Odorant quality perception: a metric individual differences approach

Perceptual spaces, in which similar stimuli are located close to each other and dissimilar stimuli are located far apart, have aided in the understanding of the physiological and psychological bases for sensory quality coding. Differences in perception between individuals should be reflected by differences in the spatial relationships between stimuli. If the dimensionality of the perceptual space is small (e.g., color space), individual differences that reflect specific pathologies are readily apparent from visual inspection. On the other hand, if the dimensionality of the perceptual space is large (as is proposed for odor space), visual inspection alone may not reveal individual differences in quality perception. The present work presents an information-theory-based method for quantifying individual differences in quality perception from perceptual confusion matrices. The ability of this method to quantify individual differences in quality perception is shown in a hypothetical example of specific anosmia. Finally, the method is applied to the examination of intrasubject consistency of odorant quality perception.     

The perception of length on curved and flat surfaces

In three experiments, observers judged the apparent extents of spatial intervals along the surface of a curved cylinder or a flat plane that was binocularly viewed in a natural, indoor environment. The observers' judgments of surface lengths were precise and reliable but were also inaccurate and subject to relatively large constant errors. These distortions differed among the observers, but they tended to perceive lengths oriented along the curved dimension of the cylinder as being longer than physically equivalent lengths in the noncurved dimension. This phenomenon did not occur when the observers judged curved and noncurved paths on the flat surface. In addition, some observers' judgments of length were affected by changes in the distance to the cylinder, whereas others were affected by the cylinder's orientation in space. These results demonstrate that the perception of length on surfaces is highly dependent on the particular context in which the length occurs.     

Testing for symmetry in the conditional discriminations of language-trained chimpanzees

If subjects are taught to match Stimulus A to B and then, without further training, match B to A, they have passed a test of symmetry. It has been suggested that non-humans' lack of success on symmetry tests might be overcome by giving them a history of symmetry exemplar training, that is, by directly teaching a large number of conditional relations (e.g., AB, CD, EF,...) and also directly training the "reverse" of these relations (e.g., BA, DC, FE,...). The chimpanzee subjects of the present study, Sherman, Austin, and Lana, had already received extensive symmetry exemplar training as a result of attempts to teach a selection-based language system of lexigrams. The present study systematically subjected 2 of these chimps (Sherman and Lana), for the first time, to standard symmetry tests in controlled conditions. Both chimps failed the tests, even when their correct responses on test trials were reinforced. The findings do not support the exemplar training hypothesis, and cast doubt upon whether the chimps can pass tests of stimulus equivalence.     

Persistence during extinction: Are judgments of persistence affected by contingency information?

The partial reinforcement extinction effect (PREE), defined as increased behavioral persistence following intermittent reward, is considered an important outcome of instrumental learning contingencies, both inside and outside the laboratory. Since adults have a rich experience with situations in which desired outcomes depend on instrumental responding, we asked whether that experience affects judgments of persistence when relevant contingency information is manipulated. Subjects read simple scenarios with information about behaviors generated by high vs. low reward rate, and then judged the resultant persistence of these behaviors under no-reward conditions. Studies 1 and 2 found no evidence that persistence judgments were affected by contingency information in naive subjects. Studies 3 and 4 compared groups with and without explicit knowledge about behavioral psychology and thus tested possible effects of that knowledge for persistence more directly. Judgments in naive subjects were not reliably influenced by reward rate information, but subjects possessing expert knowledge demonstrated judgments that were reliably affected by contingency information. The results indicate that people do not generate generalized knowledge from normal experience with occasional vs. regular reward. Possible explanations and implications of these findings are discussed.     

Assessment of weight and eating concerns in Norwegian adolescents

The aim of the present study was to test the properties of an instrument that assesses concerns about weight and eating without reference to dieting behavior. A short instrument, the Weight and Eating Concerns Inventory (WECI) was examined in a sample of 569 boys and 548 girls aged 11 to 15 years. Confirmatory factor analyses with LISREL showed a better fit with a version of the instrument that did not include a reference to dieting behavior, compared to a version that included such a reference. This was true for both boys and girls, irrespective of their age group. However, the results indicated that both versions should be used with caution for young boys. The internal consistency of the WECI (that is, the version without reference to dieting) was satisfactory, ranging from 0.78 to 0.86 for girls and from 0.68 to 0.73 for boys. The WECI correlated quite substantially with negative self-evaluations and depression for boys and girls in all the age groups assessed, suggesting that high scores on the WECI may indicate a problem that goes beyond worries or concerns, and should be taken seriously. In general, girls reported more of these concerns than boys, and the correlation between the WECI and dieting was stronger among girls compared to boys.     

