On visual speed

Summary According toJ. F. Brown the dependence of visual speed on field factors is principally due to influences which such field factors exert on phenomenal time.K. Koffka has pointed out that the same dependence may be due to variations of the spatial threshold in fields of different properties. In this paper experiments have been reported which in two cases decide in favor ofKoffka's explanation. This explanation is likely to be applicable to further instances. — Some ofBrown's own experimental results appear to be incompatible with his theory.

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Zusammenfassung J. F. Brown erkl?rt die Abh?ngigkeit gesehener Geschwindigkeiten von Feldfaktoren durch entsprechende Variationen im Gebiet der ph?nomenalen Zeit.K. Koffka hat darauf aufmerksam gemacht, da? die gleichen Tatbest?nde auf Abh?ngigkeit der Raumschwelle von Feldfaktoren beruhen k?nnten. Die vorliegende Arbeit berichtet über Versuche, die in zwei F?llen zugungsten vonKoffkas Erkl?rung entscheiden. Wahrscheinlich kann diese Erkl?rung auf andere F?lle ausgedehnt werden. —Brown selbst hat Versuche angestellt, deren Ausfall mit seiner Theorie unvereinbar erscheint.

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With 1 Figure.

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This investigation was performed under the direction of ProfessorW. K?hler. The author is indebted to him for the formulation of the problem, to him and to Dr.H. Wallach for guidance in the interpretation and presentation of the results, and to ProfessorJ. F. Brown for his courtesy in placing at his disposal published and unpublished papers.     

A Variable Response Inconsistency scale and a True Response Inconsistency scale for the Millon Adolescent Clinical Inventory

Variable Response Inconsistency (M-VRIN) and True Response Inconsistency (M-TRIN) scales were developed for the Millon Adolescent Clinical Inventory using 104 male and 78 female delinquents, ages 13-17 years. M-VRIN efficacy was assessed by comparing nonrandom protocols of 76 male and 34 female delinquents, ages 13-17 years, with 100 computer-generated random protocols. Nonrandom protocols were screened using a matched-pair Minnesota Multiphasic Personality Inventory-Adolescent or Jesness Inventory. M-TRIN efficacy was assessed by comparing protocols with 160 simulated acquiescent and nonacquiescent protocols. Specificities of .95 or higher showed sensitivities up to .89 for M-VRIN, and .90 and .79 for M-TRIN. Predictive power and overall effectiveness are reported for several base rates. Small relationships may exist between M-VRIN and race, and between M-TRIN and gender.     

Perception of visual speed while moving

During self-motion, the world normally appears stationary. In part, this may be due to reductions in visual motion signals during self-motion. In 8 experiments, the authors used magnitude estimation to characterize changes in visual speed perception as a result of biomechanical self-motion alone (treadmill walking), physical translation alone (passive transport), and both biomechanical self-motion and physical translation together (walking). Their results show that each factor alone produces subtractive reductions in visual speed but that subtraction is greatest with both factors together, approximating the sum of the 2 separately. The similarity of results for biomechanical and passive self-motion support H. B. Barlow's (1990) inhibition theory of sensory correlation as a mechanism for implementing H. Wallach's (1987) compensation for self-motion.     

The speed of visual recognition memory

Two processes are thought to support visual recognition memory (VRM): Familiarity and recollection. The former is generally considered to be faster. However, the relationship between the precise onset of the two processes is unclear. Here, we use a novel paradigm, the SAB (Speed and Accuracy Boosting procedure) that constrains participants to use their fastest strategy and provides a continuous distribution of their reaction times. We show that fast recognition occurs as early as ~370 ms, a limit that appears incompressible whatever types of stimuli were used. In a second experiment, running the SAB in conjunction with a modified version of the remember/know paradigm, we show that responses up to ~420 ms are based solely on familiarity. These time limits of 370 ms and 420 ms provide strong constraints on the neural mechanisms underlying VRM and suggest that the fastest, familiarity-based, responses could rely on the visual ventral stream only.     

Fractal fluctuations in gaze speed visual search

Visual search involves a subtle coordination of visual memory and lower-order perceptual mechanisms. Specifically, the fluctuations in gaze may provide support for visual search above and beyond what may be attributed to memory. Prior research indicates that gaze during search exhibits fractal fluctuations, which allow for a wide sampling of the field of view. Fractal fluctuations constitute a case of fast diffusion that may provide an advantage in exploration. We present reanalyses of eye-tracking data collected by Stephen and Mirman (Cognition, 115, 154-165, 2010) for single-feature and conjunction search tasks. Fluctuations in gaze during these search tasks were indeed fractal. Furthermore, the degree of fractality predicted decreases in reaction time on a trial-by-trial basis. We propose that fractality may play a key role in explaining the efficacy of perceptual exploration.     

Interocular transfer of visual aftereffects

A number of the well-known visual after-effects of adaptation exhibit interocular transfer, so that presentation of an adaptation figure to one eye produces a temporary change in the performance of the nonadapted eye. This outcome is usually attributed to the involvement of binocular visual neurons that respond to stimulation of either eye. The fact that interocular transfer is incomplete (i.e., the transferred aftereffect is smaller in magnitude than that induced and measured in the same eye) is routinely cited as evidence for the involvement of monocular neurons. This article critically examines these two interpretations, which are developed in terms of a neural model of interocular transfer. No evidence, logical or empirical, was obtained for rejecting the model. Our analysis further shows that the model must assume some type of pooling process that operates over all tested neurons, both adapted and unadapted. Finally, general implications of the interocular transfer model are discussed, the aim being to delimit the conclusions that may be drawn from interocular transfer experiments.     

