The claiming effect: Why players are more generous in social dilemmas than in ultimatum games.

The term procedural frames is introduced and defined as different representations of structurally equivalent allocation processes. Study 1 compared 2 well-known games, sequential social dilemmas and ultimatum bargaining, that share the same structure: Player 1 creates an allocation of a resource and Player 2 decides whether to allow it or deny it. Study 1 found that Player 1 made more favorable allocations and Player 2 accepted more unfavorable allocations in a social dilemma frame than in an equivalent ultimatum bargaining frame. Study 2 revealed the critical determinant was whether Player 2 had to respond to an allocation by accepting or rejecting it (as in the ultimatum game) or by making a claim (as in the social dilemma). Two additional studies explored how these actions are perceived. The inconsistency of behavior across procedural frames raises methodological concerns but illuminates construal processes that guide allocation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Activation of CPP32-like proteases is not sufficient to trigger apoptosis: inhibition of apoptosis by agents that suppress activation of AP24, but not CPP32-like activity

The 24-kD apoptotic protease (AP24) is a serine protease that is activated during apoptosis and has the capacity to activate internucleosomal DNA fragmentation in isolated nuclei. This study examined the following: (a) the functional relationship between AP24 and the CPP32-like proteases of the caspase family; and (b) whether activation of CPP32-like proteases is sufficient to commit irreversibly a cell to apoptotic death. In three different leukemia cell lines, we showed that agents that directly (carbobenzoxy-Ala-Ala-borophe (DK120) or indirectly inhibit activation of AP24 (protein kinase inhibitors, basic fibroblast growth factor, tosylphenylalaninechloromethylketone, and caspase inhibitors) protected cells from apoptosis induced by TNF or UV light. Only the caspase inhibitors, however, prevented activation of CPP32-like activity as revealed by cleavage of the synthetic substrate, DEVD-pNa, by cell cytosols, and also by in vivo cleavage of poly (ADP-ribosyl) polymerase, a known substrate of CPP32. Activation of DEVD-pNa cleaving activity without apoptosis was also demonstrated in two variants derived from the U937 monocytic leukemia in the absence of exogenous inhibitors. Cell-permeable peptide inhibitors selective for CPP32-like proteases suppressed AP24 activation and apoptotic death. These findings indicate that CPP32-like activity is one of several upstream signals required for AP24 activation. Furthermore, activation of CPP32-like proteases alone is not sufficient to commit irreversibly a cell to apoptotic death under conditions where activation of AP24 is inhibited.     

Antimicrobial action of rabbit leukocyte CAP18(106-137)

CAP18 is a cationic antimicrobial protein originally isolated from rabbit neutrophils, of which a 32-mer sequence from its C-terminal and (CAP18(106-137)) has been found to be the most active. The bactericidal action of this peptide has been characterized by conventional culture techniques and flow cytometry. Cultures of Escherichia coli NCTC10418 were exposed to the MBC (12 microM) of the peptide for up to 60 min and stained with a fluorochrome sensitive to changes in either membrane potential (bis-(1,3-dibutylbarbituric acid)trimethine oxonol [DiBAC4(3)), or membrane integrity (propidium iodide [PI]) before flow cytometric analysis. Addition of CAP18(106-137) to E. coli in broth culture resulted in immediate collapse of membrane potential [as determined by uptake of DiBAC4(3)] and loss of membrane integrity (as indicated by uptake of PI), with a corresponding 6- to 8-log decrease in viable counts as determined by colony formation on solid media. In identical experiments, the presence of Mg2+ (1 to 10 mM), K+ (50 to 250 mM), or EDTA (5 mM) or incubation in nutrient-free buffer or at 4 degrees C had no effect on peptide-induced dye uptake. In contrast, addition of Ca2+ (1 to 10 mM) or the respiratory chain poison carbonyl cyanide m-chlorophenylhydrazone (CCCP) (50 microM) inhibited the uptake of both dyes. These findings, however, did not relate to bacterial recovery on solid media, where (unless in the presence of K+ 150 to 250 mM) CAP18(106-137) at 12 microM fulfilled the MBC criteria (99.9% killing). We conclude that CAP18(106-137) exerts a rapid and profound action on E. coli cytoplasmic membranes and viability as measured by colony formation. The results suggest, however, that CAP18(106-137) may exert its action at sites additional to the cell membrane and that its activity profile is unique among cationic antimicrobial proteins.     

Misperceiving negotiation counterparts: When situationally determined bargaining behaviors are attributed to personality traits.

Several experiments provided evidence that negotiators make systematic errors in personality-trait attributions for the bargaining behaviors of their counterparts. Although basic negotiation behavior is highly determined by bargaining positions, negotiators primarily interpret their counterpart's behavior in terms of the counterpart's personality, such as his or her level of cooperativeness or agreeableness. Data support a model of 4 processes that contribute to misperceptions: (a) the primacy of situations in determining bargaining behavior, (b) the primacy of personality traits in attributions, (c) the lack of sufficient information about the other's situation to discount personality attributions, and (d) the potentially self-confirming consequences of personality attributions for subsequent interactions. The authors discuss implications for research areas such as social cognition in negotiation, accuracy in social perception, and dynamics of belief confirmation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Strategies for revising judgment: How (and how well) people use others’ opinions.

