Optical Defocusing Reverses Perceptual Organization

Perception ◽  
1979 ◽  
Vol 8 (2) ◽  
pp. 225-228 ◽  
Author(s):  
J Timothy Petersik
Keyword(s):  
Critical Point ◽  
Perceptual Organization ◽  
Reversible Figure ◽  
Similar Point ◽  
Spontaneous Reversal ◽  
Over Time

At a certain point during the defocusing of a reversible figure, the organization of the figure reversed unexpectedly, and the reversal seemed more abrupt than a spontaneous reversal. The critical point is approximately constant over time for a given subject, and a similar point occurs during refocusing. This phenomenon is discussed in terms of inhibition between competing neural structures.

scholarly journals The initial phase of auditory and visual scene analysis

2012 ◽  
Vol 367 (1591) ◽  
pp. 942-953 ◽  
Author(s):  
Jean-Michel Hupé ◽  
Daniel Pressnitzer
Keyword(s):  
Perceptual Organization ◽  
Initial Phase ◽  
Stimulus Presentation ◽  
Visual Scene ◽  
Scene Analysis ◽  
Systematic Bias ◽  
Auditory Streaming ◽  
Neurophysiological Data ◽  
Presentation Organization ◽  
Over Time

Auditory streaming and visual plaids have been used extensively to study perceptual organization in each modality. Both stimuli can produce bistable alternations between grouped (one object) and split (two objects) interpretations. They also share two peculiar features: (i) at the onset of stimulus presentation, organization starts with a systematic bias towards the grouped interpretation; (ii) this first percept has ‘inertia’; it lasts longer than the subsequent ones. As a result, the probability of forming different objects builds up over time, a landmark of both behavioural and neurophysiological data on auditory streaming. Here we show that first percept bias and inertia are independent. In plaid perception, inertia is due to a depth ordering ambiguity in the transparent (split) interpretation that makes plaid perception tristable rather than bistable: experimental manipulations removing the depth ambiguity suppressed inertia. However, the first percept bias persisted. We attempted a similar manipulation for auditory streaming by introducing level differences between streams, to bias which stream would appear in the perceptual foreground. Here both inertia and first percept bias persisted. We thus argue that the critical common feature of the onset of perceptual organization is the grouping bias, which may be related to the transition from temporally/spatially local to temporally/spatially global computation.

When Scenes Look Like Materials: René Magritte’s Reversible Figure–Ground Motif

2020 ◽  
Vol 8 (3-4) ◽  
pp. 299-310
Author(s):  
J. Brendan Ritchie ◽  
Benjamin van Buren
Keyword(s):  
Image Segmentation ◽  
Perceptual Organization ◽  
Scene Perception ◽  
Reversible Figure ◽  
Image Statistics ◽  
Figural Region ◽  
Frequent Motif ◽  
Visual Segmentation ◽  
Positive Space

We draw attention to a frequent motif in the work of the Belgian surrealist René Magritte (1898–1967). In the motif, a scene is depicted that contains a silhouette, which itself contains another depicted scene. The silhouette is bistable, appearing either as a figural region whose positive space is covered, or filled, with the interior scene texture, or as a ground region providing a window onto a more distant scene. We call this the ‘reversible figure–ground motif’. Because the stimulus does not change when our percept changes, the motif’s appearance at any particular moment cannot be explained by its local or global image statistics. Instead principles of perceptual organization, and in particular image segmentation and figure–ground assignment, appear crucial for determining whether the interior of the silhouette is processed as a material vs. a scene — which in turn reflects the fundamental role of visual segmentation in material and scene perception more generally.

Stability and Attraction of Perceptual Organizations in the Reversible Figure-Ground Phenomenon

1969 ◽  
Vol 28 (3) ◽  
pp. 983-991 ◽  
Author(s):  
Leroy H. Pelton ◽  
Charles M. Solley ◽  
Sandor B. Brent
Keyword(s):  
Perceptual Organization ◽  
Functional Integration ◽  
Reversible Figure ◽  
Temporal Duration ◽  
The Stability

The concepts of stability, defined as the temporal duration of a particular organization, and attraction, defined as the likelihood at any given moment that a particular perceptual organization is being experienced, were studied in regard to the reversible figure-ground phenomenon. Some factors that might increase the stability and attraction of a figural organization were investigated. It was found that neither “complexity” nor “meaningfulness” can increase the stability and attraction of a figural organization of a reversible pattern unless the added elements are functionally integrated with the central contour. However, it is maintained that, while some patterns of stimulation invariably elicit functional integration, there are others which elicit integration for some perceivers and not others.

