Spatial attention and reaction times during smooth pursuit eye movement

To examine the spatial shift of attention during smooth pursuit, we measured reaction times (RTs) to a visual target that appeared during pursuit. Participants pursued a moving row of circular frames and responded to a target presented within one of the frames. The results showed large RT differences between stimulus velocities up to 5o/s and 10o/s or above. RTs were faster for a target appearing in the pursuit direction than for one in the opposite direction. When an auditory precue was presented, the RTs during pursuit at 10o/s were faster with increases in the stimulus onset asynchrony (SOA) between the cue and the target. Furthermore, RTs were faster in the cued than in the uncued direction. These results not only support the idea that RTs during pursuit reflect the operation of attention, but also suggest that attention during pursuit can be shifted by the abrupt onset of a target stimulus and/or by prior information regarding the onset of a target stimulus.     

Reading performance in middle-aged adults with declines in accommodation

The present study investigated the effects of presbyopia on the reading ability of middle-aged adults in a Japanese reading context, using the rapid serial visual presentation paradigm. Japanese words, each consisting of three characters, were sequentially presented at the same location on a display screen. Participants were instructed to read the words aloud as accurately as possible, irrespective of their order within the sequence. Experiment 1 showed that the reading performance for the presbyopes was far worse for the near-viewing (35?cm) than for the far-viewing (70?cm) conditions when the words were presented at 0.4° in character size. Experiment 2 investigated in detail the effect of luminance contrast on reading at a viewing distance of 35?cm. The minimums of the exposure durations within which the participants could read the words above 89.9?% correct (minimum exposure duration) were 498?ms/word for the presbyopes and 134?ms/word for the nonpresbyopes, both of which values were obtained at 100?% contrast. The critical contrast??that is, the contrast that doubled the minimum exposure duration that had been obtained at 100?% contrast??was considerably higher for the presbyopes (39.2?%) than for the nonpresbyopes (16.4?%). However, the reading performance for the presbyopes was improved more than threefold when the contrast was increased to 100?% in both experiments. Thus, our results provide psychophysical evidence for the dependency of presbyopes?? reading on viewing distance and luminance contrast.     

Relationship between masculinity-femininity and concession in an experimental collaborative eyewitness testimony

The present study examined the relationships of masculinity and femininity with concession in an experimental collaborative eyewitness testimony task, using the MORI technique. Participants formed same sex or mixed sex pairs and watched a videotaped event. Their eyewitness memories were assessed three times: immediately after watching, after discussing the event together, and individually 1 week later . The participants' self-confidence in their recalled memories and percentages of concessions were also examined. The Masculinity-Humanity-Femininity Scale was administered to the participants at the end of the experiment. The results showed that masculinity negatively correlated with concession, and that both masculinity and femininity were associated with inaccuracy in collaborative memory recall.     

Unmasking the magnitude estimation response

The fuzzy judgement model of Ward (1979) predicts an inverse relation between the amount of stimulus information available to subjects and the magnitude of sequential dependencies on previous stimuli and responses in psychophysical scaling tasks. Ward confirmed this prediction for magnitude estimations of interdot distance for previous responses but not for previous stimuli, although the inverse relation has been repeatedly reported for both the previous stimuli and responses in absolute identification (e.g., Mori, 1989). This paper further explores this seemingly puzzling contradiction. A magnitude estimation of loudness experiment was conducted in which the amount of stimulus information available to subjects was manipulated by a modified version of informational masking (Watson, 1987). An absolute-identification-with-feedback experiment was also conducted to check the effectiveness of the informational masking in reducing the amount of stimulus information. The results of the magnitude estimation experiment show a striking similarity with those of Ward and generalize the failure of sequential dependencies on previous stimuli to vary inversely with stimulus information. An additional assumption that judgement strategies are altered under low-information conditions is necessary to explain this result.     

Biochemistry and neurotoxicology of guanidino compounds

Guanidino compounds are known to have important biological roles, such as the participation of arginine in ureagenesis, and of creatine in muscular contraction. On the other hand, the high toxicity of guanidino compounds, such as methylguanidine and guanidine, has been under study for quite a long time in the biochemical as well as clinical fields. In this review, the author summarizes the experimental results of neurophysiological and neurochemical studies on guanidino compound-induced seizures, conducted by his colleagues since 1966, and introduces several topics arising from their recent investigations on guanidino compounds and seizure mechanism,i.e., (1) α-guanidino-glutaric acid in the cobalt epileptic focus and its convulsive activity; (2) guanidino-ethanesulfonic acid and epilepsy; (3) δ-guanidinovaleric acid, and endogenous and specific GABA receptor antagonist; and (4) guanidino compounds as radical generators.     

