Parasitic egg rejection decisions of chalk-browed mockingbirds <Emphasis Type="Italic">Mimus saturninus</Emphasis> are independent of clutch composition

Obligate avian brood parasites lay their eggs in nests of other host species, which assume all the costs of parental care for the foreign eggs and chicks. The most common defensive response to parasitism is the rejection of foreign eggs by hosts. Different cognitive mechanisms and decision-making rules may guide both egg recognition and rejection behaviors. Classical optimization models generally assume that decisions are based on the absolute properties of the options (i.e., absolute valuation). Increasing evidence shows instead that hosts’ rejection decisions also depend on the context in which options are presented (i.e., context-dependent valuation). Here we study whether the chalk-browed mockingbird’s (Mimus saturninus) rejection of parasitic shiny cowbird (Molothrus bonariensis) eggs is a fixed behavior or varies with the context of the clutch. We tested three possible context-dependent mechanisms: (1) range effect, (2) habituation to variation, and (3) sensitization to variation. We found that mockingbird rejection of parasitic eggs does not change according to the characteristics of the other eggs in the nest. Thus, rejection decisions may exclusively depend on the objective characteristics of the eggs, meaning that the threshold of acceptance or rejection of a foreign egg is context-independent in this system.     

Effects of a videotape information intervention for spouses on spouse distress and patient recovery from surgery.

Shortly before hospital release, the spouses of 226 male and 70 female coronary artery bypass graft patients were randomly assigned to view an optimistically slanted information tape, a tape that featured coping with more ups and downs, or no tape at all. Results indicated that women, whether as patients or as caregivers, were at elevated risk for a variety of negative outcomes during the subsequent 6 months. However, female patients who had spouses in the optimistic, mastery-tape condition were protected from the elevated levels of problems that characterized women whose spouses received only standard discharge preparation. Results are discussed in relation to research on optimism effects and work that suggests men may generally be less effective caregivers than women.     

Effects of preoperative roommate assignment on preoperative anxiety and recovery from coronary-bypass surgery

This study examined the effect of preoperative roommate assignment on the preoperative anxiety and postoperative recovery of 27 male coronary-bypass patients. Patients were assigned preoperatively to a roommate who was either similar or dissimilar in his surgical status (preoperative vs. postoperative, respectively) and either similar or dissimilar in his type of operation (cardiac vs. noncardiac, respectively). The results indicated that the similarity/dissimilarity of a roommate's surgical status exerted important effects. Specifically, patients who before their operations had a postoperative roommate were less anxious preoperatively, were more ambulatory postoperatively, and were released more quickly from the hospital than patients who before their operations had a preoperative roommate. In contrast, the similarity/dissimilarity of the roommate's type of operation exerted no significant effects either separately or in interaction with the similarity of the roommate's surgical status. Theoretical implications, possible mechanisms, and practical implications for hospital policy are discussed.     

Social support and recovery from surgery

This study examined the relationship of naturally occurring social support from the spouse with the preoperative anxiety and postoperative recovery of 56 male coronary-bypass patients. Patients were divided into groups based on whether the overall quality of their marital relationship was perceived to be relatively good or bad at the time of surgery and on whether they received relatively high or low spouse support in the hospital (defined in terms of frequency of visits). A fifth group (n = 16), consisting of unmarried patients, enabled additional comparisons. The results indicated that, although groups were essentially equivalent in preoperative physical status, married patients who received higher hospital support took less pain medication and recovered more quickly than their low-support counterparts. In contrast, perceived quality of the marital relationship was a relatively insignificant factor. Speed of recovery for unmarried patients was generally slower than for married, high-support patients and faster than for married, low-support patients.     

Presence and television.

Film and a number of emerging entertainment technologies offer media consumers an illusion of nonmediation known as presence. To investigate the possibility that television can evoke presence, 65 undergraduate students were shown brief examples of rapid point‐of‐view movement from commercially available videotapes on a television with either a small screen (12 inches [30.5 cm], measured diagonally) or a large screen (46 inches [116.8 cm]). Participants' responses were measured via a questionnaire and a computer‐based recording of arousal (electrodermal activity). Viewers of both televisions reported an enjoyable sense of physical movement, excitement, involvement, and a sense of participation. Furthermore, as predicted, participants who watched the large screen television thought the movement in the scenes was faster, experienced a greater sense of physical movement, enjoyed the movement to a greater extent, found the viewing experience more exciting, and were more physiologically aroused. Practical and theoretical implications are discussed.