Preference Reversal Under Vulnerability

2020 ◽  
pp. 228-243
Author(s):  
Aurora Correa-Flores
Keyword(s):  
Neural Networks ◽  
Behavioral Economics ◽  
Financial Performance ◽  
Agency Theory ◽  
Critical Point ◽  
Family Firms ◽  
Preference Reversal ◽  
Financial Wealth ◽  
Over Time ◽  
Point Of Reference

The behavioral agency theory explains that preferences have not always been stable over time and might change with the framing of the problem. A concept largely used in behavioral economics has been recently adopted in family firms' literature: preference reversal. Preference reversal explains that in the presence of vulnerability, family firms are willing to change their most critical point of reference, socioemotional wealth, and that they are willing to focus on financial wealth. This chapter introduces the concept of preference reversal, explains the application of preference reversal in family firms, and makes an empirical exploration of the presence of preference reversal. The study explores one of the cases of firm vulnerability: a low financial performance by applying neural networks. The study applies to Mexican family firms and finds indications of preference reversal.

Characterizing changes in parent labelling and gesturing and their relation to early communicative development

2004 ◽  
Vol 31 (4) ◽  
pp. 821-835 ◽  
Author(s):  
LAURA L. NAMY ◽  
SUSAN A. NOLAN
Keyword(s):  
Longitudinal Study ◽  
Individual Differences ◽  
Critical Point ◽  
Vocabulary Development ◽  
Free Play ◽  
Communicative Development ◽  
Parental Input ◽  
Over Time ◽  
Parent Child

In a longitudinal study, 17 parent–child dyads were observed during free-play when the children were 1;0, 1;6, and 2;0. Parents' labelling input in the verbal and gestural modalities was coded at each session, and parents completed a vocabulary checklist for their children at each visit. We analysed how the frequency of labelling in the verbal and gestural modalities changed across observation points and how changes in parental input related to children's vocabulary development. As a group, parents' verbal labelling remained constant across sessions, but gestural labelling declined at 2;0. However, there are notable individual differences in parental trajectories in both modalities. Parents whose verbal labelling frequency increased over time had children whose vocabulary grew more slowly than those whose labelling frequency decreased, remained constant, or peaked at 1;6. There were few systematic relations between patterns of parental gesturing and children's vocabulary development. Parents' verbal and gestural labelling patterns also appeared dissociable. However, parents' words and gestures were correlated when their children were 1;6, suggesting that gestures serve an important bootstrapping function at a critical point in children's vocabulary development.

Social transmission bias and the cultural evolution of folk-economic beliefs

2018 ◽  
Vol 41 ◽  
Author(s):  
David Hirshleifer ◽  
Siew Hong Teoh
Keyword(s):  
Cultural Evolution ◽  
Social Transmission ◽  
Cognitive Approach ◽  
Economic Problems ◽  
Economic Attitudes ◽  
The Social ◽  
Economic Beliefs ◽  
Over Time

AbstractEvolved dispositions influence, but do not determine, how people think about economic problems. The evolutionary cognitive approach offers important insights but underweights the social transmission of ideas as a level of explanation. The need for asocialexplanation for the evolution of economic attitudes is evidenced, for example, by immense variations in folk-economic beliefs over time and across individuals.

The Critical Point Drying Method Applied to Scanning Electron Microscopy of L-929 Cells

1970 ◽  
Vol 28 ◽  
pp. 278-279
Author(s):  
Charles TurnbiLL ◽  
Delbert E. Philpott
Keyword(s):  
Electron Microscopy ◽  
Carbon Dioxide ◽  
Surface Tension ◽  
Critical Point ◽  
Freeze Drying ◽  
Attractive Alternative ◽  
Crystal Formation ◽  
Critical Point Drying ◽  
Time Required ◽  
Scanning Electron