A basic issue in social influence is how best to change one’s judgment in response to learning the opinions of others. This article examines the strategies that people use to revise their quantitative estimates on the basis of the estimates of another person. The authors note that people tend to use 2 basic strategies when revising estimates: choosing between the 2 estimates and averaging them. The authors developed the probability, accuracy, redundancy (PAR) model to examine the relative effectiveness of these two strategies across judgment environments. A surprising result was that averaging was the more effective strategy across a wide range of commonly encountered environments. The authors observed that despite this finding, people tend to favor the choosing strategy. Most participants in these studies would have achieved greater accuracy had they always averaged. The identification of intuitive strategies, along with a formal analysis of when they are accurate, provides a basis for examining how effectively people use the judgments of others. Although a portfolio of strategies that includes averaging and choosing can be highly effective, the authors argue that people are not generally well adapted to the environment in terms of strategy selection. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Structural and functional changes of aquatic heterotrophic bacteria to thermal, heavy, and fly ash effluents

Heterotrophic bacterial populations were sampled at 9 sites around a fossil fuel power plant to assess the ecological impact of the resulting effluents on naturally occurring heterotrophic microbes. The total colony forming units (CFU) remained relatively high at all stations, ranging from 13,804 CFU ml⁻¹ in the heavy ash basin to 2630 CFU ml⁻¹ in an uninfluenced station, Adair Run—upstream. The percent of the total colony counts which were chromagenic was correlated with physico/chemical stresses and varied from a high of 59.0% at the reference New River station to 13.2% in the heavy ash basin. A Sequential Comparison procedure (SCI) produced diversity indices which ranged from 8.21 in upstream New River to 6.23 in the ash-influenced Adair Run station. Assimilation of [³H]glucose was used to assess the functional status of the organisms and was reduced 86.0% in the heavy ash basin and 65.5% in the fly ash basin. The structure and function of bacterial communities in the ash basins were significantly different from the same parameters of populations inhabiting reference environments; however, the basin effluents had a lesser effect on New River bacteria.     

Evaluation of antimicrobial and lipopolysaccharide-neutralizing effects of a synthetic CAP18 fragment against Pseudomonas aeruginosa in a mouse model

CAP18 (cationic antimicrobial protein; 18 kDa) is a neutrophil-derived protein that can bind to and inhibit various activities of lipopolysaccharide (LPS). The 37 C-terminal amino acids of CAP18 make up the LPS-binding domain. A truncated 32-amino-acid C-terminal fragment of CAP18 had potent activity against Pseudomonas aeruginosa in vitro. We studied the antimicrobial and LPS-neutralizing effects of this synthetic truncated CAP18 peptide (CAP18106-137) on lung injury in mice infected with cytotoxic P. aeruginosa. To determine its maximal effect, the CAP18106-137 peptide was mixed with bacteria just prior to tracheal instillation, and lung injury was evaluated by determining the amount of leakage of an alveolar protein tracer (125I-albumin) into the circulation and by the quantification of lung edema. The lung injury caused by the instillation of 5 x 10(5) CFU of P. aeruginosa was significantly reduced by the concomitant instillation of CAP18106-137. However, the administration of CAP18106-137 alone, without bacteria, induced lung edema, suggesting that it has some toxicity. Also, the peptide did not significantly reduce the number of bacteria that had been simultaneously instilled, nor did it significantly improve the survival of the infected mice. The addition of CAP18106-137 to aztreonam along with the bacteria did decrease the level of antibiotic-induced release of inflammatory mediators including tumor necrosis factor alpha, interleukin-6, and nitric oxide and also improved the survival of the mice. Therefore, more investigations are needed to confirm the toxicities and the therapeutic benefits of CAP18106-137 as an adjunctive therapy to antibiotics in the treatment of infections caused by gram-negative bacteria.     

Skilled or unskilled, but still unaware of it: How perceptions of difficulty drive miscalibration in relative comparisons.

People are inaccurate judges of how their abilities compare to others'. J. Kruger and D. Dunning (1999, 2002) argued that unskilled performers in particular lack metacognitive insight about their relative performance and disproportionately account for better-than-average effects. The unskilled overestimate their actual percentile of performance, whereas skilled performers more accurately predict theirs. However, not all tasks show this bias. In a series of 12 tasks across 3 studies, the authors show that on moderately difficult tasks, best and worst performers differ very little in accuracy, and on more difficult tasks, best performers are less accurate than worst performers in their judgments. This pattern suggests that judges at all skill levels are subject to similar degrees of error. The authors propose that a noise-plus-bias model of judgment is sufficient to explain the relation between skill level and accuracy of judgments of relative standing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

When one cause casts doubt on another: A normative analysis of discounting in causal attribution.

The question of whether lay attributors are biased in their discounting of 1 cause given an alternative cause has not been resolved by decades of research, largely due to the lack of a clear standard for the rational amount of discounting. The authors propose a normative model in which the attributor's causal schemas and discounting inferences are represented in terms of subjective probability. The analysis examines Kelley's (1972b) proposed causal schemas and then other schemas for multiple causes (varying in assumptions about prior probability, sufficiency, correlation, and number of causes) to determine when discounting is rational. It reveals that discounting is implied from most, but not all, possible causal schemas, albeit at varying amounts. Hence, certain patterns of discounting previously interpreted as biases may, in fact, reflect coherent inferences from causal schemas. Results of 2 studies, which measured causal assumptions and inferences, support this interpretation (PsycINFO Database Record (c) 2010 APA, all rights reserved)