Guiding drivers towards safer driving speed: Exploiting visual dominance in speed adaptation

Inappropriate speed is a main cause of accidents. Drivers are often unaware of potential risks due to inadequate speed. To prevent dangerous situations, we need to understand perceptual factors influencing human speed perception. Due to the prominent role of vision in driving, we examined the effect of visuo-spatial stimuli on speed based on the optic flow. While developing an adaptive infrastructure measure to reduce speed, we conducted two consecutive studies, a driving simulator study and a field test to investigate findings further. In both studies, we placed lights on two sides of a highway exit and either illuminated them statically or activated them in a way that they appeared to be moving towards the driver. We expected drivers to slow down more when seeing static light stimuli compared to a baseline without lights. We also expected drivers to decrease speed more in conditions with oncoming lights compared to a baseline, and to static lights, due to distorted speed perception. The first study in a static driving simulator revealed no difference between conditions. In the field test, both static lights and lights moving towards the driver led to a speed reduction compared to a baseline but did not differ from one another. Lights in general led to lower driving speed, potentially due to their warning character, but we found no difference between the light conditions, suggesting that the effect might not be based on the optic flow. Future research should investigate the relationship between driven and perceived speed more closely.     

Human visual perceptual organization beats thinking on speed

What is the degree to which knowledge influences visual perceptual processes? This question, which is central to the seeing-versus-thinking debate in cognitive science, is often discussed using examples claimed to be proof of one stance or another. It has, however, also been muddled by the usage of different and unclear definitions of perception. Here, for the well-defined process of perceptual organization, I argue that including speed (or efficiency) into the equation opens a new perspective on the limits of top-down influences of thinking on seeing. While the input of the perceptual organization process may be modifiable and its output enrichable, the process itself seems so fast (or efficient) that thinking hardly has time to intrude and is effective mostly after the fact.     

Response latency in visual search with redundancy in the visual display

Two experiments were run to investigate the effects of redundant display items upon response latency in a visual search task. In the first study, Ss searched five-letter displays for a predesignated critical letter. Both critical and noncritical letters could be repeated in the displays. Mean response latency decreased markedly with increasing redundancy in the critical letter and was affected to a lesser extent by redundancy in the noncritical letters. In the second study, Ss were required to detect the presence of redundant letters in displays of from two to five letters, first with no information as to what letter might be repeated, then with knowledge of which letter would be repeated if the display contained a redundant letter. Response latencies in the former case were much slower than in the latter. The implications of these findings for current views of visual information processing were discussed.     

Asymmetry in visual search for targets defined by differences in movement speed.

Perception of motion speed was investigated with the visual search paradigm, using human Ss. When searching for a fast target among slow distractors, reaction time was minimally affected as the number of distractors was increased. In contrast, reaction time to detect a slow target among fast distractors was slow and linearly related to the number of distractors. The effect cannot be attributed to differences in temporal frequency, discriminability, or one type of representation that might result from spatiotemporal filtering. An alternative hypothesis that can account for the asymmetry is that speed detectors operate as high-pass filters in the velocity domain. This hypothesis is in agreement with results obtained in psychophysical studies on motion adaptation as well as data from single-cell recordings in nonhuman species.     

Response class: A Guttman scale analysis

This study addressed the problem of response class as it relates to coercive child behavior. Guttman scale analyses were used to determine if there were regular, unidimensional progressions across eight coercive response categories; that children who performed high probability coercive behaviors would also tend to perform all of the lower probability coercive behaviors. Rank-order correlations were done to determine if there was consistency in the response class across settings. Two samples of boys were observed in two school settings, classroom and playground. One sample was a derivation sample of 26 boys, the second a replication sample of 27 boys. Reproducibility coefficients for the derivation sample were .92 for the classroom Guttman scale analysis and .93 for the playground analysis. For the crossvalidation sample the reproducibility coefficients were .94 in both settings. Rankorder correlations across settings and done in terms of the number of subjects performing each of the coercive responses were .971 (df=6,p<.001) for the derivation sample and .996 df=6,p<.001) for the crossvalidation sample. It was concluded that the eight coercive responses observed appeared to constitute a response class, i.e., the ordering of the responses was transitive across subjects, and that the coercive response hierarchy was stable across school settings for groups of children.I wish to extend thanks to Gerald Patterson et al., of the Oregon Social Learning Center, for their space, time, and encouragement. Special thanks to Mark Weinrott for his excellent editorial comments.     

Interhemispheric transfer of visual information in schizophrenics

Groups of 12 male schizophrenic inpatients and 12 normal controls of the same age, sex, and schooling underwent a tachistoscopic test. Each subject was shown an alphabetical letter which he subsequently had to recognize among various other alphabetical letters also shown tachistoscopically. The visual hemifields of the two displays were ipsilateral and crossed. Relative to the normal group the schizophrenics showed higher perceptual thresholds, lower over-all mean performance, and greater lateralization. The results are discussed in terms of rigidly and poorly integrated systems of analysis of information between one hemisphere and the other for schizophrenic patients.