Community Norms and Blood Donation1

It is suggested that for social psychological theory and research on helping to provide an adequate general explanation of helping, more attention must be paid to supraindividual factors. Most studies of blood donation have failed to take into account a number of factors that may influence donations at the level of the organization, community or collectivity. This study examines the possibility that specific community norms may emerge that have an influence on the donating behavior of community members. Perceived normative support was found to exist in different degrees in communities that provide different levels of behavioral support for bloodmobile visits, and persons who report a greater degree of perceived community support for donation are more likely to have donated in the past year. Implications for donor recruitment procedures are discussed.     

Discrete dynamic choice: An extension of the choice models of thurstone and luce

The present paper deals with the extension of two well-known static discrete choice theories to the dynamic situation in which individuals make choices at several points in (continuous) time. A dynamic version of Luce's Axiom, “independence from irrelevant alternatives”, is proposed and some of its implications are derived. In the static case Yellott (J. Math. Psych. 1977, 15, 109–146) and others have demonstrated that an independent random utility model generated from the extreme value distribution exp(?e^?ax?b) becomes equivalent to Luce's Axiom. Yellott also introduced an axiom called “invariance under uniform expansions of the choice set”, and he proved that within the class of random utility models with independent identically distributed utilities (apart from a location shift) this axiom is equivalent to Luce's Axiom. These results are extended to the dynamic situation and it is shown that if the utility processes are expressed by so-called extremal processes the corresponding choice model is Markovian. A nonstationary generalization is proposed which is a substantial interest in applications where the parameters of the choice process are influenced by previous choice experience or by time-varying exogenous variables. In particular, it is demonstrated that the nonstationary model is Markovian if and only if the joint choice probabilities at two points in time have a particular form. Thus, the paper provides a rationale for applying a specific class of Markov models as the point of departure when modelling mobility processes that involve individual discrete decisions over time.     

A procedural theory of eye movements in doing arithmetic

A procedural theory of eye movement that accounts for main features of the stochastic behavior of eye-fixation durations and direction of movement of saccades in the process of solving arithmetic exercises of addition and subtraction is presented. The best-fitting distribution of fixation durations with a relatively simple theoretical justification consists of a mixture of an exponential distribution and the convolution of two exponential distributions. The eye movements themselves were found to approximate a random walk that fits rather closely in both adult and juvenile subjects the motion postulated by the normative algorithm ordinarily taught in schools. Certain structural features of addition and subtraction exercises, such as the number of columns, the presence or absence of a carry or a borrow, are well known to affect their difficulty. In this study, regressions on such structural variables were found to account for only a relatively small part of the variation in eye-fixation durations.     

The effects of distributed training on retention of operant conditioning in human infants

Long-term retention of operant footkicking acquired in the mobile conjugate reinforcement paradigm was assessed as a function of the distribution of training time. In the first study, 3-month-old infants were trained for either one 18-min session or for two 9-min or three 6-min sessions separated by 24-hr intervals. All infants exhibited retention during a test administered immediately after training, but only those trained in a single session continued to perform the conditioned response during cued-recall tests 7 or 14 days later. Infants trained in three sessions showed no evidence of remembering the contingency even after a week. A warm-up decrement, seen in the day-to-day performance of infants in the distributed conditions, was eliminated in the second study by the interpolation of a nonreinforcement period at the outset of daily sessions. This procedure also enhanced long-term retention such that infants trained in three 6-min session now remembered the contingency for 14 days and did not differ from infants who had received a single 18-min session. Whether distributed training facilitates or impairs long-term retention appears to depend on the opportunity for infants to acquire a sufficient number (or kind) of effective retrieval cues during original learning.     

Spatial representations of young children: the role of self- versus adult-directed movement and viewing

The influence of the control of movement and viewing while exploring a novel large-scale environment was assessed. Forty kindergarteners and forty second grade children served in four activity conditions that represented the factorial combination of movement (self vs adult directed) and viewing (self vs adult directed). A significant grade level X movement X viewing interaction revealed that when kindergarteners directed their own movement, estimates of interlocation distances were equivalent whether viewing was self or adult directed. If movement was directed by an adult, kindergarteners estimated interlocation distances more accurately if the adult also directed their viewing than if the children directed their own viewing. Second grade children performed comparably across all four experimental conditions.     

Variations of the Bender-Gestalt Test: implications for training and practice

Although the Bender-Gestalt Visual Motor Test has been a popular and influential clinical assessment instrument for the last half century, authoritative opinion and a substantial research literature are often inconsistent or contradictory. This paper documents variations in designs, administration procedures, forms, and applications to particular populations. A careful review of scoring systems indicates the current status of objective approaches as contrasted with interpretation that is global, intuitive, and subjective. Some implications of these variations and interpretive procedures for training and assessment practice are discussed. The major conclusions of the review are summarized in seven points.     

A review of projective test findings with older adults

The projective test literature on aging is reviewed. It was concluded that, while much critical research remains to be done and many of the studies are flawed, projective testing has contributed a great deal to the understanding of the aging process and has yielded a core of consistent findings. Suggestions for future research which would help resolve some current ambiguities were made.     

Analgesic and opioid involvement in the shock-elicited activity and escape deficits produced by inescapable shock

Three experiments examined the involvement of analgesic processes and endogenous opioids in the production of the shuttlebox escape acquisition and unconditioned activity deficits which follow exposure to inescapable shock. Experiment 1 found that the opiate antagonist naltrexone administered before the inescapable shock session interfered with the shuttlebox escape acquisition deficit which would normally follow. Experiment 2 found naltrexone to completely prevent the unconditioned activity deficit. The final experiment revealed that dexamethasone, a synthetic glucocorticoid which abolishes the analgesia produced by inescapable shock, reversed the activity deficit. These results indicate that endogenous opioids may be involved in the production of both the escape acquisition and activity deficits. They also suggest that the analgesia produced by these opioids may participate in the mediation of the activity deficit, even though analgesia is not involved in producing the shuttlebox acquisition deficit.     

A developmental-genetic analysis of aggressive behavior in mice: I. Behavioral outcomes

In order to investigate the proposal that modifications in developmental rate may mediate differences in aggressive behavior, two series of selective breeding studies were completed. Stable lines of mice that differed in the frequency and latency of attacks were rapidly established in two series (by S1 in the first series and S3 or S4 in the second series). For evaluation of the developmental-genetic proposal, an analysis was made of the ontogeny of aggressive expression in male mice of the two series, with a detailed report provided of the S1 and S4 generations of the second breeding series. Comparisons between the results of a longitudinal design and the results of a new type of cross-sectional design (involving only siblings, or co-sibial) indicated (a) a reliable developmental course of attack expression, with a sharp rise in early maturity and a slow decline thereafter; (b) a convergence in later maturity of the behavior of lines selectively bred for high or low aggressive behavior, if the animals had been assigned to the longitudinal design; (c) a strong effect of repeated testing on attack latency and frequency, even though the dyadic tests were brief in duration and separated by long intervals. In addition, cross-generational comparisons suggested that the selective breeding differences came about primarily by changes in the behavior of the low aggressive lines, in that these animals failed to show in early maturity the sharp increases in attack occurrence that were observed in earlier generations. Certain implications of these findings for developmental and evolutionary concepts (e.g., neoteny, acceleration, heterochrony) are discussed.