Psychology
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Item The structure and perception of budgerigar (Melopsittacus undulatus) warble songs(2009) Tu, Hsiao-Wei; Dooling, Robert J; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The warble song of male budgerigars (Melopsittacus undulatus) is an extraordinarily complex, multi-syllabic, learned vocalization that is produced continuously in streams lasting from a few seconds to a few minutes without obvious repetition of particular patterns. As a follow-up of the warble analysis of Farabaugh et al. (1992), an automatic categorization program based on neural networks was developed and used to efficiently and reliably classify more than 25,000 warble elements from 4 budgerigars. The relative proportion of the resultant seven basic acoustic groups and one compound group is similar across individuals. Budgerigars showed higher discriminability of warble elements drawn from different acoustic categories and lower discriminability of warble elements drawn from the same category psychophysically, suggesting that they form seven perceptual categories corresponding to those established acoustically. Budgerigars also perceive individual voice characteristics in addition to the acoustic measures delineating categories. Acoustic analyses of long sequences of natural warble revealed that the elements were not randomly arranged and that warble has at least a 5th-order Markovian structure. Perceptual experiments provided convergent evidence that budgerigars are able to master a novel sequence between 4 and 7 elements in length. Through gradual training with chunking (about 5 elements), birds are able to master sequences up to 50 elements. The ability of budgerigars to detect inserted targets taken in a long, running background of natural warble sequences appears to be species-specific and related to the acoustic structure of warble sounds.Item Cognitive and Motivational Parameters in Motivated Biases in Human Judgment(2009) Chen, Xiaoyan; Kruglanski, Arie W.; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Motivational and cognitive factors can determine the extent and direction of information processing in judgment. When biasing motives are present, information can be distorted and judgment biased. The extent of this bias can be determined by the nature of the information, the relative magnitude of competing goals, and the individual's cognitive resources. Studies 1, 2 and 3 explored the effect of resource depletion on motivated distortions in judgment. Studies 4 and 5 examined the role of relative goal magnitude (of a biasing goal vs. a specific judgment goal) in the phenomena. I departed from the assumption that human knowledge is malleable, and that its alteration in a motivationally desirable direction may vary in difficulty across instances. It was assumed that overcoming the difficulty requires cognitive and/or motivational resources hence under certain circumstances resource-depletion should diminish individuals' ability to motivationally bias judgments. I also hypothesized when information is clear-cut (rather than ambiguous) making distortion difficult, a sufficient amount of biasing motivation could overcome the "reality constraints," holding the cognitive resources constant. In my first two studies participants' resources were depleted either via complex or simple presentational format of the information given (Study 1), or via engagement in a fatiguing prior activity (Study 2). In the third study (Study 3), I measured participants' stable cognitive capacity as a proxy for their available cognitive resources. All three studies provided supportive evidence for the hypothesis that motivated distortion is resource dependent. In Study 4 I manipulated the relative goal magnitude by experimentally increasing goal importance for either an academic success goal in line with the specific judgment task or a social wellbeing goal as the biasing goal. In Study 5 I altered relative goal magnitude through enhancing either a neutral goal or health concerns as the biasing goal. In both Study 4 and 5, orthogonal to the relative goal magnitude manipulation, stimulus ambiguity was made either high or low. Findings from Study 4 and 5 supported the hypothesis that sufficient magnitude of biasing goal could overcome distortion difficulty even in highly constraining circumstances.Item Caffeine Abstinence during the Menstrual Cycle: An Evaluation of Mood, Somatic, Cognitive, and Psychomotor Effects of Withdrawal(2008) Vo, Hoa Thi; Smith, Barry D; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The purpose of the present study was to extend our understanding of caffeine withdrawal symptoms and of potentially differing symptom patterns across phases of the menstrual cycle. Forty-eight moderate habitual caffeine consumers, age 18 to 25 years, were recruited from the University of Maryland. Exclusion criteria included current or past psychiatric conditions (within six months) and premenstrual syndrome (PMS). In addition to daily diaries (including the caffeine intake survey, premenstrual syndrome questionnaires, LH surge test, and the caffeine withdrawal checklist), the effect of caffeine abstinence on psychomotor tasks was assessed during the follicular (around day 5 of the cycle) and luteal phases (approximately 4 days after the LH surge) of the menstrual cycle. Data analyses focused on withdrawal symptom ratings and psychomotor performance one day during the follicular phase and one day during the luteal phase of the cycle after 24 hours of caffeine