The Differential Effects of Simultaneous and Successive Cueing on the Detection of Bilateral Symmetry in Dot Patterns

2000 ◽  
Vol 53 (1) ◽  
pp. 165-190 ◽  
Author(s):  
Peter Wenderoth
Keyword(s):  
Visual Processing ◽  
Processing Time ◽  
Reaction Times ◽  
Vertical Axis ◽  
Bilateral Symmetry ◽  
Frame Of Reference ◽  
Symmetry Detection ◽  
Axis Orientation ◽  
Differential Effects ◽  
Orientation Ordering

Corballis and Roldan (1975) obtained speeded judgements of whether dot patterns were bilaterally symmetrical about, or translated across, a line. Reaction times (RTs) were ordered V (vertical) > D (diagonal) > H (horizontal) where “>” means faster than. Similar results occurred with blocked axis orientations, suggesting subjects cannot prepare by rotating a mental frame of reference. Blocking trials may have been ineffective because blocking cannot provide incremental benefits over those already provided by axis lines. Four experiments show that the usual axis orientation ordering of V > H > D is markedly attentuated by simultaneous but not successive axis lines. Also, axis cue lines and axis blocking are not equivalent treatments. Instead, unblocked line cues require finite processing time whereas, under blocking, subjects can prepare for the expected orientation. There was no suggestion anywhere of the V > D > H axis ordering that Corballis and Roldan reported. Successive axis line cues may only direct attention to the orientation being cued, but simultaneous line cues may change the stimulus itself, thus providing an additional means of visual processing that facilitates symmetry detection at non-vertical axis orientations.

The Effects on Bilateral-Symmetry Detection of Multiple Symmetry, near Symmetry, and Axis Orientation

Perception ◽  
1997 ◽  
Vol 26 (7) ◽  
pp. 891-904 ◽  
Author(s):  
Peter Wenderoth
Keyword(s):  
Response Bias ◽  
Human Perception ◽  
Negative Stimulus ◽  
Bilateral Symmetry ◽  
Symmetry Detection ◽  
Axis Orientation ◽  
Second Stage ◽  
Asymmetrical Pattern ◽  
Stage Process ◽  
Axes Of Symmetry

Palmer and Hemenway (1978 Journal of Experimental Psychology: Human Perception and Performance4 691–702) reported that shapes with multiple axes of symmetry are processed faster than those with single symmetry even when trials are blocked so that the subject knows that any symmetry axis will be vertical. Because their model of symmetry detection postulated a two-stage process in which all orientations are searched crudely at first, in no particular order, followed by second-stage scrutiny, the continued salience of multiple over single symmetry with blocking could not be explained. They claimed that stimuli with multiple axes of symmetry have an additional ‘goodness’. Four experiments are reported in which it is demonstrated that both sensitivity ( d′) and response bias ( β) vary considerably in symmetry detection, not just as a function of the positive (symmetrical) stimuli used but also as a function of the negative or conjugate instances selected. Although stimuli with multiple axes of symmetry may well have extra salience due to pattern ‘goodness’, this factor may have been confounded with response bias in Palmer and Hemenway's experiments. It is suggested that several of their—as well as other researchers—results could be due to some combination of the effects of type of positive stimulus, type of negative stimulus, and response bias directed towards responding positively to highly symmetrical stimuli in a mix of less symmetrical stimuli. Palmer and Hemenway appear to have been correct in suggesting that subjects are more sensitive to quadruple than single symmetry, but the experiments indicate that subjects are also more willing to respond “symmetrical” to stimuli with quadruple symmetry when trials are not blocked, as in Palmer and Hemenway's experiment 1. However, it is demonstrated that the latter effect can be removed by blocking trials so that only one class of symmetrical pattern and one class of asymmetrical pattern occur in any block.

The Role of ON- and OFF-Channel Processing in the Detection of Bilateral Symmetry

Perception ◽  
10.1068/p3387 ◽  
2002 ◽  
Vol 31 (9) ◽  
pp. 1061-1072 ◽  
Author(s):  
Anna Brooks ◽  
Rick van der Zwan
Keyword(s):  
Bilateral Symmetry ◽  
Limited Range ◽  
Visual Scene ◽  
Performance Decrement ◽  
Symmetry Detection ◽  
Axis Orientation ◽  
Present Evidence ◽  
Detection Mechanisms

We present evidence that grouping for luminance does not take precedence over the detection of bilaterally symmetrical patterns. Using single-axis and double-axis images, we found that element pairs within which luminance is held constant drive symmetry-detection mechanisms more effectively than pairs within which luminance varies. Moreover, the performance decrement observed for patterns defined by element pairs within which luminance varies is not specific to interchannel variation. Luminance variation within the ON and OFF channels has the same effect as variation between the channels on the performance of axis-orientation identification tasks. It is argued that this constitutes possible evidence for subchannels within the ON and OFF channels. One of the characteristics of the subchannels is that each processes only a limited range of luminance steps. The implications of this type of luminance processing for the detection of symmetry in the visual scene are discussed.

