahydro-9-aminoacridine (THA-C8) is a new synthesized derivative of tacrine (THA) characterized by an alkyl chain in the molecular structure which ameliorates the penetrability of the compound into the central nervous system. THA-C8 (0.1–5 mg/kg) significantly reduced spontaneous locomotor activity in CD1 mice at a dose of 3 mg/kg. Moreover, THA-C8 (0.2–2 mg/kg) significantly improved shuttle-box avoidance acquisition at doses (0.25, 0.3, 1 mg/kg) not affecting locomotion and that are much lower than the doses reported to be effective for THA in animal models. From the data reported it seems that the new compound could be interesting for therapeutic purposes.     

Figure-background segregation and the formation of illusory figures

Three experiments were carried out to test the relationship between figure-background segregation and illusory contours. Illusory figures are believed to arise as byproducts of figure-background segregation. When, in a scene, part of what should be the background becomes an illusory figure, a mechanism of contour attribution favoring the area in which the illusory figure appears takes place. This mechanism is prevented from operating when the attribution of the contour is inhibited by the presence of "groupable" (connectable) contours. Spatial proximity is one of the factors affecting such grouping: the closer the connectable contours, the more likely is their grouping in a single unit and the less likely is the emergence of an illusory figure. Experimental results showed that the illusory effect was established when contours were prevented from being connected. This outcome is interpreted as evidence that a mechanism of contour attribution is effective in the formation of illusory figures.     

Paradigms in Measure Theoretic Learning and in Informant Learning

We investigate many paradigms of identifications for classes of languages (namely: consistent learning, EX learning, learning with finitely many errors, behaviorally correct learning, and behaviorally correct learning with finitely many errors) in a measure-theoretic context, and we relate such paradigms to their analogues in learning on informants. Roughly speaking, the results say that most paradigms in measure-theoretic learning wrt some classes of distributions (called canonical) are equivalent to the corresponding paradigms for identification on informants.     

An Operational Logic of Proofs with Positive and Negative Information

The logic of proofs was introduced by Artemov in order to analize the formalization of the concept of proof rather than the concept of provability. In this context, some operations on proofs play a very important role. In this paper, we investigate some very natural operations, paying attention not only to positive information, but also to negative information (i.e. information saying that something cannot be a proof). We give a formalization for a fragment of such a logic of proofs, and we prove that our fragment is complete and decidable.