Encoding of kinesthetic extent information

The difference in codability of kinesthetic extent cues for experimenter-determined vs. subject-determined standards was investigated. The task involved moving a slide along a linear track a distance of one-half the total distance of the track. This distance (the standard) was then reproduced. During the presentation of the standard, reaction time to an auditory probe was recorded. One group of subjects determined their own standard (active condition), while the other group moved the slide to a stop located at the standard distance (constrained condition). All subjects were told that the standard was one-half the total distance. A more active encoding process was hypothesized to occur in the active condition which would be reflected in increased reaction time to the probe. The results did not support the attention hypothesis, in that probe reaction times were not significantly different for the two groups. Rather, the data suggested that the important variable in determining the codability of extent cues was the availability of a strategy and not whether the experimenter or the subject determined the standard.

     

Response competition: a major source of interference in a tactile identification task.

Two experiments investigated the ability of subjects to identify a moving, tactile stimulus. In both experiments, the subjects were presented with a target to their left index fingerpad and a nontarget (also moving) to their left middle fingerpad. Subjects were instructed to attend only to the target location and to respond "1" if the stimulus moved either to the left or up the finger, and to respond "2" if the stimulus moved either right or down the finger. The results showed that accuracy was better and reaction times were faster when the target and nontarget moved in the same direction than when they moved in different directions. When the target and nontarget moved in different directions, accuracy was significantly better and reaction times were significantly faster when the two stimuli had the same assigned response than when they had different responses. The results provide support for the conclusion that movement information is processed across adjacent fingers to the level of incipient response activation, even when subjects attempt to focus their attention on one location on the skin.     

Response competition: A major source of interference in a tactile identification task

Two experiments investigated the ability of subjects to identify a moving, tactile stimulus. In both experiments, the subjects were presented with a target to their left index fingerpad and a nontarget (also moving) to their left middle fingerpad. Subjects were instructed to attend only to the target location and to respond “1” if the stimulus moved either to the left or up the finger, and to respond “2” if the stimulus moved either right or down the finger. The results showed that accuracy was better and reaction times were faster when the target and nontarget moved in the same direction than when they moved in different directions. When the target and nontarget moved in different directions, accuracy was significantly better and reaction times were significantly faster when the two stimuli had the same assigned response than when they had different responses. The results provide support for the conclusion that movement information is processed across adjacent fingers to the level of incipient response activation, even when subjects attempt to focus their attention on one location on the skin.     

The Bourdon illusion in haptic space

A strong Bourdon illusion-the apparent bentness of a straight edge-in the active haptic mode was established in two experiments. Blindfolded subjects clasped the opposite surfaces of an object with the same frontal profile as the visual figure between thumb and forefinger and moved the latter together from end to end across the object. When the two triangular components of the objects were rotated through 180 degrees so that their bases instead of their apexes were contiguous, the illusion was reversed in direction and reduced by about half, as with the visual illusion. It was concluded that the active haptic Bourdon illusion is basically the same as the visual illusion and can be accounted for by a compromise in perception between the orientation of the test surface and that of the object of which it is an integral part.     

Automatic Spatial Updating During Locomotion Without Vision

People can update their spatial relationships relative to the environment while walking without vision. The hypothesis that such updating is automatic was tested in a locomotor task in which the subjects were asked to refrain from updating their positions. Subjects walked without vision to one of four previously seen targets via a second location. In one condition-the updating condition-the subjects were asked to walk to the real position of the target relative to the second location; in another-the ignoring condition-they were asked to imagine that they had not moved from the starting point and to walk from the second location as if walking to the target from the initial location. When the subjects were asked to start walking to the target as soon as it was named by the experimenter, they performed better in the updating condition than in the ignoring condition. When the subjects were allowed more time to respond, the difference in performance between these two conditions disappeared. The results suggest that the subjects automatically updated their positions as they moved, but that, given enough time, they could override this updating retrospectively using more deliberate cognitive processing.     