Classifying the Past: Discriminant Analysis and its Application to Medieval Farming Systems

1996 ◽  
Vol 8 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Ken Bartley
Keyword(s):  
Cluster Analysis ◽  
Discriminant Analysis ◽  
Processing Time ◽  
Farming Systems ◽  
Frame Of Reference ◽  
Analytical Models ◽  
Successful Implementation ◽  
Medieval Period ◽  
The Past ◽  
Livestock Management

This paper discusses the need for nationally based analytical models of the medieval period. The use of cluster analysis as a method for classifying demesne farms, by the crops they grew and their livestock management, is explained. Successful implementation of cluster analysis requires both the existence of a large base sample, to permit isolation of specific groupings within the data, and access to considerable processing time. The paper concludes by demonstrating how discriminant analysis can provide an efficient and systematic way of classifying even a single manor within a national frame of reference.

scholarly journals Familiarity affects the same event-related brain potential components in note readers and non-note readers

2018 ◽  
Vol 1 ◽  
pp. 205920431877823 ◽  
Author(s):  
Linda Becker
Keyword(s):  
Visual Perception ◽  
Neural Plasticity ◽  
Visual Processing ◽  
Music Perception ◽  
Reaction Times ◽  
Future Research ◽  
Familiarity Effect ◽  
Professional Musicians ◽  
Brain Potential ◽  
Cognitive Domains

Musical expertise can lead to neural plasticity in specific cognitive domains (e.g., in auditory music perception). However, not much is known about whether the visual perception of simple musical symbols (e.g., notes) already differs between musicians and non-musicians. This was the aim of the present study. Therefore, the Familiarity Effect (FE) – an effect which occurs quite early during visual processing and which is based on prior knowledge or expertise – was investigated. The FE describes the phenomenon that it is easier to find an unfamiliar element (e.g., a mirrored eighth note) in familiar elements (e.g., normally oriented eighth notes) than to find a familiar element in a background of unfamiliar elements. It was examined whether the strength of the FE for eighth notes differs between note readers and non-note readers. Furthermore, it was investigated at which component of the event-related brain potential (ERP) the FE occurs. Stimuli that consisted of either eighth notes or vertically mirrored eighth notes were presented to the participants (28 note readers, 19 non-note readers). A target element was embedded in half of the trials. Reaction times, sensitivity, and three ERP components (the N1, N2p, and P3) were recorded. For both the note readers and the non-note readers, strong FEs were found in the behavioral data. However, no differences in the strength of the FE between groups were found. Furthermore, for both groups, the FE was found for the same ERP components (target-absent trials – N1 latency; target-present trials – N2p latency, N2p amplitude, P3 amplitude). It is concluded that the early visual perception of eighth note symbols does not differ between note readers and non-note readers. However, future research is needed to verify this for more complex musical stimuli and for professional musicians.

scholarly journals The Relationship of Ultrasonic Velocities to c-axis Fabrics and Relaxation Characteristics of Ice Cores from Byrd Station, Antarctica

1979 ◽  
Vol 24 (90) ◽  
pp. 147-153 ◽  
Author(s):  
A. J. Gow ◽  
H. Kohnen
Keyword(s):  
Ice Sheet ◽  
Ice Cores ◽  
Vertical Axis ◽  
P Wave ◽  
Ultrasonic Technique ◽  
Antarctic Ice Sheet ◽  
Axis Orientation ◽  
Crystal Anisotropy ◽  
The Antarctic ◽  
Relaxation Characteristics

Abstract Deep cores from Byrd Station were used to calibrate an ultrasonic technique of evaluating crystal anisotropy in the Antarctic ice sheet. Velocities measured parallel (V p ↓) and perpendicular (V p →) to the vertical axis of the cores yielded data in excellent agreement with the observed c-axis fabric profile and with the in-situ P-wave velocity profile measured parallel to the bore-hole axis by Bentley. Velocity differences ΔV (ΔV = V p ↓ – V p→) in excess of 140 m s−1 for cores from below 1300 m attest to the tight clustering of c-axes of crystals about the vertical, especially in the zone 1 300-1800 m. A small but significant decline in V p ↓ with ageing of the core, as deduced from Bentley’s down-hole data, is attributed to the formation of oriented cracks that occur in the ice cores as they relax from environmental stresses. This investigation of cores from the 2164 m thick ice sheet at Byrd Station establishes the ultrasonic technique as a viable method of monitoring relaxation characteristics of drilled cores and for determining the gross trends of c-axis orientation in ice sheets. The Byrd Station data, in conjunction with Barkov’s investigation of deep cores from Vostok, East Antarctica, also indicate that crystal anisotropy in the Antarctic ice sheet is dominated by a clustering of c-axes about a vertical symmetry axis.

