Perceptual alternation induced by visual transients

When our visual system is confronted with ambiguous stimuli, the perceptual interpretation spontaneously alternates between the competing incompatible interpretations. The timing of such perceptual alternations is highly stochastic and the underlying neural mechanisms are poorly understood. We show that perceptual alternations can be triggered by a transient stimulus presented nearby. The induction was tested for four types of bistable stimuli: structure-from-motion, binocular rivalry, Necker cube, and ambiguous apparent motion. While underlying mechanisms may vary among them, a transient flash induced time-locked perceptual alternations in all cases. The effect showed a dependence on the adaptation to the dominant percept prior to the presentation of a flash. These perceptual alternations show many similarities to perceptual disappearances induced by transient stimuli (Kanai and Kamitani, 2003 Journal of Cognitive Neuroscience 15 664-672; Moradi and Shimojo, 2004 Vision Research 44 449-460). Mechanisms linking these two transient-induced phenomena are discussed.     

Subjective discriminability of invisibility: A framework for distinguishing perceptual and attentional failures of awareness

Conscious visual perception can fail in many circumstances. However, little is known about the causes and processes leading to failures of visual awareness. In this study, we introduce a new signal detection measure termed subjective discriminability of invisibility (SDI) that allows one to distinguish between subjective blindness due to reduction of sensory signals or to lack of attentional access to sensory signals. The SDI is computed based upon subjective confidence in reporting the absence of a target (i.e., miss and correct rejection trials). Using this new measure, we found that target misses were subjectively indistinguishable from physical absence when contrast reduction, backward masking and flash suppression were used, whereas confidence was appropriately modulated when dual task, attentional blink and spatial uncertainty methods were employed. These results show that failure of visual perception can be identified as either a result of perceptual or attentional blindness depending on the circumstances under which visual awareness was impaired.     

Perceiving the present and a systematization of illusions

Over the history of the study of visual perception there has been great success at discovering countless visual illusions. There has been less success in organizing the overwhelming variety of illusions into empirical generalizations (much less explaining them all via a unifying theory). Here, this article shows that it is possible to systematically organize more than 50 kinds of illusion into a 7 × 4 matrix of 28 classes. In particular, this article demonstrates that (1) smaller sizes, (2) slower speeds, (3) greater luminance contrast, (4) farther distance, (5) lower eccentricity, (6) greater proximity to the vanishing point, and (7) greater proximity to the focus of expansion all tend to have similar perceptual effects, namely, to (A) increase perceived size, (B) increase perceived speed, (C) decrease perceived luminance contrast, and (D) decrease perceived distance. The detection of these empirical regularities was motivated by a hypothesis, called "perceiving the present," that the visual system possesses mechanisms for compensating neural delay during forward motion. This article shows how this hypothesis predicts the empirical regularity.     

Affective auditory stimulus database: An expanded version of the International Affective Digitized Sounds (IADS-E)

Using appropriate stimuli to evoke emotions is especially important for researching emotion. Psychologists have provided several standardized affective stimulus databases—such as the International Affective Picture System (IAPS) and the Nencki Affective Picture System (NAPS) as visual stimulus databases, as well as the International Affective Digitized Sounds (IADS) and the Montreal Affective Voices as auditory stimulus databases for emotional experiments. However, considering the limitations of the existing auditory stimulus database studies, research using auditory stimuli is relatively limited compared with the studies using visual stimuli. First, the number of sample sounds is limited, making it difficult to equate across emotional conditions and semantic categories. Second, some artificially created materials (music or human voice) may fail to accurately drive the intended emotional processes. Our principal aim was to expand existing auditory affective sample database to sufficiently cover natural sounds. We asked 207 participants to rate 935 sounds (including the sounds from the IADS-2) using the Self-Assessment Manikin (SAM) and three basic-emotion rating scales. The results showed that emotions in sounds can be distinguished on the affective rating scales, and the stability of the evaluations of sounds revealed that we have successfully provided a larger corpus of natural, emotionally evocative auditory stimuli, covering a wide range of semantic categories. Our expanded, standardized sound sample database may promote a wide range of research in auditory systems and the possible interactions with other sensory modalities, encouraging direct reliable comparisons of outcomes from different researchers in the field of psychology.     

The procerebrum is necessary for odor-aversion learning in the terrestrial slug Limax valentianus

The terrestrial slug Limax has a highly developed ability to associate the odor of some foods (e.g., carrot juice) with aversive stimuli such as the bitter taste of quinidine solution. The procerebrum (PC) is a part of the slug's brain thought to be involved in odor-aversion learning, but direct evidence is still lacking. Here we present evidence showing that the PC is essential for odor-aversion learning. Unlike sham-operated slugs, PC ablation 7 d prior to conditioning showed that most slugs did not avoid carrot juice in the memory retention test conducted 24 h after the conditioning. Slugs with the PC ablated 3 h, 1 d, 3 d, or 7 d after conditioning and examined by the memory retention test at 3 d after the PC ablation were also less likely to avoid carrot juice than sham-operated slugs. The PC ablation did not damage the ability of the slugs to sense attractive odor (everyday food) or innately aversive odor (onion or garlic). These results demonstrate that the PC is a necessary component in the retention and/or retrieval of odor-aversion memory.     