The effect of motion on tactile and visual temporal order judgments

Four experiments were conducted, three with tactile stimuli and one with visual stimuli, in which subjects made temporal order judgments (TOJs). The tactile stimuli were patterns that moved laterally across the fingerpads. The subject's task was to judge which finger received the pattern first. Even though the movement was irrelevant to the task, the subjects' TOJs were greatly affected by the direction of movement of the patterns. Accuracy in judging temporal order was enhanced when the patterns moved in a direction that was consistent with the temporal order of presentation--for example, when the movement on each fingerpad was from right to left and the temporally leading site of stimulation was to the right of the temporally trailing site of stimulation. When movement was inconsistent with the temporal order of presentation, accuracy was considerably reduced, often well below chance.The bias in TOJs was unaffected by training or by presenting the stimuli to fingers on opposite hands. In a fourth experiment, subjects judged the temporal order of visual stimuli that, like the tactile stimuli, moved in a direction that was either consistent or inconsistent with the TOJ. The results were similar to those obtained with tactile stimuli. It is suggested that the bias may be affected by attentional mechanisms and by apparent motion generated between the two sites on the skin.     

Is visual information integrated across saccades?

After subjects established fixation on a target cross, 12 dots were presented parafoveally. When the dots were presented, the subjects made an eye movement to the location of the dots, and during the saccade the 12 initially presented dots were replaced by 12 other dots. The 24 dots were part of a 5 × 5 matrix, and the task of the subject was to report which dot was missing. The data were consistent with other recent studies: subjects could successfully report the location of the missing dot far above chance (54%), whereas performance in a control condition (in which the two sets of dots were presented to different spatial and retinal locations) was almost at chance level (10%). However, a number of control conditions demonstrated that the effect was due primarily to persistence from the phosphor of the cathode ray tube used for stimulus presentation and that little of the visual information integrated was across two fixations. Implications of the results for a theory of integration across saccades are discussed.     

Opponent motion interactions

Interactions in the perception of motion transparency were investigated using a signal-detection paradigm. The stimuli were the linear sum of two independent, moving, random-check \ldsignal\rd textures and a third texture consisting of dynamic random \ldnoise.\rd Performance was measured as the ratio of squared signal and noise contrasts was varied (S²/W²). Motion detectability was poorest when the two signal textures moved in opposite directions (180\dg), intermediate when they moved in the same direction (0\dg), and best when the textures moved in directions separated by 90\dg in the stimulus plane. This pattern of results held across substantial variations in velocity, field size, duration, and texture-element size. Motion identification was also impaired, relative to 0\dg, in the 180\dg but not in the 90\dg condition. These results are consistent with the idea that performance in the opponent-motion condition is limited by inhibitory (or suppressive) interactions. These interactions, however, appear to be direction specific: little, if any, inhibition was observed for perpendicular motion.     

An integration of color and motion information in visual scene analyses

To analyze complex scenes efficiently, the human visual system performs perceptual groupings based on various features (e.g., color and motion) of the visual elements in a scene. Although previous studies demonstrated that such groupings can be based on a single feature (e.g., either color or motion information), here we show that the visual system also performs scene analyses based on a combination of two features. We presented subjects with a mixture of red and green dots moving in various directions. Although the pairings between color and motion information were variable across the dots (e.g., one red dot moved upward while another moved rightward), subjects' perceptions of the color-motion pairings were significantly biased when the randomly paired dots were flanked by additional dots with consistent color-motion pairings. These results indicate that the visual system resolves local ambiguities in color-motion pairings using unambiguous pairings in surrounds, demonstrating a new type of scene analysis based on the combination of two featural cues.     

不同年级学生阅读科技文章的眼动研究

本实验使用４２００Ｒ眼动仪对小学三年级、初二、高二和大学生阅读科技文章的眼动特征进行研究。结果发现;１．随年龄的提高,被试阅读课文的总注视次数显著减少;２．高年级学生能够根据阅读内容的重要性来灵活地调节自己的眼动策略;３．随着年级的提高,各年级被试使用前进式回视的比例逐渐减少,而使用选择式回视的比例逐渐增加。     

Better than me or better than thee? Reactions to intrapersonal and interpersonal performance feedback

When people compare their own performance across domains, the comparison may be based on differences in their absolute (objective) performance and/or on diffrences in their performance relative to others Differential sensitivity to the interpersonal (relative) and intrapersonal (absolute) comparison information was examined as a function of the closeness of the social comparison target and individual differences in self-esteem Subjects (162) worked on two tasks with a partner, receiving item-by-item feedback, the partner was either a friend or a stranger The feedback was designed such that subjects' objective performance was better on one task (Task A) than on the other task (Task B), but their performance relative to that of the partner was better on Task B than on Task A High self-esteem subjects and subjects in the friend condition were more satisfied and evaluated the test more positively on the task associated with better relative performance (despite the fact that their objective performance was worse on that task) Low self-esteem subjects and subjects in the stranger condition expressed more positive reactions on the task associated with better objective performance (despite the fact that their relative performance was worse on that task) Results are discussed in terms of the informational and affective consequences of engaging in social comparison     

