Browsing by Author "Glaser, Daniel Shields"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Foraging memory: Retrieving words from one and from two semantic categories
    (2008) Glaser, Daniel Shields; Dannemiller, James L.
    Traditionally applied to an animal's search for food, the concept of foraging has been extended to include the search for information in such places as the Internet and libraries (Pirotti & Card, 1999). The premise behind the research reported here is that memory searching can also be construed as foraging. The goals of this investigation are to uncover mental factors that may affect memory production during memory search and to use this knowledge to guide a prediction of foraging production. Prior to testing, four such mental factors were identified: a time cost when producing an initial item from a different category (switch cost); a production benefit driven by a release of proactive interference (time-out benefit); a production cost caused by the additional mental load of executing an autonomous switching strategy (executive-decision cost); and sub-optimal allocation of time between categories. Experiment 1 tested whether switching between categories leads to a switch cost and/or time-out benefit by having subjects produce items from a category in a continuous three-minute block or multiple blocks that add to three minutes. Experiment 2 addressed the possibility of an "Executive-decision" cost by either allowing subjects to autonomously switch between categories or yoking them to another subject's switch schedule. Experiment 3 tested whether memory foragers divide their time optimally between categories. Data from the first experiment demonstrated that like external foraging, moving from category to category (patch to patch) results in a production downtime. These data also demonstrated that switching production between domains may lead to a time-out benefit. Experiment 2 showed that the execution of an autonomous switching strategy leads to less production then when switching is forced. The third experiment demonstrated that, unlike animals, humans do not have an innate sense of how to divide their time between patches (categories) to maximize gain. Our prediction was derived by having subjects produce category exemplars from a single category alone or from two categories at once. Data from single-category production trials as well as adjustments inspired by Experiment I through 3 were used to predict production from two categories. Though accurate, the flexibility of our prediction is limited. Research needed to allow for greater flexibility is discussed.
  • Thumbnail Image
    Item
    Implications of differences of echoic and iconic memory for the design of multimodal displays
    (2012) Glaser, Daniel Shields; Lane, David M.
    It has been well documented that dual-task performance is more accurate when each task is based on a different sensory modality. It is also well documented that the memory for each sense has unequal durations, particularly visual (iconic) and auditory (echoic) sensory memory. In this dissertation I address whether differences in sensory memory (e.g. iconic vs. echoic) duration have implications for the design of a multimodal display. Since echoic memory persists for seconds in contrast to iconic memory which persists only for milliseconds, one of my hypotheses was that in a visual-auditory dual task condition, performance will be better if the visual task is completed before the auditory task than vice versa. In Experiment 1 I investigated whether the ability to recall multi-modal stimuli is affected by recall order, with each mode being responded to separately. In Experiment 2, I investigated the effects of stimulus order and recall order on the ability to recall information from a multi-modal presentation. In Experiment 3 I investigated the effect of presentation order using a more realistic task. In Experiment 4 I investigated whether manipulating the presentation order of stimuli of different modalities improves humans' ability to combine the information from the two modalities in order to make decision based on pre-learned rules. As hypothesized, accuracy was greater when visual stimuli were responded to first and auditory stimuli second. Also as hypothesized, performance was improved by not presenting both sequences at the same time, limiting the perceptual load. Contrary to my expectations, overall performance was better when a visual sequence was presented before the audio sequence. Though presenting a visual sequence prior to an auditory sequence lengthens the visual retention interval, it also provides time for visual information to be recoded to a more robust form without disruption. Experiment 4 demonstrated that decision making requiring the integration of visual and auditory information is enhanced by reducing workload and promoting a strategic use of echoic memory. A framework for predicting Experiment 1-4 results is proposed and evaluated.