The timing of meals

In most individuals, food intake occurs as discrete bouts or meals, and little attention has been paid to the factors that normally determine when meals will occur when food is freely available. On the basis of experiments using rats, the authors suggest that when there are no constraints on obtaining food and few competing activities, 3 levels of interacting controls normally dictate when meals will start. The first is the genetically determined circadian activity pattern on which nocturnal animals tend to initiate most meals in the dark. The second is the regularly occurring changing of the light cycle: These changes provide temporal anchors. The third relates to the size of the preceding meal, such that larger meals cause a longer delay until the onset of the next meal. Superimposed on these 3 are factors related to learning, convenience, and opportunity.     

A six-factor structure of personality-descriptive adjectives: solutions from psycholexical studies in seven languages

Standard psycholexical studies of personality structure have produced a similar 6-factor solution in 7 languages (Dutch, French, German, Hungarian, Italian, Korean, Polish). The authors report the content of these personality dimensions and interpret them as follows: (a) a variant of Extraversion, defined by sociability and liveliness (though not by bravery and toughness); (b) a variant of Agreeableness, defined by gentleness, patience, and agreeableness (but also including anger and ill temper at its negative pole); (c) Conscientiousness (emphasizing organization and discipline rather than moral conscience); (d) Emotionality (containing anxiety, vulnerability, sentimentality, lack of bravery, and lack of toughness, but not anger or ill temper); (e) Honesty-Humility; (f) Intellect/Imagination/Unconventionality. A potential reorganization of the Big Five factor structure is discussed.     

The interpersonal effects of anger and happiness in negotiations

Three experiments investigated the interpersonal effects of anger and happiness in negotiations. In the course of a computer-mediated negotiation, participants received information about the emotional state (anger, happiness, or none) of their opponent. Consistent with a strategic-choice perspective, Experiment 1 showed that participants conceded more to an angry opponent than to a happy one. Experiment 2 showed that this effect was caused by tracking--participants used the emotion information to infer the other's limit, and they adjusted their demands accordingly. However, this effect was absent when the other made large concessions. Experiment 3 examined the interplay between experienced and communicated emotion and showed that angry communications (unlike happy ones) induced fear and thereby mitigated the effect of the opponent's experienced emotion. These results suggest that negotiators are especially influenced by their opponent's emotions when they are motivated and able to consider them.     

Reduction of left visual field lexical decision accuracy as a result of concurrent nonverbal auditory stimulation

To investigate whether concurrent nonverbal sound sequences would affect visual-hemifield lexical processing, lexical-decision performance of 24 strongly right-handed students (12 men, 12 women) was measured in three conditions: baseline, concurrent neutral sound sequence, and concurrent emotional sound sequence. With the neutral sequence, Naveteru, Roy, Ovelac, and Steinling (1992) had observed a right greater than left cerebral blood flow, and an opposite pattern with the emotional sequence. In the present study, the neutral sound sequence induced a significant accuracy reduction for lexical decisions to stimuli presented in the left visual field. It is hypothesized that RH activation in response to neutral sounds interferes with the limited lexical processing resources of that hemisphere.     

Perception of biological motion: A stimulus set of human point-light actions

We present a set of stimuli representing human actions under point-light conditions, as seen from different viewpoints. The set contains 22 fairly short, well-delineated, and visually “loopable” actions. For each action, we provide movie files from five different viewpoints as well as a text file with the three spatial coordinates of the point lights, allowing researchers to construct customized versions. The full set of stimuli may be downloaded fromwww.psychonomic.org/archive/.     

