How robust are the deviations in haptic parallelity?

Several studies have shown that physically parallel bars do not feel parallel and vice versa. The most plausible cause of this deviation is the biasing influence of an egocentric reference frame. The aim of the present study was to assess the strength of this egocentric contribution. The deviations from veridicality were measured in six experiments where subjects were presented with either haptic or visual information about parallelity or their deviations. It was found that even direct error feedback (either haptically or visually) did not even nearly result in veridical performance. The improvements found were attributed to a shift in focus towards a more allocentric reference frame, possibly reflecting the same mechanisms as found in delay and noninformative vision studies. We conclude that the illusionary percept of haptic parallelity is rather robust and is indeed caused by a strong reliance on an egocentric reference frame.     

The effects of curvature on haptic judgments of extent in sighted and blind people

A series of experiments was carried out to examine the effect of curvature on haptic judgments of extent in sighted and blind individuals. Experiment 1 showed that diameters connecting the endpoints of semicircular lines were underestimated with respect to straight lines, but failed to show an effect of visual experience on length judgments. In experiment 2 we tested are lengths. The effects of curvature on perceived path length were weaker, but were still present in this experiment. Visual experience had no effect on path length judgments. Another experiment was performed to examine the effect of repeated tracing (1, 5, 9, or unlimited number of traces) on judgments of the lengths of straight lines and diameters of semicircles. Judgments of extent were more accurate when subjects engaged in larger numbers of traces. There was no effect of number of traces on curve-height judgments, suggesting that subjects were not using height estimates to judge diameters of semicircles. In a further experiment we tested the effect of number of traces on curves that varied in height. Restricting subjects to a single trace magnified the effect of path length on judgments of the distance between the endpoints of curves. Additional experiments showed that curvature effects on diameter judgments were not eliminated when stimuli were in the frontal plane or when the curves were explored with the use of two hands. Arm support had no effect on judged length in experiment 7. A final experiment showed a robust horizontal vertical illusion in haptic perception of convex curves, with overestimation of the heights of the curves compared with their widths. The practical and theoretical implications of the results are discussed.     

The influence of picture size on recognition and exploratory behaviour in raised-line drawings

We demonstrate the influence of picture size on haptic recognition and exploratory behaviour. The stimuli were raised-line drawings of everyday objects. Participants were instructed to think aloud during haptic exploration of the pictures. We measured the delay between initial correct speculation and final correct response. The results indicate that picture size influences accuracy but not response latency: large drawings are recognised more often but not faster. By analysing video recordings of the experiment we found that two-handed exploration increases when picture size increases and that, on average, 83% of the exploration time involves the use of two hands. The thinking-aloud data showed that the average time difference between the initial correct speculation and final correct response amounted to 23% of the total reaction time. We discuss our results with respect to the design of tactile aids and the ecological validity of single-finger exploration.     

Haptic curvature comparison of convex and concave shapes

A sculpture and the mould in which it was formed are typical examples of objects with an identical, but opponent, surface shape: each convex (ie outward pointing) surface part of a sculpture has a concave counterpart in the mould. The question arises whether the object features of opponent shapes can be compared by touch. Therefore, we investigated whether human observers were able to discriminate the curvatures of convex and concave shapes, irrespective of whether the shape was convex or concave. Using a 2AFC procedure, subjects had to compare the curvature of a convex shape to the curvature of a concave shape. In addition, results were also obtained for congruent shapes, when the curvature of either only convex shapes or only concave shapes had to be compared. Psychometric curves were fitted to the data to obtain threshold and bias results. When subjects explored the stimuli with a single index finger, significantly higher thresholds were obtained for the opponent shapes than for the congruent shapes. However, when the stimuli were touched by two index fingers, one finger per surface, we found similar thresholds. Systematic biases were found when the curvature of opponent shapes was compared: the curvature of a more curved convex surface was judged equal to the curvature of a less curved concave surface. We conclude that human observers had the ability to compare the curvature of shapes with an opposite direction, but that their performance decreased when they sensed the opponent surfaces with the same finger. Moreover, they systematically underestimated the curvature of convex shapes compared to the curvature of concave shapes.     

