LOGO The role of attentional breadth in perceptual change detection Professor: Liu Student: Ruby

Logo Objective Examined the relationship between perceptual change detection and attention which relating individual differences in attentional breadth to observers’ ability to detect changes in driving scenes.

Logo References When changes to scenes at the same time with saccadic eye movements, we have a limited ability to detect them. (Grimes, 1996; Henderson, 1997; McConkie & Currie, 1996) The objects of central interest probably attracted attention through higher level cognitive processes. (Rensink et al. 1997)

Logo References The FFOV represents the spatial area that is needed to perform a specific visual task without occurred eye or head movements. (Ball, Roenker, & Bruni, 1990; Mackworth, 1965, 1976) The size of the FFOV decreased with age. (Ball, Beard, Roenker, Miller, & Griggs, 1988)

Logo References Older drivers had poorer driving performances on the FFOV, a skill that would seem to because an ability to detect change in the environment. (Isler, Parsonson, & Hansson, 1997; Rizzo, Rinach, McGehee, & Dawson, 1997)

Logo Method - participants 25 Younger group 13 women, 12 men. Age from 18 to 33 years. 26 Older group 18 women, 8 men. Age from 55 to 80 years. Each participant had corrected visual acuity better than 20/40. Each participant had a driver’s license for 2 years, and drove over 25 miles per month.

Logo Method - apparatus A Micron Millenia MME computer. A 12 × 16in. Viewsonic monitor. 56 cm from the screen. A Fresnel lens. Was used to remove the accommodation cues. Increased the subjective size of the image region.

Logo Method – perceptual change task Each image was displayed for 240 msec and each blank screen for 80 msec. 80 photographs were taken from the driver’s view inside a car. The objects and their changes were categorized along three parts: eccentricity, meaningfulness, and salience. When they detected the change, press the mouse button and describe the change.

Logo Method – perceptual change task The first pilot study (meaningfulness and salience) 14 younger and 10 older participants. Subjects saw two images of a scene on color printed pages in a notebook. (82 scenes) They were asked to rate the change according to a 6 point Likert scale. Meaningfulness was defined to the importance of the change to driving performance. Salience was defined to noticeable change should be the high salient.

Logo Method – perceptual change task The second pilot study (meaningfulness and salience) 6 younger and 6 older participants. Rate a single object in each of the 82 scenes. Meaningfulness was defined to the importance of the object to driving performance. Salience was defined to noticeable object should be the high salient.

Logo Method – perceptual change task The perceptual change performance, the 80 driving scenes were divided into four categories: Low meaning/low salience. Low meaning/high salience. high meaning/low salience. high meaning/high salience.

Logo Method – atentional breadth task An oblique target appearing in 11 vertical distractors. Targets and distractors appear randomly at one of three eccentricities (10, 20, and 30 deg from fixation) along 8 radial meridians for a total of 24 possible positions. After finish the change detection task, they moved the mouse to one of the 24 possible target positions to indicate their response.

Logo Results – change detection performance (RT) Main effects were significant for all four factors. Age: younger adults performed significantly faster than older adults, F(1,48)=41.02, P< Eccentricity: central changes were detected more quickly than peripheral ones, F(1,48)=35.14, P< Meaningfulness: low = 9, high = 8.2 sec; F(1,48)=9.65, P< Salient: low = 10.9, high = 6.8 sec; F(1,48)=313.93, P<0.001.

Logo Results – change detection performance (RT) A significant two-way interaction was between age and salience, F(1,48)=6.53, p< This result is not found in the previous literature. The age and eccentricity interaction was no significant. It may because didn’t control the eye movements.

Logo Results – change detection performance (RT) The three-way interaction between age, meaningfulness, and salience. F(1,48)=7.94, P< Increase meaningfulness had no effect on performance for either age group when changes were highly salient. When salience change was low, increasing meaningfulness help the performance of young, but not old.

Logo Results – change detection performance (RT) A significant three- way interaction was also found between eccentricity, meaningfulness, and salience. F(1,48)=9.64, P< When changes were both high meaning and salience, the central changes were detected faster than peripheral changes. Different meaningfulness did not influence performance when changes were both peripheral and low salience.

Logo Results – change detection performance (accuracy) Main effects were significant for: Age[ F(1,38)=39.8, P<0.001 ] Eccentricity[ F(1,38)=31.7, P<0.001 ] Salience [ F(1,48)=64, P<0.001 ]

Logo Results – change detection performance (accuracy) Two-way interactions was found for age × salience. [ F(1,48)=19.3, p<0.001 ] Also found significant two-way interactions for meaningfulness × salience. [ F(1,48)=4.7, P<0.03 ]

Logo Results – relationship between FFOV and change detection performance A larger FFOV correspond to faster detection of object changes. (r=-0.68, p<0.001)

Logo Results – relationship between FFOV and change detection performance The size of the FFOV appear to be related to change detection for central changes and perhaps even more strongly for peripheral changes. The correlation was (p<0.01), for centrally located changes. The correlation was (p<0.01), for periphery located changes.

Logo Discussion – age, change characteristic, and change detection. Salient scene characteristics were more responsible for driving attention to change than meaningful change characteristics, especially for older adults. The salient changes to objects are quickly detected, but nonsalient changes are detected by slow, serial processing.

Logo Discussion – age, change characteristic, and change detection. Older drivers had more difficulty detecting change under most situations adds a new dimensions to the present literature on change detection. Older and younger drivers showed differences in detecting changes, but not unsurprising given other findings for age- related differences on many visual search tasks.

Logo Discussion – attentional breadth and change detection A strong correlation between breadth of attention and change detection. A smaller FFOV corresponded to slower change detection. The breadth of attention plays an important role in change detection. Reducing the number of attentional samples required to detect a change.