Previous research has found that if a population were allowed to exceed a comfortable density level, then many catastrophic events occurred such as increased mortality among the young, cannibalism, homosexuality, and lack of maternal functions. The most influential researcher in this area is Calhoun (1962), after whose experimental design a pilot study was fashioned to replicate his results. The results of this pilot study inspired a more detailed research project of which this thesis is an account. Forty-eight albino mice of the Swiss Webster strain were divided into three groups of sixteen each. Each group consisted of ten females and six males chosen randomly; two groups were to serve as experimental groups and the other group as the control. The experimental groups were placed into apparatus 15 5/8” x 20 1/2"x 8" and the control group in an apparatus 47 7/8" x 61 1/2" x 8". The three groups were allowed to multiply freely with nesting material, food and water provided proportionately as their numbers grew. The experimental groups were allowed to overpopuate while the control group was not. There were six behavior variables noted as the experiment proceeded: (1) grooming, (2) homosexuality, (3) nest building, (4) retrieving of young, (5) fighting, and (6) mortality of the young. It was predicted that grooming, nest building, and retrieving of the young would decrease in frequency as the population increased, while fighting, homosexuality and mortality of the young would increase with the rising population density. The experiment was conducted for six months and fourteen days. The result of this experiment was a total lack of overpopulation. The two experimental groups never weaned any pups though they produced many, and the control group grew to the comfortable limits of its apparatus and then ceased weaning any further pups. In an effort to ascertain the reasons for these results, one of the experimental groups was artificially reduced in number; whereupon it promptly weaned forty-one percent of its first litter, thirty percent of its second, and none of its third. At the time of its first weaning, this group was technically overpopulated. In conclusion a hypothesis is proposed to explain the results. It is felt that each population has an innate knowledge of its comfortable limits with regard to density and will maintain this crucial density level if necessary. The group's ability to control its popu1ation is directly related to a time factor in that if a population were allowed to approach its crucial density level gradually it would not exceed it; however if there were little or no approach time, then this level would be exceeded.

This study examines which and how trait relevant work design characteristics moderate the relationship between proactive personality and engagement. Proactive personality is defined as an individual's tendency to intentionally and directly affect change in their environment (Bateman & Crant, 1993; Crant, 2000). Previous research has been primarily focused on the positive aspects of proactive personality; to fill this gap, I used trait activation theory (Tett & Burnett, 2003) to identify which work characteristics will activate proactive personality to affect engagement and developed specific hypotheses about which work characteristics will attenuate the proactive personality engagement relationship. In the study I identified five work characteristics (autonomy, feedback from job, problem solving, social support, and feedback from others) that may be moderators of the proactive personality- engagement relationship. Data were collected from 258 participants who worked in organizations located in north and northeast Italy. Data were collected at two time points. At time 1, proactive personality and work design characteristics were collected. Work engagement was collected at time 2. Although main effects for proactive personality and the job characteristics on engagement were found, the data did not support most of the hypotheses in this study. However, supplemental analyses found interesting interactions with regards to the impact of decision making autonomy and feedback from others on the relation between proactive personality and work engagement. The supplemental results suggest that proactive personality may act as a personal resource when work design characteristics are lacking. However, when decision making autonomy or feedback from others is high there is a negative relationship between proactive personality and engagement. The results of this study have several implications for management theory and practice. On the theoretical side there are at least three contributions. First, while the majority of research on PAP has focused on main effects, few studies have identified moderators (Crant, 2000). Second, this study adds to research by extending trait activation theory to apply to how proactive workers view work characteristics. Third, while all work design characteristics coexist simultaneously within a work environment, they are usually discussed individually, not simultaneously. Additionally, the results of this study have implications for practice. The results of this study suggest that organizations should consider the work design characteristics and their impact on proactive workers prior to selecting proactive workers. Also organizations who are interested in employing proactive workers can use the results of this study to optimize the success of both high- and low-proactivity workers. By having a more in depth understanding of how work design characteristics impact proactive people organizations will be better able to meet an employee's needs, and the theoretical understanding of proactive personality is advanced.

