Context switch effects on acquisition and extinction in human predictive learning

Four experiments tested context switch effects on acquisition and extinction in human predictive learning. A context switch impaired probability judgments about a cue-outcome relationship when the cue was trained in a context in which a different cue underwent extinction. The context switch also impaired judgments about a cue trained in a context different from the extinction context, whenever this training was concurrent with extinction of another cue. After extinction, new cue-outcome relationships learned, even in a different task, became context specific. Moreover, renewal was consistently observed. It is suggested that context switch effects result from a process by which ambiguity leads participants to attend to the contexts.     

Animal groups and social ontology: an argument from the phenomenology of behavior

Through a critical engagement with Merleau-Ponty’s discussion of the concepts of nature, life, and behavior, and with contemporary accounts of animal groups, this article argues that animal groups exhibit sociality and that sociality is a fundamental ontological condition. I situate my account in relation to the superorganism and selfish individual accounts of animal groups in recent biology and zoology. I argue that both accounts are inadequate. I propose an alternative account of animal groups and animal sociality through a Merleau-Pontian inspired definition of behavior. I criticize Merleau-Ponty’s individualistic prejudice, but show that his philosophy contains the resources necessary to overcome this bias. I define behavior as a holistic, ongoing, meaningful and Umwelt-oriented intrinsically configured expression of living forms of existence. By looking at cases of animal groups drawn from contemporary studies in zoology and behavioral ecology, I show that animal groups, in the fact that they behave, manifest themselves to be a fundamental form of existence, namely, the social form of existence.     

Distributive lattices with an operator

It was shown in [3] (see also [5]) that there is a duality between the category of bounded distributive lattices endowed with a join-homomorphism and the category of Priestley spaces endowed with a Priestley relation. In this paper, bounded distributive lattices endowed with a join-homomorphism, are considered as algebras and we characterize the congruences of these algebras in terms of the mentioned duality and certain closed subsets of Priestley spaces. This enable us to characterize the simple and subdirectly irreducible algebras. In particular, Priestley relations enable us to characterize the congruence lattice of the Q-distributive lattices considered in [4]. Moreover, these results give us an effective method to characterize the simple and subdirectly irreducible monadic De Morgan algebras [7].The duality considered in [4], was obtained in terms of the range of the quantifiers, and such a duality was enough to obtain the simple and subdirectly irreducible algebras, but not to characterize the congruences.I would like to thank my research supervisor Dr. Roberto Cignoli for his helpful suggestions during the preparation of this paper and the referee for calling my attention to Goldblatt's paper [5].     

Experiencing the mastership in transdisciplinary studies for sustainability

In this article, we describe the transdisciplinarity process in our education postgraduate program at the University of Veracruz. The program emphasizes the main processes of the eco-formation experience for sustainability through a transdisciplinarity methodology that is focused on three processes: (a) Re-Learning; (b) Eco-literacy; and (c) Dialogue of Knowledge. The experience of self-knowledge is described through our specific re-learning practices in the Mastership program, which represents a central tenet in the process for creating our Learning Community through holarchy practices, profound dialogues, and self-organization processes. Finally we discuss three central ideas: creativity, spirituality, and play, which express and nurture our Learning Community.     

Visual attention and the apprehension of spatial relations: The case of depth

Several studies have shown that targets defined on the basis of the spatial relations between objects yield highly inefficient visual search performance (e.g., Logan, 1994; Palmer, 1994), suggesting that the apprehension of spatial relations may require the selective allocation of attention within the scene. In the present study, we tested the hypothesis that depth relations might be different in this regard and might support efficient visual search. This hypothesis was based, in part, on the fact that many perceptual organization processes that are believed to occur early and in parallel, such as figure-ground segregation and perceptual completion, seem to depend on the assignment of depth relations. Despite this, however, using increasingly salient cues to depth (Experiments 2–4) and including a separate test of the sufficiency of the most salient depth cue used (Experiment 5), no evidence was found to indicate that search for a target defined by depth relations is any different than search for a target defined by other types of spatial relations, with regard to efficiency of search. These findings are discussed within the context of the larger literature on early processing of three-dimensional characteristics of visual scenes.     

