We examined the perception of depth and stability when viewing a video movie made with a camera that moved laterally back and forth 65mm. The two viewing conditions were: (a) head movement synchronized to the stimulus movement and (b) head stationary. In Experiment 1 (N=16), both conditions showed approximately the same magnitude of apparent depth. We argue that (a) in the head movement condition, observers used the cue produced by observer-produced motion parallactic depth, whereas (b) in the no head movement condition, they used the kinetic depth cue or cue(s) from "structure from motion". In Experiment 2 (N=15), the head movement condition showed a greater stability (less perceived motion) compared to the head stationary condition. The results indicate that simulating observer-produced motion parallax (head movement condition) on a video movie of an actual object has no advantages in terms of depth perception. The advantage lies in producing greater stability.
Two experiments were conducted to investigate the effects of word length on item and order memory. In both experiments, a free recall test and a reconstruction test were conducted to measure item and order memory, respectively. Five short words or 5 long words were presented at the learning phase and tested after a delay of 7.5s. In Experiment 1, both free recall and reconstruction tests were intermingled. In Experiment 2, each of these tests was presented in a blocked format. Both experiments demonstrated that long words had an advantage at the last serial position and short words had an advantage at other serial positions in a free recall test, while word length had no effect in a reconstruction test. These results suggest that the encoding of item information is processed at different stages or subsystems than the encoding of order information.
The current study investigates the effect of training on visual span size and reading speed. The visual span for reading refers to the range of letters, formatted as text, which can be reliably recognized without moving the eyes. It has been hypothesized that the size of the visual span imposes a fundamental limit on reading speed. However, the relationship between visual span expansion and increased reading speed has not been clarified. The present study involved two types of training. During word recognition training, eight undergraduate students were asked to recognize three or four words simultaneously. During saccade training, ten students were asked to read texts with larger saccades than usual. Reading speeds increased by 30% in both training groups. Word recognition training was more effective than saccade training on visual span expansion, especially in the left visual field. Changes in reading speed, however, were correlated with visual span expansion of the right visual field.
Post-conditioning manipulation of a non-target stimulus sometimes affects conditioned responses evoked by a target stimulus. In the present study, we investigated the effect of post-training extinction of a conditioned excitor on conditioned inhibition in an instrumental conditioning situation. Food reinforcement was delivered as the outcome of lever pressing following the presentation of a single discriminative stimulus (i.e., A+), but not a compound stimulus (i.e., AX-), in order to establish a conditioned inhibitor. Omission training to an excitatory discriminative stimulus (i.e., A-) following the conditioned inhibition training did not attenuate the inhibitory property of the target stimulus. These results suggested the difficulty of obtaining a retrospective revaluation effect in the conditioned inhibition of instrumental behavior. The possible associative structure of instrumental conditioning and clinical implications are discussed.
In cognitive psychology, increasing task load impairs effortful processing such as selective attention and working memory operations (accessing/updating). However, it is unclear whether stress, which is assumed to be a factor that consumes cognitive resources, has a similar effect as task load on selective attention and working memory. Herein a literature review reveals that the apparently mixed findings with regard to working memory can be interpreted based on task load; the effect of stress emerges only with high task loads. In contrast, psycho-social stress tends to impair selective attention, but physical stress may improve it. Moreover, some recent studies have found that psycho-social stress interacts with perceptual load, suggesting that load and stress manipulations consume common cognitive resources.
Depression is a general term of a broad syndrome with various clinical symptoms such as depressive mood, diminished interest, agitation, insomnia, and decreased appetite. Although dysregulation of hypothalamus-pituitary-adrenal system and abnormality of monoaminergic neuron have been pointed out since 1950', it has not yet reached a conclusion whether it is a cause of depression, a result of depression, or an accompanied change of depression even today. In this article, present findings for the pathophysiology of depression are reviewed from a wide viewpoint including animal model studies, genetic studies, neuroendocrinological studies, neurochemical and molecular biological studies and brain imaging studies.
