A method of optimal scaling for multivariate ordinal data and its extensions

This paper develops a method of optimal scaling for multivariate ordinal data, in the framework of a generalized principal component analysis. This method yields a multidimensional configuration of items, a unidimensional scale of category weights for each item and, optionally, a multidimensional configuration of subjects. The computation is performed by alternately solving an eigenvalue problem and executing a quasi-Newton projection method. The algorithm is extended for analysis of data with mixed measurement levels or for analysis with a combined weighting of items. Numerical examples and simulations are provided. The algorithm is discussed and compared with some related methods.Earlier results of this research appeared in Saito and Otsu (1983). The authors would like to acknowledge the helpful comments and encouragement of the editor.     

Interference from irrelevant features on visual discrimination by macaques (Macaca fuscata): a behavioral analogue of the human Stroop effect

To study the operation of selective attention in a conflict situation with automatic processes, we trained 4 Japanese macaques (Macaca fuscata) extensively on a manual go/no-go task. The monkey had to discriminate either the color, shape, motion direction, or location of a visual stimulus. In each trial, the behavioral meaning of the relevant feature (go or no-go) could either be congruent or incongruent with irrelevant features of the same stimulus. Reaction times were slowed, and error rates increased when irrelevant stimulus features were incongruent with the required response. The effects were obtained when the monkey attended to the color, shape, or motion direction, but not when it attended to the location of the stimulus. The effects were cumulative so that the interference from 1 incongruent feature was smaller than that from 2 incongruent features. We propose that the present paradigm provides a behavioral analogue of the human Stroop effect.     

Change deafness for simultaneous voices

Apparent changes in auditory scenes are often unnoticed. This change deafness phenomenon was examined in auditory scenes that comprise human voices. In two experiments, listeners were required to detect changes between two auditory scenes comprising two, three, and four talkers who voiced four‐syllable words. One of the voices in the first scene was randomly selected and was replaced with a new word in change trials. The rationale was that higher stimulus familiarity conferred by human voices compared to other everyday sounds, together with encoding and memory advantages for verbal stimuli and the modular processing of speech in auditory processing, should positively influence the change detection efficiency, and the change deafness phenomenon should not be observed when listeners are explicitly required to detect the obvious changes. Contrary to the prediction, change deafness was significantly observed in three‐ and four‐talker conditions. This indicates that change deafness occurs in listeners even for highly familiar stimuli. This suggests the limited ability for perceptual organization of auditory scenes comprising even a relatively small number of voices (three or four).     

Advantage of dichromats over trichromats in discrimination of color-camouflaged stimuli in humans

This study investigated whether 12 participants with color-vision deficiency had superior visual discrimination of color-camouflaged stimuli shown on a computer screen compared with 12 participants with normal trichromatic vision. Participants were asked to distinguish a circular pattern from other patterns in which textural elements differed from the background in orientation and thickness. In one condition, stimuli were single-colored, green or red; in the other condition, stimuli were color camouflaged with a green and red mosaic overlaid onto the pattern. Color-vision deficient participants selected the correct stimuli in the color-camouflaged condition as quickly as they did in the single-colored condition. However, normal color-vision participants took longer to select the correct choice in the color-camouflaged condition than in the single-colored condition. These results suggest that participants with color-vision deficiency may have a superior visual ability to discriminate the color-camouflaged stimuli.     

Increasing distractor strength improves accuracy

Attention enhances task-relevant signals while filtering task-irrelevant signals; however, this selection process is not perfect. It is generally assumed that the stronger the irrelevant signal, the more strongly performance is disrupted. The effect of irrelevant coherent motion signals on performance on a color-discrimination task was systematically examined. Motion direction was either congruent or incongruent with response selection. Performance was most impaired when motion signal strength was just above perceptual threshold and improved when the motion signal strength increased. These results suggest that distractors of higher strength increase attentional modulation and are filtered before they interfere with task performance.     