Change of a frame of reference with velocity in visual motion perception

The present study examined how a frame of reference was affected by velocity. This question was examined with respect to a system consisting of two points: one moved rectilinearly with constant velocity, and the other moved on a track in the shape of a cycloid (defined as the movement of two points—one on the hub and the other on the rim of a rolling wheel). The results indicated that (1) a frame of reference in which the centroid of the total picture was stationary was chosen mainly in a low-velocity range (0.1–0.7 deg/sec), (2) a frame of reference in which a picture point moved rectilinearly was chosen mainly in a medium-velocity range (0.8–40.0 deg/sec), and (3) an absolute coordinate system was chosen mainly in a high-velocity range (>40.0 deg/sec). The current evidence and other findings seem to be consistent with the idea that groups of neurons related to the three frames of reference are independent of one another, that the velocity ranges of the groups of neurons roughly overlapped each other, and that the most salient frame of reference is chosen (i.e., exclusion principle in choice of a frame of reference).     

The nature of the task-stimulus interaction in the tachistoscopic recognition of kana and kanji words

To investigate the nature of the task-stimulus interaction in tachistoscopic recognition of kana and kanji, right-handed normal subjects performed two phonological tasks and two visual tasks. In the phonological tasks, the subjects compared the members of a pair of kana or kanji appearing in the right or left visual field on the basis of phonological identity; while in the visual tasks, they compared the members of a pair of kana or kanji on the basis of visual identity. The results showed a significant Visual Field × Task interaction as well as a significant Task × Stimulus interaction, indicating that both the type of stimuli and the nature of task demands contribute importantly to the determination of visual field asymmetry and hence the relative participation of each hemisphere.     

Nitroglycerin relieves emotional stress-induced stomach ulcers in rats

It is known that nitroglycerin (GTN) can be converted to form a nitric oxide (NO) molecule which is a highly reactive and unstable free radical species. NO is known to have many beneficial effects such as relaxing blood vessels, promoting digestive activity, and regulating blood pressure. The first experiment established an additional effect of NO, that GTN can help prevent emotionally-induced stomach stress ulcers in rats. In Experiment 2, we sought to estimate the quantity of nitrogen oxides in serum produced by GTN that is administered subcutaneously to rats. The results indicated that rats administered GTN increased significantly the amount of serum NO₂ and NO₃, relative to values for a control group. Since amounts of NO₂ and NO₃ reflect amount of NO, the administration of GTN significantly increased amount of NO. An implication of this research is that chemicals such as GTN may be used in therapy with humans for the prevention of some kinds of ulcers. Furthermore, while NO is commonly recognized as a pollutant, it has a number of beneficial effects on the body, e. g., it may slow the aging process, contribute to therapy for improtency, and facilitate memory processes.     

Pure feedback effects in absolute identification

To reveal the pure effects of trial-by-trial feedback on judgmental accuracy and sequential dependencies independent of global anchoring effects and other influences, we presented subjects with sequences consisting alternately (within an experimental session) of short runs of trials with feedback (feedback sequences) and without feedback (no-feedback sequences). In Experiments 1 and 2 (absolute identification of sound intensity and sound frequency, respectively), judgmental accuracy was the same in the feedback and the no-feedback sequences, contrary to previous results. Also, in the feedback sequences, the dependency of the current response on the immediately preceding stimulus was larger than that in the no-feedback sequences, while the dependency on the previous response was larger in the no-feedback sequences. In Experiment 3 (absolute identification of sound frequency), we attempted to separate the effects of the number of response categories on sequential dependencies from the effects of the number of stimuli. The results showed that the number of response categories had a larger effect than the number of stimuli on most aspects of performance, but that both affected sequential dependencies. These results are generally consistent with a theory of absolute identification in which feedback affects judgmental accuracy by improving long-term memory for judgmental anchors, while feedback affects sequential dependencies by altering response biases.     

The Role of Gender and Ethnicity in Perceptions of Rape and Its Aftereffects

Caucasian-, Hispanic-, and Asian-American male and female students (n?=?764) attending a California (USA) public university reported their perceptions of sexual assault. After reading a rape vignette, participants gave their impressions of the victim; estimated time needed for recovery and treatment; and recommended a sentence for the assailant. Half of the sample received information regarding state sentencing guidelines. Relative to female participants, males perceived the victim as more responsible. Caucasian-American males had stronger reservation about the victim’s judgment. Males were less inclined to assign blame than were females. Ethnicity was the only factor influencing perceptions of recovery. Ethnicity and sentencing guidelines, but not gender, impacted imprisonment decisions. Issues impeding a unified theoretical understanding of perceptions of rape victims were considered.