This document discusses how symbolic compatibility may affect visual-motor performance. It reviews relevant literature on human error theories and classifications. It then describes an experiment conducted to test the effects of different levels of stimulus-response compatibility (mapping, visual field) and symbolic compatibility on a novel visual-motor task. The results showed that poor stimulus-response compatibility negatively impacted both reaction time and accuracy, while higher symbolic compatibility was associated with fewer errors. The conclusion is that stimulus-response compatibility is important for task design and performance, and symbolic cues may be processed differently than spatial aspects of a task.

1. Does Symbolic Compatibility affect visual-motor performance? Rebeca Alonso

2. Error To err is human. “An erroneous action can be defined as an action which fails to produce the expected result and/or which produces an unwanted consequence” Hollnagel 1993 “An error is an out of tolerance action, where the limits of tolerable performance are defined by the system” Swain and Guttman 1983

3. error Errors vary from the simplest mistakes as forgetting to lock the back door, turn the wrong button on the stove… or at times might join together an lead to more serious accidents. Human error started to be referred to as the “new disease” in the 1980’s, as it seemed responsible for major disasters in industry and transportation. In 1988 it was estimated that up to 90% of general workplace accidents had human error as its cause (Feyer & Williamson, 1988). Similarly, James Reason (1990) studied the causes of 180 incidents in nuclear power plants in 1983 and 1984 and concluded that 52% of them were human related. Since the 1980’s techniques have been developed in critical industries to try and assess human contribution in system performance. Although human error cannot be predicted with the same accuracy as mechanical errors, most researchers would agree that human error do follow certain patterns (E.g. Nagel, 1998).

4. In psychology regardless of the approach used the first thing that needs to be looked at when trying to address human factors in the workplace is peoples’ capabilities and limitations. The most relevant psychological theories on human error (Norman, 1981; Reason, 1990; C. D. Wickens, 1992) and their assessment tools focus on individuals’ cognitive capabilities. Some of which (C. D. Wickens, 1992) attribute error causality to poor design by allowing cognitive confusion. These are the primary theories from which the contemporary streams, error analysis, identification, and this current study will draw upon.

5. SKR Classification of errors Skill, Rule and Knowledge Based.

6. Classification of Errors Slips , mistakes and violations

7. S-R Compatibility S-R Mapping. Response is matched to the location of the stimuli.

8. S-R Compatibility S-R Visual-Field . Where a motor response is matched to the location and direction of the element in the visual field

9. S-R Compatibility S-R Symbolic. Level of cognitive association of some elements of the display to 3D cues. For example: Green=Field Blue=Sky

10. The task The novel visual-motor task was designed specifically to: 1) operate at a skill-base level and, through enough practice, to become ‘automatic’. 2) have responses that are implemented through different input devices. 3) that these input devices are configured for different mapping and visual-field compatibility (high, medium and low). 4) have stimuli that has at least two levels of symbolic compatibility (high and low). Distracters were included in the task in order to check for differences between performance, using different Stimulus-Response Compatible devices.

11. Method

12. Method

13. Results

14. Results

15. Results

16. Conclusion The results from this research primarily support the extended previous findings on the importance of S-RC (mapping and visual-field) in design for speed performance. Poor S-RC in task design seemed to affect reaction times to a similar degree as higher cognitive load. At the same time, this test fails to show any advantages or disadvantages on speed performance from Joystick to Keyboard as input devices for simple spatial-motor 2D displays tasks. Results also support previous findings on the importance of S-RC (mapping and visual-field) in terms of accuracy. Poor S-RC in task design seemed to affect accuracy in the Keyboard task which effects again resemble similar pattern as cognitive load.

17. Conclusion The Joystick test was introduced in this study as a measure/control for visual-field compatibility because it has proven compatibility in 3D virtual environments. One of the explanations why participants had almost no errors at the high Symbolic Compatibility trials is perhaps due to this task’s success in triggering 3D cues through the visual symbolic relationships. Although this study is based on a very small sample the data seems sufficiently normalized to make such basic assumptions. Findings from this study might then point towards a disassociation between response time delay and errors when it comes to symbolic association to visual cues. It could perhaps also point towards a multimodal perception system where symbolic information is processed through a different channel and hence not be affected by the cognitive load. An additional recommendation for further research would be to acquire a larger sample, with fewer experimental cells. This could test the different here theorized levels of visual Symbolic Compatibility in isolation, before testing its in interaction with any other types of S-RC. A test where there are two or more conditions with exactly the same spatial relations, but perhaps replacing pictures for shapes (e.g. square instead of plane, triangle instead of cloud.)

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