Sex differences in judgement of facial affect: a multivariate analysis of recognition errors

The present paper investigated recognition errors in affective judgement of facial emotional expressions. Twenty-eight females and sixteen males participated in the study. The results showed that in both males and females emotional displays could be correctly classified, but females had a higher rate of correct classification; males were more likely to have difficulty distinguishing one emotion from another. Females rated emotions identically regardless of whether the emotion was displayed by a male or female face. Furthermore, the two-factor structure of emotion, based on a valence and an arousal dimension, was only present for female subjects. These results further extend our knowledge about gender differences in affective information processing.     

Proactive and reactive aggression in delinquent adolescents: relations to aggression outcome expectancies

Investigated whether the relation between aggression and the tendency to expect positive outcomes for aggressive behavior is specific to the proactive subtype of aggression (as opposed to the reactive subtype). In a sample of 86 incarcerated adolescent boys ages 13 to 18, we measured outcome expectancies for aggression using audiotaped hypothetical vignettes. For each participant, staff members completed proactive and reactive aggression rating scales. Regression analyses revealed that the relation between aggression and outcome expectancies was indeed specific to proactive aggression. Furthermore, this finding was supported regardless of whether outcome expectancies were assessed using vignettes describing proactive-aggressive behavior or those describing reactive-aggressive behavior. We discuss these findings and argue that interventions to reduce proactive or reactive aggression should differ from each other by addressing the specific social cognitive processes involved in each type of aggression.     

Do Positive Self-Perceptions Have a “Dark Side”? Examination of the Link between Perceptual Bias and Aggression

The hypothesis that positive self-perceptions may have a dark side was investigated in the present study by examining the relationship between positively biased self-perceptions and aggression. Ratings of actual and perceived social acceptance of third-grade (n = 278), fourth-grade (n = 260), and fifth-grade (n = 321) students were compared to form a measure of perceptual bias. Peers provided nominations for overt and relational aggression. Gender differences were found for aggression (males were more overtly and relationally aggressive than females) but not perceptual bias. African-American children held more positive perceptions of their social acceptance and were perceived by peers as more aggressive than Caucasian children. Even after controlling for the effects of gender and ethnicity, more positively biased perceptions were associated with more peer nominations for overt and relational aggression. Contrary to an optimal range of bias hypothesis, even moderately positive self-perceptions were associated with elevated levels of aggression.     

Relations of Tripartite Dimensions of Emotion to Childhood Anxiety and Mood Disorders

This study examined preliminary higher-order models relating tripartite dimensions of emotion to severity of anxiety and depressive disorders in 100 clinically referred children and adolescents. In light of the accumulating support for multifactor models of vulnerability and negative emotion in children, the present investigation was designed to establish preliminary estimates of the structure and magnitude of the relations of three emotion factors with dimensions of social anxiety, depression, panic, generalized anxiety, obsessions/compulsions, and separation anxiety. Results were consistent with structures that minimally specified two higher-order emotion factors, yet only some parameter estimates were consistent with theory regarding the tripartite model. Problems with the measurement of tripartite factors and possibilities for further research are outlined.     

A perception-action coupling type of control in long jumping

The authors' goal was to identify the control mechanisms used by long jumpers (N = 6) to precisely position their foot at the board. In addition to the intertrial method usually used in previous research, an original method based on a trial-by-trial analysis was also implemented. If the approach to the board in long jumping encompasses two distinct sequences separated by a key step that marks the initiation of visual control, then a trial-by-trial analysis should reveal those sequences, regardless of the amount of adjustment: The step number at which regulation is initiated should be the same irrespective of the amount of adjustment. If, in contrast, a perception-action coupling mechanism operates, then the step number at which regulation is initiated should be a function of the amount of adjustment: A linear relation between those 2 variables should emerge. The results of the present study are compatible with continuous control mechanisms based on a perception-action coupling.