Development of form similarity as a Gestalt grouping principle in infancy

Given evidence demonstrating that infants 3 months of age and younger can utilize the Gestalt principle of lightness similarity to group visually presented elements into organized percepts, four experiments using the familiarization/novelty-preference procedure were conducted to determine whether infants can also organize visual pattern information in accord with the Gestalt principle of form similarity. In Experiments 1 and 2, 6- to 7-month-olds, but not 3- to 4-month-olds, presented with generalization and discrimination tasks involving arrays of X and O elements responded as if they organized the elements into columns or rows based on form similarity. Experiments 3 and 4 demonstrated that the failure of the young infants to use form similarity was not due to insufficient processing time or the inability to discriminate between the individual X and O elements. The results suggest that different Gestalt principles may become functional over different time courses of development, and that not all principles are automatically deployed in the manner originally proposed by Gestalt theorists.

A gestalt-experiential perspective on resistance

The authors present background on the gestalt-experiential understanding of resistance, conceptualized to be either resistance to awareness or resistance to contact. The authors discuss why they do not use the term resistance and describe the phenomena as a client's self-protective attempt to avoid the anxiety necessitated by change. Such resistant behaviors occur outside a client's awareness and often result in an ambivalence or conflict about change. The authors also describe using in-session experiments as a way to engage with the client in exploring such a state of ambivalence or conflict. Finally, they respond to the case studies presented elsewhere in this issue and propose intervention strategies consistent with the gestalt-experiential perspective.

A case illustration of resistance from a gestalt-experiential perspective

The case of Victoria illustrates psychotherapy with a woman faced with a difficult and unexpected divorce. The authors present a summary of typical struggles faced by Victoria through three phases of therapy. The therapy focused initially on coping with the divorce, then moved to work on her career dissatisfaction, and finally to her efforts to develop a new relationship. The case presentation illustrates resistance as it manifested itself in both a behavioral manner and as in-session resistance to awareness of internal states. The behavioral mode of resistance is manifested by her inability to follow through on decisions made in therapy sessions and by her interruptions of ongoing therapy. A transcript of a typical in-session exchange illustrates the resistance to awareness. The authors also describe interventions intended to work with the resistance.

[Concepts of anthropological medicine]

Medical anthropology is the teaching of the ill human being, of being ill; anthropological medicine is the realization of this teaching in practice. This concept was first developed and assessed in the "Gestaltkreis" and in the Pathosophy (44), in Medicine in Motion (39), and in the Bipersonality (10). The four most important concepts are represented, which have their origin and aim in anthropological medicine: anthropological medicine, Balint-work, family-oriented medicine, and salutogenesis. These concepts are exemplified in the Aachen psychosomatic liaison model, the Aachen Balint cooperation model, and the Aachen model of psychosomatic care. We wish to portray the meaning of these resources for the medicine of the future, since they have proven to be effective, cost-saving, and easy to be handled. In the latter part of our presentation, we will document this point with a pilot study conducted in Israel and in our own clinic in Aachen.

Detecting change in patients with stroke using the Berg Balance Scale

The Berg Balance Scale (BBS) was designed to help determine change in functional standing balance over time. The purpose of this paper was to estimate the minimum detectable change score (MDC) using the standard error of measure (SEM), thereby providing a means to decide if genuine change had occurred. Calculation of the agreement regarding the presence of change as determined by the MDC and clinicians' perceptions was performed to give an indication of the validity of this criterion value. Forty-eight subjects who were receiving inpatient rehabilitation after stroke were assessed on consecutive days by two raters using the BBS. The MDC analysis suggests that a change of +/- 6 BBS points is necessary to be 90% confident of genuine change. Only 25/45 subjects showed agreement between the statistically derived presence of change and clinicians' perceptions of change. The lack of agreement may relate to the validity of the SEM/MDC methodology to determine the criterion BBS value, the heterogeneity of the subjects, or the use of clinician gestalt impressions of change.

On the reality of the incorporeal intelligibles: a reflection on the metaphysics of psychology

An argument is made for the existence of entities which are neither necessarily material nor mental as real and which are apprehensible and generatable by human beings. Money, color, triangle, natural and social law, instruction, danger, and invention are given as examples. It is the task of the science of psychology to grasp, conceptualise, and characterise the human being that lives in a world of incorporeal intelligibles and makes them as well. The tradition of Aristotle, Brentano and his two students, Freud and Husserl, and Wertheimer is identified favorably in this connection.

