How primates acquire their gestures: evaluating current theories and evidence

Animal Cognition - Mechanisms underlying gesture acquisition in primates are largely unstudied, yet heavily debated. While some studies suggest that gestural repertoires are largely innate, others...     

Empirical evaluation of the axioms of multiplicativity, commutativity, and monotonicity in ratio production of area

Although direct scaling methods have been widely used in the behavioral sciences since the 1950s, theoretical approaches which could clarify the implicit assumptions inherent in Stevens' ratio scaling approach were developed only recently. Today, it is generally accepted that the axioms of commutativity and multiplicativity are fundamental to the subjects' ratio scaling behavior. Therefore, both axioms were evaluated in ratio production of area. Participants were required to adjust the area of a variable circle to prescribed ratio production factors. The results are in accordance with previous empirical findings: commutativity was satisfied, whereas multiplicativity failed to hold. Additionally, the validity of the monotonicity property was analyzed, which postulates that the subjects' adjustments in a ratio production experiment preserve the mathematical order of the ratio production factors. Monotonicity was satisfied empirically, which is consistent with all the current theories of ratio scaling.     

Neurocognitive aspects of pain perception

The perception of pain is sensitive to various mental processes such as the feelings and beliefs that someone has about pain. It is therefore not exclusively driven by the noxious input. Attentional modulation involving the descending pain modulatory system has been examined extensively in neuroimaging studies. However, the investigation of neural mechanisms underlying more complex cognitive modulation is an emerging field in pain research. Recent findings indicate an engagement of the ventrolateral prefrontal cortex during more complex modulation, leading to a change or reappraisal of the emotional significance of pain. Taking placebo-induced analgesia as an example, we discuss the contribution of attention, expectation and reappraisal as three basic mechanisms that are important for the cognitive modulation of pain.     

Crossed categorization and stereotyping: Structural analyses, effect patterns, and dissociative effects of context relevance

Based on the “Who said what?” paradigm, a new method is proposed for investigating social categorization and non-evaluative stereotype application in crossed categorization. The method is applied in 5 studies that manipulated relative context relevance of crossed age and gender categories. Social categorization is characterized by 2 indices: Relative subgroup memory assesses the amount of subgroup formation represented in memory, and relative category dominance the relative weight of each dimension of categorization. Both indices were affected by context relevance. There was strong evidence for social categorization at the subgroup level, whereas stereotype application followed a simple pattern of category dominance, in which only the context-relevant dimension exerted an effect. The results bear on current models of category-based impression formation and intergroup perception, and on category-activation cum stereotype-inhibition models.     

The man who wasn't there: Subliminal social comparison standards influence self-evaluation

Life provides an endless stream of social comparison information. Because opportunities to compare with others are so abundant, social comparison theory traditionally assumes that people are selective in their comparison activities and primarily compare with deliberately selected standards. Recent research, however, demonstrates that social comparisons often occur spontaneously, even if no standard is explicitly provided or deliberately selected. We examined whether comparisons are so spontaneous that they are even engaged if people are fleetingly exposed to a potential standard—so fleetingly that they remain unaware of the standard. In three studies, participants were subliminally primed with moderate versus extreme, high versus low standards during self-evaluation. Results demonstrate that self-evaluations are influenced by subliminally presented standards. Specifically, self-evaluations are assimilated towards moderate standards and contrasted away from extreme standards. These self-evaluative consequences of subliminal standards, however, were only obtained if participants engaged in self-reflection during standard exposure. These findings emphasize that social comparisons are truly ubiquitous processes that are engaged even for fleeting exposure to standard information.     

Using latent semantic analysis to assess reader strategies

We tested a computer-based procedure for assessing reader strategies that was based on verbal protocols that utilized latent semantic analysis (LSA). Students were given self-explanation—reading training (SERT), which teaches strategies that facilitate self-explanation during reading, such as elaboration based on world knowledge and bridging between text sentences. During a computerized version of SERT practice, students read texts and typed self-explanations into a computer after each sentence. The use of SERT strategies during this practice was assessed by determining the extent to which students used the information in the current sentence versus the prior text or world knowledge in their self-explanations. This assessment was made on the basis of human judgments and LSA. Both human judgments and LSA were remarkably similar and indicated that students who were not complying with SERT tended to paraphrase the text sentences, whereas students who were compliant with SERT tended to explain the sentences in terms of what they knew about the world and of information provided in the prior text context. The similarity between human judgments and LSA indicates that LSA will be useful in accounting for reading strategies in a Web-based version of SERT.     

Boundary effects of vague risk information on taxpayer decisions

In compliance decisions, the decision maker usually has only vague or ambiguous knowledge of the probability of being caught and the outcome (amount of penalty). An experiment is reported which extends work on effects of probability ambiguity by manipulating outcome ambiguity as well. When outcomes were limited to a bounded range and probabilities ranged between their natural boundaries [0, 1] in experimental tax decisions, symmetrical boundary effects were found in which vague estimates for both the probability and outcome dimensions caused vagueness aversion (and higher compliance) when the vague estimate was near the more favorable lower boundary of either dimension and vagueness seeking (and lower compliance) when the vague estimate was near the less favorable upper boundary. Probability and outcome vagueness effects were found to be independent of the vagueness of the other dimension, and vagueness effects were not systematically related to the level of the other dimension.The results suggest that a common cognitive process mediates the impact of vagueness on both dimensions. This may be a vagueness-adjustment process in which vague estimates are adjusted toward the middle of the bounded range, or a vagueness-preference process in which vague outcomes, and vague probabilities as well, are evaluated based on utility considerations, as though probability were a tangible commodity. For increasing compliance, the results suggest that risk information should be disseminated only when risks of punishment are relatively high. When risks are low, random enforcement techniques that enhance vagueness become more effective.     

Evaluating the validity of short witness reports using behavioral and psychophysiologic parameters]

Within the context of credibility assessment, the impact of behavioral and physiological adaptation and response patterns of truly and falsely testifying eyewitnesses was examined in a laboratory study. It was further examined statements concerning characteristics of the delict and the experimental situation itself. 20 subjects were instructed to truly or falsely testify after having witnessed a willful destruction. Eye movements, respiration, heart rate and skin conductance were recorded and analyzed by computer. Witnesses instructed to falsely testify showed elevated skin conductance responses and an increased variability of horizontal eye movements at the beginning of the session. Additionally, they also showed stronger responses in eye-blink rate, respiration rate and variability of skin conductance and heart rate to questions related to the behavior in the experimental situation. Reactivity to questions concerning the culprit was less pronounced. Results are discussed in terms of their application within the German law system.     

Computerized process control in behavioral science research

A general approach to the design and development of real-time operating systems is discussed. Operating system design for small to medium scale laboratory computers is described at a moderately elementary level. Analysis of system design as a supervisory control hierarchy is presented in an attempt to bridge the gap between an elementary general understanding of computer operation and the more sophisticated understanding assumed by the writers of most computer systems operator’s manuals. PROSS, a programming language developed at Indiana University, is presented as an example of the highest level of supervisory control.