The advent of the scanning electron microscope (SCEM) has renewed interest in preparing specimens by avoiding the forces of surface tension. The present method of freeze drying by Boyde and Barger (1969) and Small and Marszalek (1969) does prevent surface tension but ice crystal formation and time required for pumping out the specimen to dryness has discouraged us. We believe an attractive alternative to freeze drying is the critical point method originated by Anderson (1951; for electron microscopy. He avoided surface tension effects during drying by first exchanging the specimen water with alcohol, amy L acetate and then with carbon dioxide. He then selected a specific temperature (36.5°C) and pressure (72 Atm.) at which carbon dioxide would pass from the liquid to the gaseous phase without the effect of surface tension This combination of temperature and, pressure is known as the "critical point" of the Liquid.

SEM Cold Stage Techniques for the Observation of Vegetative and Floral Apices of Oat (Avena sativa L.) Plants

1977 ◽  
Vol 35 ◽  
pp. 590-591
Author(s):  
B. K. Kirchoff ◽  
L.F. Allard ◽  
W.C. Bigelow
Keyword(s):  
Critical Point ◽  
Avena Sativa ◽  
Substantial Improvement ◽  
Fresh Tissue ◽  
Cold Stage ◽  
Critical Point Drying ◽  
Almost All ◽  
Cell Collapse ◽  
Conductive Paint ◽  
Carbon Based

In attempting to use the SEM to investigate the transition from the vegetative to the floral state in oat (Avena sativa L.) it was discovered that the procedures of fixation and critical point drying (CPD), and fresh tissue examination of the specimens gave unsatisfactory results. In most cases, by using these techniques, cells of the tissue were collapsed or otherwise visibly distorted. Figure 1 shows the results of fixation with 4.5% formaldehyde-gluteraldehyde followed by CPD. Almost all cellular detail has been obscured by the resulting shrinkage distortions. The larger cracks seen on the left of the picture may be due to dissection damage, rather than CPD. The results of observation of fresh tissue are seen in Fig. 2. Although there is a substantial improvement over CPD, some cell collapse still occurs.Due to these difficulties, it was decided to experiment with cold stage techniques. The specimens to be observed were dissected out and attached to the sample stub using a carbon based conductive paint in acetone.

The Effects of Drying Techniques on Clay-Rich Soil Texture

1974 ◽  
Vol 32 ◽  
pp. 466-467
Author(s):  
T. G. Naymik
Keyword(s):  
Critical Point ◽  
Liquid Nitrogen ◽  
Liquid Nitrogen Temperature ◽  
Drying Methods ◽  
Air Drying ◽  
Freeze Dried ◽  
Critical Point Drying ◽  
Set Up ◽  
The Relationship ◽  
Quartz Grains

Three techniques were incorporated for drying clay-rich specimens: air-drying, freeze-drying and critical point drying. In air-drying, the specimens were set out for several days to dry or were placed in an oven (80°F) for several hours. The freeze-dried specimens were frozen by immersion in liquid nitrogen or in isopentane at near liquid nitrogen temperature and then were immediately placed in the freeze-dry vacuum chamber. The critical point specimens were molded in agar immediately after sampling. When the agar had set up the dehydration series, water-alcohol-amyl acetate-CO2 was carried out. The objectives were to compare the fabric plasmas (clays and precipitates), fabricskeletons (quartz grains) and the relationship between them for each drying technique. The three drying methods are not only applicable to the study of treated soils, but can be incorporated into all SEM clay soil studies.

Preservation of Plant Cell Surfaces For Scanning Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 472-473
Author(s):  
Linda M. Sicko ◽  
Thomas E. Jensen
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Critical Point ◽  
Filter Paper ◽  
Freeze Drying ◽  
Cell Surfaces ◽  
Air Drying ◽  
Popular Method ◽  
Critical Point Drying ◽  
Scanning Electron

The use of critical point drying is rapidly becoming a popular method of preparing biological samples for scanning electron microscopy. The procedure is rapid, and produces consistent results with a variety of samples. The preservation of surface details is much greater than that of air drying, and the procedure is less complicated than that of freeze drying. This paper will present results comparing conventional air-drying of plant specimens to critical point drying, both of fixed and unfixed material. The preservation of delicate structures which are easily damaged in processing and the use of filter paper as a vehicle for drying will be discussed.

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