Induced Colors and Colors Produced by Chromatic Illumination May Have Similar Physiological Bases

Thirteen Os obtained afterimages of each of two targets. The “induced” target was a green ring surrounding an achromatic (but phenomenally magenta) disk; the “neutralized” target was the same as the induced one, except that chromatic green illumination was added to the disk so as to make it phenomenally achromatic. Two findings support the conjecture that the retinal process underlying perception of induced colors is similar to that underlying perception of colors produced by chromatic illumination: (1) an induced magenta can be mixed with a green produced by chromatic illumination so as to yield a phenomenally neutral color, and (2) the green in the afterimage of the disk in the induced target was more saturated than the green in the afterimage of the disk in the neutralized target.

Some Laboratory Measures of Extraversion-Introversion

The Maudsley Personality Inventory was given to a pool of 309 Ss from which three groups were selected along the extraversion dimension, two to represent each extreme (extravert N = 20, introvert N = 19), and an intermediate group ( N = 19). The three groups were equated for neuroticism. Ss were tested on the following measures: time-judgment, breath-holding, digit repetition, line reproduction, leg persistence, set change, kinaesthetic figural after-effect, and size constancy. Extraverts were superior in breath-holding, had a longer time span in digit repetition, showed longer leg persistence, greater variability in line reproduction, a tendency to underestimation in time judgment, but were inferior in arithmetic computation under slow set change conditions. No significant difference between extraverts and introverts was observed in the kinaesthetic figural after-effect or in size constancy.

Asymmetry of Aftereffects in the Upper and Lower Visual Fields

The movement aftereffect was used to study the asymmetry of aftereffects in the median plane. The results show significantly greater aftereffects in the lower part of the visual field as compared with the upper part. These results are inconsistent with the Koehler-Wallach proposals concerning asymmetry but are consistent with the metabolic hypotheses of Wertheimer.

Tracking Rotary Motion After-Effect with Different Illuminations of Inspection and Test Fields

Taylor's psychophysical theory of figural after-effects was used to predict the effect of changes in illumination of inspection and test fields on the amount and the rate of decay of the rotary motion after-effect. As predicted, the brighter inspection disc produced more after-effect, while the brighter test disc produced a smaller and faster-decaying after-effect.

Bodily Activity and Perceptual Activity

This report describes the results of 2 studies designed to test the hypothesis that there is an inverse relation between bodily and perceptual activity. In Study I 100 college students' bodily movements were recorded by kymograph while they were tested for the autokinetic illusion, reversible figure-ground, Necker cube reversals, and visual figural aftereffects. No significant correlations were found between bodily movement and perceptual scores. Study II involved only autokinetic illusion scores and induced bodily activity of 200 Ss. Significant linear correlations were found in the expected direction, i.e., bodily movement correlated positively with autokinetic latency in both males and females; bodily movement was negatively correlated with extent of autokinetic movement in females. Female Ss in both studies showed significantly greater autokinetic latency than males.

Effects of Temporal Order of Stimulus Presentation on the Direction of Figural Aftereffects

An investigation into the aftereffects of simultaneously presented parallel contours was carried out to demonstrate the attraction of these contours. These attraction effects contrasted significantly with the repulsion effects obtained in the orthodox figural-aftereffect situation. An interpretation was offered in terms of the interaction of separate processes of primary adaptation and in terms of more complex processes of temporal comparison.

Gamma Movement: Apparent Movement in Figural Aftereffects Experiments

Standard contour circles, 40 mm. in diameter, were tachistoscopically presented for 1 sec. With each presentation, .8 sec. after the onset, one of a number of comparison circles, varying in diameter from 32 to 48 mm., was presented alongside for .2 sec. Those comparison circles which were equal to and slightly smaller than the standard circles were judged larger significantly more often than chance. Thus, the initial phase of gamma movement, the apparent expansion of briefly exposed figures, was elicited under conditions comparable to those of some figural aftereffect experiments.

Viewing Distance and the Aftereffects of Fixation

In a previous experiment, a fixated three-dimensional object was shown to recede from the position it held prior to fixation. Since this phenomenon may be accounted for in terms of a visual compensation for the strain of convergence during prolonged fixation, it was expected that fixation of a near figure would result in a greater aftereffect than fixation of a far figure. The results of this study indicated that, while there was a greater frequency of expected aftereffects with the near figures, there was also a greater frequency of reversed aftereffects with the far figures. The latter finding raised problems of an interpretation of the theory under consideration, the implications of which were discussed.