In this study, it was proposed that the extent to which an individual accepts the collection of attitudes, mannerisms, and abilities the culture endorses as being feminine or masculine (which we are referring to as sex-role orientation) is related to the appearance of inhibiting fears of social rejection and uneasiness about one’s femininity (which we refer to as the need or motive to avoid success). We further hypothesized that women interested in achievement, being less strongly sex-typed, would feel deviant and exposed as women and would be likely to place a premium on the maintenance of other feminine attributes. Ever since Freud’s time, the suppression of aggression has been identified as the very essence of femininity. This pinpointing of aggression as a particularly differentiating quality between male and female has been maintained by some to the present. We proposed that this particularly feminine quality (which we refer to as fear of aggression) would appear more strongly in masculinely-oriented women. Horner proposed in her original study that the motive to Avoid Success is a psychological barrier to achievement in women. When aroused, the motive to avoid success is a most effective suppressant of performance in a competitive situation (especially if the competitor is masculine). This finding raised the suspicion in our minds that it might be the aggressive qualities inherent in competition that makes it seem especially incompatible with femininity. The aggressiveness of competition, of course, resides in the implicit set to defeat another person, to overpower an adversary, and to gain the psychological advantage. In order to obtain a high grade or graduate with distinction or secure the best job, you must defeat a peer. We hypothesized finally, that not only would fear of aggression and Motive to Avoid Success (M-S) each be related to sex-role orientation, but that these two inhibitors would be positively correlated with each other. Our Ss were 173 white college women from introductory psychology classes at Portland state University. To test our hypotheses that inhibition of aggression and Motive to Avoid Success would each be related to an individual's sex-role orientation, we used the following measures: The Gough femininity-masculinity scale and Franck Drawing Completion test to assess manifest and latent levels of M-F respectively; Horner's thematic cues to elicit Motive to Avoid Success; and a tachistoscopically-presented series of visual stimuli to assess the Ss tendency to inhibit aggression. Results indicated that fear of aggression is related to sex-role orientation in the expected direction, i.e., more masculinely-oriented women appear more likely to suppress aggression. The M-S was also related to a particular constellation of sex-role orientations but not the expected set. Unlike the fear of aggression, high M-S was related primarily to those individuals who held masculine orientations at the manifest level only. Considering that both M-S and fear of aggression were related to masculine orientations in women, it was puzzling that these two measures were negatively correlated.

Forty-five male, Sprague Dawley rats were used to determine if external stimuli could influence the length of a conditioned taste aversion. Animals were given a novel taste (sucrose), and then injected with one of three different substances, marihuana, LiCI, or saline. The animals were then placed into either a stimulation condition, a non-stimulation condition, or returned to the home cage. The stimulation condition contained aversive stimuli in the form of bright, flashing lights and loud noises. The other conditions had no aversive stimulation. It was expected that the animals receiving injections of marihuana would have an increase in their responsiveness to events in their environment, and thus be more sensitive to the aversive stimulation. By reacting to not only the internal toxicosis, but also the aversive external stimulation, it was hoped that the animals would undergo a more totally aversive experience in the stimulation condition. This increase in discomfort with the addition of external aversive stimuli was expected to be reflected in the development of longer conditioned aversions in animals receiving the marihuana and stimulation. The LiCI group was expected to show no reactiveness to the external aversive stimuli. Although taste aversions did develop in the marihuana and LiCI groups, no differences were found between treatment conditions nor between toxins. This study shows that external aversive stimuli do not play a role in an animal's conditioned aversion to sucrose after injection of a toxic drug such as marihuana or LiCI.

