Grasping movement plans

Despite the great amount of research that has been done regarding the time it takes to move the hand to targets of varying distances and widths, it is unclear whether target distance and width are both represented in movement plans prior to movement initiation. We addressed this question by studying performance in an object manipulation task. Our participants reached out and took hold of a familiar object (a bathroom plunger) to move it to wide or narrow targets of varying heights. Grasp heights on the plunger were additively affected by target height and target width, suggesting that both factors were taken into account by participants prior to moving the plunger from its initial position. Another factor we manipulated was the width of the base from which the plunger was lifted on its way to its next position. This factor also affected grasp heights, but no more so than target widths. The latter result contradicts the view that movement starts are planned in more detail than movement ends, as might be expected from the fact that movement starts come sooner. Together, our results suggest that forthcoming movements are planned in considerable detail. A surprising methodological implication of this study is that recording how people prepare to move can reveal as much—or in some cases more—about what they have planned than can recording their subsequent movements.     

Audiovisual tau effect

This study investigated how spatial intervals between successive visual flashes are influenced by the temporal intervals between auditory pure tones presented concurrently with the flashes. Three successive visual flashes defined two spatial intervals with different extents as well as two equal temporal intervals. The onsets of the first and third tones were temporally aligned with those of the first and third flashes, while the onset of the second tone was temporally offset to that of the second visual flash, resulting in shorter or longer temporal intervals between pairs of tones. Observers judged which of the first or second spatial intervals between flashes was shorter. The results showed that the shorter temporal interval between tones caused underestimation of the spatial interval between flashes. On the other hand, stimuli without the first and third tones did not result in underestimation of spatial intervals between flashes. These results indicate an audiovisual tau effect, which is triggered by a constant velocity assumption applied to moving objects defined by more than one modality.     

A Further Study of Grasping

The aim of the present study is to examine prospectively the quality of social networks of Hong Kong Chinese adults. A randomized household survey was employed. A total of 1170 Hong Kong Chinese respondents were recruited to the study. Participants ranged in age from 18 to 79 years, 43% of respondents were male. Findings revealed a negative association between familial trust and social network size. Network trust, social identification, and structural networks were all found to be positively associated with social network size and perceived respect from social network. The importance of family and the prioritization of the needs of the family over individual needs has implications on social network size and formation for Hong Kong Chinese individuals. More research is needed to further examine the importance of familial relationships and the prioritization of family and the impact this has on social network development and maintenance among Hong Kong Chinese.     

Grasping spheres,not planets

Memory for objects helps us to determine how we can most effectively and appropriately interact with them. This suggests a tightly coupled interplay between action and background knowledge. Three experiments demonstrate that grasping circumference can be affected by the size of a visual stimulus (Experiment 1), whether that stimulus appears to be graspable (Experiment 2), and the presence of a label that renders that object ungraspable (Experiment 3). The results are taken to inform theories on conceptual representation and the functional distinction that has been drawn between the visual systems for perception and action.     

Grasping the Nature of Pictures

The role of experience in the development of pictorial competence has been the center of substantial debate. The four studies presented here help resolve the controversy by systematically documenting and examining manual exploration of depicted objects by infants. We report that 9-month-old infants manually investigate pictures, touching and feeling depicted objects as if they were real objects and even trying to pick them up off the page. The same behavior was observed in babies from two extremely different societies (the United States and the Ivory Coast). This investigation of pictures occurs even though infants can discriminate between real objects and their depictions. By the time infants are 19 months of age, their manual exploration is replaced by pointing at depicted objects. These results indicate that initial uncertainty about the nature of pictures leads infants to investigate them. Through experience, infants begin to acquire a concept of "picture." This concept includes the fact that a picture has a dual nature (it is both an object and a representation of something other than itself), as well as knowledge about the culturally appropriate use of pictures.     

把握当代心理学的发展趋势

本文认为,开展心理学的科学研究与学术交流,必须把握当代心理学的发展趋势,作者提出当前的主要趋势是：1．心理学的综合化;2．心理学的本土化或中国化;3．心理学的实用化     

Grasping the concept of personal property

The concept of property is integral to personal and societal development, yet understanding of the cognitive basis of ownership is limited. Objects are the most basic form of property, so our physical interactions with owned objects may elucidate nuanced aspects of ownership. We gave participants a coffee mug to decorate, use and keep. The experimenter also designed a mug of her own. In Experiment 1, participants performed natural lifting actions with each mug. Participants lifted the Experimenter’s mug with greater care, and moved it slightly more towards the Experimenter, while they lifted their own mug more forcefully and drew it closer to their own body. In Experiment 2, participants responded to stimuli presented on the mug handles in a computer-based stimulus–response compatibility task. Overall, participants were faster to respond in trials in which the handles were facing in the same direction as the response location compared to when the handles were facing away. The compatibility effect was abolished, however, for the Experimenter’s mug – as if the action system is blind to the potential for action towards another person’s property. These findings demonstrate that knowledge of the ownership status of objects influences visuomotor processing in subtle and revealing ways.     

