The effect of visual search strategies on learning using computer-assisted instruction (CAI) for people with mild mental handicap

Abstract

The purpose of this study was to investigate the effect of different visual search strategies incorporated in a computer-assisted instruction typing program for people with mild mental handicap in Hong Kong. The study was divided into two phases; phase I of the study investigated the efficacy of two visual search strategies on search behavior vary as a function of level of intelligence (i.e. people with MH and people with normal intelligence) through a series of experiments. Based on the results obtained in Phase I of the study and the pilot test, an innovative CAI program for teaching typing English was developed, which was culturally appropriate and specific to people with MH in Hong Kong. The effect of the visual search strategies for people with MH in the CAI program was then conducted in Phase II of the study. In phase I of the study, a total of 36 subjects (18 with MH and the other 18 with normal intelligence) was recruited using convenient sampling method. A series of experiments was conducted to compare visual search strategies using either guided motion (i.e. motion contrast) or guided cue (i.e. additional cue) with the basic search tasks. Repeated measure ANOVA and Post-hoc multiple comparison tests were used to compare the performance of different visual search strategies. The results showed that the use of guided strategies was able to capture focal attention in an autonomic manner among people with MH (Pillai's Trace = 5.99, p < 0.0001). Effective visual search was demonstrated by reaction time (RT) x set size slope < 10msec/item, which implied the RT for visual searching was independent of the set size, and thus was evident of parallel search for the features. Both guided cue and guided motion search tasks demonstrated functionally similar effects, with guided motion search being more superior when compared with guided cue search. The results revealed that the visual search efficiency of people with MH was greatly improved if the target was made salient using visual search strategies (i.e. guided motion). Therefore, this phase of study provided an important practical implication and rationale for the use of visual search strategies that would be incorporated in CAI typing program design in phase II of the study. In phase II of the study, a pilot test was conducted prior to the main study. A total of 36 people with MH was recruited and randomly allocated to either the Group I i.e. CAI typing without cue (n=18) or the Group II i.e. CAI typing with visual cue (n=18). All the participants completed the posttest-1 assessment, except that two of them in the experimental group missed posttest-2 assessment for the reason of lack of time and loss of contact. Two-way repeated measure MANOVA was performed for the outcome measures including typing speed and accuracy. The results showed that the overall model was significant for the difference on a linear combination of the two dependent variables (i.e. typing speed and accuracy) between the control and experimental groups (Wilk's Lambda = 0.456, F(4,31) = 9.248, p<0.001). The search performance of typing speed was significantly higher for the experimental group (p<0.001). However, there was no statistically significant difference on accuracy between the two groups. This study further supported the role of visual search strategies that could attract and maintain attention to the critical elements in the arrays, and thus promote the encoding process for long-term storage. It also supported the positive effect of using CAI with appropriate in enhancing functional cueing performances among people with MH. In conclusion, this study supported the use of visual search strategies for CAI programs that might be extended to other CAI for community living skills and vocational training for people with MH such as learning IT platform, using ETC machine.