Eye movement monitoring as a process tracing methodology in decision making research.

Over the past half century, research on human decision making has expanded from a purely behaviorist approach that focuses on decision outcomes, to include a more cognitive approach that focuses on the decision processes that occur prior to the response. This newer approach, known as process tracing, has employed various methods, such as verbal protocols, information search displays, and eye movement monitoring, to identify and track psychological events that occur prior to the response (such as cognitive states, stages, or processes). In the present article, we review empirical studies that have employed eye movement monitoring as a process tracing method in decision making research, and we examine the potential of eye movement monitoring as a process tracing methodology. We also present an experiment that further illustrates the experimental manipulations and analysis techniques that are possible with modern eye tracking technology. In this experiment, a gaze-contingent display was used to manipulate stimulus exposure during decision making, which allowed us to test a specific hypothesis about the role of eye movements in preference decisions (the Gaze Cascade model; Shimojo, Simion, Shimojo, & Scheier, 2003). The results of the experiment did not confirm the predictions of the Gaze Cascade model, but instead support the idea that eye movements in these decisions reflect the screening and evaluation of decision alternatives. In summary, we argue that eye movement monitoring is a valuable tool for capturing decision makers' information search behaviors, and that modern eye tracking technology is highly compatible with other process tracing methods such as retrospective verbal protocols and neuroimaging techniques, and hence it is poised to be an integral part of the next wave of decision research. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Identification of Pathways, Gene Networks, and Paralogous Gene Families in Daphnia pulex Responding to Exposure to the Toxic Cyanobacterium Microcystis aeruginosa

Although cyanobacteria produce a wide range of natural toxins that impact aquatic organisms, food webs, and water quality, the mechanisms of toxicity are still insufficiently understood. Here, we implemented a whole-genome expression microarray to identify pathways, gene networks, and paralogous gene families responsive to Microcystis stress in Daphnia pulex . Therefore, neonates of a sensitive isolate were given a diet contaminated with Microcystis to contrast with those given a control diet for 16 days. The microarray revealed 2247 differentially expressed (DE) genes (7.6% of the array) in response to Microcystis , of which 17% are lineage-specific (i.e., these genes have no detectable homology to any other gene in currently available databases) and 49% are gene duplicates (paralogues). We identified four pathways/gene networks and eight paralogous gene families affected by Microcystis . Differential regulation of the ribosome, including three paralogous gene families encoding 40S, 60S, and mitochondrial ribosomal proteins, suggests an impact of Microcystis on protein synthesis of D. pulex . In addition, differential regulation of the oxidative phosphorylation pathway (including the NADH:ubquinone oxidoreductase gene family) and the trypsin paralogous gene family (a major component of the digestive system in D. pulex ) could explain why fitness is reduced based on energy budget considerations.     

Linking associative and serial list memory: Pairs versus triples.

Paired associates and serial list memory are typically investigated separately. An "isolation principle" (J. B. Caplan, 2005) was proposed to explain behavior in both paradigms by using a single model, in which serial list and paired associates memory differ only in how isolated pairs of items are from interference from other studied items. In the present study, 2 experiments identify a critical dissociation between the 2 paradigms, challenging this unified account. Specifically, forward and backward probes were highly correlated for pairs and less so for short lists (triples). The authors asked whether the isolation principle could quantitatively accommodate this type of dissociation. A simulation confirmed that a single model incorporating the isolation principle can adequately explain this and other dissociations, supporting the common processes view. (PsycINFO Database Record (c) 2010 APA, all rights reserved)