The effect of orientation on tactual braille recognition: optimal touching positions.

Subjects in five experiments matched tangible braille against a visible matching code. In Experiment 1, braille recognition suffered when entire lines of braille characters were tilted in varying amounts from the upright. Experiment 2 showed that tilt lowered performance for tangible, large embossed letters, as well as for braille. However, recognition was better for print letters than it was for braille. In Experiment 3, subjects attempted to match the upright array against embossed braille that was left/right reversed, inverted up/down, or rotated +180 degrees. Performance was close to that for normal braille in the left/right reversal condition, and very low for the +180 degrees rotation group. These results on braille tilt in the "picture plane" may reflect difficulty in manipulating the tangible "image." Braille recognition performance was not lowered when the visible matching array was tilted -45 degrees or -90 degrees from the upright but the tangible stimuli were upright. In Experiment 4, recognition of left/right reversed braille that was physically horizontal (on the bottom of a shelf) was compared with that of braille left/right reversed due to its location on the back of a panel, in the vertical plane. Braille recognition accuracy was higher with braille located vertically. An additional experiment showed the beneficial effect of locating braille in the vertical, frontoparallel plane, obtained with +90 degree rotated braille. It is proposed that optimal tactual performance with tangible arrays might depend on touching position, and on the physical position of stimuli in space. Just as there are good and poor viewing positions, there may be optimal touching positions.(ABSTRACT TRUNCATED AT 250 WORDS)     

Letter visibility and word recognition: The optimal viewing position in printed words

It has repeatedly been shown that the time and accuracy of recognizing a word depend strongly on where in the word the eye is fixating. Word-recognition performance is maximal when the eye fixates a region near the word’s center, and decreases to both sides of this “optimal viewing position.” The reason for this phenomenon is assumed to be the strong drop-off of visual acuity: the visibility of letters decreases with increasing eccentricity from fixation location. Consequently, fewer letters can be identified when the beginning or ending of a word is fixated than when its center is fixated. The present study is a test of this visual acuity hypothesis. If the phenomenon is caused by letter visibility, then it should be sensitive to variations of visual conditions in which the letters are presented. By increasing the interletter distances of the word(e.g.,a_t_t_e_m_ p_ t), letter visibility was decreased. As expected from our hypothesis, the viewing-position effect became more exaggerated. An additional experiment showed that destroying word-shape information (e.g., aTtEmPt) decreased overall word-recognition performance but had no influence on the viewingposition effect. Varying the viewing position in words might thus be used as a paradigm, allowing one to separate out the contribution of letter information and supraletter information to word recognition.     

A Sequential Analysis of Depressive Behaviors Within Adolescent Peer Interactions

This study examined depressive and positive patterns of interactions among clinical and nonclinical adolescent peers within an interpersonal context. Ten clinical dyads with a depressed partner and 10 nonclinical dyads engaged in 16-min audiotaped conversations under positive and negative task instructions discussing positive and negative experiences. Conversations were unitized and coded according to depressive, aggressive, positive, and neutral behaviors. The clinical dyad-group demonstrated over two times more depressive behaviors than did the nonclinical dyad-group. Both dyad-groups exhibited increased depressive interactions during negative task instructions and increased positive interaction during positive task instructions. The loglinear approach to sequential analysis demonstrated significant overall bidirectional influence in the adolescents' dyadic interaction. Specifically, we found that the depressed adolescents' depressive behaviors decreased the likelihood of partners' aggressive behaviors, and increased the likelihood of partners' positive behaviors. Clinical and nonclinical dyad-groups showed reliable patterns of positive interaction sequences. Results demonstrate that depressive and positive behaviors are functional in adolescent dyadic interaction.     