Contour-based object identification and segmentation: Stimuli,norms and data,and software tools

We summarize five studies of our large-scale research program, in which we examined aspects of contour-based object identification and segmentation, and we report on the stimuli we used, the norms and data we collected, and the software tools we developed. The stimuli were outlines derived from the standard set of line drawings of everyday objects by Snodgrass and Vanderwart (1980). We used contour curvature as a major variable in all the studies. The total number of 1,500 participants produced very solid, normative identification rates of silhouettes and contours, straight-line versions, and fragmented versions, and quite reliable benchmark data about saliency of points and object segmentation into parts. We also developed several software tools to generate stimuli and to analyze the data in nonstandard ways. Our stimuli, norms and data, and software tools have great potential for further exploration of factors influencing contour-based object identification, and are also useful for researchers in many different disciplines (including computer vision) on a wide variety of research topics (e.g., priming, agnosia, perceptual organization, and picture naming). The full set of norms, data, and stimuli may be downloaded fromwww.psychonomic.org/archive/.     

Parallel allocation of attention prior to the execution of saccade sequences

In a series of 5 experiments, the allocation of attention prior to the execution of saccade sequences was examined by using a dual-task paradigm. In the primary task, participants were required to execute a sequence of 2 endogenous saccades. The secondary task was a forced-choice letter identification task. During the programming of the saccade sequences, letters were briefly presented at the saccade goals and at no-saccade locations. The results showed that performance was better for letters presented at any of the saccade goals than for letters presented at any of the no-saccade locations. The results support a spatial model that assumes that prior to the execution of a saccade sequence, attention is allocated in parallel to all saccade goals. ((c) 2003 APA, all rights reserved)     

Perception of surface reflectance of 3-D geometrical shapes: influence of the lighting mode

We examined in three experiments whether the perception of surface reflectance in 3-D geometrical shapes is influenced by the mode of lighting, the level of surface reflectance, the number of polyhedral faces, and the regularity of polyhedral shape. As stimuli, we used simulations of regular polyhedra in a 2AFC constant-stimuli procedure to measure how large variations in the reflectance needed to be for observers to be able to tell whether the whole surfaces were uniform or non-uniform. In almost all the cases observers were more successful in discriminating non-uniform polyhedra in the hemispherical diffuse lighting conditions than in the collimated lighting conditions. The different levels of reflectance had no effect on the discrimination of non-uniformity. Second, as the number of faces of the shape increased, discrimination thresholds became lower, indicating that the interpretation of reflectance variations was better when a shape had many faces. Finally, the regularity of the shape, such as the central symmetry, was not an important factor. These results suggest that the interpretation of surface reflectance is more precise when surfaces have less variance in relative strengths between the face luminance values; these surfaces were the ones obtained under hemispherical diffuse lighting.     

Global and local processing of hierarchical visual stimuli in tufted capuchin monkeys (Cebus apella)

Capuchin monkeys' (Cebas apella) relative accuracy in the processing of the global shape or the local features of hierarchical visual stimuli was assessed. Three experiments are presented featuring manipulations of the arrangement and the density of the local elements of the stimuli. The results showed a clear advantage for local level processing in this species, which is robust under manipulations of the density of the local elements of the stimuli. By contrast the density of the component elements linearly affected accuracy in global processing. These findings, which support those from other studies in which a local superiority emerged in animals, challenge the generality of early claims concerning the adaptive value of global advantage in the processing of hierarchical visual patterns.     

MMPI-2 and MCMI-III scores among dutch inpatient substance abusers: Assessing correspondence and cross-cultural equivalence

The Millon Clinical Multiaxial Inventory (MCMI-II and MCMI-III) and the Minnesota Multiphasic Personality Inventory (MMPI-2) were applied to 263 Dutch inpatient substance abusers with multiple psychiatric diagnoses, and the results compared with those of 306 North-American substance abusers studied by Ward (1995). We looked for structural similarity both across groups (per instrument) and across the two instruments (per sample), using principal components analysis and congruence analysis. The component structure found by Ward was partly replicated in the Dutch group, thus cross-validating the use of the two instruments with these patients. Moreover, as found by Ward, the MMPI-2 content and supplementary scales of the Dutch sample proved to be important determinants of the first three MMPI-2 components, adding to convergent validity. Questions remained about the influence of the (dis)continuity of MCMI-II and MCMI-III on the replicability of the MCMI components.