abstinence. A series of repeated measures ANOVAs were used to assess caffeine withdrawal effects and differences in these effects between the follicular and luteal phases. Results confirmed the presence of certain withdrawal symptoms, but did not provide support for phase-differentiated effects of self-reported withdrawal symptoms or of psychomotor and cognitive performance differentials across the menstrual cycle. However, withdrawal, as a result of caffeine abstinence, did impact self-report symptom ratings during select days of abstinence, as compared with days of non-abstinence, during the both the follicular and the luteal phase. The present study is the first multi-method study to examine the effects of caffeine abstinence on habitual consumers across the menstrual cycle.Item HEAD-EYE COORDINATION DURING A NATURAL TAPPING TASK(2009) Herst, Andrew Neal; Dougherty, Michael R; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This thesis describes the research of Herst et al. (2001) who examined the coordination of head and eye movements while participants searched for targets under natural conditions in which the head was free to move. This investigation was done because, while the technical difficulties in measuring these patterns of head-eye coordination in humans have been overcome, the results obtained over the last 35 years have yet to show what the typical pattern of head-eye coordination looks like. Herst et al. (2001) described the `natural' temporal coordination of head and eye of four participants who tapped a sequence of targets arranged in 3D on a worktable in front of them. The results were not expected based on prior studies of head-eye coordination performed under less natural conditions. This thesis reinterprets the original (2001) findings and draws new conclusions in the light of new research on head-eye coordination conducted since then.Item THE EFFECT OF GOAL DISTANCE ON GOAL VALUE AND ESCALATION OF COMMITMENT(2009) Ting, Hsuchi; Wallsten, Thomas S; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Escalation of commitment describes individuals' tendencies to persist in a chosen course of action. The traditional account of escalation of commitment assumes that sunk cost is the primary antecedent for this behavior. However, it has been noted that high sunk costs are confounded with progress made toward a goal and hidden payoff information. Thus, the apparent escalation tendency may be a consequence of goal proximity and information search rather than of sunk costs. Experiments 1 and 2 show that individuals' tendencies to escalate reflect the classical goal-gradient effect after controlling for the sunk costs. Moreover, Experiment 1 also shows that controlling for progress toward the goal, increased sunk costs decreases escalation. In addition, Experiment 2 shows that individuals attribute more value to the goal as they get closer to it, thus providing an alternative explanation for escalation of commitment. Experiments 3a and 3b demonstrate that individuals committed to a course also devalue other course of actions not chosen. These results suggest a new interpretation for escalation of commitment and new approaches to guiding people to avoid it.Item Social Exclusion and the Choice of Important Groups(2009) Fishman, Shira; Kruglanski, Arie W.; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Social connections are fundamental to our existence. As a result, social exclusion is a painful and distressing experience. When belonging is thwarted, people seek inclusion which can be achieved through group membership. Thus, excluded individuals and/or those whose need to belong is particularly strong will be particularly motivated to join groups. Moreover, to the extent that the need to belong is satisfied by closeness with other group members, and closeness is a feature of group cohesion, excluded individuals or ones with a strong need to belong are likely to be attracted to highly cohesive groups. Finally, the subjective importance of a group to its members should determine the degree of perceived cohesion. Importance of a group is defined as the group's centrality to individuals' social identity. The more central a given dimension is to one's identity, the greater the attraction to individuals sharing that dimension (Byrne, 1961). Hence, the more important the group, the greater the attraction of the members to each other, defining group cohesion. Ultimately then, the greater the individuals' prior experience of exclusion or the greater their need to belong, the greater their motivation should be to join important (vs. less important) groups. These notions are investigated in the present dissertation. A review of the literature on social exclusion and the similarity-attraction hypothesis is presented followed by two studies showing that, both in the lab and in the real world, individuals who have been socially excluded want to join and/or feel more connected to important groups.Item SOCIAL ATTENTION THEORY: A NEW LOOK AT KNOWLEDGE FORMATION IN GROUPS(2009) Shteynberg, Garriy; Gelfand, Michele J; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Individuals in crowded theaters, stadiums and lecture halls know that they attend to the events on the stage, on the field, and at the podium with others. Extending the literature on social foundations of knowledge formation, Social Attention Theory posits that knowingly attending to a stimulus with one's group renders that stimulus more cognitively accessible in memory. The theory is tested across three studies where