The optimum decision rules in thesame-different paradigm

In this paper we derive the optimum (likelihood-ratio) decision statistic for asame-different paradigm. The likelihood ratio is dependent on the degree of correlation between the two observations on each trial. For the two extreme cases in which the observations are either independent or highly correlated, the optimum decision rule is identical to each of two previously suggested decision rules. For these two cases, the receiver-operating characteristic (ROC) curves are calculated. Finally, an experimental procedure is suggested for assessing the decision rule actually used by the observer in asame-different task.     

The optimum decision rules for the oddity task

This paper presents the optimum decision rule for an m-interval oddity task in whichm-1 intervals contain the same signal and one is different or odd. The optimum decision rule depends on the degree of correlation among observations. The present approach unifies the different strategies that occur with “roved” or “fixed” experiments (Macmillan & Creelman, 1991, p. 147). It is shown that the commonly used decision rule for anm-interval oddity task corresponds to the special case of highly correlated observations. However, as is also true for thesame-different paradigm, there exists a different optimum decision rule when the observations are independent. The relation between the probability of a correct response andd’ is derived for the three-interval oddity task. Tables are presented of this relation for the three-, four-, and five-interval oddity task. Finally, an experimental method is proposed that allows one to determine the decision rule used by the observer in an oddity experiment.     

Evaluation of maximum-likelihood estimators in nonintensive auditory psychophysics

This is a brief report on the use of maximum-likelihood (ML) estimators in auditory psychophysics. Slope parameters of psychometric functions are characterized for three nonintensive auditory tasks: forced-choice discrimination of interaural time differences (ΔITD), frequency (Δf), and duration (Δt). Using these slope estimates, the ML method is implemented and threshold estimates are obtained for the three tasks and compared with previously published data. ΔITD thresholds were additionally measured for human observers by means of two other psychophysical procedures: the constant-stimuli (CS) and the 2-down 1-up methods (Wetherill & Levitt, 1965). Standard errors were smallest for the ML method. Finally, simulations showed ML estimates to be more efficient than the CS andk-down 1-up procedures fork=2 to 5. For up—down procedures, efficiency was highest fork values of 3 and 4. The entropy (Shannon, 1949) of ML estimates was the smallest of the simulated procedures, but poorer than ideal by 0.5 bits.     

Subordinate Performance, Leader-Subordinate Compatibility, and Exchange Quality in Leader-Member Dyads: A Field Study

A model examining factors related to quality of exchange in leader-member dyads was developed and tested. Subordinates and supervisors in 223 dyads in a manufacturing setting provided demographic data and completed measures of performance and attitude towards work. Results found organization citizenship behaviors, leader-member attitude similarity, and similarity of education to be related to quality of leader-member exchange.     

Influences of job type, job status, and gender on achievement motivation

This study explored two issues. First, the stereotype was explored that teachers are lower in intrinsic achievement motivation than those in other occupations; second, that job type, job status, and/or gender influence intrinsic achievement motivation. Job type was explored based on the stereotype of a high achievement motivation condition (banking) versus a low condition (teaching). Job status was examined as currently working versus retirement from the occupation. Gender referred to sex, male and female. Each of the eight cells of a 2x2x2 factorial design contained 15 subjects randomly drawn from population pools (N=264) screened for membership on specific age, years of employment, and years of retirement. Intrinsic achievement motivation was assessed by the four factors of the Helmreich and Spence (1974) Work and Family Orientation Questionnaire (WOFO). Data were analyzed for main and interaction effects using multivariate analysis of variance (MANOVA). No support was found for the proposition that banking personnel are higher in motivation than teachers. On the second issue, gender and job status yielded statistically significant effects, suggesting that a person’s gender and whether he is working or retired both exert an influence upon his intrinsic achievement motivation.     

Change in affective state assessed by impaired color-naming of threat-related words

This study investigated the effects of mood induction on Stroop color-naming times for threat-related words. The subjects’ task was to color-name sets of threat-related words and affectively neutral matched control words both before and after mood-induction. Subjects were shown a short film about the medical effects of nuclear war (negative affect manipulation), a humorous cartoon, or no film. A significant and highly reliable color-naming decrement of the threat-related words was observed only after the negative affect manipulation. This indicates that the attentional bias towards the processing of threat-related material observed in clinically anxious or high Trait-Anxious subjects can be induced in initially nonanxious subjects. An incidental recall task included in the procedure provided no evidence of mood state dependent recall.     

Stories we tell each other: A comparison of families' and their therapists' explanations of presenting problems

This study reports the explanations of presenting problems given by 10 mothers of children referred to a department of child and family psychiatry and their therapists. Video-recordings of therapists' pre-session meetings and the initial therapy sessions were searched for explanatory statements. These statements were then coded. It was found that therapists referred to past events, present circumstances, relationships, and possible future events in their explanations of presenting problems significantly more frequently than mothers. It was rare for mothers to speak in terms of past or future events at all. The mothers explained difficulties in terms of character traits significantly more often than did the therapists. The implications of these findings are discussed.Thanks to all of the child and family consultation team at 1 Wolverton Gardens for their participation in this research and particularly to Ruth Kossoff for her great help with organising data collection.     

Infant crying: Acoustics,perception and communication

This paper first reviews briefly the literature on the acoustics of infant cry sounds and then presents two empirical studies on the perception of cry and noncry sounds in their social-communicative context. Acoustic analysis of cry sounds has undergone dramatic changes in the last 35 years, including the introduction of more than a hundred different acoustic measures. The study of cry acoustics, however, remains largely focused on neonates who have various medical problems or are at risk for developmental delays. Relatively little is known about how cry sounds and cry perception change developmentally, or about how they compare with noncry sounds. The data presented here support the notion that both auditory and visual information are important in caregivers' interpretations of infant sounds in naturalistic contexts. When only auditory information is available (Study 1), cry sounds become generally more recognizable from 3 to 12 months of age; perception of noncry sounds, however, generally does not change over age. When auditory and visual information contradict each other (Study 2), adults tend to perform at chance levels, with a few interesting exceptions. It is suggested that broadening studies of acoustic analysis and perception to include both cry and noncry sounds should increase our understanding of the development of communication in infancy. Finally, we suggest that examining the cry in its developmental context holds great possibility for delineating the factors that underlie adults' responses to crying.