Extrinsic and intrinsic motivation at 30: Unresolved scientific issues

The undermining effect of extrinsic reward on intrinsic motivation remains unproven. The key unresolved issues are construct invalidity (all four definitions are unproved and two are illogical); measurement unreliability (the free-choice measure requires unreliable, subjective judgments to infer intrinsic motivation); inadequate experimental controls (negative affect and novelty, not cognitive evaluation, may explain "undermining" effects); and biased metareviews (studies with possible floor effects excluded, but those with possible ceiling effects included). Perhaps the greatest error with the undermining theory, however, is that it does not adequately recognize the multifaceted nature of intrinsic motivation (Reiss, 2004a). Advice to limit the use of applied behavior analysis based on "hidden" undermining effects is ideologically inspired and is unsupported by credible scientific evidence.     

Can sample-specific simulations help detect low base-rate taxonicity?

The authors examined the role of the sample-specific simulations (SSS; A. M. Ruscio & J. Ruscio, 2002; J. Ruscio & A. M. Ruscio, 2004) procedure in detecting low base-rate taxa that might otherwise prove elusive. The procedure preserved key distributional characteristics for moderate to high base-rate taxa, but it performed inadequately for low base-rate taxa, with low to moderate nuisance covariance, decreasing indicator validity, and increasing average nuisance covariance. Visual inspection of the curves produced by the SSS procedure, combined with the expectation that the inchworm test should produce a clear peak for low base-rate taxonic samples, led to inappropriate conclusions about the suitability of data. The authors speculate that examination of low base-rate taxa using SSS may require other algorithms for generating comparison distributions, consideration of the shape of the whole curve, and/or relaxation of the expectation that a clear peak will emerge with the inchworm test.     

Dana-Farber Cancer Institute ethics rounds: life-threatening illness and the desire to adopt

Originally presented during Ethics Rounds at the Dana-Farber Cancer Institute, this commentary on the case of a patient treated for life-threatening cancer explores the responsibilities of health care providers when addressing the patient's desire to adopt a child.     

Acquired distinctiveness and equivalence in human discrimination learning: Evidence for an attentional process

In a first stage of training, participants learned to associate four visual cues (two different colors and two different shapes) with verbal labels. For Group S, one label was applied to both colors and another to both shapes; for Group D, one label was applied to one color and one shape, and the other label to the other cues. When subsequently required to learn a task in which a given motor response was required to one of the colors and one of the shapes, and a different response to the other color and the other shape, Group D learned more readily than Group S. The task was designed so that the associations formed during the first stage of training could not generate differential transfer to the second stage. The results are consistent, however, with the proposal that training in which similar cues are followed by different outcomes will engage a learning process that boosts the attention paid to features that distinguish these cues.     

Hypercoagulable states and stroke: a selective review

Blood disorders have been implicated in approximately 5% to 10% of ischemic stroke, with an increased frequency in younger patients. Most disorders are associated with an increased thrombotic tendency and, therefore, an increased risk of ischemic stroke. Less commonly, a bleeding diathesis may predispose a patient to intracranial hemorrhage. While many conditions predisposing to thrombosis have been associated with stroke, there are relatively few prospective, epidemiological studies addressing hypercoagulable states and arterial stroke compared with the number of studies on the genetic thrombophilias, which are predominantly associated with venous thrombosis. When ordering tests of coagulation in stroke patients, one should keep in mind whether the results will influence therapy and/or patient outcome. It is generally not advocated to screen all stroke patients for a "hypercoagulable workup". Typically, patients to be screened for coagulation defects will have a prior history of one or more unexplained thromboembolic events. The yield for diagnosing a hypercoagulable state is typically greatest for young stroke patients or those with a family history of thrombosis and who have no other explanations for their stroke (cryptogenic stroke). The yield in typically low in unselected ischemic stroke patients and older patients. Treatment of a first stroke with a documented hypercoagulable state is typically long-term or indefinite duration warfarin, although there is a paucity of clinical trial data supporting this clinical approach.     

Chimpanzee (Pan troglodytes) intentional communication is not contingent upon food

Studies of great apes have revealed that they use manual gestures and other signals to communicate about distal objects. There is also evidence that chimpanzees modify the types of communicative signals they use depending on the attentional state of a human communicative partner. The majority of previous studies have involved chimpanzees requesting food items from a human experimenter. Here, these same communicative behaviors are reported in chimpanzees requesting a tool from a human observer. In this study, captive chimpanzees were found to gesture, vocalize, and display more often when the experimenter had a tool than when she did not. It was also found that chimpanzees responded differentially based on the attentional state of a human experimenter, and when given the wrong tool persisted in their communicative efforts. Implications for the referential and intentional nature of chimpanzee communicative signaling are discussed.     

Are there interactions among dysfunctional beliefs in obsessive compulsive disorder?

Contemporary cognitive models of obsessive-compulsive disorder emphasize the importance of various types of dysfunctional beliefs, such as beliefs about inflated responsibility, perfectionism and the importance of controlling one's thoughts. These beliefs have been conceptualized as main effects, each influencing obsessive-compulsive symptoms independent of the contributions of other beliefs. It is not known whether beliefs interact with one another in their influence on obsessive-compulsive symptoms. To investigate this issue, data from 248 obsessive-compulsive disorder patients were analyzed. Dependent variables were the factor scores on the 4 Padua Inventory subscales. Predictor variables were the factor scores from the 3 factors (inflated responsibility, perfectionism and controlling one's thoughts) of the Obsessive Beliefs Questionnaire and their 2- and 3-way interactions. Regression analyses revealed significant main effects; in almost all analyses one or more of inflated responsibility, perfectionism, and controlling one's thoughts factors predicted scores on the Padua factors even after controlling for general distress. There was no evidence that beliefs interact in their effects on obsessive-compulsive symptoms, thereby providing a relatively unusual instance in which a simpler explanation (main effects only) is just as powerful as a more complex model.