In subject-performed tasks (SPTs) the participants are given verbal action phrases and perform the required actions before they recall the phrases. It is hypothesized that the item-specific memory encoding of SPTs may be related to verbal and motor component which are produced by planning and execution. The present study was to verify this item-specific processing theory. Under conditions of an expected-verbal or motor recall, and using a standard procedure, three experiments were used to compare the subjects memory span: SPTs; experimenter-performed tasks (EPTs); and verbal tasks (VTs). In each experiment the interference effect was measured for each concurrent task: concurrent articulation; concurrent movement; and a concurrent spatial task. In all of the encoding and concurrent task procedures 48 subjects participated under either of the recall conditions. The results indicated that only concurrent movement interfered with the length of SPTs with an expected verbal recall was different from that of SPTs with an expected motor recall. It is concluded from these findings that enactment may not lead to planning and execution, but that item-specific encoding of SPTs be related to and integration of verbal and motor components.
We performed four experiments to investigate the relation between neon color spreading, subjective contours, and induced brightness inside the contours. Subjects rated the clarity of subjective contours and the perceived brightness of areas surrounded by the contours in Ehrenstein figures and the clarity of neon color spreading in van Tuijl figures. The Ehrenstein figure consisted of black radial lines surrounding a circular area on a gray background, and the van Tuijl figure was produced by inserting a colored cross in the circular area of the Ehrenstein figure. It was shown that the clarity of the neon color spreading did not always covary with that of the subjective contours and the perceived brightness. It was also found that when the luminance of the radial lines was higher than that of the background, the neon color spreading was not perceived, whereas the subjective contours and the induced brightness were perceived. These results are partially consistent with two theories of neon color spreading; the transparency theory and Grossberg and his colleagues' theory.
As a way to investigate false memory in the laboratory, the DRM paradigm (Deese-Roediger-McDermott paradigm; Roediger & McDermott, 1995) has received much attention recently. This study was conducted to make 15-word Japanese lists which induce false memory of critical nonpresented words (CNWs) at high probabilities for the DRM paradigm. In experiment 1, we made 30 candidate lists each consisting of 12 words from Umemoto (1969)'s word association test and tested the false recall rates of CNWs. In experiment 2, we added 3 more words, to make 15-word lists, to each of the 16 lists which induced false recall at high probabilities in experiment 1, and tested the false recall rates of CNWs. Then in experiment 3, we changed some words in the 8 lists that induced false recall of CNWs at low probabilities in experiment 2 to improve the false recall rates, and again tested the false recall rates of CNWs. Finally we could propose 12 lists of 15 Japanese words that induce false memory at high probabilities (average: 70%, range: 38〜88%).
Verbal materials chosen by participants are better remembered than those assigned to be learned. Two explanations for the effect have been offered. One explanation argues that the opportunity to choose enhances motivation, which in turn not only improves the learning of chosen materials but also generalizes to assigned materials. The process explanation, on the other hand, argues that choice strengthens item specific learning only. The purpose of this study is to evaluate the adequency of these two explanations. Sixty four female college students were asked to remember one to-be-remembered (TBR) word from each pair words. In the choice condition, TBR words were chosen by the participants. In the force condition, TBR words were selected randomly by the experimenter. In a within participants design with two sets of materials, one group initially learned chosen materials followed by the learning of force or assigned materials. The other group received the opposite sequence. The beneficial effects of choice were limited to participant-chosen materials. These results are consistent with the process explanation for the self-choice effect.
This study investigated the nature of visual orienting triggered by gaze perception using the spatial cuing procedure in research of spatial attention. A schematic face looking left or right was used as cuing stimuli to induce visual orienting. Pupils of the face were removed except at cuing. Participants were asked to locate the target appeared left or right of the face. Stimulus onset asynchrony (SOA) between a cue and the target was also manipulated. For the relatively short SOAs (100 ms, 300 ms), the response time to the target was faster when the direction of the gaze was consistent with that of the target than when it was not. For the long SOAs (700 ms, 1000 ms), on the other hand, a small but significant amount of inhibition of return (i. e., a slowing response toward the gaze-congruent target) was observed. Some theoretical implications for the nature of gaze perception and spatial attention were discussed.
