Small-sample characterization of stochastic approximation staircases in forced-choice adaptive threshold estimation

Despite the widespread use of up-down staircases in adaptive threshold estimation, their efficiency and usability in forced-choice experiments has been recently debated. In this study, simulation techniques were used to determine the small-sample convergence properties of stochastic approximation (SA) staircases as a function of several experimental parameters. We found that satisfying some general requirements (use of the accelerated SA algorithm, clear suprathreshold initial stimulus intensity, large initial step size) the convergence was accurate independently of the spread of the underlying psychometric function. SA staircases were also reliable for targeting percent-correct levels far from the midpoint of the psychometric function and performed better than classical up-down staircases with fixed step size. These results prompt the utilization of SA staircases in practical forced-choice estimation of sensory thresholds.     

On the ethics of facial transplantation research

Transplantation continues to push the frontiers of medicine into domains that summon forth troublesome ethical questions. Looming on the frontier today is human facial transplantation. We develop criteria that, we maintain, must be satisfied in order to ethically undertake this as-yet-untried transplant procedure. We draw on the criteria advanced by Dr. Francis Moore in the late 1980s for introducing innovative procedures in transplant surgery. In addition to these we also insist that human face transplantation must meet all the ethical requirements usually applied to health care research. We summarize the achievements of transplant surgery to date, focusing in particular on the safety and efficacy of immunosuppressive medications. We also emphasize the importance of risk/benefit assessments that take into account the physical, aesthetic, psychological, and social dimensions of facial disfiguration, reconstruction, and transplantation. Finally, we maintain that the time has come to move facial transplantation research into the clinical phase.     

PIGEONS (COLUMBA LIVIA) APPROACH NASH EQUILIBRIUM IN EXPERIMENTAL MATCHING PENNIES COMPETITIONS

The game of Matching Pennies (MP), a simplified version of the more popular Rock, Papers, Scissors, schematically represents competitions between organisms with incentives to predict each other's behavior. Optimal performance in iterated MP competitions involves the production of random choice patterns and the detection of nonrandomness in the opponent's choices. The purpose of this study was to replicate systematic deviations from optimal choice observed in humans when playing MP, and to establish whether suboptimal performance was better described by a modified linear learning model or by a more cognitively sophisticated reinforcement‐tracking model. Two pairs of pigeons played iterated MP competitions; payoffs for successful choices (e.g., “Rock” vs. “Scissors”) varied within experimental sessions and across experimental conditions, and were signaled by visual stimuli. Pigeons' behavior adjusted to payoff matrices; divergences from optimal play were analogous to those usually demonstrated by humans, except for the tendency of pigeons to persist on prior choices. Suboptimal play was well characterized by a linear learning model of the kind widely used to describe human performance. This linear learning model may thus serve as default account of competitive performance against which the imputation of cognitively sophisticated processes can be evaluated.     

Failure to find a distance effect in pigeon choice: Manipulating amount and delay of reinforcement

The choice behavior of primates, including humans, displays a distance effect: Latency to choose between alternatives appears to increase with smaller differences in value. There is, so far, no demonstration of this effect in birds. Tests of distance effects in birds have been conducted in binary choice situations with a dominant alternative, where one alternative is superior to the other in all aspects that meaningfully contribute to value (e.g., provides access to the same reinforcer, but with a shorter delay). The present study considers the possibility that including dominant alternatives in choice tests precludes distance effects. Four pigeons were presented with binary choices between alternatives that varied in amount and delay. Some choices had a dominant alternative (smaller–sooner or larger–later vs. smaller–later) and some did not (smaller–sooner vs. larger–later). Across phases, only the delay to the smaller–sooner reinforcer varied. Distance effects were expected to be expressed as longer latencies as choice between smaller–sooner and larger–later reinforcers approached indifference. Despite the sensitivity of choice to differences in amount and delay, no distance effect was observed. Alternative explanations for the failure to find a distance effect in pigeon choice, including the Sequential Choice Model (SCM), are discussed.     

Predicting attitude extremity: the interactive effects of schema development and the need to evaluate and their mediation by evaluative integration

Research on attitude extremity suggests that schemas containing more information about a particular attitude domain are more likely to be associated with extreme attitudes toward objects in that domain when perceivers' responses toward features of the domain are evaluatively integrated. The present study argues that a high need to evaluate may play an important role in determining when schema development will be associated with the integrated responses to different domain features necessary for extremity. Consistent with this argument, data from a nationally representative survey of political attitudes indicated that the need to evaluate was associated with increased extremity across two different indices of the latter; that it moderated the relationships between schema development (in the form of political expertise), on one hand, and increased extremity and integration, on the other; and that the moderating effects of the need to evaluate vis-a-vis extremity were mediated by integration.     

