Perception and its neuronal mechanisms

A classic view of the relation between sensorineural activity and perception has assumed that the former is somehow transformed into the latter at some locus in the brain. This notion conflicts with the modern view that the activity of the nervous system is restricted to transmitting and processing information. It is suggested that the conflict may be resolved by considering perception as reflective activity rather than passive reception. This cognitive process entails information about the perceiving self and the general context and not merely the stimulus input. Some aspects of perception can be related to neuronal mechanisms and even to neuronal activity at specific loci. How is this done? By identifying the characteristics of the perceptual process and finding a necessary and sufficient neuronal mechanism that receives information about the stimulus input and can perform the implied computation. Examples are taken from the study of visual development in human infants.     

The development of separability in visual perception

Under conditions that do not allow focused attention, reports of illusory conjunctions (i.e. errors that wrongly recombine the features of different objects) constitute evidence of the separate registering of features at an early processing level. The occurrence of illusory conjunctions was used to determine whether there is preattentive analysis of component dimensions (colour and form) and of parts of shapes (triangles and arrows) in young children aged 5 to 8 years. Evidence of preattentive analysis was found, even for the youngest children, for colour and form but not for parts of shapes. Although developmental effects hardly reached significance, inspection of abilities assumed to affect the illusory conjunctions phenomenon suggests that at the preattentive stage children can integrate spatially separate segments but lack the capacity to fully analyse connected segments.     

Testing between the TRACE model and the fuzzy logical model of speech perception

The TRACE model of speech perception (McClelland & Elman, 1986) is contrasted with a fuzzy logical model of perception (FLMP) (Oden & Massaro, 1978). The central question is how the models account for the influence of multiple sources of information on perceptual judgment. Although the two models can make somewhat similar predictions, the assumptions underlying the models are fundamentally different. The TRACE model is built around the concept of interactive activation, whereas the FLMP is structured in terms of the integration of independent sources of information. The models are tested against test results of an experiment involving the independent manipulation of bottom-up and top-down sources of information. Using a signal detection framework, sensitivity and bias measures of performance can be computed. The TRACE model predicts that top-down influences from the word level influence sensitivity at the phoneme level, whereas the FLMP does not. The empirical results of a study involving the influence of phonological context and segmental information on the perceptual recognition of a speech segment are best described without any assumed changes in sensitivity. To date, not only is a mechanism of interactive activation not necessary to describe speech perception, it is shown to be wrong when instantiated in the TRACE model.     

Can we imagine how objects look from other viewpoints?

Many psychologists who study cognition believe that perception achieves object-centered representations that make it possible to extract representations of how the object would appear from differing viewpoints. Others believe we can achieve representations of how an object would appear by a process of visualization or mental rotation. We report experiments in which the subject tries to imagine how three-dimensional novel wire objects would appear from positions other than the one they are in. Subjects are unable to perform this task unless they make use of strategies that circumvent the process of visualization. It is suggested that the linear increase in time required to succeed in mental rotation tasks as a function of the angular discrepancy between the figures compared is the result of increasing difficulty rather than of the time required for rotation.     

Patterns of movement in the first 6 months of life: new directions

The field of infant perceptual development has relied heavily on the preferential-looking and habituation paradigms. Despite the obvious advantages of employing standardized methodologies, there is a need to study how perceptual variables give rise to and guide action beginning in the neonatal period. It is argued here that, in the first 5 months of life, it is important to distinguish reflexive patterns of movement from voluntary and cortically controlled patterns. Some criteria are defined. This paper describes three experiments which utilized movement counters to record developmental changes in the frequency and synchrony of limb movements in infants under 5 months. The results show that there is a general increase in frequency of limb movements from 1 to 5 months, but with a plateau or even a decrease in activity from the middle of the third month to the end of the fourth month. It was also demonstrated that synchrony scores (co-activation) for pairs of limbs showed significant increases from 1 month to 5 months. Finally, in all three experiments the presentation of an attractive toy resulted in suppression of activity. The results of the three experiments are interpreted to measure a gradual increase in cortically controlled movement patterns.     

Dynamic organization of intersensory function

Issues related to infant intersensory functioning are reviewed. The argument is offered that limitations of sensory inputs during early stages of development are necessary and provide structure and organization which determine behavioural characteristics at later stages. It is also suggested that infant organisms respond to the intensity of stimulation rather than organizational characteristics and that this is responsible for the form of sensory equivalence apparent during early development. A scheme for the investigation of sources of intersensory organization is presented which involves a prospective analysis of how consideration of the times of onset of sensory functions helps us to understand intra- and intersensory development. The advantages of this experimental approach are outlined.     

The composition of imaginal transformations

Three experiments examine the performance of composite imaginal spatial transformations using tasks in which people perform pairs of distinct imaginal transformations either in close succession or simultaneously. The principal aim of the investigation is to determine, for both modes of composition, whether imaginal transformations combine interactively or noninteractively to determine the temporal course of imaging performance. Specifically, does the time to imagine a given composite transformation reflect the independent contributions of its component transformations, or do component transformations have different effects within different composites? Results obtained under a number of distinct task conditions are most consistent with the proposal of noninteractive composition. However, the temporal effects of particular imaginal transformations are neither consistent nor readily predictable across different task conditions. Implications of these results for analogue-spatial models, task demand, and procedural accounts of imaging are discussed.     

Defining a family heritage and a new relationship identity: two central tasks in the making of a marriage

The roles of origin family environmental characteristics and couple consensus-building process within the development of marital relationships were examined prospectively in 16 premarital couples. Three important findings emerged. First, significant correlations were found between dimensions of origin family environment and the reported level of satisfaction within the couple's current relationship. Second, measures of the couple's ability to reach consensus concerning important interpersonal relationships appeared to be important mediators of the association between origin family environment and current relationship satisfaction. Third, important gender differences emerged that replicate and extend prior findings that portray women in the role of "relationship specialist" within their marriages. As a group, these findings were best explained by a developmental model of early marriage that envisions the young couple as facing two entwined tasks: to define both their family heritage and their new relationship identity. Overall, the importance of examining family-of-origin characteristics and consensus-building process as critical determinants of the fate of intimate relationships received strong support. The gender differences found in the literature reviewed, as well as the results of this study, have largely been overlooked by the theory and practice of family therapy. Efforts on both the research and theory construction fronts are needed to increase our understanding of the mechanisms whereby prior family experience is brought forward into current intimate relationships.     

Occupational choices of daughters of practicing rabbis

This paper examines the psychological impact that rabbis, as character types, have on their daughters. It describes how the father's impact psychologically predisposes these women to enter the helping professions in disporportionate numbers, and it shows how these job choices are often a means of coping with psychological issues connected to their upbringing.She is a candidate to become a psychoanalyst at the Chicago Center for Psychoanalytic Psychology.     

The final portrait of Christ

Artistic presentations of Jesus are as numerous and varied as the artists who created them. Whether on canvas or in music, Jesus has been portrayed as a redeemer, revolutionary, teacher, and clown. While some people are inspired by a particular presentation of Jesus, others are angered and incensed at what they perceive to be blasphemous. An example of the latter is Martin Scorsese's film, The Last Temptation of Christ. This article examines why people responded so negatively to this and other artistic presentations of Jesus. It suggests they have failed to recognize how the portrayal reflects a personal experience of the artist and is not meant to be a final portrait of Christ. And on a more unconscious level, these works of art evoke feelings within people which they fear to acknowledge and which they escape by condemning the work.