Information integration in judgements of time to contact

Time to contact (TTC) is specified optically by tau, and studies suggest that observers are sensitive to this information. However, TTC judgements also are influenced by other sources of information, including pictorial depth cues. Therefore, it is useful to identify these sources of information and to determine whether and how their effects combine when multiple sources are available. We evaluated the effect of five depth cues on TTC judgements. Results indicate that relative size, height in field, occlusion, and motion parallax influence TTC judgements. When multiple cues are available, an integration (rather than selection) strategy is used. Finally, the combined effects of multiple cues are not always consistent with a strict additive model and may be task dependent.     

Visual information: The control of aiming movements

The study examined the contribution of various sources of visual information utilised in the control of discrete aiming movements. Subjects produced movements, 15.24 cm in amplitude, to a 1.27 cm target in a movement time of 330 ms. Responses were carried out at five vision-manipulation conditions which allowed the subject complete vision, no vision, vision of only the target or stylus, and a combination of stylus and target. Response accuracy scores indicated that a decrement in performance occurred when movements were completed in the absence of visual information or when only the target was visible during the response. The stylus and the target plus stylus visual conditions led to response accuracy which was comparable to movements produced with complete vision. These results suggest that the critical visual information for aiming accuracy is that of the stylus. These findings are consistent with a control model based on a visual representation of the discrepancy between the position of the hand and the location of the target.     

Feasibility of a Web‐based Gatekeeper Training: Implications for Suicide Prevention

Web‐based training programs have advantages such as increased scheduling flexibility and decreased training costs. Yet the feasibility of applying them to injury prevention programs such as suicide prevention gatekeeper training has not been empirically verified. Two studies were conducted to assess the feasibility and effectiveness of a web‐based version of the Question, Persuade, and Refer (QPR) gatekeeper training program. Results of Study 1 revealed that participants in a web‐based training demonstrated significant gains in knowledge of suicide prevention, self‐efficacy for suicide prevention, and behavioral intentions to engage in suicide prevention, as compared to those in a control group. Results of Study 2 further showed that the web‐based training may be as effective as the face‐to‐face QPR training across pre‐ (T1) and post training (T2); however, knowledge, self‐efficacy, and behavioral intentions in both groups generally declined from T2 to 6‐months after the training. Overall, these results provide initial evidence to support the feasibility of adopting web‐based media to deliver gatekeeper training. Moreover, the present findings suggest the need to understand how to maintain gatekeepers’ knowledge, confidence, motivation, and skills after training.