Generating an image from an ambiguous visual input: an electroencephalographic (EEG) investigation

Fourteen right-handed males were shown slides of common objects (e.g., wristwatch), familiar situations (e.g., two people shaking hands), and inkblots from a popular projective test (Holtzman, 1986) and then asked to name the object, assess the situation, or describe the most salient image emerging from the inkblot. Alpha power suppression was monitored over the left and right frontal, temporal, parietal, and occipital lobes to determine the brain circuitry responsible for the processing of each type of stimulus. When processing common objects and familiar situations there was bilateral activation of the parietal and occipital lobes; when processing inkblots, bilateral activation of the parietal and occipital lobes was again obtained, but complemented by selective activation of the right frontal lobe. The later suggests that anterior regions of the right cerebral hemisphere contribute to the generation of dynamic images like those evoked by visually ambiguous inkblots.     

我用一道"符"治好一位病人

我是精神科医生,退休在家,有人找我看病,我就给看。2003年3月4日晚7:00时左右,来了一     

Adapting to an irrelevant item in an immediate recall task

Recall of the last one or two items of a spoken list is impaired when the list is followed by a nominally irrelevant item. At issue here was whether this suffix effect is reduced with repeated exposure to the irrelevant item. The effect was found to decline over successive blocks of trials, but only slightly (Experiment 1). No decisive evidence for adaptation to the irrelevant item was found when it was spoken after each of the list items rather than after the last one only (Experiments 2 and 3). The strongest evidence for adaptation was obtained when the irrelevant item was repeated in an unbroken stream that extended through the presentations and recall periods of successive lists: The recency effect and the level of recall at the last position within a list were greater under these conditions than when the irrelevant item was presented only once after each list (Experiments 4, 5, and 6).     

Human performance on an analogue of an interval bisection task

Two experiments used normal adult human subjects in an analogue of a time interval bisection task frequently used with animals. All presented durations were defined by the time between two very brief clicks, and all durations were less than 1 sec, to avoid complications arising from chronometric counting. In Experiment 1 different groups of subjects received standard durations of either 0.2 and 0.8 or 0.1 and 0.9 sec and then classified a range of durations including these values in terms of their similarity to the standard short (0.2- or 0.1-sec) and long (0.8- or 0.9-sec) durations. The bisection point (defined as the duration classified as "long" on 50% of trials) was located at 0.43 sec in the 0.2-0.8 group, and at 0.46 sec in the 0.1-0.9 group. Experiment 2 replicated Experiment 1 using a within-subject procedure. The bisection point of both 0.2- and 0.8 sec and 0.1- and 0.9-sec durations was found to be 0.44 sec. Both experiments thus found the bisection point to be located at a duration just lower than the arithmetic mean of the standard short and long durations, rather than at the geometric mean, as in animal experiments. Some other performance measures, such as difference limen, and Weber ratio, were, however, of similar values to those found in bisection tasks with animals. A theoretical model assuming that humans bisect by taking the difference between a presented duration and the short and long standards, as well as having a bias to respond "long", fitted the data well. The model incorporated scalar representations of standard durations and thus illustrated a way in which the obtained results, although different from those found with animal subjects, could be reconciled with scalar timing theory.     

Effect of following an excitatory-inhibitory compound with an intermediate reinforcer

Pavlovian-conditioned inhibition training of the form A++, AB- (where ++ is a strong reinforcer and - is nonreinforcement) was conducted in 3 experiments with rats and 1 with pigeons. Then AB+ training was given (in which + is an effective reinforcer that is weaker than ++). The + reinforcer was achieved by reducing the frequency, lessening the amount, or lengthening the delay with which ++ was delivered. All 4 experiments found the AB+ treatment to enhance responding to both the excitatory A and the inhibitory B in comparison with untreated control stimuli. However, when appropriate assessments were made, the increase was more substantial for the inhibitory B. This pattern of results presents challenges for most current theories of associative learning.     

Novel popout is an attention-based phenomenon: an ERP analysis

When observers are given a brief glimpse of a display containing one novel object and three repeated objects, they are often better able to report the location of the novel object than the location of any one of the repeated objects. The present study contrasted two interpretations of this "novel popout" effect. The attention-based interpretation suggests that the novel popout is an attentional phenomenon, occurring during the initial processing of the four-object display. The retrieval-based interpretation suggests that novel popout is due to differential processing occurring when observers are subsequently probed for the location of one of the objects in the display. ERP measures recorded while subjects performed the novel popout task revealed differences during the initial processing of the four-object display but not subsequent to the presentation of a localization probe. The findings are most consistent with the attention-based interpretation of novel popout, which suggests that attention is rapidly drawn to the novel object in an otherwise familiar display.     

Is information reduction an item-specific or an item-general process?

An important aspect of cognitive skill acquisition is the ability, developed through task practice, to ignore task-irrelevant information (i.e., information reduction, Haider & Frensch, 1996 1996). By this account, practice not only affects how information is processed, but also what information is processed. Performance increases because, with practice, cognitive resources are used more and more efficiently as irrelevant aspects of the task are discarded from processing. Human–machine interaction, educational and sports psychology are just some contexts where behaviour consistent with the notion of information reduction has been reported. Information reduction applies in situations in which tasks contain both relevant and irrelevant information, and denotes a change from a processing-all-elements-of-a-task strategy to a processing-relevant-elements-only strategy. In two experiments, we tested empirically if information reduction is an item-specific or an item-general process by manipulating the frequency with which items were repeated during task practice. Participants verified alphanumeric strings containing task-relevant and task-irrelevant information. As the latter was not mentioned in the instructions, information reduction was studied in an incidental learning situation. We found that string-specific repetition frequency was related to the amount of time participants spent processing relevant portions of the stimuli, but was not related to the time spent processing the irrelevant portions. Thus, repetition frequency did not affect the degree of information reduction. The conclusion that information reduction is an item-general phenomenon was further supported by frequency-independent high rates of transfer errors when, late in practice, the former regularity of an irrelevant and relevant string-part no longer applied. The findings are incompatible with most data-driven theories of skill acquisition that attribute strategy changes during task practice exclusively to automatically occurring learning mechanisms. The results are compatible with theories that assume a top-down influence on skill acquisition.     

Beobachtungen an Ziegen

Ohne Zusammenfassung     

Having an interpretation

I investigate what it means to have an interpretation of our language, how we manage to bestow a determinate interpretation to our utterances, and to which extent our interpretation of the world is determinate. All this is done in dialogue with van Fraassen’s insightful discussion of Putnam’s model-theoretic argument and of scientific structuralism.     

Erinnerungen an Hannes

Dein Tod hat eine Leere hinterlassen, die schwer zu füllen sein wird. Seltsamerweise ist kein Schmerz in mir, nur ein dankbares Erinnern an fünf Jahre, die ich für dich da war, für dich da sein durfte. T?glich bin ich um die Mittagszeit zu dir gefahren, um dich zu füttern, dir ein wenig Gesellschaft zu leisten, dein unweigerliches Versinken in deine eigene Welt, wenn schon nicht aufzuhalten, denn das war unm?glich, so doch zumindest ein wenig hinauszuz?gern.