One of the goals of neuroscience is to classify all of the neurons in the brain. Neuronal types can be defined using a combination of morphology, electrophysiology, and gene expression profiles. Gene expression profiles allow differentiation between cells that share similar characteristics. Leveraging the advantage of Berghia stephanieae (Gastropoda; Nudibranchia), which has around 28,000 neurons, I constructed high-throughput single-neuron transcriptomes for its whole brain. I produced a single-cell dissociation protocol and a custom data analysis pipeline for data of this nature. Around 129,000 cells were collected from 18 rhinophore ganglia and 20 circumesophageal ring ganglia (brain), consisting of the cerebropleural, pedal, and buccal ganglia. Messenger RNA libraries were constructed using the 10X Genomics’ Chromium platform. After library preparation, around 1,000 cells were recovered and sequenced. The HTStream package was utilized to trim off unwanted sequences from the raw reads and remove PCR duplicates and other contamination, then the salmon alevin package was employed to construct gene-by-cell matrices containing all the transcripts for each gene in each cell. The Seurat pipeline was used to extract this expression data from the matrices, normalize it, and perform dimensionality reduction. The cells were clustered based on similarities in their gene expression profiles. The cells formed eight clusters on a UMAP graph, each having distinct marker genes. Additionally, one cluster was composed of almost exclusively cells from the rhinophore ganglia, accounting for 30% of all rhinophore ganglion cells in the sample. Cells from the rhinophore ganglia are as heteregenous as cells from the rest of the brain, with cells forming six clusters. Cell populations that express the same neurotransmitter were identified for a wide range of both small-molecule neurotransmitters and neuropeptides. In a separate project, the locomotion of Berghia was recorded over 9 days with 2 lighting regimes: LD first and DD first. The results suggest that locomotion of Berghia is governed by circadian clock and that Berghia is nocturnal. Hunger state likely plays a role in modulating this circadian rhythm.

Economic pressure and concomitant financial stress have been associated with mental and physical health problems, conflict, and poorer education and employment outcomes. Moreover, financial stress can be seen in specific hardships (e.g., food insecurity) and lead to maladaptive attempts to regulate emotions stemming from financial stressors. Women may be more vulnerable to consequences of food insecurity and attempts to regulate emotions with eating than men. Thus, the current study examined the impact of a randomized financial stress induction on affect and snack food choice while accounting for the influence of food insecurity and gender. Participants included 269 validly responding individuals. Participants completed a measure of implicit affect prior to as well as following random assignment to one of three possible financial stress inductions with varying levels of stress. Participants then predicted the food items they would eat and their overall desired for a specific food from an array of unhealthy snack foods items. Food insecurity was associated with higher stress response to the stress induction, which was experimentally shown to increase negative affect. Positive affect after the stress induction associated with increased desire for snacks among females but not their male counterparts. Additionally, female participants with difficulties with emotion regulation reported higher desire for snacks as compared to their male peers. Future research should include examination of emotion regulation, food insecurity, and gender differences.

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The 2 goals of the present investigation were to 1) examine the reliability of the Children’s Behavior Questionnaire: Short Form (CBQ) in a sample of 4-7 year-old children from the Ukraine and 2) compare those children’s temperament profiles to a) one another when the form was administered in 2 different languages and b) their American counterparts from the CBQ standardization sample. Three waves of data were collected from the parents of 167 children residing in Kiev, Ukraine. Internal reliability analyses showed good internal consistency of the instrument. Comparative analyses conducted both within and between cultures showed similarities and differences across the 15 CBQ dimensions. The observed differences were in the predicted directions: Ukrainian children were rated higher than American children on dimensions reflecting negative affectivity. However, the language of the instrument was a mitigating factor. This finding supports the possibility that parental ethnotheories are embedded in specific languages.

Casual sex is common on college campuses and is potentially relevant to a person's self-esteem. Unfortunately, data are mixed regarding how self-esteem is influenced by casual sex. This thesis is an attempt to understand how casual sex influences women's self-esteem through a series of questionnaires. Three hypotheses were of interest. The first predicted that sociosexuality and desire would explain casual sex engagement. Second, that casual sex behaviors and attitudes would predict self-esteem. Third, looking only at those who engaged in casual sex; casual sex attitudes and affect would predict self-esteem. Using hierarchical regression, results indicated that there was a curvilinear effect for sociosexuality on number of casual sex partners. Results for the second hypothesis showed an interaction between behavior and attitudes to predict selfesteem. Finally, for hypothesis three, results showed a moderation effect for attitudes on negative affect regarding overall casual sex experience and self-esteem.