1. It is planned to recruit 60 subjects to complete this study. The data presented was based on results from 36 subjects. Subjects were asked to make a lexical decision about a word (e.g. determine if a word can be used as a noun or not) by saying “Yes” or “No” through a voicekey. The oral response was recorded through the keyboard by the experimenter and response time was registered by the voicekey. This task was repeated with three prime types randomized within a block of 90 words, including: Visual prime (VP), Semantic prime (SP), and Neutral prime (NP). (e.g., Target: CLASS, VP: GLASS, SP: CATEGORY, NP: WATCH.) Each block was exposed to a different visual stress: glare, small font, and blur, plus a control condition (total: 360 lexical decision trials). Visual Stress and Cognition: An investigation of the impacts of visual stress on lexical decision making Joshua Gietzen, Yu-Chi Tai, PhD, John R. Hayes, PhD, James E. Sheedy, OD, PhD College of Optometry | Pacific University | 2043 College Way | Forest Grove | Oregon 97116 PURPOSE Visually taxing conditions strain the visual system, oftentimes resulting in the clinical diagnosis of asthenopia, or eyestrain. Human subjects can perform cognitive tasks under visual stress, but the task takes longer (Garzia et al., 1989). Is this increased duration due to an increase in the time it takes to cognitively process the information presented? METHODS CONCLUSIONS CONTACT INFORMATION Since stimuli presented in a small font is difficult for the visual system to acquire, this study shows that it is also difficult for the brain to process. In this case, the impact on cognition is the added processing time. The visual and semantic primes decrease the response time because they both provide the participant a glimpse, whether by content or by shape, of what is to come. This brief hint allows the brain to begin processing the target word before it is actually seen. The results from this study suggest that the effects of visual stress on cognitive processes are not equal between stress types. Small font creates difficulties for the brain that must be overcome. Though these effects are only a few milliseconds in size, this type of lag can accumulate over long periods of time. Principal Investigator Joshua Gietzen 503-307-2502 jagietzen1@pacificu.edu ACKNOWLEDGEMENTS The Advanced Reading Group of Microsoft Corporation supported this research with a grant to James E. Sheedy, O.D., Ph.D. 100 ms 50 ms Lexical Decision through voice key (times out: 1500ms) glass XXXXX class Priming Scheme RESULTS Figures 1 & 2: Response time measured in milliseconds to a lexical decision stimulus between nouns and non- nouns. Bars indicate an 84% Confidence Interval; non- overlapping CI provide a test for statistical significance at an unadjusted p<0.05. Figure 3. Percent correct for lexical decision trials between nouns and non- nouns. Bars indicate an 84% Confidence Interval; non-overlapping CI provide a test for statistical significance at an unadjusted p<0.05. Fig. 1 Fig. 3 Fig. 2 Important Trends. Small font (SF) response time shows a significant latency over other visual presentation types. VP and SP response times show a faster response than the NP, indicating that the prime scheme had an effect on the cognitive processing time needed to make a lexical decision. SF condition also shows a smaller percentage of correct responses. This shows evidence that the SF condition is more difficult to process.