Conceiving of entities as objects and as stuff

What is the difference between conceiving of an entity as an object of some kind and conceiving of it as an amount of solid stuff? We propose that the difference lies in how one thinks about the entity's structure. Object construals require thinking of the structure as being nonarbitrary, whereas substance construals require thinking of the structure as being arbitrary. We report six experiments that provide empirical support for this proposal. Regularity of structure, repetition of structure, and the existence of structure-dependent functions, all of which provide reasons to consider the structure of an entity to be nonarbitrary, were shown to bias participants towards object construals. We also discuss how the proposed account of what it means to construe an entity as an object or as some stuff can account for a range of findings in the literature on lexical development. These include the relation between cohesiveness and ontological category, shape and ontological category, and complexity of shape and ontological category. Finally, we discuss the nature of construals and the relation of object and substance construals to the physical, design, and intentional stances.     

Reappraising the link between peritraumatic dissociation and PTSD symptom severity: evidence from a longitudinal study of community violence survivors

Cross-lagged panel analysis of longitudinal data collected from young adult survivors of community violence was used to examine the relationship between recall of peritraumatic dissociation and posttraumatic stress disorder (PTSD) symptom severity. Recollections of peritraumatic dissociation assessed within days of exposure differed from recollections measured at 3- and 12-month follow-up interviews. Peritraumatic dissociation was highly correlated with PTSD symptoms within each wave of data collection. Baseline recollections of peritraumatic dissociation were not predictive of follow-up PTSD symptom severity after controlling for baseline PTSD symptom severity. This pattern of results replicates previous work demonstrating a correlation between peritraumatic dissociation and subsequent symptom severity. However, findings are not consistent with the prevailing view that peritraumatic dissociation leads to increased PTSD symptom severity.     

Generalizing a neuropsychological model of visual categorization to auditory categorization of vowels

Twelve male listeners categorized 54 synthetic vowel stimuli that varied in second and third formant frequency on a Bark scale into the American English vowel categories [see text]. A neuropsychologically plausible model of categorization in the visual domain, the Striatal Pattern Classifier (SPC; Ashby & Waldron, 1999), is generalized to the auditory domain and applied separately to the data from each observer. Performance of the SPC is compared with that of the successful Normal A Posteriori Probability model (NAPP; Nearey, 1990; Nearey & Hogan, 1986) of auditory categorization. A version of the SPC that assumed piece-wise linear response region partitions provided a better account of the data than the SPC that assumed linear partitions, and was indistinguishable from a version that assumed quadratic response region partitions. A version of the NAPP model that assumed nonlinear response regions was superior to the NAPP model with linear partitions. The best fitting SPC provided a good account of each observer's data but was outperformed by the best fitting NAPP model. Implications for bridging the gap between the domains of visual and auditory categorization are discussed.     

Mental simulation inflates performance estimates for physical abilities

In five experiments, we examined how mental simulation of physical activities affected estimates of one's ability to perform the same activities. In Experiment 1, participants who simulated lifting aheavy object estimated that they could lift more weight than did participants who did not perform the simulation. In Experiment 2A, the frequency with which participants performed the simulation exercises was manipulated. In Experiments 2B and 2C, we manipulated the amount of weight that people simulated lifting in order to address potential alternative explanations of the inflation effect. In Experiment 3, mental simulations were manipulated within subjects. In all the experiments, the simulated events showed inflated estimates, as compared with nonsimulated events. These results were interpreted in the context of the misattribution-of-familiarity account of imagination inflation.     

MMPI-A scores and high points of male juvenile delinquents: scales 4, 5, and 6 as markers of juvenile delinquency

The Minnesota Multiphasic Personality Inventory-Adolescent (MMPI-A) clinical, supplementary, and content scale score patterns for 655 male delinquents were examined. Low scores on Scale 5 (Masculinity/Femininity) were found to be the most frequent deviation, followed by elevations on Scales 6 (Paranoia) and 4 (Psychopathic Deviate). This is consistent with previous research, although the importance of Scale 5 deviations has been little noted because of the traditional focus on scale elevations only. Classification analysis indicated that a combination of MMPI-A scales discriminated between this delinquent sample and the normative sample, with a sensitivity of 90%-95% and a specificity of 80%-85%. This level of sensitivity was maintained in a replication sample (N = 473).     

Précis of Simple heuristics that make us smart

How can anyone be rational in a world where knowledge is limited, time is pressing, and deep thought is often an unattainable luxury? Traditional models of unbounded rationality and optimization in cognitive science, economics, and animal behavior have tended to view decision-makers as possessing supernatural powers of reason, limitless knowledge, and endless time. But understanding decisions in the real world requires a more psychologically plausible notion of bounded rationality. In Simple heuristics that make us smart (Gigerenzer et al. 1999), we explore fast and frugal heuristics--simple rules in the mind's adaptive toolbox for making decisions with realistic mental resources. These heuristics can enable both living organisms and artificial systems to make smart choices quickly and with a minimum of information by exploiting the way that information is structured in particular environments. In this précis, we show how simple building blocks that control information search, stop search, and make decisions can be put together to form classes of heuristics, including: ignorance-based and one-reason decision making for choice, elimination models for categorization, and satisficing heuristics for sequential search. These simple heuristics perform comparably to more complex algorithms, particularly when generalizing to new data--that is, simplicity leads to robustness. We present evidence regarding when people use simple heuristics and describe the challenges to be addressed by this research program.     

Montrose M. Wolf (1935-2004)

Montrose Madison Wolf, who discovered the reinforcing power of adult attention for children and based on that discovery invented and named the nonviolent parenting procedure time-out; who discovered that absent speech and social development could be artificially created with operant conditioning techniques; who first engineered a token economy into a useful motivational system; who invented the good behavior game; who orchestrated the massive research program that developed and refined the Teaching-Family Model as a residential treatment solution for delinquent development; who reinvented field observation, repeated measurement, and single-subject research methods; who introduced and named the concept of social validity; and who led the founding of the discipline of problem-solving real-world research called applied behavior analysis, died of Huntington's disease on March 19, 2004, at his home in Lawrence, Kansas.     

Differential acquisition of lever pressing in inbred and outbred mice: comparison of one-lever and two-lever procedures and correlation with differences in locomotor activity

Recent progress in mouse genetics has led to an increased interest in developing procedures for assessing mouse behavior, but relatively few of the behavioral procedures developed involve positively reinforced operant behavior. When operant methods are used, nose poking, not lever pressing, is the target response. In the current study differential acquisition of milk-reinforced lever pressing was observed in five inbred strains (C57BL/6J, DBA/2J, 129X1/SvJ, C3H/HeJ, and BALB/cJ) and one outbred stock (CD-1) of mice. Regardless of whether one or two levers (an "operative" and "inoperative" lever) were in the operant chamber, a concomitant variable-time fixed-ratio schedule of milk reinforcement established lever pressing in the majority of mice within two 120-min sessions. Substantial differences in lever pressing were observed across mice and between procedures. Adding an inoperative lever retarded acquisition in C57BL/6J, DBA/2J, 129X1/SvJ, and C3H/HeJ mice, but not in CD-1 and BALB/cJ mice. Locomotor activity was positively correlated with number of lever presses in both procedures. Analyses of durations of the subcomponents (e.g., time to move from hopper to lever) of operant behavior revealed further differences among the six types of mice. Together, the data suggest that appetitively reinforced lever pressing can be acquired rapidly in mice and that a combination of procedural, behavioral, and genetic variables contributes to this acquisition.