Visual inter-attribute contour completion

A new visual phenomenon, inter-attribute illusory (completed) contours, is demonstrated. Contour completions are perceived between any combination of spatially separate pairs of inducing elements (Kanizsa-like 'pacman' figures) defined either by pictorial cues (luminance contrast or offset gratings), temporal contrast (motion, second-order-motion or 'phantom' contours), or binocular-disparity contrast. In a first experiment, observers reported the perceived occurrence of contour completion for all pair combinations of inducing elements. In a second experiment they rated the perceived clarity of the completed contours. Both methods generated similar results contour completions were perceived even though the inducing elements were defined by different attributes. Ratings of inter-attribute clarity were no lower than in either of the two corresponding intra-attribute conditions and seem to be the average of these two ratings. The results provide evidence for the existence of attribute-invariant Gestalt processes, and on a mechanistic level indicate that the completion process operates on attribute-invariant contour detectors.

[Gestalt theory of V. v. Weizsäcker from the viewpoint of the psychology emotions]

The "Gestaltkreis" represents an important part in the psychosomatic theory-discussion, which can be understood as an incomplete contribution towards a general theory of emotions. Especially the relationship between perception and motion requires further consideration. Instead of a causal attribution, cyclic complementaries are important. Furthermore different degrees of organisation within the body-scheme and the affect-apparatus are mentioned.

Approaches to learning spatial relationships in gross anatomy: perspective from wider principles of learning

When students learn spatial relationships in gross anatomy, as in other areas of study, fundamentals should be learned first; otherwise confusion results. The fundamentals in gross anatomy are defined not in conceptual terms but by principles of visual perception. In particular, they derive from Gestalt principles such as collinearity and symmetry, which generally make learning and recognition of visual patterns easier. The collinearity (straight line formations) and symmetry in the body cavities are obvious when one studies the empty cavities, or body cavities with only a few symmetrical structures in place. These principles are, however, totally obscured if one starts one's study, as in traditional dissection, with the body cavities crammed full of a complex mass of interlocking organs. and their ducts, vessels, etc. Therefore, it is recommended that learning gross anatomy (especially of the body cavities) would be an easier exercise if it started with empty body cavities, then building up, with a careful sequence of prosections, to the more complex and realistic anatomy of the full cavities. This system of learning is perceptually preferable to traditional dissection. However, it needs to be enlivened in several ways, e.g., with respect to design principles evident in anatomical structure (especially for the musculoskeletal system), developmental processes, and sometimes by explicit reference to clinical relevance.

[Heautoscopy. Delusions of a double and rare hallucinations of personal gestalt]

In the psychiatric literature, the phenomenon of the doppelganger or double is characterized into different types of delusional misidentification syndromes and heautoscopic symptoms. Specifically, we focus attention on heautoscopy, which might also be named "dissociative" after excluding an organic etiology. We report a case of heautoscopy in a woman and discuss the clinical variability of this psychopathological phenomenon. Furthermore, a short treatment of the historical and literary implications of this delusion is presented.

Purely temporal figure-ground segregation

Visual figure-ground segregation is achieved by exploiting differences in features such as luminance, colour, motion or presentation time between a figure and its surround. Here we determine the shortest delay times required for figure-ground segregation based on purely temporal features. Previous studies usually employed stimulus onset asynchronies between figure- and ground-containing possible artefacts based on apparent motion cues or on luminance differences. Our stimuli systematically avoid these artefacts by constantly showing 20 x 20 'colons' that flip by 90 degrees around their midpoints at constant time intervals. Colons constituting the background flip in-phase whereas those constituting the target flip with a phase delay. We tested the impact of frequency modulation and phase reduction on target detection. Younger subjects performed well above chance even at temporal delays as short as 13 ms, whilst older subjects required up to three times longer delays in some conditions. Figure-ground segregation can rely on purely temporal delays down to around 10 ms even in the absence of luminance and motion artefacts, indicating a temporal precision of cortical information processing almost an order of magnitude lower than the one required for some models of feature binding in the visual cortex [e.g. Singer, W. (1999), Curr. Opin. Neurobiol., 9, 189-194]. Hence, in our experiment, observers are unable to use temporal stimulus features with the precision required for these models.

Gestalt perception modulates early visual processing

We examined whether early visual processing reflects perceptual properties of a stimulus in addition to physical features. We recorded event-related potentials (ERPs) of 13 subjects in a visual classification task. We used four different stimuli which were all composed of four identical elements. One of the stimuli constituted an illusory Kanizsa square, another was composed of the same number of collinear line segments but the elements did not form a Gestalt. In addition, a target and a control stimulus were used which were arranged differently. These stimuli allow us to differentiate the processing of colinear line elements (stimulus features) and illusory figures (perceptual properties). The visual N170 in response to the illusory figure was significantly larger as compared to the other collinear stimulus. This is taken to indicate that the visual N170 reflects cognitive processes of Gestalt perception in addition to attentional processes and physical stimulus properties.

