How obstructing is an obstacle? The influence of starting posture on obstacle avoidance

The introduction of non-target objects into a workspace leads to temporal and spatial adjustments of reaching trajectories towards a target. Currently, there are two different explanations for this phenomenon: the non-target objects are considered as either physical obstacles to which we maintain a preferred distance (see Tresilian, 1998) or as distractors that interfere with movement planning (see Tipper, Howard, & Jackson, 1997). These components are difficult to disentangle, however. Our aim was to determine the unique contribution of the avoidance of a physical obstacle to the adjustments of reaching trajectories. In this study, we manipulate the degree of physical obstruction by non-target objects while keeping the a priori visual layout of the workspace more or less constant. This is achieved by placing participants in different starting postures with respect to the orientation of their limb segments. Participants reach towards and grasp target objects with non-targets present in the workspace in a frontal and a lateral starting posture. In the frontal conditions participants showed larger movements away from the non-target on the ipsilateral side of the workspace than in the lateral conditions. The results provide evidence for the interpretation that non-targets influence the movement trajectory partly because they are 'obstructing'.     

Is the hand to speech what speech is to the hand?

Interference between the manual and the verbal performance on two types of concurrent verbal-manual tasks was studied on a sample of 48 female right-handers. The more complex verbal task (storytelling) affected both hands significantly, the less complex (essentially phonemic) task affected only the right hand, with insignificant negative influence on the left-hand performance. No significant reciprocal effects of the motor task on verbalization were found.     

Neuromuscular control of posture in the infant and child: is vision dominant?

This study explored the effects of vision and maturation on the characteristics of neuromuscular responses underlying balance control in both seated and standing children of five age groups (3 1/2-5 months, 8-14 months, 2-3 years, 4-6 years, and 7-10 years). A platform was used to unexpectedly disturb the child's balance in the anterior or posterior direction. Responses of the leg, trunk, and neck muscles were recorded using surface electromyograms. Vision was not required for the activation of these responses in any of the age groups tested. However, comparison of the muscle response latencies of standing children to posterior platform translation in the two visual conditions showed a significant reduction in latency for neck flexors in the 2- to 3-year-olds with vision removed and ann increase in the total number of monosynaptic reflexes. No reduction in latency was found in the older age groups. The hypothesis of a shift from an early long latency visual dominance to a shorter latency proprioceptive one during childhood is discussed. Postural control showed a cephalo-caudal developmental gradient with postural responses appearing first in the neck, then trunk, and finally, legs, as children developed from 3 to 14 months of age. A wide variety of response patterns was seen in the 3- to 5-month-olds, indicating that postural responses are not functional prior to experience with stabilizing the center of mass.     

What is chosen first,the hand used for reaching or the target that is reached?

Models of information processing generally assume that stimuli are processed before actions are selected, at least in typical laboratory experiments where stimuli are presented and responses follow. In everyday life, however, there are generally fewer constraints on the ordering of decisions pertaining to stimuli and actions. This raises the question of which sorts of decisions normally precede which others. To address this question, we asked participants to aim for either of two targets with either hand on the basis of whichever combination seemed easiest. We analyzed the choices made in this free condition with choices made when the hand was specified or when the target was specified. We found that a model assuming similar selection processes in the hand-specified condition and the free condition provided the best account for the data. The data accord with the hypothesis that hand was generally chosen first in the free-choice condition.     

Men and women holding hands: II. Whose hand is uppermost?

Sex differences in the way men and women hold hands were investigated in a series of six studies. Specifically, it was hypothesized that men would have the uppermost hand in male-female couples holding hands in public significantly more often than women. Also, the American couples observed in Study 1 were classified by height, those in Study 2 by age, those in Study 3 by hand preference, those in Study 4 by ethnic group, and those in Study 6 by sex of initiator of the handholding; the handholding couples in Study 5 were Japanese adults. A combined total of 15,008 handholding couples were observed in these six studies, and across differences in height, age, hand preference, ethnicity, culture, and sex of the initiator of handholding in public, men were significantly more likely than women to have the uppermost hand.     