Beck's cognitive model suggested dysfunctional cognition interacts with depressed mood. This interaction is defined as core features of depression. Cognitive behavioral therapy (CBT) is effective treatment for depression that alters dysfunctional interaction between cognition and emotion. However, psychophysiological mechanism of action of CBT is still unclear. Recently, some neuroimaging studies reported effect of CBT for depression on brain function and clarified neural basis of CBT. This article summarizes recent neuroimaging studies for CBT for depression, and discusses psycho-physiological mechanism of action of CBT.
The subliminal mere exposure effect is a psychological phenomenon where people tend to prefer stimuli that they have been subliminally exposed to even if they cannot recognize the observed stimuli. One explanation for this effect is that the resulting perceptual fluency is misattributed to a feeling of preference. Thus, an increased perceptual fluency should correspond to decreased invested mental effort. Because the pupil constricts as mental effort decreases, we predict that if perceptual fluency does induce a preference for the exposed stimulus, then participants showing pupil constriction during subliminal exposure will exhibit the mere exposure effect later. To examine our hypothesis, we measured the pupil diameter while participants were visually exposed to subliminal stimuli. After exposure, participants judged their preferences to the stimuli. We found that pupil diameter during subliminal exposure was significantly smaller for participants who later exhibited the mere exposure effect, suggesting that perceptual fluency may be the underlying mechanism of the subliminal mere exposure effect.
We investigated the ability of a person to predict people's collective liking, namely, the average liking of others. Participants performed two tasks. In the likability rating task, they observed images of common object (e.g., car, chair) and rated visual likability of the object (1: very bad-7: very good). In the prediction task, each of 20 participants were shown the same objects and asked to predict the average likability rating of 20 other people. The prediction validity was measured as a correlation between prediction and the result of the actual likability rating. Each participant's prediction modestly correlated with the average likability rating; r=.32 on average. However, the correlation was not higher than the correlation of the participant's own likability rating with the average likability rating. We also found that the predictions were biased toward one's own liking; each participant's prediction correlated more with his or her own likability rating than the observed average likability rating. The results indicate that a person's knowledge of a collective liking is incorrect and is biased toward one's own liking.
When two participants sitting side-by-side are engaged in complementary go/no-go tasks, each participant's performance is better when the stimulus is presented on one's own side rather than the other actor's side (joint Simon effect). This study investigated the roles of perception-related (target stimulus assignment) and action-related (response button) complementarity in the joint Simon effect. Half of the pairs were subjected to full complementary go/no-go tasks where each participant had a different target color (e.g., one responded for red and the other for green). The other half shared the same target color (e.g., both responded for red). Thus only response button complementarity, but not task complementarity, was maintained in the latter condition. Similar joint Simon effects were observed for both conditions. The results indicate that the adjacent partner's action, rather than the task, is co-represented in the joint Simon effect.
Our previous study showed that detection performance was impaired for a visual target in an apparent motion (AM) trajectory. Moreover, the magnitude of this AM interference became weaker when the orientation information of the target was inconsistent with that of AM stimuli. These findings suggest that internal object representations of AM stimuli established in the AM trajectory can induce perceptual masking. The present study demonstrates auditory effects on AM interference: 1) Transient sounds presented together with AM stimuli can enhance the magnitude of AM interference, 2) this auditory effect weakened when the frequencies of the sounds changed during AM, and 3) the sounds wholly strengthened the magnitude of AM interference against the inconsistency in orientation information between the target and AM stimuli. These results suggest that sounds can contribute to the robust establishment and spatiotemporal maintenance of the internal object representation of an AM stimulus.
A perceived contrast of a texture pattern is decreased by a surrounding texture of higher contrast. Although this contrast-contrast illusion has been considered to be based on the spatial interactions between visual sensors that encode the absolute (unsigned) contrast, we recently demonstrated that contrast-contrast is selective to the polarity of contrast. The apparent contrast of a texture composed of sparse bright (dark) elements was strongly suppressed by surrounding textures of bright (dark) elements, but not at all by those of dark (bright) elements. Polarity selectivity does not appear for textures with densely placed elements because these texture unavoidably activates both the on and off sensors. Hence, we conclude that the contrast-contrast illusion is largely due to polarity-selective interactions between visual sensors.