Empirical and hermeneutic approaches to phenomenological research in psychology: a comparison

Empirical phenomenology and hermeneutic phenomenology, the 2 most common approaches to phenomenological research in psychology, are described, and their similarities and differences examined. A specific method associated with each form of phenomenological inquiry was used to analyze an interview transcript of a woman's experience of work-family role conflict. A considerable degree of similarity was found in the resulting descriptions. It is argued that such convergence in analyses is due to the human capacities of reflection and intuition and the presence of intersubjective meanings. The similarity in the analyses is also encouraging about researchers' ability to reveal meaning despite the use of different methods and the difficulties associated with interpreting meaning.

Edge co-occurrence in natural images predicts contour grouping performance

The human brain manages to correctly interpret almost every visual image it receives from the environment. Underlying this ability are contour grouping mechanisms that appropriately link local edge elements into global contours. Although a general view of how the brain achieves effective contour grouping has emerged, there have been a number of different specific proposals and few successes at quantitatively predicting performance. These previous proposals have been developed largely by intuition and computational trial and error. A more principled approach is to begin with an examination of the statistical properties of contours that exist in natural images, because it is these statistics that drove the evolution of the grouping mechanisms. Here we report measurements of both absolute and Bayesian edge co-occurrence statistics in natural images, as well as human performance for detecting natural-shaped contours in complex backgrounds. We find that contour detection performance is quantitatively predicted by a local grouping rule derived directly from the co-occurrence statistics, in combination with a very simple integration rule (a transitivity rule) that links the locally grouped contour elements into longer contours.

On a common circle: natural scenes and Gestalt rules

To understand how the human visual system analyzes images, it is essential to know the structure of the visual environment. In particular, natural images display consistent statistical properties that distinguish them from random luminance distributions. We have studied the geometric regularities of oriented elements (edges or line segments) present in an ensemble of visual scenes, asking how much information the presence of a segment in a particular location of the visual scene carries about the presence of a second segment at different relative positions and orientations. We observed strong long-range correlations in the distribution of oriented segments that extend over the whole visual field. We further show that a very simple geometric rule, cocircularity, predicts the arrangement of segments in natural scenes, and that different geometrical arrangements show relevant differences in their scaling properties. Our results show similarities to geometric features of previous physiological and psychophysical studies. We discuss the implications of these findings for theories of early vision.

Detecting collinear dots in noise

We estimated the sensitivity for detecting a row of collinear target elements (usually dots) by measuring the maximum density of randomly positioned noise elements that allowed 75% correct detection of the orientation of alignment (binary choice: horizontal versus vertical) of the target elements. We varied the number of target elements, their mode of generation, and their accuracy of positioning. As reported previously (Moulden (1994) Higher-order processing in the visual system. Ciba Foundation Symposium 184. Chichester: Wiley), target detection improved rapidly until the number of target elements reached about seven, and then improved more slowly beyond this point. However, this break was reduced (and often removed entirely) when the target array was formed by repositioning pre-existing noise elements lying close to the target location, rather than by superimposition of additional target elements onto the noise array. This almost linear slope of improvement, coupled with the observation that target detection was disrupted more by random jitter of target elements at right angles to their axis of alignment than by jittering along this axis, argues against a two-stage process of perceptual grouping (Moulden, 1994) and supports instead an explanation based on the operation of a single mechanism. This single mechanism explanation is further supported by the observation that intrinsic positional uncertainty (estimated from the results of jitter experiments) was independent of target element number. Additional experiments showed that target detection is facilitated by aperiodic noise dots that fall close to the target axis. The results are discussed in relation to alternative explanations of perceptual grouping.

Simplicity versus likelihood in visual perception: from surprisals to precisals

The likelihood principle states that the visual system prefers the most likely interpretation of a stimulus, whereas the simplicity principle states that it prefers the most simple interpretation. This study investigates how close these seemingly very different principles are by combining findings from classical, algorithmic, and structural information theory. It is argued that, in visual perception, the two principles are perhaps very different with respect to the viewpoint-independent aspects of perception but probably very close with respect to the viewpoint-dependent aspects which, moreover, seem decisive in everyday perception. This implies that either principle may have guided the evolution of visual systems and that the simplicity paradigm may provide perception models with the necessary quantitative specifications of the often plausible but also intuitive ideas provided by the likelihood paradigm.