Information Processing at Successive Stages of Decision Making: Need for Cognition and Inclusion-Exclusion Effects

Levin and Jasper's (1995) phased narrowing technique for tracking changes in information usage across successive stages of the decision-making process was combined with Huneke's (1996) “pull-down menu” extension of Payne, Bettman, and Johnson's (1988) software package for generating measures of information processing. Because this technique provided considerable data for each individual subject at each stage, we were able to focus on individual differences in information processing across stages, most notably differences related to need for cognition (NC; Cacioppo & Petty, 1982). In a computerized information search and decision task, 60 college students were first asked to narrow their options for purchasing a notebook computer to form a consideration set and were then asked to make a final choice from this set. At the consideration set formation stage, half the subjects were instructed to adopt a mindset to include options while the other half were asked to exclude options. Especially in the inclusion condition where subjects showed greater narrowing of options, high NC subjects processed information in a more focused manner with greater depth and breadth than did low NC subjects, and the quality of their selections tended to be higher. There was no evidence of widespread shifts in strategy as individuals moved from set formation to final choice but, as a group, high NC subjects were more successful at adaptive decision making.     

A specific role for efferent information in self-recognition

We investigated the specific contribution of efferent information in a self-recognition task. Subjects experienced a passive extension of the right index finger, either as an effect of moving their left hand via a lever ('self-generated action'), or imposed externally by the experimenter ('externally-generated action'). The visual feedback was manipulated so that subjects saw either their own right hand ('view own hand' condition) or someone else's right hand ('view other's hand' condition) during the passive extension of the index finger. Both hands were covered with identical gloves, so that discrimination on the basis of morphological differences was not possible. Participants judged whether the right hand they saw was theirs or not. Self-recognition was significantly more accurate when subjects were themselves the authors of the action, even though visual and proprioceptive information always specified the same posture, and despite the fact that subjects judged the effect and not the action per se. When the passive displacement of the participants right index finger was externally generated, and only afferent information was available, self-recognition performance dropped to near-chance levels. Differences in performance across conditions reflect the distinctive contribution of efferent information to self-recognition, and argue against a dominant role of proprioception in self-recognition.     

Dynamic occlusion and motion parallax in depth perception

Random-dot techniques were used to examine the interactions between the depth cues of dynamic occlusion and motion parallax in the perception of three-dimensional (3-D) structures, in two different situations: (a) when an observer moved laterally with respect to a rigid 3-D structure, and (b) when surfaces at different distances moved with respect to a stationary observer. In condition (a), the extent of accretion/deletion (dynamic occlusion) and the amount of relative motion (motion parallax) were both linked to the motion of the observer. When the two cues specified opposite, and therefore contradictory, depth orders, the perceived order in depth of the simulated surfaces was dependent on the magnitude of the depth separation. For small depth separations, motion parallax determined the perceived order, whereas for large separations it was determined by dynamic occlusion. In condition (b), where the motion parallax cues for depth order were inherently ambiguous, depth order was determined principally by the unambiguous occlusion information.     

The effect of hand position and pattern motion on temporal order judgments

Subjects made temporal order judgments (TOJs) of tactile stimuli presented to the fingerpads. The subjects judged which one of two locations had been stimulated first. The tactile stimuli were patterns that simulated movement across the fingerpads. Although irrelevant to the task, the direction of movement of the patterns biased the TOJs. If the pattern at one location moved in the direction of the second location, the subjects tended to judge the first location as leading the second location. If the pattern moved in the opposite direction, that location was judged as trailing. In a series of experiments, the effect of the spatial position of the hands and fingers on TOJs and the perception of the direction of pattern movement were examined. Changing the position of the hands so that the patterns no longer moved directly toward each other reduced or eliminated the effect of motion on TOJs. In a variation of Aristotle's illusion, the moving patterns were presented to crossed and uncrossed fingers. The results indicated that, contrary to Aristotle's illusion, the subjects processed the moving patterns relative to an environmental framework, rather than to the local direction of motion on the fingerpads. Presenting the patterns to crossed hands produced results similar to those obtained with crossed fingers: The subjects processed the patterns according to an environmental framework.     

