Facilitative orthographic neighborhood effects: the SERIOL model account

A large orthographic neighborhood (N) facilitates lexical decision for central and left visual field/right hemisphere (LVF/RH) presentation, but not for right visual field/left hemisphere (RVF/LH) presentation. Based on the SERIOL model of letter-position encoding, this asymmetric N effect is explained by differential activation patterns at the orthographic level. This analysis implies that it should be possible to negate the LVF/RH N effect and create an RVF/LH N effect by manipulating contrast levels in specific ways. In Experiment 1, these predictions were confirmed. In Experiment 2, we eliminated the N effect for both LVF/RH and central presentation. These results indicate that the letter level is the primary locus of the N effect under lexical decision, and that the hemispheric specificity of the N effect does not reflect differential processing at the lexical level.     

Effects of domain-specific knowledge on memory for serial order

Knowledge concerning domain-specific regularities in sequential structure has long been known to affect recall for serial order. However, very little work has been done toward specifying the exact role such knowledge plays. The present article proposes a theory of serial recall in structured domains, based on Bayesian decision theory and a set of representational assumptions proceeding from recent computational and neurophysiologic research. The theory suggests that the accuracy with which a target sequence will be recalled is influenced by two interacting factors: (1) the 'goodness' of the sequence, i.e. its fit with the sequencing constraints that characterize its source domain, and (2) the sequence's neighborhood relations, i.e. the degree to which it resembles other sequences in the source domain. A specific prediction of the theory is that recall will be relatively poor for target lists with high-goodness near neighbors (the good neighbor effect). This prediction was tested and confirmed in an experiment evaluating recall for sequences based on an artificial grammar.     

Interfering neighbours: the impact of novel word learning on the identification of visually similar words

We assessed the impact of visual similarity on written word identification by having participants learn new words (e.g. BANARA) that were neighbours of familiar words that previously had no neighbours (e.g. BANANA). Repeated exposure to these new words made it more difficult to semantically categorize the familiar words. There was some evidence of interference following an initial training phase, and clear evidence of interference the following day (without any additional training); interference was larger still following more training on the second day. These findings lend support to models of reading that include lexical competition as a key process.     

Age changes in the missing-letter effect revisited

When participants search for a target letter while reading, they make more omissions if the target letter is embedded in frequent function words than in less frequent content words. Reflecting developmental changes in component language and literacy skills, the size of this effect increases with age. With adults, the missing-letter effect is due to both word function and word frequency. With children, it is unclear whether the growing size of the missing-letter effect across development is due to a larger effect of word function, word frequency, or both because previous studies with children seeking to isolate the influence of word frequency and word function suffer from important methodological limitations. With these methodological limitations eliminated (Experiments 1 and 2), performance in a letter detection task was assessed for children in Grades 1, 2, 3, 4, and 7 as well as for undergraduate students. The results revealed that the influence of word function increases with age, whereas the effect of frequency is fairly stable across ages. Furthermore, normative predictability data collected in Experiment 3 revealed that third graders and undergraduate students were equally good at predicting function slots in a sentence.     

Simultaneous visual discrimination in Asian elephants

Two experiments explored the behavior of 20 Asian elephants (Elephas aximus) in simultaneous visual discrimination tasks. In Experiment 1, 7 Burmese logging elephants acquired a white+/black- discrimination, reaching criterion in a mean of 2.6 sessions and 117 discrete trials, whereas 4 elephants acquired a black+/white- discrimination in 5.3 sessions and 293 trials. One elephant failed to reach criterion in the white+/black- task in 9 sessions and 549 trials, and 2 elephants failed to reach criterion in the black+/white- task in 9 sessions and 452 trials. In Experiment 2, 3 elephants learned a large/small transposition problem, reaching criterion within a mean of 1.7 sessions and 58 trials. Four elephants failed to reach criterion in 4.8 sessions and 193 trials. Data from both the black/white and large/small discriminations showed a surprising age effect, suggesting that elephants beyond the age of 20 to 30 years either may be unable to acquire these visual discriminations or may require an inordinate number of trials to do so. Overall, our results cannot be readily reconciled with the widespread view that elephants possess exceptional intelligence.     