In a discrete-trial procedure we examined the choice behavior of pigeons under concurrent fixed-interval (FI) 30-s and random-interval 30-s schedules. In one condition, a discriminative stimulus that was associated with the FI schedule remained unchanged through the trials. In the other conditions, it was changed after a fixed period (9, 15, or 21 s) had passed since the onset of the concurrent schedules. In the latter conditions, the pigeons' responses to the FI schedule were suppressed in the period before the discriminative stimulus was changed. This result suggests that in the present procedure the immediacy of a reinforcer had a minimal effect on choice.
The present study used a concurrent-chains schedule to examine the effect of reward amount on delay discounting in rats. Delay periods defined by fixed-interval schedules in the terminal links were fixed at 2 s in one alternative and varied in the other alternative across five conditions ranging from 2 s to 40 s. The reward amounts were varied across three conditions by manipulating the number of food pellets (1 pellet vs. 1 pellet, 5 pellets vs. 1 pellet, and 5 pellets vs. 5 pellets). The discounting rate estimated with a modified hyperbolic function was higher in the smaller reward amount condition than in the larger reward amount conditions. This finding indicates that in animals the rate of delay discounting decreases as the reward amount increases.
The present study addressed the relationship between an individual difference in the reading span test (RST) and the performance in text comprehension with respect to storage and retrieval systems. In Experiment 1 a comparison was made of an effect of the serial recall task on performance in text comprehension on high and low RST score groups. Experiment 2 was an investigation of an effect of the word fluency task on performance in text comprehension of two groups. The results of both experiments showed that the performance in text comprehension of the low RST score group was decreased by the serial recall task. In contrast, the performance of the high RST score group was influenced by the word fluency task. The results suggested that the high RST score group comprehended text not only by using a temporary storage system but also by using a retrieval system.
This study investigated comprehension processes of Japanese sentences which included an adjective-noun phrase. Specifically, we examined whether evaluation of a consistent semantic relation between an adjective and a noun in a sentence of reading material was suspended until the argument structure of the sentence was constructed. Twenty-three participants read two types of sentences: acceptable sentences that contained a plausible adjective-noun phrase, and unacceptable sentences that contained an implausible adjective-noun phrase. In comparison with the acceptable sentences, phrase-by-phrase reading time for the unacceptable sentences was prolonged not only at the position of adjective-noun phrase but also at the position of the verb that constructed the propositional representation of the sentence. This result suggests that evaluation of a semantic relation of an adjective-noun phrase is postponed until the coherent argument structure is constructed.
The present study was designed to investigate the relationship between a weapon focus and a physical feature of a weapon, that is, whether a sharp knife attracts more attention than a not-sharp knife. Sixty participants watched a cooking scene depicted in pictures where a woman held one of three items: a sharp knife, a not-sharp knife, or a detergent spray. A weapon focus effect was measured as recognition of the central information related to the knife or spray. In the three conditions recognition of the central information was better for the sharp knife condition than for the other conditions. This result suggests that a weapon focus can be produced by the sharpness of a knife.
To investigate how visual information is coded by cell populations, we simultaneously recorded light-evoked spike discharges from multiple OFF-sustained type ganglion cells (the dimming detectors) of the frog retina using a planar multi-electrode array. Auto- and cross-correlation analyses were performed to evaluate temporal properties of the spike trains. With full-field, sinusoidally modulated diffuse illumination, cross-correlation analysis revealed the presence of long-range synchronous oscillations. The strength of the synchronous oscillations depended on the spatial properties of the light stimulus, which extended far beyond the "classical" receptive field that is defined by the spike discharge rate. These results suggest that synchronous oscillations may encode global features of visual stimuli and play a key role in perceptual integration.
The present study used a contextual cueing paradigm to investigate contextual information in a complex visual scene which changed dynamically. An observer had to track five identical targets which moved independently and unpredictably among five identical distractors (a multiple object tracking task). The motion patterns (trajectories) of the items were made invariant by repeating them throughout the entire experimental session. The results showed that repetition of the target motion pattern facilitated the tracking performance. A more important finding was that repeating the motion pattern of the distractor resulted in greater facilitation. An incidental recognition test confirmed that an observer could not notice the repetition procedure. We conclude that not only the target motion pattern, but also the distractor motion pattern, was encoded as contextual information in an implicit manner.
Synchrony is an important factor for binding visual information across space. It is also one of the basic attributes in time perception. To understand the mechanism underlying synchrony perception I explored visual grouping based on the 'synchrony of orientation' between spatially separated patterns whose orientations changed periodically in time. The results showed that the central element tended to be grouped not with the element whose orientation changed in a physical synchrony but with the element whose orientation changed slightly earlier. Moreover, this tendency became more profound as the spatial distance between elements increased. This illusory synchrony was explained by a proposal that synchrony perception is mediated by spatial interactions between feature detectors, which essentially involve mutual delays of propagating signals.
