A method for identifying eggs laid by individual birds

A method for identifying eggs laid by different subsections or individual members of groups of domestic hens is described. Fat-soluble dyes are placed in gelatin capsules and fed to selected birds. These dyes produce discrete colored bands in the yolks of eggs laid by those birds. The presence of dye in eggs can be detected through the shell, and different patterns of rings can be distinguished by boiling and sectioning eggs. Application of the method to other species and other circumstances is considered.     

A low-stress restraint procedure for EEG acquisition in awake rats

A restraint procedure was developed to reduce movement-related artifacts during the acquisition of EEG data from unanesthetized, unparalyzed rats. It combines the low-stress properties of a cloth restraint bag with the improved immobility of a rigid restraint device. The spontaneous behavior of the rat facilitates both the induction of and the subsequent release from restraint.     

The relationship of mathematics self-efficacy expectations to the selection of science-based college majors

The major purpose of the present study was to investigate the relationship of mathematics self-efficacy expectations to the selection of science-based majors in college males and females. Based on results obtained from a pilot sample of college students, an instrument assessing mathematics self-efficacy expectations was developed. The items used in the mathematics self-efficacy scale included everyday math tasks, math problems, and math-based college courses. Subjects, 153 female and 109 male undergraduates, completed the mathematics self-efficacy scale, the Bem Sex Role Inventory, an adapted version of the Fennema-Sherman Mathematics Attitudes Scales, and a questionnaire concerning their college major choices. Results indicated that mathematics self-efficacy expectations were significantly related to the extent to which students selected science-based college majors, thus supporting the postulated role of cognitive mediational factors in educational and career choice behavior. In addition, the math-related self-efficacy expectations of college males were significantly stronger than were those of college females. Implications of the findings for the process of educational and career decision-making are discussed.     

The relative efficacy of simulation experiments

A complex in-basket simulation and a paper-and-pencil scenario experiment were used to study relationships between organizational leadership and gender. Separate samples completed identical attitude instruments in the independent studies. Analysis revealed that substantially more of the total variance was accounted for in the simulation study than in the scenario investigation. Also, more overt, gender-based responses were observed in the scenario study. It was concluded that social simulation may tap a deeper level of psychological process and may elicit more subject involvement than typical experimental methods. Thus, the more complex procedures of the simulation, as compared to those of a typical method such as a scenario study, are justified in the study of organizational behavior.     

The effect of sound on visual apparent movement

Twelve subjects found the longest possible interstimulus interval (ISI) at which they perceived continuous apparent motion of one light instead of partial motion or succession between two lights. In the visual condition, two lights only were presented. In the bimodal conditions, binaurally presented tones were presented synchronously with the lights, and the lights and tones were either spatially congruent (in phase) or incongruent (180 degrees out of phase). Bimodal presentations lowered the upper ISI threshold for the perception of visual apparent motion, and the reduction was greater when the tones and lights were spatially congruent. The threshold reduction may be caused by a perceptual inference about localization of the lights in space or by a change in visual persistence.     

Learned helplessness in groups

Group learned helplessness is demonstrated in Experiment I. Groups of 2 tried to turn off noise by their joint action. In the solvable group (S), noise offset was contingent on their sequence of button pushing. In the yoked, unsolvable group (U), noise offset was independent of all sequences of button pushes they produced. In a practice group (O). subjects practiced coordinated sequences of button pushes with their partners, but heard no noise. Later, all 3 groups were tested in pairs in a shuttlebox which required coordinated joint responding to turn off noise. The unsolvable group escaped more poorly than the other 2 groups, paralleling helplessness effects with individuals. Experiment 2 and 3 found no transfer from individual helplessness training to group testing and no transfer from group helplessness training to individual testing. We suggest that the same mechanism, the expectation of response ineffectiveness, may mediate both individual and group learned helplessness.     

Vicarious and operant experiences in the etiology of illness behavior: A replication with healthy individuals

The purpose of the present investigation was to replicate a previous study of diabetic patients on the role of parental modeling in the etiology of illness behavior. A random sample of healthy individuals were assigned to an avoidant model (AM) (i.e. parent reported to have avoided work. chores etc. when ill) or non-avoidant model (NAM) group. Subjects subsequently provided retrospective and current information concerning their illness-behavior experiences. The results indicated that individuals with an AM reported more responsibility avoidance when ill currently and as a child compared to the NAM subjects. Additionally. AM subjects reported receiving more positive reinforcement for current illness compared to NAM subjects. It was concluded that the process by which individuals learn to respond to illness may be similar in healthy and chronically-ill individuals but that positive reinforcement for illness may be more likely to be received by healthy individuals during acute illness than by chronically-ill individuals. The present study provides further preliminary support for the learningtheory model of illness behavior.     

Factor structure of the Menstrual Symptom Questionnaire: relationship to oral contraceptives, neuroticism and life stress

The Menstrual Symptom Questionnaire was administered to initial and cross-validation samples of college-age women. Factor analyses performed on the data from each sample failed to support Dalton's distinction between spasmodic and congestive forms of primary dysmenorrhea. Instead, a more complicated factor structure evolved, closely resembling Webster's findings, with factors representing menstrual pain, pre-menstrual negative affect, pre-menstrual water retention, pre-menstrual pain, menstrual backache and menstrual gastrointestinal symptoms. Oral contraceptive use was negatively related to menstrual pain and backache. Neuroticism scores were positively related to all six factors, and negative life changes to four of these factors, suggesting a role for psychogenic factors in both pre-menstrual and menstrual symptomatology.     

Disrupted retrieval in directed forgetting: a link with posthypnotic amnesia

Certain reliable findings from research on directed forgetting seem difficult to accommodate in terms of the theoretical processes, such as selective rehearsal or storage differentiation, that have been put forward to account for directed-forgetting phenomena. Some kind of "missing mechanism" appears to be involved. In order to circumvent the methodological constraints that have limited the conclusions investigators could draw from past experiments, a new paradigm is introduced herein that includes a mixture of intentional and incidental learning. With this paradigm, a midlist instruction to forget the first half of a list was found to reduce later recall of the items learned incidentally as well as those learned intentionally. This result suggests that a cue to forget can lead to a disruption of retrieval processes as well as to the alteration of encoding processes postulated in prior theories. The results also provide a link between intentional forgetting and the literature on posthypnotic amnesia, in which disrupted retrieval has been implicated. With each of these procedures, the information that can be remembered is typically recalled out of order and often with limited recollection for when the information had been presented. It therefore was concluded here that retrieval inhibition plays a significant role in nonhypnotic as well as in hypnotic instances of directed forgetting. The usefulness of retrieval inhibition as a mechanism for memory updating was also discussed.     

Reconceptualizing of the overjustification effect: A template-matching approach

The paper reviews traditional attributional explanations for the over-justification effect in task motivation, isolates their weaknesses, and proposes an alternative account based on the notion that individuals process task information schematically. It is proposed that task information relating to motivation is interpreted by cognitive schema or “templates,” which identify tasks as being either instrumental or expressive in nature. When the expressive template is evoked, the task is perceived to be playlike and is experienced as inherently motivating. When the instrumental template is evoked, the task is perceived as a means to an end and task motivation results from the perceived value of the task for attaining intrinsic and/or extrinsic rewards. Structural characteristics of these templates are proposed. According to this account, overjustification effects occur when the perceived characteristics of tasks change such that the expressive template is replaced by the instrumental template and expressive motivation is transformed into instrumental motivation.