Bimanual reaching across the hemispace: Which hand is yoked to which?

When both hands perform concurrent goal-directed reaches, they become yoked to one another. To investigate the direction of this coupling (i.e., which hand is yoked to which), the temporal dynamics of bimanual reaches were compared with equivalent-amplitude unimanual reaches. These reaches were to target pairs located on either the left or right sides of space; meaning that in the bimanual condition, one hand's contralateral (more difficult) reach accompanied by the other hand's ipsilateral (easier) reach. By comparing which hand's difficult reach was improved more by the presence of the other hand's easier ipsilateral reach, we were able to demonstrate asymmetries in the coupling. When the cost of bimanual reaching was controlled for the contralateral reaching left hand's performance was improved, suggesting that the left hand is yoked to the right during motor output. In contrast, the right hand showed the greatest improvements for contralateral reaching in terms of reaction time, pointing toward a dominant role for the left hand in the processes prior to movement onset. The results may point toward a mechanism for integrating the unitary system of attention with bimanual coordination.     

Corrections for extreme proportions and their biasing effects on estimated values ofd′

Estimatingd′ from extreme false-alarm or hit proportions (p = 0 orp = 1) requires the use of a correction, because thez score of such proportions takes on infinite values. Two commonly used corrections are compared by using Monte-Carlo simulations. The first is the 1/(2N) rule for which an extreme proportion is corrected by this factor befored′ is calculated. The second is the log-linear rule for which each cell frequency in the contingency table is increased by 0.5 irrespective of the contents of each cell. Results showed that the log-linear rule resulted in less biased estimates ofd′ that always underestimated populationd′. The 1/(2N) rule, apart from being more biased, could either over- or underestimate populationd′.     

Physical posture: Could it have regulatory or feedback effects on motivation and emotion?

Four studies were conducted in a laboratory setting to examine whether variations in physical posture can have a regulatory or feedback role affecting motivation and emotion. The results of the first study, which were replicated in the second study, revealed that subjects who had been temporarily placed in a slumped, depressed physical posture later appeared to develop helplessness more readily, as assessed by their lack of persistence in a standard learned helplessness task, than did subjects who had been placed in an expansive, upright posture; surprisingly, there were no differences in verbal reports. The third study established that physical posture was an important cue in observers' verbal reports of depression in another person. The fourth study further explored the role of posture in self-reports of emotion using another posture. The results indicated that subjects who were placed in a hunched, threatened physical posture verbally reported self-perceptions of greater stress than subjects who were placed in a relaxed position. The findings of these studies are interpreted in terms of self-perception theory. It is suggested that physical postures of the body are one of several types of cues that can affect emotional experience and behavior.The thanks of the authors are extended to Irving L. Janis, Myron Rothbart, and some previous anonymous reviewers for their helpful comments on this article.     

Keep your hands crossed: The valence-by-left/right interaction is related to hand,not side,in an incongruent hand–response key assignment

The body-specificity hypothesis (Casasanto, 2009) associates positive emotional valence and the space surrounding the dominant hand, and negative valence and the space surrounding the non-dominant hand. This effect has not only been found for manual responses, but also for the left and right side. In the present study, we investigated whether this compatibility effect still shows when hand and side carry incongruent information, and whether it is then related to hand or to side. We conducted two experiments which used an incongruent hand–response key assignment, that is, participants had their hands crossed. Participants were instructed to respond with their right vs. left hand (Experiment 1) or with the right vs. left key (Experiment 2). In both experiments, a compatibility effect related to hand emerged, indicating that the association between hand and valence overrides the one between side and valence when hand and side carry contradicting information.     

