Contextual conditioning and reinstatement of extinguished instrumental responding

In three experiments we studied the relationship between contextual conditioning and the reinstatement of extinguished lever pressing that occurs when noncontingent food is introduced following extinction. In all three experiments the non-contingent food was presented off-baseline (with the response levers not present). On subsequent tests, with the response levers present, animals that had been exposed to food showed more reinstatement of lever pressing than control animals. This finding rules out alternative mechanisms for the reinstated responding that rely on the interaction of non-contingent food and responding, such as superstitious reinforcement or the discriminative after-effects of food. In addition, in each experiment we demonstrated that manipulations known to affect contextual conditioning (signalling the food in Experiment 1, context extinction in Experiment 2, and switching contexts in Experiment 3) reduced the reinstatement. These results are consistent with the claim that contextual conditioning is important in controlling instrumental conditioning and closely parallel findings concerning the reinstatement of Pavlovian responsing following extinction.     

Default Probability

A probability may be called “default” if it is neither derived from preestablished probabilities nor based on considerations of frequency or symmetry. Default probabilities presumably arise through reasoning based on causality and similarity. This article advances a model of default probability based on a featural approach to similarity. The accuracy of the model is assessed by comparing its predictions to the probabilities provided by undergraduates asked to reason about mammals.     

Discounting in causality and covariation judgements

In two experiments, humans were asked to judge the strength of a moderate contingency between a cue and an outcome in the presence of a second strong contingency between another cue and the outcome. The first experiment replicated the discounting effect whereby a strong contingency causes subjects to reduce or discount judgements of a moderate contingency. This experiment used a video-game procedure in which subjects camouflaged a tank to make it safe from mines. The second causal cue was the presence or absence of a spotter plane. Experiment 1 also ruled out the possibility that judgements might be determined by the number of co-occurrences of the cue and outcome as opposed to the level of contingency. The second experiment used an abstract scenario in which discounting was demonstrated when subjects were asked to judge the relationship between the occurrence of geometric objects. The instructions were neutral to discourage causal hypotheses. These results support the notion that judgements result from associative or connectionist processes and not from a two-step cognitive retrospective process in which an estimate of covariation is calculated between cue and outcome and then in a second step this information is used in a normative manner when a decision is made.     

The effects of post-encoding stress on recognition memory: examining the impact of skydiving in young men and women

Prior studies have indicated that post-encoding stress can protect memories from the effects of forgetting, and this has been taken as evidence that stress facilitates memory consolidation. However, it is not known whether stress acts by directly influencing the strength of the underlying memories or whether it influences the generation process that plays a critical role in tests such as free recall. To address this issue, we examined the effects of stress produced by skydiving on recognition memory for negative and neutral pictures. Relative to a non-stress control condition, post-encoding stress in males was found to increase recognition memory for neutral pictures. However, stress was not found to improve recognition for emotional pictures, nor was it found to influence recognition memory in female participants. Additional analysis of recognition performance suggested that stress increased familiarity-based recognition rather than recollection. This study indicates that stress can improve familiarity-based recognition, thus showing that stress directly increases the strength of the underlying memories.     

The moral behavior of ethics professors: Relationships among self-reported behavior,expressed normative attitude,and directly observed behavior

Do philosophy professors specializing in ethics behave, on average, any morally better than do other professors? If not, do they at least behave more consistently with their expressed values? These questions have never been systematically studied. We examine the self-reported moral attitudes and moral behavior of 198 ethics professors, 208 non-ethicist philosophers, and 167 professors in departments other than philosophy on eight moral issues: academic society membership, voting, staying in touch with one's mother, vegetarianism, organ and blood donation, responsiveness to student emails, charitable giving, and honesty in responding to survey questionnaires. On some issues, we also had direct behavioral measures that we could compare with the self-reports. Ethicists expressed somewhat more stringent normative attitudes on some issues, such as vegetarianism and charitable donation. However, on no issue did ethicists show unequivocally better behavior than the two comparison groups. Our findings on attitude-behavior consistency were mixed: ethicists showed the strongest relationship between behavior and expressed moral attitude regarding voting but the weakest regarding charitable donation. We discuss implications for several models of the relationship between philosophical reflection and real-world moral behavior.     

Process demands of rejection mechanisms of recognition memory

A surge of research has been conducted to examine memory editing mechanisms that help distinguish accurate from inaccurate memories. In the present experiment, the authors examined the ability of participants to use novelty detection, recollection rejection, and plausibility judgments to reject lures presented on a recognition memory test. Participants studied a list of word pairs that were arranged in a category relationship (both words from the same category) or an unrelated relationship (both words from different categories) under full or divided attention. At test, participants were given a yes/no recognition test in which they were to respond after seeing the test items for 400 ms or 2,800 ms. Some of the test items were rearranged word pairs that were consistent with the study relationship, whereas others were inconsistent with the study relationship. The results demonstrate that the participants required full attention at study to use novelty detection, recollection rejection, and plausibility judgments to reject lures. Moreover, the results indicate that a long response deadline at test was needed for participants to use both recollection rejection and plausibility judgments to reject lures.     

Research in Adolescent Suicide: Implications for Training,Service Delivery,and Public Policy

Four domains of research in adolescent suicide are reviewed: (1) the role of psychopathology, (2) family history of psychopathology, (3) mental health treatments, and (4) firearms in the home. Based on the extant literature, recommendations are made for changes in training, service delivery, and public policy. Among the recommendations for training professionals are: an emphasis on diagnostic proficiency, skill and attentiveness in the assessment of the entire family unit, and assessment of the availability of firearms in the home. With respect to changes in service delivery, we recommend treatment of the entire family system, and treatment of psychiatric and substance abuse problems in the same setting, and we show the need for a continuum of intensity of care from inpatient to outpatient. With respect to policy changes, we recommended parity of mental and physical health insurance coverage, screening for psychiatrically at-risk youngsters in schools and physicians' offices, providing funding to support a continuum of care between inpatient and outpatient, and gun control laws to restrict access to handguns. We believe that these changes can result in a substantial reduction in the adolescent suicide rate.     

Prosociality enhances meaning in life

A central feature of meaning in life is a consideration of more than oneself. We extend this logic to suggest that altruistically motivated prosociality – acting in ways that benefit others – is a self-transcending action that may provide meaning in life. Study 1 provided evidence of a relationship between self-reported prosocial behavior and meaning in life, even after statistically controlling for personality traits and self-esteem. Study 2 provided evidence that engaging in a prosocial action, via writing notes of gratitude, increased meaning in life. Study 3 provided evidence that individuals bolster perceptions of prosociality following threats to meaning. Study 4 suggested relationship satisfaction partially mediates the link between prosocial actions and meaning in life. These studies provide initial evidence that prosociality enhances meaning in life.