Detection versus Discrimination of Visual Orientation

Perception ◽  
1984 ◽  
Vol 13 (5) ◽  
pp. 619-628 ◽  
Author(s):  
Dov Sagi ◽  
Bela Julesz
Keyword(s):  
Line Segment ◽  
Vertical Line ◽  
Visual Orientation ◽  
Focused Attention ◽  
Vertical Orientation ◽  
Serial Search ◽  
Line Segments ◽  
Focal Attention ◽  
Conspicuous Feature

The role of focused attention in vision is examined. Recent theories of attention hypothesize that serial search by focal attention is required for discrimination between different combinations of features. Experiments are reported which show that the mixture of a few (less than five) horizontal and vertical line segments embedded in an aggregate of diagonal line segments can be rapidly counted (also called ‘subitizing’) by a parallel (preattentive) process, while the discrimination between horizontal and vertical orientation requires serial search by shifting focal attention to each line segment. Thus detecting and counting targets that differ in orientation can be done in parallel by a preattentive process, whereas knowing ‘what’ the orientation of a target is (horizontal or vertical, ie of a single conspicuous feature) requires a serial search by focal attention.

Less is more: Simple stimuli provoke more variable search strategies.

2020 ◽  
Author(s):  
Anna Nowakowska ◽  
Alasdair D F Clarke ◽  
Jessica Christie ◽  
Josephine Reuther ◽  
Amelia R. Hunt
Keyword(s):  
Line Segment ◽  
Search Strategies ◽  
Complex Objects ◽  
Search Behaviour ◽  
Line Segments ◽  
Surface Level ◽  
Efficient Search ◽  
Less Is More ◽  
Dramatic Shift

We measured the efficiency of 30 participants as they searched through simple line segment stimuli and through a set of complex icons. We observed a dramatic shift from highly variable, and mostly inefficient, strategies with the line segments, to uniformly efficient search behaviour with the icons. These results demonstrate that changing what may initially appear to be irrelevant, surface-level details of the task can lead to large changes in measured behaviour, and that visual primitives are not always representative of more complex objects.

Explanation for Neon Color Effect in Achromatic Line Segments on Chromatic Inducers Based on the Multiple Interpretation Hypothesis

2005 ◽  
Vol 101 (1) ◽  
pp. 267-282
Author(s):  
Seiyu Sohmiya
Keyword(s):  
Visual System ◽  
Line Segment ◽  
Color Contrast ◽  
Achromatic Color ◽  
Line Segments ◽  
Color Effect ◽  
Complementary Color ◽  
Multiple Interpretation ◽  
Color Induction ◽  
Simultaneous Color Contrast

In van Tuijl's neon configurations, an achromatic line segment on a blue inducer produces yellowish illusory color in the illusory area. This illusion has been explained based on the idea of the complementary color induced by the blue inducer. However, it is proposed here that this illusion can be also explained by introducing the assumption that the visual system unconsciously interprets an achromatic color as information that is constituted by transparent and nontransparent colors. If this explanation is correct, not only this illusion, but also the simultaneous color contrast illusion can be explained without using the idea of the complementary color induction.

ALPHA-REGULAR STICK UNKNOTS

2012 ◽  
Vol 21 (06) ◽  
pp. 1250059 ◽  
Author(s):  
CHRISTOPHER FRAYER ◽  
CHRISTOPHER SCHAFHAUSER
Keyword(s):  
Line Segment ◽  
Line Segments

Suppose Pn is a regular n-gon in ℝ2. An embedding f : Pn ↪ ℝ3 is called an α-regular stick knot provided the image of each side of Pn under f is a line segment of length 1 and any two consecutive line segments meet at an angle of α. The main result of this paper proves the existence of α-regular stick unknots for odd n ≥ 7 with α in the range [Formula: see text]. All knots constructed will have trivial knot type, and we will show that any non-trivial α-regular stick knot must have [Formula: see text].