When multiple elements are present in an apparent-motion display, the visual system must solve a motion correspondence problem. The proximity between matching elements is a factor determining motion correspondence. Previous studies have suggested that the proximity computation uses distances in retinal coordinates (e.g. Ullman, 1979), but we recently demonstrated that distances in environmental coordinates are also considered during smooth pursuit eye movement (Terao et al., 2008, SfN). Our finding indicates the processing stage is later than the integration of retinal inputs with extra-retinal signals of smooth pursuit eye movements. Here we report that the subjective proximity modulated by extra-retinal signals of saccade determines the motion correspondence computation, but consistent with the hypothesis that peri-saccadic space compression affects motion correspondence, this effect weakens as the saccadic amplitude decreases. Our findings suggest that the proximity computation for motion correspondence is based on the apparent distance, which is affected the extra-retinal signals of saccade.
We examined whether pigeons demonstrated a search asymmetry between expansion and contraction targets, using a rotating logarithmic spiral pattern that induces illusory expansion and contraction in humans without changes in the pattern's physical size. Four pigeons were arbitrarily divided into two groups. Two pigeons in the Target-Expansion Group were trained to search for 1 expanding spiral (target) among 5 contracting ones (distractors) in displays comprising a total of 6 spirals (display size=6). Two pigeons in the Target-Contraction Group were trained to search for 1 contracting spiral among 5 expanding ones. Pigeons successfully learned to search for the target and they were later tested with display sizes of 3, 6, 9, and 12. The pigeons in the Target-Expansion Group showed higher search accuracy scores and shorter reaction times than the pigeons in the Target-Contraction Group. The pigeons thus demonstrated a search asymmetry between expansion and contraction targets as shown in previous studies in humans. We discuss the results in relation to optic flow.
The identification of a target is impaired by a salient distractor. It has been suggested that this impairment is caused by the temporal or spatial deviation of attentional focus from a task-related location to the distractor. The present study examined whether this impairment, known as attentional capture, differs between sexes. Robust attentional capture was observed in temporal and spatial search tasks. Importantly, attentional capture was more profound for females than males, though only in the temporal search task. No such differences were found in the spatial search task. These results suggest that females are more sensitive than males to bottom-up signals from the distractor. The finding that sex differences in attentional capture were limited to the temporal task implies that different mechanisms are involved in temporal and spatial attentional capture.
When a colored line is juxtaposed with a darker contour, its color will spread over the area enclosed by the line (watercolor effect). Although this spreading is assimilative, non-assimilative color spreading has also been demonstrated using the same spatial configuration; e.g., when the inner contour is black and the outer contour is blue, yellow spreading can be observed. We previously reported that the optimal luminance conditions for these two types of color spreading differ, and that the two types of spreading can simultaneously occur on opposite sides of the contours. Extending the previous study, this study investigates the conditions for non-assimilative color spreading with an emphasis on the contribution of S-cone signals. The results demonstrate that non-assimilative spreading is stronger when the outer contour has a larger S-cone contrast than the inner contour. Thus, the present study suggests that the interaction between luminance and the S-cone signals is critical for non-assimilative spreading, and that different mechanisms contribute to different types of color spreading in the watercolor configuration.
Perception of a briefly presented target is impaired when a simultaneously onsetting sparse mask persists beyond the target duration, compared to when the target and the mask offset together. This is a type of backward masking, called object substitution masking (OSM). Previous studies have reported a mask preview effect in which OSM is largely attenuated by prior presentation of the mask. We investigated whether and how the abrupt color change of a previewed mask affects the mask preview effect. The basic mask preview effect was replicated. Furthermore, introducing a transient color change of the mask at target onset disrupted the mask preview effect, that is, OSM was reinstated. In terms of the role of surface features in establishment and maintenance of episodic object representations, we propose that a large color change allows the previewed mask to recompete with the target.
Although eye contact facilitates effective interpersonal exchanges during social interactions, the perception of eye contact is subjective and often inaccurate. To date, the fundamental spatial range of eye contact perception remains unknown. In the present study, a perceiver is asked to press a button to indicate whether eye contact was established when a viewer gazed at either a control point or the perceiver's eyes. The results show that humans have an inherent ability to perceive eye contact within a broad gaze range and that voluntary awareness of eye contact elicits a greater pupil dilation. These findings suggest that the fundamental form of eye contact is one-sided, subjective, and ambiguous even in face-to-face situations.