In the visual search paradigm using shading stimuli it is suggested that concavity is more dominant than convexity. However, in a figure and ground segregation task, the opposite is true. We proposed that a discrepancy in dominance could be based on whether or not subjects identified the properties of objects such as shape and orientation, and we confirmed this in four experiments. The results of the first and second experiments showed that searching for and identifying items composed of convex disks was more efficient than items composed of concave disks. The results of the third and fourth experiments showed that in detection and localization tasks, there were no significant differences in the dominance between convexity and concavity. These results suggest that convexity is dominant when subjects conduct a task requiring identification of the properties of objects, and that the visual system extracts appropriate information according to task demand.
This study concerned the effects of spatio-temporal configuration of superimposed grating stimuli on the depth attraction/repulsion phenomena. When a sinusoidal grating of ambiguous depth (a "target") was superimposed on another grating of unambiguous depth (an "inducer"), the inducer had either an attractive or repulsive effect on the target's depth perception, depending on the spatial-frequency relationship. In the first experiment depth attraction still occurred but depth repulsion vanished when a target did not temporally overlap with an inducer. The result suggested that different mechanisms contributed the attraction and repulsion. In the second experiment a target of the same height as an inducer was always attracted, regardless of the other parameters. The result suggested that there was a contribution of shape processing.
We investigated the role of response mapping, or the effect of response representation, with the assumption that visual processing needs not only a stimulus representation but also a response representation. The participants were required to react to both the prime and the probe displays with a Go/No-Go response. We examined response repetition which facilitated performance and task switching which caused a cost in performance. The main result indicated that a response for the prime display inhibited a response to the target for the probe display. This suggests that the response mapping affected a response to the target even when participants gave only a response representation without a translating action or motor response.
The spatial layout of objects can be acquired implicitly and facilitate visual search under incidental learning conditions (the contextual cueing effect; Chun & Jiang, 1998). The present study investigated whether the learned layouts are limited to two-dimensional configurations or can encompass three dimensions. We found that the reaction times for the repetition condition increased significantly when the disparity of the repeated distractors was reversed in the end of the session. These results indicate that three-dimensional layouts can be preserved as implicit visual spatial contexts.
In visual amodal completion, we can aware the presence of occluded surfaces in spite of the fact that the surfaces are invisible. By contrast, in the case of modal completion, we can actually perceive the quality of the completed surfaces. We reviewed and compared the psychophysical findings on amodal and modal completion. The studies on the shrinkage phenomenon of the completed surface indicated that the magnitude of the distortion decreases if the occluded part is modally visible. The microgenetic studies revealed that the speed of amodal completion is much slow in comparison with that of modal completion, while both types of completion occur preattentively and automatically. The experiments on local and global factors in figural completion showed that global processes play a major role in amodal completion, while local processes dominate in modal completion. These facts are discussed in relation to the theoretical assumptions that awareness provides flexibility on the output side, while qualia guarantee irrevocability on the input side (Ramachandran, 1998), and that qualia have a function of flagging the present (Gregory, 1998).
The study of visual illusion has been ignoring the awareness or qualia of illusion. However, the perception of visual illusion is based upon the awareness of illusion (Tanaka, 1998, 2000). If observers are not aware of the discrepancy between the physical feature and the appearance of an object, the distorted image is not at all illusion. Qualia are also related to illusion. Actually, illusory figures give several pieces of qualia specific to illusion, e.g. "beauty" (Noguchi & Rentschler, 1999) or "motion feeling". Yet the transmission of the qualia to other people might be difficult since qualia are just subjective. Thus, those who try to study illusion in terms of consciousness need not only abilities of art and science but also the ability of "rhetoric".
It has been a long-standing belief that attention is the cause of conscious awareness. However, there are some recent counter-arguments and evidence against this opinion. In this article, it is suggested that these two mental faculties are, though surely intimately related, separate functions. There are cases where attention does not lead to conscious awareness, such as attention without conscious awareness in a blindsight patient and attentional facilitation of figural disappearance. On the other side of the coin, there are cases where there is conscious awareness without attention. An ongoing experiment in our laboratory on change blindness suggests that conscious detection of peripheral changes can be achieved with attention fully concentrated on a central high demanding task.