Effects of stimulus variation on the reinforcing capability of nonpreferred stimuli

We examined the effects of stimulus (reinforcer) variation in several different contexts. In Study 1, we identified high-quality (HQ) and low-quality (LQ) stimuli based on results of a paired-stimulus assessment and examined their effects when available under concurrent-reinforcement schedules for 8 participants. No participants showed preference for the LQ stimuli when compared singly or in a varied arrangement to the HQ stimulus. In Study 2, we identified nonpreferred (NP) stimuli based on results of a single-stimulus assessment and examined their effects when available under single-reinforcement schedules for 3 participants. Results of Study 2 were mixed. One participant's data indicated that the varied presentation of NP stimuli produced a modest improvement in performance over that observed when the stimuli were presented singly. By contrast, a second participant's data showed no facilitative effect for the varied delivery of NP stimuli and that the inclusion of an HQ stimulus in the varied arrangement obscured the reinforcing effects of the HQ stimulus. The 3rd participant's data showed no effect for the varied delivery of NP stimuli but an apparent facilitative effect when an HQ stimulus was included in the varied arrangement, which was attributable solely to the presence of the HQ stimulus.     

Breaking the waves: age differences in electrical brain activity when reading text with distractors

The authors tested whether older adults have greater difficulty than younger adults in ignoring task-irrelevant information during reading as a result of age-related decline in inhibitory processes. Participants were shown target sentences containing distractor words. They were instructed to read aloud each sentence and ignore distractors. The N400 event-related potential (ERP) was used to measure the extent of semantic processing of target and distracting information. It showed that younger adults semantically processed both target and distracting material, whereas online processing of target sentences in older adults was disrupted by the distractors. In older adults, memory for target information related to their susceptibility to distraction and inhibition efficiency. Implications for age-differences in inhibitory control, working memory, and resource capacity are discussed.     

Multiple semantic encoding of homophones and homographs in contexts biasing dominant or subordinate meanings

The resolution of lexical ambiguity was studied in two experiments. While subsequent selection would appear to limit longer term storage to one meaning of an ambiguous word, multiple initial encoding of homophones and homographs was indicated by the intrusion of their alternative meanings across trials in a Brown-Peterson paradigm. In Experiment 1 subjects heard four words and then engaged in a 10osec distractor task. Written recall was then demanded. On context trials a homophone with two distinct alternative meanings was presented with other words biasing either a dominant or subordinate meaning, for example, look, stare,peer, glance. On the next trial words related to an alternative meaning were presented, for example, dock, wharf, quay, jetty. Intrusions of the graphic forms of alternative meanings le.g.,PIER) into critical trial recall occurred whether the dominant or subordinate meaning of the homophone had been biased by context. Experiment 2 employed visual presentation of homographs, for example, GOLD, IRON,LEAD, and oral recall, but was logically similar to Experiment 1. Intrusions of the alternative codings of homographs across trials again occurred, for example, GUIDE, DIRECT,lead, regardless of the meaning originally biased by context.     

Color is necessary for face discrimination in the Northern paper wasp,Polistes fuscatus

Animal Cognition - Visual individual recognition requires animals to distinguish among conspecifics based on appearance. Though visual individual recognition has been reported in a range of taxa...     

The Disclosure–Intimacy Link in Computer‐Mediated Communication: An Attributional Extension of the Hyperpersonal Model

The present research investigated whether the attribution process through which people explain self‐disclosures differs in text‐based computer‐mediated interactions versus face to face, and whether differences in causal attributions account for the increased intimacy frequently observed in mediated communication. In the experiment participants were randomly assigned to a face‐to‐face or computer‐mediated interaction with a confederate who made either high‐ or low‐intimacy self‐disclosures. Results indicated that computer‐mediated interactions intensified the association between disclosure and intimacy relative to face‐to‐face interactions, and this intensification effect was fully mediated by increased interpersonal (relationship) attributions observed in the computer‐mediated condition. The article presents an attributional extension of the hyperpersonal model ( Walther, 1996 ) by demonstrating the role of causal attributions in interpersonal intensification processes in text‐based computer‐mediated interactions.     

Behavioral and electrical brain measures of semantic priming in patients with Alzheimer's disease: implications for access failure versus deterioration hypotheses

This study investigated the nature of anomia and semantic memory deficits in patients with Alzheimer's disease (DAT). We measured reaction time (RT) and the N400 event-related brain potential (ERP) in a word-picture semantic priming paradigm for DAT patients and elderly controls. For patients, pictures were classified as a function of the individual's naming ability to determine whether naming deficits reflected a failure to access a picture's name or reflected a deterioration of its semantic representation. As expected, DAT patients had significantly poorer naming performance than controls. For successfully named pictures, robust RT and ERP priming effects were obtained in both groups. In DAT patients, priming for unnamed pictures was heterogeneous. The results are discussed in terms of current hypotheses of semantic memory deficits in DAT.     

The medical student experience with disasters and disaster response

Medical students from New York City were integrally involved in the response by health professionals to aid the families of victims of the September 11, 2001, attacks on the World Trade Center. The present study was performed to investigate the emotional impact of this involvement on medical students from the Mount Sinai School of Medicine in New York City. One hundred fifty-seven students responded to a mail survey that explored their personal and professional involvement in the disaster as well as their psychiatric symptoms in the week after the event and at the time of the survey (3.5 months after the event). Findings suggested a differential emotional impact on female students and on students involved in less supervised and more emotionally intense activities. However, involvement in the relief effort, per se, did not contribute to psychiatric symptomatology. It may have been associated with enhanced professional self-esteem among the students. These findings have implications for future planning of psychiatric response to disasters.