A Developmental Perspective of Marriage and Family Therapist's Ethical Principles: Support for the Practitioner–Ethics Relationship Model

This study explored therapists' professional ethics by assessing therapist at-risk behaviors as they relate to ethical proficiency in the field of Marriage and Family Therapy. A survey assessing practice behaviors was distributed among marriage and family therapists (MFTs) of varying levels of experience. Data gathered were analyzed using factor analysis, structural equation modeling, and multiple regression. Results indicate a positive relationship between the latent variables of risk and justification, as well as a significant relationship between these variables and years of clinical experience. Findings provide evidence to support the practitioner–ethics relationship model proposed by the authors. Implications of these findings, as well as future directions for research and policy are suggested.     

Ethical Issues and At-Risk Behaviors in Marriage and Family Therapy: A Qualitative Study of Awareness

This exploratory study investigated perceptions of and relationship with professional ethics of therapists-in-training. A focus group of marriage and family therapy doctoral students explored self-awareness and at-risk behaviors regarding ethical competence and compliance. A grounded theory analysis of data is presented as a conditional matrix, which offers a theory of development between therapists and their perception of ethics. The Practitioner-Relationship Ethics Model represents findings of interaction between confidence in ethical principles, field experience, use of justification, and at-risk behaviors. Implications and limitations of these findings are presented, as are suggestions for research.     

The role of cortical cholinergic pre- and post-synaptic receptors in taste memory formation

A number of studies have implicated cholinergic activity in the mediation of learning and memory processes. However, the specific role of muscarinic receptors in memory formation mechanisms is less known. The aim of the present study is to evaluate the effects of muscarinic antagonist M2 presynaptic receptor, AFDX-116 (0.5mM) and M1 and M3 post-synaptic receptor pirenzepine (100mM), as well as a non-selective muscarinic antagonist, scopolamine (136mM), in the insular cortex (IC) during acquisition and retrieval of conditioned taste aversion (CTA). In addition, we evaluate the effects of those antagonists in cortical ACh release by in vivo microdialysis and the effects on the induction of in vivo LTP in the BLA-IC projection. The results showed that the cortical microinjections of scopolamine and pirenzepine, but not AFDX-116, produced significant disruption in the acquisition of CTA, without effects during retrieval. Microinjections of scopolamine and AFDX-116 produced significant cortical ACh release, while infusions of pirenzepine did not produce any release. Application of scopolamine and pirenzepine diminished induction of LTP in the BLA-IC projection, but not AFDX-116, as compared with vehicle. The induction of BLA-CI LTP seems to be modulated by post-synaptic muscarinic acetylcholine receptors and not by pre-synaptic muscarinic receptors. These results suggest a differential involvement of cholinergic receptors during acquisition and retrieval of aversive memory formation, as well as a differential role of muscarinic receptors in the biochemical and electrophysiological processes that may underlay aversive memory.     

Gesture production and text structure

In the present pilot study, we examined the relationship between gesture and verbal production. Subjects were asked to read a story and then to narrate what they remembered. We analyzed verbal production according to Kintsch's procedure and obtained a list of hierarchically organized propositions that represented the meaning of subject's narration. Propositions were subdivided into High- and Low-level propositions. Further, we analyzed gesture production by identifying hand or arm movement that accompanied subject's narration. Each gesture was associated with the word simultaneously produced, and then with the proposition to which the word belonged. Analysis showed subjects were more likely to produce gestures in association with High- rather than with Low-level propositions. High-level propositions may elicit the production of gestures which, in turn, mark the importance of verbal meaning conveyed simultaneously.     

A cognitive and an affective dimension of alexithymia in six languages and seven populations

The Dutch Bermond–Vorst Alexithymia Questionnaire (BVAQ) is translated into various languages. The aim of this research was to establish the factor structure of subscales on seven cultural groups. The BVAQ consists of five subscales of eight items each: Emotionalising, Fantasising, Analysing, Identifying, and Verbalising emotions. The BVAQ was administered to a group of Dutch students (n=375), a group of English students (n=175), a group of Australian students, university employees and visitors (n=216), a group of French speaking Belgian students (n=175), a group of Italian people (n=791; a mix of various clinical groups), a group of Polish people (n=427; also a mix of various clinical groups) and a group of Russian people (n=141; general population). The hypothesised two-factor structure of an affective alexithymia dimension (Emotionalising, Fantasising) and a cognitive alexithymia dimension (Insight and Verbalising), with “Analysing emotions” loading on both factors, was clearly supported by confirmatory factor analyses (CFA). Both orthogonal and oblique principal components analyses (PCA), without restriction concerning the number of factors, provided the same two-factor solution in all groups explaining between 55% and 64% of the variance. Oblique rotation further demonstrated that the correlations between these two factors were low in all populations. The combined CFA and PCA results, therefore, indicated that a model with two independent factors has to be preferred over the model assuming two correlated factors.