Belief Change in Branching Time: AGM-consistency and Iterated Revision

We study belief change in the branching-time structures introduced in Bonanno (Artif Intell 171:144–160, 2007). First, we identify a property of branching-time frames that is equivalent (when the set of states is finite) to AGM-consistency, which is defined as follows. A frame is AGM-consistent if the partial belief revision function associated with an arbitrary state-instant pair and an arbitrary model based on that frame can be extended to a full belief revision function that satisfies the AGM postulates. Second, we provide a set of modal axioms that characterize the class of AGM-consistent frames within the modal logic introduced in Bonanno (Artif Intell 171:144–160, 2007). Third, we introduce a generalization of AGM belief revision functions that allows a clear statement of principles of iterated belief revision and discuss iterated revision both semantically and syntactically.     

Dementia and working memory

This study explored the hypothesis that patients suffering from dementia of the Alzheimer type (DAT) are particularly impaired in the functioning of the Central Executive component of working memory, and that this will be reflected in the capacity of patients to perform simultaneously two concurrent tasks. DAT patients, age-matched controls and young controls were required to combine performance on a tracking task with each of three concurrent tasks, articulatory suppression, simple reaction time to a tone and auditory digit span. The difficulty of the tracking task and length of digit sequence were both adjusted so as to equate performance across the three groups when the tasks were performed alone. When digit span or concurrent RT were combined with tracking, the deterioration in performance shown by the DAT patients was particularly marked.     

Man-Machine interaction in natural language: Computational models of dialogue

This article presents a state-of-the-art review of studies on computational modeling of dialogue. Particular attention is given to the treatment of ill-formed input, the prevention of the hearer’s misconceptions, the inference of the speaker’s plans, the generation of language, and the recognition of dialogue focus—particularly in terms of implications for linguistics. Specifications and initial results of some recent studies carried out by the author are provided. This article is a revised version of a lecture held at the Third Scientific Meeting “Computer Processing of Linguistic Data,” Bled, 1985.     

What do children with autism attend to during imitation tasks?

Individuals with autism show a complex profile of differences in imitative ability, including a general deficit in precision of imitating another’s actions and special difficulty in imitating nonmeaningful gestures relative to meaningful actions on objects. Given that they also show atypical patterns of visual attention when observing social stimuli, we investigated whether possible differences in visual attention when observing an action to be imitated may contribute to imitative difficulties in autism in both nonmeaningful gestures and meaningful actions on objects. Results indicated that (a) a group of 18 high-functioning 8- to 15-year-olds with autistic disorder, in comparison with a matched group of 13 typically developing children, showed similar patterns of visual attention to the demonstrator’s action but decreased attention to his face when observing a model to be imitated; (b) nonmeaningful gestures and meaningful actions on objects triggered distinct visual attention patterns that did not differ between groups; (c) the autism group demonstrated reduced imitative precision for both types of imitation; and (d) duration of visual attention to the demonstrator’s action was related to imitation precision for nonmeaningful gestures in the autism group.     

Sentences with Strong Psychological Impact in Psychotherapy: Research in Progress

After a brief exposition of Elementary Pragmatic Model about changes in dyadic interactions, the validity and clinical usefulness of the model was evaluated with a newly created test, called SISCI-Sentences. This test is composed of 90 Sentences with strong psychological impact. Administration of this test to non-clinical and clinical participants produced statistically significant differences between the choices of participants in the two groups. Implications of these results for the use of these Sentences in the course of psychotherapy are discussed.

Recognition memory and prefrontal cortex: dissociating recollection and familiarity processes using rTMS

Recognition memory can be supported by both the assessment of the familiarity of an item and by the recollection of the context in which an item was encountered. The neural substrates of these memory processes are controversial. To address these issues we applied repetitive transcranial magnetic stimulation (rTMS) over the right and left dorsolateral prefrontal cortex (DLPFC) of healthy subjects performing a remember/know task. rTMS disrupted familiarity judgments when applied before encoding of stimuli over both right and left DLPFC. rTMS disrupted recollection when applied before encoding of stimuli over the right DLPFC. These findings suggest that the DLPFC plays a critical role in recognition memory based on familiarity as well as recollection.     

Do binding deficits account for age-related decline in visual working memory?

Remembering visual material, such as objects, faces, and spatial locations, over a short period of time (seconds) becomes more difficult as we age. We investigated whether these deficits could be explained by a simple reduction in visual working memory capacity or by an impairment in one's ability to form or maintain appropriate associations among pieces of related information. In three experiments, we used recognition and recall tests to address the efficacy with which older adults can create bound object representations by varying the number of features of each object that had to be remembered for a subsequent memory test. Results demonstrated that whereas older adults exhibited reduced memory capacity as compared with that of younger adults, both groups stored integrated object representations in visual working memory. These results are contrasted with other work that suggests that age-related memory decline is due, at least in part, to associative deficits.     

Relationship between object-related gestures and the fractionated object knowledge system

The praxic semantic system comprises a conceptual knowledge system, which stores functional information about objects, and an action knowledge system, which stores information about the correct manipulation of objects. Moreover, mechanical problem solving abilities permit to take advantages from objects structure to use unfamiliar tools or discover alternative ways of using familiar tools. This study aims at investigating whether conceptual knowledge, action knowledge and mechanical problem solving abilities intervene in the production of gestures with objects (i.e. pantomimes and object use) by testing a group of brain damaged patients. Results showed that the mechanical problem solving abilities are not sufficient to produce pantomimes and that only severe deficits in the praxic semantic system would affect the production of these gestures. Furthermore, a double dissociation was observed between mechanical problem solving abilities and the capacity to use multiple objects. Overall, the results indicate that the praxic semantic system can be disrupted at different levels, suggesting that the semantic system for object has to be conceived as fractionated in different entities.     

Serial color-word test predicts outcome of pharmacological treatment for panic disorder.

A group of 50 outpatients with Panic Disorder were given the Serial Color-Word Test at the beginning of a standard pharmacological treatment (selective serotonin reuptake inhibitors and benzodiazepines). A single treating psychiatrist, blind to test results, judged therapy outcome at a 5-mo. follow-up. Among the main types of adaptation to conflict assessed by the test (Stabilized, Cumulative, Dissociative, and Cumulative-Dissociative), the Stabilized pattern predicted a good therapy outcome. Response to therapy among the patients with a Stabilized pattern was judged as more often good and less often moderate or poor, compared with the members of the other three adaptation classes (p=.004), and specifically with the patients resorting to a Cumulative strategy (p=.005).