A computational procedure for tau correlation

Thetau coefficient is defined, and a computational procedure for tied ranks is described. The procedure maintains continuous computational checks, saves labor, and particularly facilitates the use oftau with large samples. It is also shown howtau correlation may be applied toQ-sorts with any shape of forced distribution or with unforced distributions.The procedure described was developed in connection with research at the Counseling Center, University of Chicago. The research is supported by a grant (PHS M 903) from the National Institute of Mental Health, of the National Institutes of Health, Public Health Service.     

The Role of Consciousness in Grasping and Understanding

One sometimes believes a proposition without grasping it. For example, a complete achromat might believe that ripe tomatoes are red without grasping this proposition. My aim in this paper is to shed light on the difference between merely believing a proposition and grasping it. I focus on two possible theories of grasping: the inferential theory, which explains grasping in terms of inferential role, and the phenomenal theory, which explains grasping in terms of phenomenal consciousness. I argue that the phenomenal theory is more plausible than the inferential theory.     

Grasping of extrafoveal targets: A robotic model

We present a computational model of grasping of non-fixated (extrafoveal) target objects which is implemented on a robot setup, consisting of a robot arm with cameras and gripper. This model is based on the premotor theory of attention (Rizzolatti et al., 1994) which states that spatial attention is a consequence of the preparation of goal-directed, spatially coded movements (especially saccadic eye movements). In our model, we add the hypothesis that saccade planning is accompanied by the prediction of the retinal images after the saccade. The foveal region of these predicted images can be used to determine the orientation and shape of objects at the target location of the attention shift. This information is necessary for precise grasping. Our model consists of a saccade controller for target fixation, a visual forward model for the prediction of retinal images, and an arm controller which generates arm postures for grasping. We compare the precision of the robotic model in different task conditions, among them grasping (1) towards fixated target objects using the actual retinal images, (2) towards non-fixated target objects using visual prediction, and (3) towards non-fixated target objects without visual prediction. The first and second setting result in good grasping performance, while the third setting causes considerable errors of the gripper orientation, demonstrating that visual prediction might be an important component of eye–hand coordination. Finally, based on the present study we argue that the use of robots is a valuable research methodology within psychology.     

Mouthing and Grasping of Objects by Young Infants

Mouthing and grasping objects are two common behaviors observed in young infants, although little is known about the relations between these activities. Data from two previously published experiments on 4- to 8-month-old infants (N = 133) are further analyzed to investigate if: (a) variation in object size and shape influences whether objects are mouthed after being picked up, and (b) infants modify their grip configurations in order to mouth objects as opposed to performing other prehensile actions. The results showed that larger objects increased the propensity of young infants to mouth objects; object size also contributed to differentiating the grip configuration according to the intent of the action. The findings suggest that infants as young as 4 months perceive that object properties afford different actions and differentiate grip configurations to realize specific task goals.     

Grasping the pain: Motor resonance with dangerous affordances

Two experiments, one on school-aged children and one on adults, explored the mechanisms underlying responses to an image prime (hand vs. control object) followed by graspable objects that were, in certain cases, dangerous. Participants were presented with different primes (a male, a female and a robotic grasping-hand; a male and a female static-hand; a control stimulus) and objects representing two risk levels (neutral and dangerous). The task required that a natural/artifact categorization task be performed by pressing different keys. In both adults and children graspable objects activated a facilitating motor response, while dangerous objects evoked aversive affordances, generating an interference-effect. Both children and adults were sensitive to the distinction between biological and non-biological hands, however detailed resonant mechanisms related to the hand-prime gender emerged only in adults. Implications for how the concept of “dangerous object” develops and the relationship between resonant mechanisms and perception of danger are discussed.     

Grasping the nettle: gay men's experiences in therapy

Qualitative research was carried out into gay men's experiences of being in therapy. One of the findings was that, while the overall experience of being in therapy was usually perceived to be helpful, the experience of discussion of areas relating to the clients’ experience of their sexuality was not. A common reaction was that this aspect of their experience had been silenced or not adequately explored. This finding gives rise to a consideration of what 'gay-affirmative' counselling means – and in particular to the ideas of whether affirmative counselling can be implicit or must involve a more active stance on the part of the therapist. These differing approaches and the implications which arise are discussed.