Subjectively divided tone components in the gap transfer illusion

When a long glide with a short temporal gap in its middle crosses with a continuous short glide at the temporal midpoint of both glides, the gap is perceived in the short glide instead of in the long glide. In the present article, we tested possible explanations for this "gap transfer illusion" by obtaining points of subjective equality of the pitches and durations of the two short tones that are subjectively divided by the gap. The results of two experiments showed that neither an explanation in terms ofenvelope patterns nor explanations in terms of combinationtones or acoustic beats could account for the perception of the short tones in the gap transfer illusion. Rather, the results were compatible with the idea that the illusory tones were formed by the perceptual integration of onsets and offsets of acoustically different sounds. Implications for the perceptual construction of auditory events are discussed.     

SINGLE‐SAMPLE DISCRIMINATION OF DIFFERENT SCHEDULES' REINFORCED INTERRESPONSE TIMES

Food‐deprived rats in Experiment 1 responded to one of two tandem schedules that were, with equal probability, associated with a sample lever. The tandem schedules' initial links were different random‐interval schedules. Their values were adjusted to approximate equality in time to completing each tandem schedule's response requirements. The tandem schedules differed in their terminal links: One reinforced short interresponse times; the other reinforced long ones. Tandem‐schedule completion presented two comparison levers, one of which was associated with each tandem schedule. Pressing the lever associated with the sample‐lever tandem schedule produced a food pellet. Pressing the other produced a blackout. The difference between terminal‐link reinforced interresponse times varied across 10‐trial blocks within a session. Conditional‐discrimination accuracy increased with the size of the temporal difference between terminal‐link reinforced interresponse times. In Experiment 2, one tandem schedule was replaced by a random ratio, while the comparison schedule was either a tandem schedule that only reinforced long interresponse times or a random‐interval schedule. Again, conditional‐discrimination accuracy increased with the temporal difference between the two schedules' reinforced interresponse times. Most rats mastered the discrimination between random ratio and random interval, showing that the interresponse times reinforced by these schedules can serve to discriminate between these schedules.     

The Problem of local optimality with OSMOD

The possibility of obtaining locally optimal solutions with categorical data is pointed out for the original version of OSMOD development by Saito and Otsu. A revision of the initialization strategy in OSMOD is suggested, and its effectiveness in diminishing this possibility is demonstrated.     

Matrix Training for Generative Spelling in Children with Autism Spectrum Disorder

Children with autism often have difficulty in generative learning. Effective training program for generative learning in these children is needed. In this study, we examined the effectiveness of matrix training for generative spelling in two children with autism spectrum disorder (ASD). Matrix training is a procedure in which stimuli used in teaching are arranged with overlapping within‐syllable units. After training with a Constructed‐Response Matching to Sample (CRMTS) with matrix training, both participants' generative spelling was assessed by CRMTS test using untrained combinations of characters. In this study, spoken syllables (auditory stimuli) are presented as the sample stimulus, and written characters (visual stimuli) are presented as comparison stimuli in CRMTS task. As a result, both participants showed generative spelling by matrix training, however, one of the two participants needed additional matrix training. The results discussed the effectiveness of matrix training as a procedure for teaching generative spelling and some issues to be conducted in applying this procedure for Japanese reading and spelling in children with ASD. Copyright © 2011 John Wiley & Sons, Ltd.     

Spatiotemporal balance in competing apparent motion is not predicted from the strength of the single-motion percept

Apparent motion is useful for investigating how spatiotemporal cues are integrated to determine the identity of a moving object. To examine its spatiotemporal properties, a competing-motion paradigm has advantages in strict psychophysical evaluation, despite difficulty in object-identity determination, over a non-competing subjective-grading paradigm. The latter has been often used, whereas the former has not been fully investigated. Here, we compared these two paradigms. In the competing-motion experiment, a sample spot was followed by a far and a near test spot with onset asynchrony. We found that the onset asynchrony between the near and far test spots was directly related to the distance ratio between them. This spatial size-invariant relation was not predicted from the strength of the single-apparent-motion percept, estimated from the non-competing subjective-grading experiment in which a sample spot was followed by only one test spot. Moreover, the spatiotemporal balance in competing apparent motion was found not to be valid under negative interstimulus-interval conditions, although a single apparent motion is perceived in those conditions. These clear discrepancies suggest that competing and single apparent motions are processed in a different way according to the difficulty in object identification.