Fluidized bed heat treatment of aluminum cast components

2004 ◽  
Vol 120 ◽  
pp. 555-562
Author(s):  
D. Apelian ◽  
S. K. Chaudhury
Keyword(s):  
Heat Treatment ◽  
Fluidized Bed ◽  
Processing Time ◽  
Reaction Times ◽  
Experimental Results ◽  
Fluidized Bed Reactors ◽  
The Past ◽  
Conventional Furnace ◽  
Time Required ◽  
Solutionizing Time

Heat Treatment and post casting treatments of cast components has always been an important step in the control of microstructure, and resultant properties. In the past, the solutionizing, quenching and ageing process steps may have “required” in total over 20 hours of processing time. With the advent of fluidized bed reactors (FB), processing time has been dramatically reduced. For example, instead of 8-10 hours solutionizing time in a conventional furnace, the time required in FB is less than an hour. Experiments with Al-Si-Mg alloy, (both modified with Sr, and unmodified) were performed, having different diffusion distances (different DAS), and for different reaction times and temperatures. Both the model and the experimental results are presented and discussed.

Spatial organization of visual messages of the rabbit's cerebellar flocculus. II. Complex and simple spike responses of Purkinje cells

1988 ◽  
Vol 60 (6) ◽  
pp. 2091-2121 ◽  
Author(s):  
W. Graf ◽  
J. I. Simpson ◽  
C. S. Leonard
Keyword(s):  
Purkinje Cells ◽  
Horizontal Plane ◽  
Rotation Axis ◽  
Modulation Depth ◽  
Vertical Axis ◽  
Axis Orientation ◽  
Complex Spike ◽  
Full Field ◽  
Simple Spike ◽  
Dominant Eye

1. Complex and simple spike responses of Purkinje cells were recorded in the flocculus of anesthetized, paralyzed rabbits during rotating full-field visual stimuli produced by a three-axis planetarium projector. 2. On the basis of the spatial properties of their complex spike responses, floccular Purkinje cells could be placed into three distinct classes called Vertical Axis, Anterior (45 degrees) Axis and Posterior (135 degrees) Axis. The first two classes occurred in both monocular and binocular forms; the third class was encountered only in binocular form. For the binocular response forms, stimulation through one eye, called the dominant eye, elicited a stronger modulation of the complex spike firing rate than did stimulation of the other eye. The approximate orientation of that axis about which full-field rotation elicited the deepest modulation (the preferred axis) when presented to the dominant eye served as the class label. These classes are the same as those determined qualitatively for inferior olive neurons in the previous paper (47). The present study provides a quantitative description of their spatial tuning. 3. For Vertical Axis cells, the dominant eye was ipsilateral with respect to the flocculus recording site. The preferred axis was vertical and null (no-response) axes were in the horizontal plane. For the binocular response form of Vertical Axis cells (less than 10% of this class), the direction preferences for the two eyes were synergistic with respect to rotation about the vertical axis. 4. The dominant eye for the Anterior (45 degrees) Axis cells was contralateral, with the preferred axis oriented in the horizontal plane at approximately 45 degrees contralateral azimuth. The modulation depth showed a close to cosine relation with the angle between the preferred axis and the stimulus rotation axis. The average orientation (n = 10) for the dominant eye preferred axis, determined by the best-fit sinusoid, was 47 degrees contralateral azimuth. The preferred axis orientation for the ipsilateral (nondominant) eye in the binocular response forms was between 45 and 90 degrees azimuth in the horizontal plane. A null axis for each eye was at approximately 90 degrees to the preferred axis. 5. The Posterior (135 degrees) Axis cells were encountered only in binocular response forms. The dominant eye was ipsilateral, with the preferred axis oriented at approximately 135 degrees ipsilateral azimuth close to the horizontal plane. The modulation depth showed a close to cosine relation with the angle between the preferred axis and the stimulus rotation axis.(ABSTRACT TRUNCATED AT 400 WORDS)

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