Abstract Perspectives on past climate using lake sediments are critical for assessing modern and future change. These perspectives especially important water-stressed regions such as the western United States. One region is northwestern California (CA), where Holocene-length hydroclimatic records scarce. Here, we present a 9000-year, relative level record from Maddox Lake (CA) multi-indicator a...

See-saw nystagmus is a rare ocular abnormality, only 15 cases having been recorded to date (Maddox, 1914; Rucker, 1946; Larsen, 1957; Jensen, 1959; Smith and Mark, 1959; Mark, Smith, and Kjellberg, 1960; Lourie, 1963; Schurr, 1963; Kinder and Howard, 1963; Slatt and Nykiel, 1964; and Daroff, 1965). As initially described by Maddox (1914), the eye movements consist of regular reciprocating oscil...

Parkinson's disease (PD) patients and normal controls were tested in three category learning experiments to determine if previously observed rule-based category learning impairments in PD patients were due to deficits in selective attention or working memory. In Experiment 1, optimal categorization required participants to base their decision on a single stimulus dimension and ignore irrelevant...

ACKNOWLEDGEIVIENTS I would like to thank my thesis advisor Drs. Shubhra Gangopadhyay and Jordan Berg for their support, encouragement and valuable guidance throughout this work. I would not have been able to finish this work without their guidance and moral support. I am grateful to Dr. Gangopadhyay, La Pierre Chair Professor at the University of Missouri at Columbia, for giving her valuable ti...

The authors compared the exemplar-based random-walk (EBRW) model of Nosofsky and Palmeri (1997) and the decision-bound model (DBM) of Ashby and Maddox (1994; Maddox & Ashby, 1996) on their ability to predict performance in Garner's (1974) speeded classification tasks. A key question was the extent to which the models could predict facilitation in the correlated task and interference in the filt...

The performance of a decision bound model of categorization (Ashby, 1992a; Ashby & Maddox, in press) is compared with the performance of two exemplar models. The first is the generalized context model (e.g., Nosofsky, 1986, 1992) and the second is a recently proposed deterministic exemplar model (Ashby & Maddox, in press), which contains the generalized context model as a special case. When the...

The dopaminergic system is known to play a central role in reward-based learning (Schultz, 2006), yet it was also observed to be involved when only cognitive feedback is given (Aron et al., 2004). Within the domain of information-integration category learning, in which information from several stimulus dimensions has to be integrated predecisionally (Ashby and Maddox, 2005), the importance of c...