Flanked objects are difficult to identify using peripheral vision. This is visual crowding. Crowding is the perceptual bottleneck for reading (Pelli et al., 2007) and object recognition (Pelli & Tillman, 2008). Theories for crowding had been suggested, but the underlying neural mechanism remained unclear. Some perceptual manipulations had been shown to break crowding, hinting the cortical locus of crowding. In the first part of the current study, we ask whether illusory contour formation survives crowding of illusion inducers. We measured the contrast thresholds for discriminating the rotation angle of a target Kanizsa inducer with and without flankers. When the other three Kanizsa inducers were rotated to misalign with the target, we observed strong crowding indicated through contrast threshold elevation. Interestingly, however, subjects were able to judge the shape (thin vs. fat) of the illusory Kanizsa square even when the individual inducers were flanked. Internal representation of the percept in the inducer-aligned condition was further studied through the classification image technique. Classification images indicated that illusory contours were formed and used in the perceptual decision task in both the non-flanked and flanked conditions. These findings suggest that crowding happens after illusory contour formation. In the second part, we ask if Chinese character orientation affects crowding. Fifty commonly used traditional Chinese characters were selected as stimuli. We measured the contrast threshold for identifying upright and inverted target surrounded by either upright or inverted flankers. At 5? eccentricity, we observed an interaction effect between target and flanker orientation on crowding: upright flankers produced a stronger crowding effect than inverted flankers for inverted but not upright target. Follow-up experiments showed that the observation was not due to a rise of detection sensitivity for upright flankers or a change of spatial extent between upright and inverted target. Yet, adding an enclosure to flankers eliminated the flanker orientation effect, suggesting that the flanker orientation effect may be attributed to the facilitation of texture perception in the periphery. At 10? eccentricity, upright target was generally more immune from crowding, further supporting that crowding takes place after Chinese character orientation has been coded. From previous fMRI studies, we know that lateral occipital complex (LOC) is the cortical site that first responds to Kanizsa?s illusory contours (Murray et al., 2002) and the fusiform gyrus is sensitive to the inversion of Chinese character (Kao, Chen, & Chen, 2009). Taken together with our findings, we infer that crowding happens at or after the two cortical locations. / published_or_final_version / Psychology / Master / Master of Philosophy

Thesis (B.A.(Hons.)) -- University of Adelaide, Dept. of Psychology, 1978.

Thesis (Ph. D.)--Ohio State University, 1977. / Includes bibliographical references (leaves 103-108). Available online via OhioLINK's ETD Center.

No description available.

Thesis (Ed. D.)--Illinois State University, 1980. / Title from title page screen, viewed March 11, 2005. Dissertation Committee: Max R. Rennels (chair), Melvin Goldstein, Susan Amster, George Barford, Gary Weede. Includes bibliographical references (leaves 126-130) and abstract. Also available in print.

Forty-four introductory psychology students from Virginia Tech took part in a study concerning manning levels and the perception of crowding and related experiences. A new apparatus was designed and built (an HO-gauge train set) to manipulate manning level, physical constraint (using two different control designs), and cognitive load, variables suggested as important in the perception of crowding. Two methods of manipulating manning level were attempted: 1) changing the task and keeping the number of participants constant, and 2) Changing the number of participants and keeping the task constant. The former was found to be more successful in this study, the latter apparently confounded with the number of participants in the group. Both physical constraint and cognitive load affected the participants' expressed experiences. The results indicate that physical constraint had a more consistent negative impact on subjective experiences than did cognitive load. / Master of Science

Store image research has attempted to identify factors contributing to formation of positive or negative perceptions of stores by consumers. These factors include tangible and intangible elements. Of the tangible factors, store atmosphere (including store layout and congestion level) is often identified as contributing to store image. Intangible factors influencing store image include emotional or psychological reactions that consumers have in response to various tangible store factors. One of these emotional responses is retail crowding. Retail crowding is a state of psychological stress occurring in consumers in response to perceived high density levels in stores. Crowding literature suggests that environmental cues, including layout and density level, contribute to this stress level. The overall purpose of this study was to expand on current research by incorporating the concept of retail crowding with store image research.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 134-145). Also available via the Internet.

