Attention Switching vs Attention Sharing in Searching Dual RSVP Streams

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 122-122
Author(s):  
N Prins ◽  
J F Juola

Ideas about how visual attention is distributed over space include spotlight, zoom lens, and various resource allocation models. Spotlight and serial allocation models assume that attention is narrowly focused and switches from one object to another in visual search. Zoom lens and parallel allocation models, on the other hand, describe a flexible gradient within which attention can be shared among several items simultaneously. We report two experiments in which simultaneous rapid serial visual presentations (RSVPs) of two streams of digits were used, one above and one below a fixation point. In experiment 1, subjects were told to report the digit immediately following a uniquely coloured signal digit. In some trial blocks the coloured signal digit always appeared in either the top or bottom stream, and in other blocks the signal digit could occur in either stream. Stream location probabilities were varied between blocks in order to induce strategic variations in attentional allocation. In experiment 2, subjects were told to report the first two digits visible when the fixation point changed colour. Subjects were instructed to report one digit from the top stream and one from the bottom, with report order counterbalanced between blocks. The lag between the response signal and the actual digit reported was shown to vary strongly with signal location probability (experiment 1), and the lag between items reported from the top and bottom streams depended heavily on the order of report (experiment 2). The results were more consistent with an attention-switching model than with an attention-sharing model of visual attention.

1993 ◽  
Vol 76 (3_suppl) ◽  
pp. 1287-1295 ◽  
Author(s):  
Masaki Tomonaga

Two chimpanzees and two humans were trained on visual search tasks with several sets of geometric forms composed of 1 and 2 elements (graphemes). When the double-grapheme item was the target and single grapheme item was the distractor, both chimpanzees and humans searched the target quickly irrespective of the display size. On the other hand, when the single-grapheme item was the target and double-grapheme item was the distractor, they showed an increase in response times as a function of the display size on some sets of stimuli. These results were considered as evidence for search asymmetry by chimpanzees.


Author(s):  
Natalie McGlynn

This study involved two experiments. The goal of the first was to evaluate how visual attention is distributed spatially within an object, and how a spatial distribution may change over time. We accomplished this by having people press a button as soon as they noticed a target appear at various onset times and locations within an arch-shaped object. In the second experiment, we extended the arch-object and cued one end of it, in order to examine whether attention is biased to follow the shape of an object even if such a mechanism reduces the efficiency of a visual search. Results from the first experiment indicate that initially, there is no attentional bias to any location within an object. However, as looking time increases, a developing bias to the centre of objects occurs before attention adopts a strategic spatial distribution within the object. Results from the second experiment indicate that after attention is captured by a cued area, attention shifts away from the cued location. The path attention takes from the cued area is not constrained within the object. With increased time, however, attention does not move back to the cued location. Therefore, although attention is not constrained to follow the shape of the object one focuses on, it seems that the efficiency of a visual search is still jeopardized due to reluctance for attention to move to previously attended locations.


2018 ◽  
Author(s):  
Bernt Skottun

In tests of visual search it is found that the response time increases with set size under some stimulus conditions whereas it may be relatively independent of set size under other conditions. The present study investigates interference in the kinds of stimuli employed in such experiments. Interference takes place in the stimuli and does not depend on the visual system or on attention. Two scenarios were explored: (1) Interference between all elements, and (2) interference between a target and a single background made up of a set of elements. In the former case interference increases monotonically with set size. In the latter case there is a mild amount of interference which remains relatively independent of set size. By assuming the response time increases with the inverse of stimulus power (response time ∝ 1/(1 - interference)) it is found that when there is interference between all the elements the simulated response time increases monotonically with set size. On the other hand, when the interference is between a target and a single background the simulated response time remains largely unaffected by set size.


1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.


Author(s):  
A. V. Crewe

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.


Author(s):  
K.H. Westmacott

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.


2005 ◽  
Vol 19 (3) ◽  
pp. 129-132 ◽  
Author(s):  
Reimer Kornmann

Summary: My comment is basically restricted to the situation in which less-able students find themselves and refers only to literature in German. From this point of view I am basically able to confirm Marsh's results. It must, however, be said that with less-able pupils the opposite effect can be found: Levels of self-esteem in these pupils are raised, at least temporarily, by separate instruction, academic performance however drops; combined instruction, on the other hand, leads to improved academic performance, while levels of self-esteem drop. Apparently, the positive self-image of less-able pupils who receive separate instruction does not bring about the potential enhancement of academic performance one might expect from high-ability pupils receiving separate instruction. To resolve the dilemma, it is proposed that individual progress in learning be accentuated, and that comparisons with others be dispensed with. This fosters a self-image that can in equal measure be realistic and optimistic.


Author(s):  
Stefan Krause ◽  
Markus Appel

Abstract. Two experiments examined the influence of stories on recipients’ self-perceptions. Extending prior theory and research, our focus was on assimilation effects (i.e., changes in self-perception in line with a protagonist’s traits) as well as on contrast effects (i.e., changes in self-perception in contrast to a protagonist’s traits). In Experiment 1 ( N = 113), implicit and explicit conscientiousness were assessed after participants read a story about either a diligent or a negligent student. Moderation analyses showed that highly transported participants and participants with lower counterarguing scores assimilate the depicted traits of a story protagonist, as indicated by explicit, self-reported conscientiousness ratings. Participants, who were more critical toward a story (i.e., higher counterarguing) and with a lower degree of transportation, showed contrast effects. In Experiment 2 ( N = 103), we manipulated transportation and counterarguing, but we could not identify an effect on participants’ self-ascribed level of conscientiousness. A mini meta-analysis across both experiments revealed significant positive overall associations between transportation and counterarguing on the one hand and story-consistent self-reported conscientiousness on the other hand.


2019 ◽  
Vol 50 (2) ◽  
pp. 80-93
Author(s):  
Jort de Vreeze ◽  
Christina Matschke

Abstract. Not all group memberships are self-chosen. The current research examines whether assignments to non-preferred groups influence our relationship with the group and our preference for information about the ingroup. It was expected and found that, when people are assigned to non-preferred groups, they perceive the group as different to the self, experience negative emotions about the assignment and in turn disidentify with the group. On the other hand, when people are assigned to preferred groups, they perceive the group as similar to the self, experience positive emotions about the assignment and in turn identify with the group. Finally, disidentification increases a preference for negative information about the ingroup.


1961 ◽  
Vol 6 (6) ◽  
pp. 222-223
Author(s):  
Edwin G. Boring
Keyword(s):  

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