participants attend to stimuli such as words (study 1), goals (study 2), and time pressure (study 3) with members of their group or a control group. Across all three experiments, participants exhibited greater cognitive accessibility for the stimuli attended to with their group (i.e., similar others). Results also showed that individuals felt more social when attending to stimuli with their group, but did not feel happier, more motivated or more alert.Item Testing a dynamic account of neural processing: Behavioral and electrophsyiological studies of semantic satiation(2008-08-13) Tian, Xing; Dougherty, Michael; Neuroscience and Cognitive Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)In everyday perception, we easily and automatically identify objects. However, there is evidence that this ability results from complicated interactions between levels of perception. An example of hierarchical perception is accessing the meaning of visually presented words through the identification of line segments, letters, lexical entries, and meaning. Studies of word reading demonstrate a dynamic course to identification, producing benefits following brief presentations (excitation) but deficits following longer presentations (habituation). This dissertation investigates hierarchical perception and the role of transient excitatory and habituation dynamics through behavioral and neural studies of word reading. More specifically, the effect of interest is 'semantic satiation', which refers to the gradual loss of meaning when repeating a word. The reported studies test the hypothesis that habituation occurs in the associations between levels. As applied to semantic satiation, this theory supposes that there is not a loss of meaning, but, rather, an inability to access meaning from a repeated word. This application was tested in three behavioral experiments using a speeded matching task, demonstrating that meaning is lost when accessing the meaning of a repeated category label, but is not lost when accessing the category through new exemplars, or when the matching task is changed to simple word matching. To model these results, it is assumed that speeded matching results from detection of novel meaning to the target word after presentation of the cue word. This model was tested by examining neural dynamics with MEG recordings. As predicted by semantic satiation through loss of association, repeated cue words produced smaller M170 responses. M400 responses to the cue also diminished, as expected by a hierarchy in which lower levels drive higher levels. If the M400 corresponds to the post-lexical detection of new meaning, this model predicted that the M400 to targets following repeated cues would increase. This unique prediction was confirmed. These results were tested using a new method of analyzing MEG data that can differentiate between response magnitude versus differences in activity patterns. By considering hierarchical perception and processing dynamics, this work presents a new understanding of transient habituation and a new interpretation of electrophysiological data.Item Control of Vocal Production in Budgerigars (Melopsittacus undulatus)(2008-05-23) Osmanski, Michael; Dooling, Robert J.; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Budgerigars engage in dynamic vocal interactions with conspecifics, learn their vocalizations in a rich social environment, and rely to some extent on auditory feedback to acquire and maintain normal vocal output. However, little is known about the exact role of sensory input and sensory feedback in the control of vocal production in these birds. For example, we know that these birds learn best in a social environment that contains both auditory and visual information, yet we know very little about how this information guides and influences vocal production. Although we suspect that budgerigars rely on auditory feedback for the learning and maintenance of vocal behavior, we do not know whether there are refined, compensatory feedback mechanisms similar to that of humans. Finally, we do not know whether, or to what extent, calls can be modified in structure during learning. This dissertation describes a series of experiments that use more highly controlled and regimented conditions than previous studies with songbirds to investigate the control of vocal production in budgerigars and to provide a more detailed description of some of the mechanisms underlying vocal learning in budgerigars.Item Arousal theory and the interrelationships of caffeine, nicotine and impulsivity(2008-03-06) White, Thomas James; Smith, Barry D; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Nicotine, caffeine, impulsivity, and arousal are all intercorrelated: both drugs increase arousal, and impulsivity is theoretically related to arousal. However, the independent and joint effects of nicotine and caffeine on impulsive behavior are unclear. In this study, male college students (N = 63) were administered either caffeine or lactose placebo (double-blind) and either nicotine or placebo cigarettes (double-blind). Participants engaged in three behavioral tasks: the Stop Signal Task (SST), the Stroop Color-Word Test (SCWT), and the Delay Discounting Task (DDT). Drug intake did not produce significant changes across conditions on any of the three tasks. The hypothesis that caffeine and nicotine have an interactive effect on impulsivity in men was not supported by the data. Potential reasons for the lack of significant findings include variability within the sample on consumption history.