Visual short-term memory during smooth pursuit eye movements

Visual short-term memory (VSTM) was probed while observers performed smooth pursuit eye movements. Smooth pursuit keeps a moving object stabilized in the fovea. VSTM capacity for position was reduced during smooth pursuit compared with a condition with eye fixation. There was no difference between a condition in which the items were approximately stabilized on the retina because they moved with the pursuit target and a condition in which the items moved across the retina because they were stationary in space. The reduction of capacity for position was eliminated when miniature items were presented on the pursuit target. Similarly, VSTM capacity for color did not differ between smooth pursuit and fixation. The results suggest that visuospatial attention is tied to the target during smooth pursuit, which impairs VSTM for the position of peripheral objects. Sensory memory during smooth pursuit was only slightly impaired.     

Are long compound words identified serially via their constituents? Evidence from an eyemovement-contingent display change study

The processing of two-constituent 12- to 18-letter Finnish compound nouns was studied by using an eye-movement-contingent display change technique. In the display change condition, all but the first 2 letters of the second constituent were replaced by visually similar letters until the eyes moved across an invisible boundary. When the eyes crossed the boundary, the second constituent was changed to its intended form. In the control condition, there was no display change. The frequency of the first constituent was also varied. The major findings were that (1) fixation time on the first constituent was strongly affected by the frequency of the first constituent but was not at all affected by whether the second constituent was visible, but (2) fixation time on the word subsequent to the first constituent's having been left was strongly affected by the display change. These results are most parsimoniously explained by the serial access of the two constituents for these long compound words.     

Conjugate lateral eye movements as an index of hemispheric activation.

Right handers moved their eyes leftward when solving spatial problems and rightward for verbal problems when the questioner sat behind them. When facing the questioner, the same subjects moved their eyes predominantly in only one direction, either right or left, regardless of problem type. The results indicate that the cerebral hemispheres, though specialized for problem type, are also preferentially activated within the same individuals.     

ASSESSING AND PROGRAMMING GENERALIZED BEHAVIORAL REDUCTION ACROSS MULTIPLE STIMULUS PARAMETERS

Generalization across three stimulus parameters was examined for 5 individuals whose self-injurious behavior was maintained by escape from task demands. Prior to treatment, three stimulus parameters (therapist, setting, and demands) were systematically varied across baseline sessions. These variables were held constant during treatment, which consisted of escape extinction. When treatment was completed, three novel stimulus parameters were probed. If the rate of self-injury was high during this probe, treatment was reimplemented with one new stimulus parameter (the other two were the same as in the original treatment condition). Following this second treatment, another probe with three novel stimuli was conducted. If the rate of self-injury was again high, treatment was implemented again while a second stimulus parameter was changed. This sequence continued until generalization was observed across the three parameters. Results showed idiosyncratic differences in generalization. The behavior of 2 subjects showed complete generalization during the first novel probe. A 3rd subject's behavior showed generalization following treatment across two stimulus parameters (setting and therapist). The behavior of the 2 remaining subjects showed a complete lack of generalization across the three parameters; both subjects required training for novelty by randomly varying the stimulus parameters for a substantial number of sessions.     

EEG captures affective touch: CT-optimal touch and neural oscillations

Tactile interactions are of developmental importance to social and emotional interactions across species. In beginning to understand the affective component of tactile stimulation, research has begun to elucidate the neural mechanisms that underscore slow, affective touch. Here, we extended this emerging body of work and examined whether affective touch (C tactile [CT]-optimal speed), as compared to nonaffective touch (non-CT-optimal speed) and no touch conditions, modulated EEG oscillations. We report an attenuation in alpha and beta activity to affective and nonaffective touch relative to the no touch condition. Further, we found an attenuation in theta activity specific to the affective, as compared to the nonaffective touch and no touch conditions. Similar to theta, we also observed an attenuation of beta oscillations during the affective touch condition, although only in parietal scalp sites. Decreased activity in theta and parietal-beta ranges may reflect attentional-emotional regulatory mechanisms; however, future work is needed to provide insight into the potential neural coupling between theta and beta and their specific role in encoding slow, tactile stimulation.