Immigration and the metropolis: Reflections on urban history

This article presents an outline of the relationship between migration and the city in its evolution over time. I sketch the central aspects of this historical relation as a prelude to examining three aspects of the contemporary scene: the various determinants of contemporary labour flows; the political sources of resistance to international migration; and the renewed protagonist role of metropolitan areas as strategic nodes of the international system. As part of the latter process, I sketch the rise of transnationalism as a novel form of adaptation to immigration and as a potential response to the overriding logic of global capitalism. Implications of a migration-centred approach to cities for theory and policy are dismissed.     

Viewing Cognitive Conflicts as Dilemmas: Implications for Mental Health

The idea that internal conflicts play a significant role in mental health has been extensively addressed in various psychological traditions, including personal construct theory. In the context of the latter, several measures of conflict have been operationalized using the Repertory Grid Technique (RGT). All of them capture the notion that change, although desirable from the viewpoint of a given set of constructs, becomes undesirable from the perspective of other constructs. The goal of this study is to explore the presence of cognitive conflicts in a clinical sample (n = 284) and compare it to a control sample (n = 322). It is also meant to clarify which among the different types of conflict studied provides a greater clinical value and to investigate its relationship to symptom severity (SCL-90-R). Of the types of cognitive conflict studied, implicative dilemmas were the only ones to discriminate between clinical and nonclinical samples. These dilemmas were found in 34% of the nonclinical sample and in 53% of the clinical sample. Participants with implicative dilemmas showed higher symptom severity, and those from the clinical sample displayed a higher frequency of dilemmas than those from the nonclinical sample.     

Focused spatial attention is independent of rapid resumption of an interrupted search

In three experiments, we examined possible relationships between the spatial focus of attention and the rapid resumption of a visual search following a brief interruption. In Experiment 1, we tested the role of involuntary (exogenous) spatial orienting to one region (quadrant) of a search display; in Experiment 2, we tested the role of voluntary (endogenous) spatial orienting to the same region; and in Experiment 3, we tested the role of voluntary orienting to the specific location in which the target item appeared. All three experiments indicated that spatial orienting speeds correct responding and greatly increases the probability of search success in the look immediately following the presentation of a spatial cue. However, these benefits of spatial cues were also shown to be completely independent of the rapid resumption effect, which depends on observers’ forming a perceptual hypothesis about a target in one look, but being unable to confirm that hypothesis until a second one (Lleras, Rensink, & Enns, 2005).     

Is place-value processing in four-digit numbers fully automatic? Yes,but not always

Knowing the place-value of digits in multi-digit numbers allows us to identify, understand and distinguish between numbers with the same digits (e.g., 1492 vs. 1942). Research using the size congruency task has shown that the place-value in a string of three zeros and a non-zero digit (e.g., 0090) is processed automatically. In the present study, we explored whether place-value is also automatically activated when more complex numbers (e.g., 2795) are presented. Twenty-five participants were exposed to pairs of four-digit numbers that differed regarding the position of some digits and their physical size. Participants had to decide which of the two numbers was presented in a larger font size. In the congruent condition, the number shown in a bigger font size was numerically larger. In the incongruent condition, the number shown in a smaller font size was numerically larger. Two types of numbers were employed: numbers composed of three zeros and one non-zero digit (e.g., 0040–0400) and numbers composed of four non-zero digits (e.g., 2795–2759). Results showed larger congruency effects in more distant pairs in both type of numbers. Interestingly, this effect was considerably stronger in the strings composed of zeros. These results indicate that place-value coding is partially automatic, as it depends on the perceptual and numerical properties of the numbers to be processed.     

The Δ–∑ hypothesis: How contrast and reinforcement rate combine to generate suboptimal choice

When given a choice between two alternatives, each offering food after the same delay with different but signaled probabilities, pigeons often prefer the low probability alternative. This preference is surprising because pigeons fail to maximize the rate of food intake; they exhibit a suboptimal preference. We advance a new explanation, the Δ–∑ hypothesis, in which the difference in probability of reinforcement within terminal links (Δ) and the overall reinforcement probability rate of each alternative (∑) are the key variables responsible for such suboptimal preference. We tested the Δ–∑ hypothesis in two experiments. In Experiment 1, we manipulated the Δs while maintaining constant all other parameters of the task, in particular the ∑s. We predicted a preference for the alternative with the larger Δ. In Experiment 2, we examined the effect of the overall reinforcement probabilities, the ∑s, while maintaining constant all other parameters of the task, in particular the Δs. We predicted a preference for the larger ∑. The results of both experiments support the Δ–∑ hypothesis.