The Experts below are selected from a list of 8973 Experts worldwide ranked by ideXlab platform
Gianluca Stamerra - One of the best experts on this subject based on the ideXlab platform.
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Web usability evaluation with screen reader users: implementation of the partial concurrent thinking aloud technique
Cognitive Processing, 2010Co-Authors: Federici Stefano, Simone Borsci, Gianluca StamerraAbstract:A Verbal Protocol technique, adopted for a web usability evaluation, requires that the users are able to perform a double task: surfing and talking. Nevertheless, when blind users surf by using a screen reader and talk about the way they interact with the computer, the evaluation is influenced by a structural interference: users are forced to think aloud and listen to the screen reader at the same time. The aim of this study is to build up a Verbal Protocol technique for samples of visual impaired users in order to overcome the limits of concurrent and retrospective Protocols. The technique we improved, called partial concurrent thinking aloud (PCTA), integrates a modified set of concurrent Verbalization and retrospective analysis. One group of 6 blind users and another group of 6 sighted users evaluated the usability of a website using PCTA. By estimating the number of necessary users by the means of an asymptotic test, it was found out that the two groups had an equivalent ability of identifying usability problems, both over 80%. The result suggests that PCTA, while respecting the properties of classic Verbal Protocols, also allows to overcome the structural interference and the limits of concurrent and retrospective Protocols when used with screen reader users. In this way, PCTA reduces the efficiency difference of usability evaluation between blind and sighted users.
David Peebles - One of the best experts on this subject based on the ideXlab platform.
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the different effects of thinking aloud and writing on graph comprehension
Cognitive Science, 2011Co-Authors: Nadia Ali, David PeeblesAbstract:We report an experiment which seeks to determine how novice users' conceptual understanding of graphs differs depending on the nature of the interaction with them. Undergraduate psychology students were asked to interpret three-variable "interaction" data in either bar or line graph form and were required to either think aloud while doing so or to produce written interpretations. Analysis of the Verbal Protocols and written interpretations showed that producing a written interpretation revealed significantly higher levels of comprehension than interpreting them while thinking aloud. Specifically, a significant proportion of line graph users in the Verbal Protocol condition was either unable to interpret the graphs, or misinterpreted information presented in them. The occurrence of these errors was substantially lower for the bar graph users in the Verbal Protocol condition. In contrast, analysis of the written condition revealed no significant difference in the level of comprehension between the two graph types. Possible explanations for these findings are discussed.
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CogSci - The different effects of thinking aloud and writing on graph comprehension
Cognitive Science, 2011Co-Authors: Nadia Ali, David PeeblesAbstract:We report an experiment which seeks to determine how novice users' conceptual understanding of graphs differs depending on the nature of the interaction with them. Undergraduate psychology students were asked to interpret three-variable "interaction" data in either bar or line graph form and were required to either think aloud while doing so or to produce written interpretations. Analysis of the Verbal Protocols and written interpretations showed that producing a written interpretation revealed significantly higher levels of comprehension than interpreting them while thinking aloud. Specifically, a significant proportion of line graph users in the Verbal Protocol condition was either unable to interpret the graphs, or misinterpreted information presented in them. The occurrence of these errors was substantially lower for the bar graph users in the Verbal Protocol condition. In contrast, analysis of the written condition revealed no significant difference in the level of comprehension between the two graph types. Possible explanations for these findings are discussed.
Federici Stefano - One of the best experts on this subject based on the ideXlab platform.
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Web usability evaluation with screen reader users: implementation of the partial concurrent thinking aloud technique
Cognitive Processing, 2010Co-Authors: Federici Stefano, Simone Borsci, Gianluca StamerraAbstract:A Verbal Protocol technique, adopted for a web usability evaluation, requires that the users are able to perform a double task: surfing and talking. Nevertheless, when blind users surf by using a screen reader and talk about the way they interact with the computer, the evaluation is influenced by a structural interference: users are forced to think aloud and listen to the screen reader at the same time. The aim of this study is to build up a Verbal Protocol technique for samples of visual impaired users in order to overcome the limits of concurrent and retrospective Protocols. The technique we improved, called partial concurrent thinking aloud (PCTA), integrates a modified set of concurrent Verbalization and retrospective analysis. One group of 6 blind users and another group of 6 sighted users evaluated the usability of a website using PCTA. By estimating the number of necessary users by the means of an asymptotic test, it was found out that the two groups had an equivalent ability of identifying usability problems, both over 80%. The result suggests that PCTA, while respecting the properties of classic Verbal Protocols, also allows to overcome the structural interference and the limits of concurrent and retrospective Protocols when used with screen reader users. In this way, PCTA reduces the efficiency difference of usability evaluation between blind and sighted users.
Nadia Ali - One of the best experts on this subject based on the ideXlab platform.
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the different effects of thinking aloud and writing on graph comprehension
Cognitive Science, 2011Co-Authors: Nadia Ali, David PeeblesAbstract:We report an experiment which seeks to determine how novice users' conceptual understanding of graphs differs depending on the nature of the interaction with them. Undergraduate psychology students were asked to interpret three-variable "interaction" data in either bar or line graph form and were required to either think aloud while doing so or to produce written interpretations. Analysis of the Verbal Protocols and written interpretations showed that producing a written interpretation revealed significantly higher levels of comprehension than interpreting them while thinking aloud. Specifically, a significant proportion of line graph users in the Verbal Protocol condition was either unable to interpret the graphs, or misinterpreted information presented in them. The occurrence of these errors was substantially lower for the bar graph users in the Verbal Protocol condition. In contrast, analysis of the written condition revealed no significant difference in the level of comprehension between the two graph types. Possible explanations for these findings are discussed.
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CogSci - The different effects of thinking aloud and writing on graph comprehension
Cognitive Science, 2011Co-Authors: Nadia Ali, David PeeblesAbstract:We report an experiment which seeks to determine how novice users' conceptual understanding of graphs differs depending on the nature of the interaction with them. Undergraduate psychology students were asked to interpret three-variable "interaction" data in either bar or line graph form and were required to either think aloud while doing so or to produce written interpretations. Analysis of the Verbal Protocols and written interpretations showed that producing a written interpretation revealed significantly higher levels of comprehension than interpreting them while thinking aloud. Specifically, a significant proportion of line graph users in the Verbal Protocol condition was either unable to interpret the graphs, or misinterpreted information presented in them. The occurrence of these errors was substantially lower for the bar graph users in the Verbal Protocol condition. In contrast, analysis of the written condition revealed no significant difference in the level of comprehension between the two graph types. Possible explanations for these findings are discussed.
John W Payne - One of the best experts on this subject based on the ideXlab platform.
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how people respond to contingent valuation questions a Verbal Protocol analysis of willingness to pay for an environmental regulation
Journal of Environmental Economics and Management, 1994Co-Authors: David A Schkade, John W PayneAbstract:Abstract This paper investigates what a respondent is thinking when answering a willingness-to-pay question in a contingent valuation, using a "think aloud" technique from psychology called Verbal Protocol analysis. The willingness-to-pay responses we observed seem to be constructed from a variety of considerations, including an obligation to pay a fair share of the cost of the solution and signaling concern for a larger set of environmental issues. The finding that respondents seem to construct their values at the time they are asked, rather than reporting a more well-defined value, is seen as consistent with over two decades of research on the psychology of decision making. Potential uses of Verbal Protocols in contingent valuation studies are also discussed.