The population biology and socio-spatial organisation of the woodland dormouse, Graphiurus murinus (Desmarest, 1822), was investigated in a riverine forest at the Great Fish River Reserve (GFRR), South Africa. Data were collected by means of a monthly live trapping and nestbox monitoring programme. Between February 2006 and June 2007, 75 woodland dormice were trapped and/or found in nestboxes and marked: these were 39 adults (13 males, 21 females, five undetermined) and 36 juveniles (five males, 14 females, 17 undetermined). The population showed a steady increase from June 2006–November 2006 and a peak in December 2006–January 2007 as a result of the influx of juveniles. The minimum number of dormice known to be alive (MNA) varied between 40 in December 2006– January 2007 (summer), and a low of three in June 2007 (winter). The range in population density was therefore between 1.2 and 16 dormice per ha. Winter mortality and/or spring dispersal accounted for the disappearance of 55 percent of juveniles. The overall annual adult:juvenile ratio was 1.08. The overall sex ratio was 1.94 female per one male. In females, reproductive activity was observed from September 2006 to end January 2007. The pattern observed in males was similar, as dormice with descended testes were exclusively found from October to end January. Females gave birth during the second half of October to beginning of February. Litters (n = 11) consisted of an average (± SD) 3.73 ± 0.47 young. Over the study period, 27 dormice were trapped or found in nestboxes more than eight times, thus allowing me to estimate their home range size and the spatial overlap between these individuals. On average, dormouse home range size was 2,514 m2 (range: 319 – 4,863 m2). No difference was recorded between one-year old adults and older adults, or between all adults and juveniles. However, adult male dormice (3,989 m2, n = 5) had home ranges almost twice as large as females (2,091 m2, n = 9). No similar trend was found in juveniles. Intrasexual home range overlap was on average 62 percent in adult males, and 26 percent in adult females. However, females overlapped with more neighbouring female home ranges than did males with neighbouring male home ranges, so that, as for males, only small parts of female home ranges were really exclusive. On average, males overlapped a larger Abstract Ecology of woodland dormice M.Sc. Thesis 16 proportion (48 percent) of female home ranges than did females with neighbouring male home ranges (27 percent). In addition, males overlapped with significantly more female home ranges (7.8) than did females with male home ranges (4.9). Trapping success and nestbox data agree with the socio-ecological model. Females showed increased mobility during summer, more likely to find suitable nesting sites, and food for milk production during the reproductive season. The use of nestboxes, however, was constant throughout the year. In males, both the trapping success and nestbox use were higher during the mating season (spring), when an increased mobility and occupation of nestboxes probably increased the chances to locate and mate with (a) receptive female(s). Hence, food and (artificial) nest sites may constitute an important resource for females, whereas females seem to represent the main resource for males. Although food availability was not determined, a comparison of female and male distribution patterns provided interesting information on the mating system of woodland dormice. In GFRR, the dispersion pattern of female woodland dormice was “rather” clumped, i.e. females were non-territorial. As some females showed a dyadic intrasexual overlap of up to 90 percent, and population density was very high at the study site, this may indicate that food was very abundant and/or renewed rapidly. Based on the wide range of birth dates observed during the study period, females clearly come into oestrus at different times. In such circumstances (asynchronous sexual receptivity in females), the Female in Space and Time Hypothesis (Ims 1987a) predicts that males will be non-territorial and promiscuous. Live-trapping, nestbox use and home range data indeed suggested that male woodland dormice do not defend territories, but search for and aggregate around receptive females during the mating season.

Submitted in partial fulfilment of the requirements for the Degree of Master of Arts (Clinical Psychology) at the University of Zululand, 2003. / The problems associated with the relationship between humans and their environment are especially marked within the remains of a political system enforced on millions in South Africa. One of the complications of the Apartheid regime was the practice of migrant labour. Migrant labour in itself led to other complications such as disrupted family life, the disintegration of existing social structures and crowding in low-cost housing compounds, commonly known as hostels. It is obvious that the removal of Apartheid from the Statute Books has not resolved the practical problems stemming from its practice. South African hostels are generally characterised by high levels of both social and spatial density. Research (for example Oliver-Evans, 1992; Payze & Keith, 1993; Ramphele, 1993) indicates that several people often share the same bed in one hostel, while a minimum of four beds are usually found in a room of about 3m x 3m. This is usually accompanied by an insufficient infrastructure resulting in for example 16 families sharing one toilet. Other factors also seem to exacerbate the subjective experience of crowding, such as the lack of privacy which frequently accompanies inadequate infrastructure, and a lack of services such as garbage removal, sewerage maintenance, and water and electricity supply. The above research illustrates several discrepancies between the needs of hostel residents and the realities of their physical environment. Within this context the current study qualitatively investigates the subjective experience of household crowding at Kwesine Hostel on the Reef.