Duration of Spiral Aftereffect as a Function of Retinal Size, Retinal Place, and Hemiretinal Transfer

This experiment has shown that, although both rods and cones mediate the spiral aftereffect, cone areas give a larger response. Increasing size of the retinal image results in longer durations of SAE but rods are more affected by this increase than are cones. There is a general weakening in aftereffect resulting from “transfer” from one hemiretina to another with cone areas showing greater loss than rod areas. Size of retinal image has been shown to be a potent variable and, in fact, under some small size conditions, normal Ss fail to observe any effect whatsoever. In view of these findings, it is apparent that size of retinal image is a variable which must be carefully controlled if comparable results are to be obtained. Review of the clinical literature, however, reveals that distance from S to spiral and objective spiral size often vary from experiment to experiment. This variation could well account for some of the differences in results of clinical studies. It is proposed that a standard spiral size and testing distance be introduced for clinical use.

Massed Practice and Motion After-Effect

No significant change in the duration of motion after-effect was found in 20 massed trials using a rotating windmill stimulus pattern. However, there was a reliable tendency for each S to repeat his performance on 2 separate days, either to shorten or to lengthen the after-effect during the session.

Duration as a Measure of the Spiral Aftereffect

The purpose of this experiment was to study the reliability of duration as a measure of the spiral aftereffect. The results for 10 Ss indicate that duration is a highly reliable measure and that duration is a simple monotonic function of exposure-time.

Kinesthetic Aftereffects are in the Hands, Not in Phenomenal Space

Kinesthetic figural aftereffects (KFAE) were measured in 44 Ss to determine whether satiation occurs in the hands or in phenomenal three-dimensional space. KFAE of equal sign and magnitude occurred in the hands handling the satiation objects whether the arms were crossed or uncrossed during the satiation period. Therefore the satiation effect is in the hands, not in phenomenal space.

Adaptation to Spiral Motion in Crowding Condition

When a single, moving stimulus is presented in the peripheral visual field, its direction of motion can be easily distinguished, but when the same stimulus is flanked by other similar moving stimuli, observers are unable to report its direction of motion. In this condition, known as ‘crowding’, specific features of visual stimuli do not access conscious perception. The aim of this study was to investigate whether adaptation to spiral motion is preserved in crowding conditions. Logarithmic spirals were used as adapting stimuli. A rotating spiral stimulus (target spiral) was presented, flanked by spirals of the same type, and observers were adapted to its motion. The observers' task was to report the rotational direction of a directionally ambiguous motion (test stimulus) presented afterwards. The directionally ambiguous motion consisted of a pair of spirals flickering in counterphase, which were mirror images of the target spiral. Although observers were not aware of the rotational direction of the target and identified it at chance levels, the direction of rotation reported by the observers during the test phase (motion aftereffect) was contrarotational to the direction of the adapting spiral. Since all contours of the adapting and test stimuli were 90° apart, local motion detectors tuned to the directions of the mirror-image spiral should fail to respond, and therefore not adapt to the adapting spiral. Thus, any motion aftereffect observed should be attributed to adaptation of global motion detectors (ie rotation detectors). Hence, activation of rotation-selective cells is not necessarily correlated with conscious perception.

Heads First: Visual Aftereffects Reveal Hierarchical Integration of Cues to Social Attention

Determining where another person is attending is an important skill for social interaction that relies on various visual cues, including the turning direction of the head and body. This study reports a novel high-level visual aftereffect that addresses the important question of how these sources of information are combined in gauging social attention. We show that adapting to images of heads turned 25° to the right or left produces a perceptual bias in judging the turning direction of subsequently presented bodies. In contrast, little to no change in the judgment of head orientation occurs after adapting to extremely oriented bodies. The unidirectional nature of the aftereffect suggests that cues from the human body signaling social attention are combined in a hierarchical fashion and is consistent with evidence from single-cell recording studies in nonhuman primates showing that information about head orientation can override information about body posture when both are visible.

[MOTION AFTEREFFECT AS A UNIVERSAL PHENOMENON IN SENSORY SYSTEMS INVOLVED IN SPACE ORIENTATION. II. AUDITORY MOTION AFTEREFFECT]

Adaptation to sound source motion can cause noticeable changes in spatial perception of the following sound stimuli. Neural mechanisms of selective sensitivity to motion are the basis of this phenomenon, called the auditory motion aftereffect. The auditory motion aftereffects were demonstrated under different stimulation conditions, both after the presentation of different motion models and in the real sound source motion. The auditory aftereffects are specifically characterized by its spatial and frequency selectivity as well as by the optimal motion velocity at which the effect is maximal. These features and the presence of the intersensory motion adaptation effects indicate a common nature of the auditory and visual motion aftereffects and allow suggesting the existence of the common system of motion adaptation for different modalities that provide spatial orientation.