Visual onset expands subjective time

We report a distortion of subjective time perception in which the duration of a first interval is perceived to be longer than the succeeding interval of the same duration. The amount of time expansion depends on the onset type defining the first interval. When a stimulus appears abruptly, its duration is perceived to be longer than when it appears following a stationary array. The difference in the processing time for the stimulus onset and motion onset, measured as reaction times, agrees with the difference in time expansion. Our results suggest that initial transient responses for a visual onset serve as a temporal marker for time estimation, and a systematic change in the processing time for onsets affects perceived time.     

Workaholism Among Japanese Blue-Collar Employees

A survey study was conducted in order to examine the hypothesis that workaholism may be a mode of adapting to a stressful work environment. A questionnaire was distributed to members of the Japan Federation of Automobile Workers' Unions in Japan. A total of 4,621 workers (4,083 men, 509 women, 29 unidentified) returned usable data (response rate = 71.9%). The results of a correlation analysis indicated that work overload-quantity and work overload-quality had significantly positive relations with Driven and little or no significant relations with Enjoyment of work. Blue-collar employees who work in highly structured and controlled environments were less likely to be workaholic than white-collar employees (in particular those in sales divisions). The results of ANOVA indicated that work overload had different effects on workaholism by age groups among blue-collar employees. It was found that work overload increased the degree of Driven and Enjoyment of work for those under 34 years old and it increased Driven and decreased Enjoyment of work for those over 35 years old.     

Prevalence, antecedent causes and consequences of domestic violence in Myanmar

The present study explored women's experiences of domestic violence in Myanmar. In particular, the study examined the relation between antecedents and outcomes of their experiences as well as influences of attribution styles, response styles and different types of violence on their experiences. Using the Myanmar version of the Revised Conflict Tactic Scale, survey data from a representative sample of 286 women in Myanmar were conducted. Results indicated that 27% of women experienced physical assault and 69% of women experienced psychological aggression in a 1-year period. The factors associated with increased risks of violence included witnessing parental violence, husbands' unemployment, husbands' frequent alcohol use, and women's feminism attitudes. Severe physical assault was a strong predictor of negative outcomes and formal intervention. Formal intervention was related to fewer negative outcomes.     

Relationship between types of humour and stress response and well‐being among children in Japan

This study examined the relationship between three types of children's humour (aggressive, self‐defeating, and playful) and the children's stress response and well‐being in the Japanese context, where a collectivistic culture is prevalent. To do so, 500 study participants (250 elementary and 250 junior high school students) were recruited. The participants reported the types of humour, stress responses, and level of well‐being that they experienced. After correlation analysis, aggressive humour and playful humour showed a positive correlation with stress responses; in addition, aggressive humour showed a negative correlation with well‐being. Self‐defeating humour showed a negative correlation with stress responses and a positive correlation with well‐being. We also conducted a cluster analysis using the scores for the three types of humour, analysing four groups: “aggressive humourists” (respondents who demonstrated above‐average aggressive humour and scored average for all other humours), “nonhumourists” (below‐average humour in all areas), “self‐deprecating humourists” (above‐average self‐defeating humour, below‐average aggressive humour, and average playful humour), and “multiple humourists” (above‐average humour in all areas). Upon comparing the results of stress responses and well‐being scores among the four groups, we found that self‐deprecating humourists reported the highest level of well‐being. These results show that in collectivistic cultures, self‐defeating humour may be adaptive.     

Recognising the forest, but not the trees: an effect of colour on scene perception and recognition

Colour has been shown to facilitate the recognition of scene images, but only when these images contain natural scenes, for which colour is 'diagnostic'. Here we investigate whether colour can also facilitate memory for scene images, and whether this would hold for natural scenes in particular. In the first experiment participants first studied a set of colour and greyscale natural and man-made scene images. Next, the same images were presented, randomly mixed with a different set. Participants were asked to indicate whether they had seen the images during the study phase. Surprisingly, performance was better for greyscale than for coloured images, and this difference is due to the higher false alarm rate for both natural and man-made coloured scenes. We hypothesized that this increase in false alarm rate was due to a shift from scrutinizing details of the image to recognition of the gist of the (coloured) image. A second experiment, utilizing images without a nameable gist, confirmed this hypothesis as participants now performed equally on greyscale and coloured images. In the final experiment we specifically targeted the more detail-based perception and recognition for greyscale images versus the more gist-based perception and recognition for coloured images with a change detection paradigm. The results show that changes to images are detected faster when image-pairs were presented in greyscale than in colour. This counterintuitive result held for both natural and man-made scenes (but not for scenes without nameable gist) and thus corroborates the shift from more detailed processing of images in greyscale to more gist-based processing of coloured images.