Scopes of perception: The experimental manipulation of space and time

Discussions of space and time have been grist to the philosophers' mill for centuries. We argue that the evolution of psychology as an independent discipline was in part a consequence of addressing philosophical questions concerning the perception of space and time by recourse to experiment rather than exposition. Two initially separate factors assisted in establishing this independence. On the one hand, it was driven by the invention of instruments for stimulus control so that the methods of physics could be applied to the study of perceptual phenomena. On the other hand and somewhat later, it was followed by the development of psychophysical methods, which opened the possibility of quantifying the responses to such controlled stimulation. The principal instruments were invented in the first half of the nineteenth century, and they consisted of simple contrivances that manipulated time and space in ways that had not previously been appreciated. This article examines the devices that were invented, like stroboscopes, anorthoscopes, stereoscopes, tachistoscopes, chronoscopes, and more recently oscilloscopes, and the ways in which they influenced the scope of perceptual psychology in the past as well as in the present. In contemporary experimental psychology all these instruments have been replaced by the computer. While it has extended the scope of experiments even further it has introduced a new set of limitations.     

The tactual horizontal-vertical illusion depends on radial motion of the entire arm

Wesought to clarify the causes of the tactual horizontal-vertical illusion, where vertical lines are overestimated as compared with horizontals in Land inverted-T figures. Experiment 1 did not use L or inverted-T figures, but examined continuous or bisected horizontal and vertical lines. It was expected that bisected lines would be perceived as shorter than continuous lines, as in the inverted-T figure in the horizontal-vertical illusion. Experiment 1 showed that the illusion could not be explained solely by bisection, since illusory effects were similar for continuous and bisected vertical and horizontal lines. Experiments 2 and 3 showed that the illusory effects were dependent upon stimulus size and scanning strategy. Overestimation of the vertical was minimal or absent for the smallest patterns, where it was proposed that stimuli were explored by finger movement, with flexion at the wrist. Larger stimuli induce whole-arm motions, and illusory effects were found in conditions requiring radial arm motion. The illusion was weakened or eliminated in Experiment 4 when subjects were forced to examine stimuli with finger-and-hand motion alone, that is, their elbows were kept down on the table surface, and they were prevented from making radial arm motions. Whole-arm motion damaged performance and induced perceptual error. The experiments support the hypothesis that overestimation of the vertical in the tactual horizontal-vertical illusion derives from radial scanning by the entire arm.     

How the bimodal format of presentation affects working memory: an overview

The best format in which information that has to be recalled is presented has been investigated in several studies, which focused on the impact of bimodal stimulation on working memory performance. An enhancement of participant’s performance in terms of correct recall has been repeatedly found, when bimodal formats of presentation (i.e., audiovisual) were compared to unimodal formats (i.e, either visual or auditory), in providing implications for multimedial learning. Several theoretical frameworks have been suggested in order to account for the bimodal advantage, ranging from those emphasizing early stages of processing (such as automatic alerting effects or multisensory integration processes) to those centred on late stages of processing (as postulated by the dual coding theory). The aim of this paper is to review previous contributions to this topic, providing a comprehensive theoretical framework, which is updated by the latest empirical studies.     

How implicitly activated and explicitly acquired knowledge contribute to the effectiveness of retrieval cues

The extralist cued recall task simulates everyday reminding because a memory is encoded on the fly and retrieved later by an unexpected cue. Target words are studied individually, and recall is cued by associatively related words having preexisting forward links to them. In Experiments 1 and 2, forward cue-to-target and backward target-to-cue strengths were varied over an extended range in order to determine how these two sources of strength are related and which source has a greater effect. Forward and backward strengths had additive effects on recall, with forward strength having a consistently larger effect. The PIER2 model accurately predicted these findings, but a plausible generation-recognition version of the model, called PIER.GR, could not. In Experiment 3, forward and backward strengths, level of processing, and study time were varied in order to determine how preexisting lexical knowledge is related to knowledge acquired during the study episode. The main finding indicates that preexisting knowledge and episodic knowledge have additive effects on extralist cued recall. PIER2 can explain these findings because it assumes that these sources of strength contribute independently to recall, whereas the eSAM model cannot explain the findings because it assumes that the sources of strength are multiplicatively related.