Adding years to your life (or at least looking like it): a simple normalization underlies adaptation to facial age

Adaptation has been widely used to probe how experience shapes the visual encoding of faces, but the pattern of perceptual changes produced by adaptation and the neural mechanisms these imply remain poorly characterized. We explored how adaptation alters the perceived age of faces, a fundamental facial attribute which can uniquely and reliably be scaled by observers. This allowed us to measure how adaptation to one age level affected the full continuum of perceived ages. Participants guessed the ages of faces ranging from 18-89, before or after adapting to a different set of faces composed of younger, older, or middle-aged adults. Adapting to young or old faces induced opposite linear shifts in perceived age that were independent of the model's age. Specifically, after adapting to younger or older faces, faces of all ages appeared 2 to 3 years older or younger, respectively. In contrast, middle-aged adaptors induced no aftereffects. This pattern suggests that adaptation leads to a simple and uniform renormalization of age perception, and is consistent with a norm-based neural code for the mechanisms mediating the perception of facial age.

[Motion aftereffect as a universal phenomenon for sensory systems involved in orientation in space. I. Visual aftereffects]

At present there are serious grounds to believe that motion aftereffect is characteristic for all sensory systems involved in spatial orientation, and that adaptation to movement in one sensory system causes changes in another one and that such adjustment is of critical adaptive significance. In this part of the review there are briefly presented developments and the current state of studies on this issue in visual modality. The visual motion aftereffect has been studied considerably more completely as compared with other modalities. The main concepts about mechanisms of this phenomenon and employment of adaptation to motion in studies of visual analysis of movement at its different levels are actively used in the current scientific literature to understand mechanisms of this phenomenon in other sensory systems. The leading role of vision for orientation in space is manifested in the multimodal interaction where visual adaptation to movement produces significant changes of perception in other modalities.

The spiral aftereffect technique (SAT) can differentiate between depressive and somatoform disorder patients

This study examined how differences in visuo-perceptual patterns are related to psychopathology. Fifty-six patients (37 women, 19 men; M age = 43.8 yr., SD = 13.4) with a main diagnosis of unipolar depression and 42 patients (22 women, 20 men; M age = 42.0 yr., SD = 11.1) with a main diagnosis of somatoform disorder were compared. The duration and trend of a visual motion aftereffect were measured with the Spiral Aftereffect Technique (SAT). The results indicated that successively increasing aftereffect durations characterized the depressive patients, whereas patterns of very short or short final aftereffect preceded by successively decreasing aftereffect durations characterized the patients with a somatoform disorder. The SAT is thus a valuable tool for linking objectively measured perceptual-personality characteristics with some mental disorders.

Decision-dependent aftereffects for faces

Adaptation-related aftereffects (AEs) have been found in the perception of face identity, in that perception of an ambiguous face is typically biased away from the identity of a preceding unambiguous adaptor face. In previous studies, we could show that both perceptual ambiguity and physical similarity play a role in determining perceived face identity AEs, Cortex 49 (2013) 1963-1977, Plos One 8 (2013) e70525. Here, we tested further the role of ambiguity by manipulating participants' task such that the very same target stimuli were either ambiguous or unambiguous regarding stimulus classification. We created two partially overlapping continua spanning three unfamiliar face identities each, by morphing identity A via B to C, and B via C to D. In a first session, participants were familiarised with faces A and C and asked to classify faces of the A-B-C continuum as either identity A or C in an AE paradigm. Following adaptation to A or C, we observed contrastive AEs for the ambiguous identity B, but not for the unambiguous identities A or C. In a second session, the same participants were familiarised with faces B and D, followed by tests of AEs for the B-C-D continuum now involving a B-D classification task. We again observed contrastive AEs but only for target identity C (ambiguous for the decision) and not for B or D (unambiguous). Our results suggest that perceptual ambiguity, as given by the task-context, determines whether or not AEs are induced.

High-level aftereffects to global scene properties

Adaptation is ubiquitous in the human visual system, allowing recalibration to the statistical regularities of its input. Previous work has shown that global scene properties such as openness and mean depth are informative dimensions of natural scene variation useful for human and machine scene categorization (Greene & Oliva, 2009b; Oliva & Torralba, 2001). A visual system that rapidly categorizes scenes using such statistical regularities should be continuously updated, and therefore is prone to adaptation along these dimensions. Using a rapid serial visual presentation paradigm, we show aftereffects to several global scene properties (magnitude 8-21%). In addition, aftereffects were preserved when the test image was presented 10 degrees away from the adapted location, suggesting that the origin of these aftereffects is not solely due to low-level adaptation. We show systematic modulation of observers' basic-level scene categorization performances after adapting to a global property, suggesting a strong representational role of global properties in rapid scene categorization.