A sensorimotor account of vision and visual consciousness

Many current neurophysiological, psychophysical, and psychological approaches to vision rest on the idea that when we see, the brain produces an internal representation of the world. The activation of this internal representation is assumed to give rise to the experience of seeing. The problem with this kind of approach is that it leaves unexplained how the existence of such a detailed internal representation might produce visual consciousness. An alternative proposal is made here. We propose that seeing is a way of acting. It is a particular way of exploring the environment. Activity in internal representations does not generate the experience of seeing. The outside world serves as its own, external, representation. The experience of seeing occurs when the organism masters what we call the governing laws of sensorimotor contingency. The advantage of this approach is that it provides a natural and principled way of accounting for visual consciousness, and for the differences in the perceived quality of sensory experience in the different sensory modalities. Several lines of empirical evidence are brought forward in support of the theory, in particular: evidence from experiments in sensorimotor adaptation, visual "filling in," visual stability despite eye movements, change blindness, sensory substitution, and color perception.     

Longitudinal findings from the Normative Aging Study: III. Personality, individual health trajectories, and mortality

Individual differences in physical and psychological health trajectories were examined in 1,515 Normative Aging Study men. Mean age at baseline was 47.15 years (range = 28-80), and average follow up was 18.55 years (range = 8-25). Both linear and nonlinear growth curves were estimated with random-effects models and then clustered to identify patterns of change. Men whose physical health trajectories were characterized by high, increasing symptoms were higher in hostility and anxiety, were overweight, and smoked. Those whose trajectories were characterized by low symptoms were emotionally stable, educated, nonsmokers, and thin. Men with high, stable psychological trajectories had high hostility; those with low, stable trajectories had high emotional stability; those with moderate anxiety levels had nonlinear trajectories with peaks in psychological symptoms at different life stages. Personality had life-long effects on health trajectories, but these effects varied across traits and health outcomes.     

How golden hamsters (Mesocricetus auratus) discriminate top from bottom flank scents in over-marks

Using a habituation-discrimination paradigm, the authors investigated what cues male golden hamsters (Mesocricetus auratus) use to determine the top and bottom positions in flank gland over-marks. A difference in the ages of 2 hamsters' marks did not, by itself, produce differential memory or evaluation of the 2 scents. A spatial configuration of marks suggestive of an overlap was sufficient for the apparently overlapping scent to be remembered or valued more than the apparently underlying scent. Cues from the overlap of 2 hamsters' marks were also sufficient. These results, consistent with those previously found for responses to hamster vaginal scent over-marks, suggest that hamsters use similar cues to analyze scent over-marks that are different in chemical composition and in social functions.     

The use of bouts and frequencies in the evaluation of hand preferences for a coordinated bimanual task in chimpanzees (Pan troglodytes): an empirical study comparing two different indices of laterality

Hand preferences for a coordinated bimanual task were assessed in 109 chimpanzees (Pan troglodytes). Hand preference was evaluated for 4 test sessions using bouts and frequencies of hand use to compare the sensitivity of each level of analysis in evaluating individual variation in handedness. Overall, significant population-level right-handedness was found using several different measures of hand use. Handedness indices based on bouts and frequencies were highly and significantly correlated. Moreover, hand preferences were consistent across tests despite efforts to situationally bias preference during each test. Taken together, these data do not support the view that bouts are a better level of analysis for evaluating hand preference. The results further suggest that hand preferences for coordinated bimanual actions are not influenced by situational factors and may reflect an inherent specialization of the left hemisphere for motor skill.     

How tree shrews (Tupaia belangeri) perform in a searching task: evidence for strategy use

This study investigated how male tree shrews (Tupaia belangen) performed in a searching task while in their home cages and assessed whether different food distributions affected their performance. The animals were faced with a holeboard containing 9 food sources arranged in a 3 x 3 matrix or in 3 clusters, each containing 3 sources. Animals tended to start and end the trials from preferred locations, thereafter solving the task by strategically organizing the reward collection according to a minimum-distance principle. In the cluster configuration, they visited the sources hierarchically. Food distribution did not affect the performance. Comparison with data from mice and capuchin monkeys revealed that tree shrews and capuchins solved the task in a similar strategic way, whereas mice did not. These findings attract particular attention because of the phylogenetic position of tree shrews, which are regarded as closely related to primates.     

Runway width effects in the visual approach to landing

The effect of changes in runway width on the perception of glide-slope has been the subject of extensive investigations. Despite considerable research, an explanation of this effect has been elusive. A mathematical model for glide-slope perception was published recently based on the premise that a desirable goal of perception is to form a perception with minimal uncertainty. One of the qualitative predictions of that model was that changes in the aspect ratio of the runway would affect the perceived glide-slope. In this article, the predictions of the model are quantified and are shown to be in close agreement with experimental results in the literature.     

Knowledge gained by mothers enrolled in a home visitation program

This study examined whether new mothers would gain knowledge of child development after participating in a home visitation program for six months, and whether there would be differences between adolescent mothers and older mothers. Forty-seven mothers were administered the Knowledge Inventory of Development and Behavior: Infancy to School-age (KIDS) after the birth of their babies and six months later. Results indicated an overall increase in total knowledge of child development for mothers (of all ages) participating in a home visitation program. KIDS subscale scores indicated a significant increase in new mothers' knowledge about both infant and school-age development. There was no significant difference between the adolescent and older mothers in knowledge of infant development.     

Concurrent therapies: a model for collaboration between psychoanalysts and other therapists

Many psychoanalysts treat individuals who are simultaneously in couples therapy or whose partners are in individual therapy. If such cases stall, some analysts may seek consultation from a colleague, though most have accepted the tacit historical prohibition against communication between therapists treating members of the same family. Experience, however, suggests that a certain form of communication between such therapists can have a powerfully enhancing effect on the concurrent therapies. After a review of the literature, the advantages, disadvantages, and impediments to collaborative cross-communication are examined. A model is then presented for use in ongoing discussion between therapists, and is illustrated with two clinical examples. The proposed model centers on the transference-countertransference configurations within the therapeutic field, and serves as an organizer highlighting areas for discussion.