How age affects memory task performance in clinically normal hearing persons

The main objective of this study is to investigate memory task performance in different age groups, irrespective of hearing status. Data are collected on a short-term memory task (WAIS-III Digit Span forward) and two working memory tasks (WAIS-III Digit Span backward and the Reading Span Test). The tasks are administered to young (20–30 years, n = 56), middle-aged (50–60 years, n = 47), and older participants (70–80 years, n = 16) with normal hearing thresholds. All participants have passed a cognitive screening task (Montreal Cognitive Assessment (MoCA)). Young participants perform significantly better than middle-aged participants, while middle-aged and older participants perform similarly on the three memory tasks. Our data show that older clinically normal hearing persons perform equally well on the memory tasks as middle-aged persons. However, even under optimal conditions of preserved sensory processing, changes in memory performance occur. Based on our data, these changes set in before middle age.     

Replications and extensions in arousal assessment for sex offenders with developmental disabilities

Three adult male sex offenders with developmental disabilities participated in phallometric assessments that involved repeated measures of arousal when exposed to various stimuli. Arousal assessment outcomes were similar to those obtained by Reyes et al. (2006). Additional data-analysis methods provided further information about sexual preferences, thus replicating and extending previous research. The results provide preliminary data for establishing a preference gradient by age. Implications for the use of repeated measures and preference gradients in arousal assessments are discussed.     

A cross-cultural study of relationships between daily social interaction and the five-factor model of personality

Two studies, one in the United States (N = 130) and another in Germany (N = 100), examined relationships between daily social interaction and the traits of the Five-Factor Model. In both studies, student participants described their social interactions for 2 weeks using the Rochester Interaction Record. In both countries, Agreeableness and Conscientiousness were positively related to reactions to social interaction, whereas Neuroticism was unrelated to reactions to interactions. In the United States, Extraversion and Openness were positively related to reactions to interactions, whereas these factors were not related to reactions to interactions in Germany. In the United States, Extraversion was positively related to how socially active participants were, whereas none of the FFM traits was related to amount of social interaction in the German sample. In both countries, Extraversion was positively related to percent of interactions involving friends. The results highlight the importance of taking into account the sociocultural milieus within which personality unfolds.     

Matters of Interest: The Objects of Research in Science and Technoscience

This discussion paper proposes that a meaningful distinction between science and technoscience can be found at the level of the objects of research. Both notions intermingle in the attitudes, intentions, programs and projects of researchers and research institutions—that is, on the side of the subjects of research. But the difference between science and technoscience becomes more explicit when research results are presented in particular settings and when the objects of research are exhibited for the specific interest they hold. When an experiment is presented as scientific evidence which confirms or disconfirms a hypothesis, this agrees with traditional conceptions of science. When organic molecules are presented for their capacity to serve individually as electric wires that carry surprisingly large currents, this would be a hallmark of technoscience. Accordingly, we propose research on the ontology of research objects. The focus on the character and significance of research objects makes this a specifically philosophical project.     

Revisiting the African origins of attachment research—50 years on from Ainsworth: A descriptive review

Culture plays a significant role in the variations observed in the manifestation, expression, and meaning of attachment behaviors. Africa is home to multiple cultures, with distinct organizations of caregiving relationships underlying the development of attachment. This review aims to consolidate knowledge about African attachment by describing studies of infant attachment conducted in Africa since Mary Ainsworth's Ugandan findings in 1967. Electronic databases were searched with the terms “Africa” (“attachment” or “bond”) and “infant.” Nine studies that assessed infant attachment style with self-report or observation methods were included, but spanned only five countries. The Strange Situation Procedure was most frequently used. Most studies described dyads living in peri-urban or township areas. Multiple socioeconomic factors affecting living conditions were identified, including, unemployment, financial difficulties, limited education, poor housing, single parenthood, lack of partner support, substance abuse, and depression. Overall distributions of attachment classification proportions appear consistent with global attachment-classification patterns. Despite adverse conditions, secure attachment was relatively widespread, and some populations had low rates of avoidant attachment. Relatively high rates of disorganized attachment were found when the category was included. Africa remains an understudied continent regarding infant attachment. The continent's cultural diversity may hold important truths necessary for understanding the complex relationship between infant and attachment figure.