On the effects of signaling reinforcer probability and magnitude in delayed matching to sample

Two experiments examined whether postsample signals of reinforcer probability or magnitude affected the accuracy of delayed matching to sample in pigeons. On each trial, red or green choice responses that matched red or green stimuli seen shortly before a variable retention interval were reinforced with wheat access. In Experiment 1, the reinforcer probability was either 0.2 or 1.0 for both red and green responses. Reinforcer probability was signaled by line or cross symbols that appeared after the sample had been presented. In Experiment 2, all correct responses were reinforced, and the signaled reinforcer durations were 1.0 s and 4.5 s. Matching was more accurate when larger or more probable reinforcers were signaled, independently of retention interval duration. Because signals were presented postsample, the effects were not the result of differential attention to the sample.     

Memory for action events: findings in neurological patients

Encoding action phrases by enacting leads normally to better memory performance than verbal encoding. In order to gain additional insight into the representational basis of the enactment effect, neurological patients are contrasted with healthy participants. Persons suffering from Parkinson's disease, which primarily impairs the motor system, and patients suffering from Frontal Lobe Syndrome, which primarily affects action-related planning processes, were involved. We investigated whether the enactment effect would be differentially affected by these disorders. In addition, the characteristics of information processing after encoding by enacting was analyzed by varying memory material (unrelated versus clusterable actions) and by adding an encoding condition that included obligatory action planning (director condition). The findings indicate that the impact of motor information for the enactment effect is not dominant compared to the role of action-related cognitive and motivational processes, in particular planning processes. The findings of the two experiments are explained within traditional conceptual memory theories.     

Evaluation of a High School Peer Group Intervention for At-Risk Youth

The purpose of this paper is to examine the effectiveness of Reconnecting Youth, a prevention program for at-risk high school youth. Data are from a large, independently evaluated effectiveness trial in two diverse urban school districts. A total of 1,218 students participated; 50% were male; average age was 15. We tested whether positive efficacy trial effects could be replicated, and whether any negative behavioral effects occur when clustering high-risk youth. Although mixed program effects were observed at immediate post-intervention, only negative effects were found at 6-month follow-up. These effects included less optimal scores on measures of GPA, Anger, School Connectedness, Conventional Peer Bonding, and Peer High-Risk Behaviors. Overall, we found little support for the use of this social-influence—model intervention aimed at increasing school connectedness for high-risk youth. Further, this study provides evidence that clustering high-risk youth in preventive interventions has the potential for iatrogenic effects.     

The Double Life of Double Effect

The U.S. Supreme Court's majorityopinion in Vacco v. Quill assumes thatthe principle of double effect explains thepermissibility of hastening death in thecontext of ordinary palliative care and inextraordinary cases in which painkilling drugshave failed to relieve especially intractablesuffering and terminal sedation has beenadopted as a last resort. The traditionaldoctrine of double effect, understood asproviding a prohibition on instrumental harmingas opposed to incidental harming or harming asa side effect, must be distinguished from otherways in which the claim that a result is notintended might be offered as part of ajustification for it. Although double effectmight appropriately be invoked as a constrainton ordinary palliative care, it is not clearthat it can be coherently extended to justifysuch practices as terminal sedation. A betterapproach would reconsider double effect'straditional prohibition on hastening death as ameans to relieve suffering in the context ofacute palliative care.     

The placebo effect in popular culture

This paper gives an overview of the placebo effect in popular culture, especially as it pertains to the work of authors Patrick O’Brian and Sinclair Lewis. The beloved physician as placebo, and the clinician scientist as villain are themes that respectively inform the novels, The Hundred Days and Arrowsmith. Excerpts from the novels, and from film show how the placebo effect, and the randomized clinical trial, have emerged into popular culture, and evolved over time. An earlier version of this paper was presented at an international conference, “Placebo: Its Action and Place in Health Research Today,” held in Warsaw, Poland on 12–13 April, 2003.