Processual responsiveness in dialogic facilitation

2020 ◽  
Vol 33 (2) ◽  
pp. 137-148
Author(s):  
Helle Alrø ◽  
Lise Billund
Keyword(s):  
Special Interest ◽  
Design Methodology ◽  
Interpersonal Relations ◽  
Focused Attention ◽  
Content Type ◽  
Pragmatic Analysis ◽  
Audio Recordings ◽  
Dialogic Approach

Purpose The purpose of this paper is to elaborate on the role of a group facilitator when taking a dialogical stance. A special interest is facilitator’s processual responsiveness and its potential for supporting a dialogic approach to process facilitation. Design/methodology/approach Theoretically, the article is based on dialogue and dialectic relationship theory. Empirically, it is based on pragmatic analysis of excerpts from audio recordings of a two-day process facilitation with an organizational group called KUDIAS. Findings The analysis highlights the importance of processual responsiveness of the facilitator in terms of focused attention to the process as well as to the interpersonal relations between the participants in the process. Being processually responsive, the facilitator supports the process in becoming dialogic toward all participants’ perspectives and in creating a climate characterized by curiosity, wondering, exploration and recognition. However, facilitator’s processual responsiveness also requires the ability to balance the process between support and confrontation. Originality/value Processual responsiveness is developed and discussed theoretically as well as empirically.

Nothing left in store . . . but how do we measure attentional capacity?

2001 ◽  
Vol 24 (1) ◽  
pp. 132-133
Author(s):  
Sergio Morra
Keyword(s):  
Working Memory ◽  
Procedural Knowledge ◽  
Short Term Memory ◽  
Memory Development ◽  
Compelling Evidence ◽  
Short Term ◽  
Term Memory ◽  
Focal Attention ◽  
And Storage

I compare the concepts of “activation” and “storage” as foundations of short-term memory, and suggest that an attention-based view of STM does not need to posit specialized short-term stores. In particular, no compelling evidence supports the hypothesis of time-limited stores. Identifying sources of activation, examining the role of activated procedural knowledge, and studying working memory development are central issues in modelling capacity-limited focal attention.

Hope in the Unexpected: How Can Teachers Still Make a Difference in the World?

2010 ◽  
Vol 112 (2) ◽  
pp. 386-406
Author(s):  
Julian Edgoose
Keyword(s):  
Social Change ◽  
Research Question ◽  
Focused Attention ◽  
The World ◽  
Agents Of Change ◽  
Hard Times ◽  
The Impact ◽  
Background Context ◽  
Objective Research

Background/Context The central role of hope in teaching has long been acknowledged by authors such as Sonia Nieto and Larry Cuban, but hope has received little focused attention from scholars. This article seeks to compare multiple understandings of hope to examine how teachers can find hope in times of global crises that challenge the promise of a better future that is implicit in modern schooling. Purpose/Objective/Research Question/Focus of Study How can teachers find hope in hard times, when the usual promise of schools for a better future seems difficult to sustain? Research Design This article is an analytic essay. Conclusions/Recommendations This article concludes that while the long-dominant understandings of hope are inadequate for many teachers at times like these, Arendt's view of the hope that emerges in the unexpected occurrences of classroom life resonates strongly with the most rewarding and hopeful experiences of many teachers. Yet Arendt explains how the hope that teachers experience from these unpredictable and unexpected occurrences is not just a source of immediate reward, but rather contributes to political and social change. The article concludes with an account of Arendt's critique of historians’ narratives of social change and an affirmation of the impact that teachers can have as agents of change.

A Duplicate Chinese Document Image Retrieval System Based on Line Segment Feature in Character Image Block

2011 ◽  
pp. 14-23
Author(s):  
Yung-Kuan Chan ◽  
Tung-Shou Chen ◽  
Yu-An Ho
Keyword(s):  
Image Retrieval ◽  
Line Segment ◽  
Document Image ◽  
Experimental Results ◽  
Document Images ◽  
Rapid Progress ◽  
Image Block ◽  
Line Segments ◽  
Image Retrieval System ◽  
On Line

With the rapid progress of digital image technology, the management of duplicate document images is also emphasized widely. As a result, this paper suggests a duplicate Chinese document image retrieval (DCDIR) system, which uses the ratio of the number of black pixels to that of white pixels on the scanned line segments in a character image block as the feature of the character image block. Experimental results indicate that the system can indeed effectively and quickly retrieve the desired duplicate Chinese document image from a database.

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