The visual cortical association field: a Gestalt concept or a psychophysiological entity?

The receptive field of a visual neurone is classically defined as the region of space (or retina) where a visual stimulus evokes a change in its firing activity. Intracellular recordings in cat area 17 show that the visually evoked synaptic integration field extends over a much larger area than that established on the basis of spike activity. Synaptic depolarizing (dominant excitation) responses decrease in strength for stimuli that are flashed at increasing distances away from the centre of the discharge field, while their onset latency increases. A detailed spatio-temporal analysis of these electrophysiological data shows that subthreshold synaptic responses observed in the 'silent' surround of cortical receptive fields result from the intracortical spread of activation waves carried by slowly conducting horizontal axons within primary visual cortex. They also predict that a perceptual facilitation may occur when feedforward activation produced by the motion signal in the retina travels in phase in the primary visual cortex with the visually induced spread of horizontal activation. A psychophysical correlate has been obtained in humans, showing that apparent motion produced by a sequence of co-linear Gabor patches, known to preferentially activate V1 orientation selective cells, are perceived by human observers as much faster than non co-linear sequences of the same physical speed.

Object memory effects on figure assignment: conscious object recognition is not necessary or sufficient

In three experiments we investigated whether conscious object recognition is necessary or sufficient for effects of object memories on figure assignment. In experiment 1, we examined a brain-damaged participant, AD, whose conscious object recognition is severely impaired. AD's responses about figure assignment do reveal effects from memories of object structure, indicating that conscious object recognition is not necessary for these effects, and identifying the figure-ground test employed here as a new implicit test of access to memories of object structure. In experiments 2 and 3, we tested a second brain-damaged participant, WG, for whom conscious object recognition was relatively spared. Nevertheless, effects from memories of object structure on figure assignment were not evident in WG's responses about figure assignment in experiment 2, indicating that conscious object recognition is not sufficient for effects of object memories on figure assignment. WG's performance sheds light on AD's performance, and has implications for the theoretical understanding of object memory effects on figure assignment.

Magnetic brain activity evoked and induced by visually presented words and nonverbal stimuli

Evoked and induced magnetic brain activity measured over the left hemisphere were tested for their specificity to language-related processing. Induced activity refers to oscillatory alterations time locked but not phase locked to the stimulus. Words, false font stimuli, and two types of nonverbal patterns were presented visually while subjects performed a nonlinguistic visual feature detection task. The comparison of evoked and induced brain activity around 200 ms after stimulus onset revealed differential sensitivity to the stimuli. The M180 component of the evoked magnetic field was larger at the processing of words and false font stimuli compared with nonverbal stimuli. The induced magnetic brain activity in the 60-Hz band at a compatible latency range was correlated with the familiarity of the visual Gestalt. Sensitivity to language-specific information processing can be concluded if a parameter differentiates the word condition from the nonlexical conditions. Such a difference was observed at sensors located over the frontal-temporal scalp regions for induced but not evoked magnetic brain activity. Thus, evoked and induced magnetic brain activity revealed a differential sensitivity to elements of cognitive processing during the given task.

[Rethinking nursing education and investing in persons: various contributions to the gestalt approach]

Despite the widespread emphasis on human wholeness, the training of health professionals has privileged technical competence, desconsidering the need to strengthen the person's process of inner growth. The purpose of this article is to reflect on the importance of a person's development as a basic tool of one's own work. The authors consider that there is no way to separate the personal from the professional dimension since each person interacts as a totality. Thus, the person exists in the professional Being or, dialectically speaking, the professional integrates the human being that it really is. These considerations, which are fundamental to each one's development, usually are not part of one's life, personal or professional learning. It is necessary to make this an essential part of nursing training, broadening the possibilities of integrating and transcending either side of the person, by introducing an holistic approach which contemplates the human being development in an integral and integrated way.

Contextual fear, gestalt memories, and the hippocampus

This review examines the relationship between exploration and contextual fear conditioning. The fear acquired to places or contexts associated with aversive events is a form of Pavlovian conditioning. However, an initial period of exploration is necessary to allow the animal to form an integrated memory of the features of the context before conditioning can take place. The hippocampal formation plays a critical role in this process. Cells within the dorsal hippocampus are involved in the formation, storage and consolidation of this integrated representation of context. Projections from the subiculum to the nucleus accumbens regulate the exploration necessary for the acquisition of information about the features of the context. This model explains why electrolytic but not excitotoxic lesions of the dorsal hippocampus cause enhanced exploratory activity but both cause deficits in contextual fear. It also explains why retrograde amnesia of contextual fear is greater than anterograde amnesia.