When meaning matters,look but don’t touch: The effects of posture on reading

Much of the reading that we do occurs near our hands. Previous research has revealed that spatial processing is enhanced near the hands, potentially benefiting several processes involved in reading; however, it is unknown whether semantic processing—another critical aspect of reading—is affected near the hands. While holding their hands either near to or far from a visual display, our subjects performed two tasks that drew on semantic processing: evaluation of the sensibleness of sentences, and the Stroop color-word interference task. We found evidence for impoverished semantic processing near the hands in both tasks. These results suggest a trade-off between spatial processing and semantic processing for the visual space around the hands. Readers are encouraged to be aware of this trade-off when choosing how to read a text, since both kinds of processing can be beneficial for reading.     

Do conversational hand gestures communicate?

In 5 experiments, male and female undergraduates viewed gestures and tried to select the words that originally accompanied them; read interpretations of gestures' meanings and tried to select the words that originally had accompanied them; tried to recognize gestures they previously had seen, presented either with or without the accompanying speech; and assigned gestures and the accompanying speech to semantic categories. On all 4 tasks, performance was better than chance but markedly inferior to performance when words were used as stimuli. Judgments of a gesture's semantic category were determined principally by the accompanying speech rather than gestural form. It is concluded that although gestures can convey some information, they are not richly informative, and the information they convey is largely redundant with speech.     

Are juvenile offenders extreme future discounters?

It has been the prevailing view that young offenders are more present oriented than their peers, but this view has little empirical basis other than the actions that have defined these youth as offenders. In the present study, we used a decision task with actual monetary consequences to assess the tendency of young offenders and a control group of high school students to discount the future. The young offenders were not significantly different from the students in discounting the future, even though the young offenders scored significantly higher on a sensation-seeking personality scale, were less likely to have lived with their fathers, and had changed schools more often. Young offenders and control participants were also similar in the extent to which they manifested a clear vision of the future by anticipating which future milestones would occur sooner, in a task pairing milestones with each other and with year markers.     

Comment on Paul Boghossian, “What is inference”

This is a response to Paul Boghossian’s paper: What is inference? (doi:10.1007/s11098-012-9903-x). The paper and the abstract originate from a symposium at the Pacific Division Meeting of the APA in San Diego in April 2011. John Broome was a co-commentator.     

“Openness and progress with communication and confidence have all gone hand in hand”: Reflections on the experience of transitioning between concealment and openness among adults who stutter

PurposeThe purpose of this study was to gain a deeper understanding of the experience of people who stutter as they navigate through the growth process from concealment to openness.MethodTwelve adults who stutter who are active in self-help/support groups for stuttering described their experiences of concealment and openness in a semi-structured interview. Purposeful selection was utilized to recruit participants who could comment thoughtfully on previous concealing, but became more open about their stuttering. A phenomenological approach was utilized to gain a deeper understanding of how people who stutter experience the transition from concealment to openness regarding their stuttering and identity. Thematic analysis contributed to identification of themes and subthemes describing participants’ experiences.ResultsParticipants described precursors to concealment that led to hiding and avoidance, which grew in strength until they reached a turning point. They then changed how they related to their stuttering by changing their behaviors and perceptions of stuttering, which led to increased openness about their identity. This process of continued adaptation to stuttering was ongoing and non-linear, but suggested general trends from concealment to more openness over time. Level of openness was impacted by situational context and individual differences.ConclusionsThe findings extend our understanding of how people who stutter navigate transitions from concealment to openness. This deeper understanding could be helpful in explaining the complexities involved in managing the identity of a person who stutters, and the process of adapting to living with stuttering over time.     

The long way to “extreme psychologism”

In “Clearing Space for Extreme Psychologism about Reasons”, Mitova argues against two main views about the ontology of reasons. Instead, she presents an argument by elimination for “extreme psychologism” as a prima facie superior alternative. I will argue for the following claims. First, the case against the Standard Story – the view that normative and motivating reasons are facts and psychological states, respectively – includes premises that are in need of support. Second, the critical examination of factualism – the view that normative and motivating reasons are facts – misses a relevant distinction between motivating and explanatory reasons. This distinction brings new resources to factualism to answer the raised worries. Third, the case for extreme psychologism rests on a requirement that is either too easy to threaten other alternatives, or so strong as to challenge extreme psychologism itself.