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Individual differences in spatial frequency-dependent visible persistence: The role of temporal summation

Persanyi, Mary Wylie
http://rave.ohiolink.edu/etdc/view?acc_num=case1057952547

Abstract Details

1995, Doctor of Philosophy, Case Western Reserve University, Psychology.
The relationship between visible persistence and temporal summation was examined in young and elderly subjects. Four experiments were conducted. In Experiment 1, temporal sensitivity was determined for young and elderly subjects for low and high spatial frequencies over five levels of contrast ranging from 5 to 62 percent. Subjects identified the missing element in a 5 x 5 matrix. The results indicated that elderly subjects had lower temporal sensitivity with larger high spatial frequency effects. In the remaining experiments visible persistence was tested with the two-frame Di Lollo paradigm (1977). The matrices had the same characteristics (spatial frequency, visual angle, mean luminance) as those in Experiment 1 except that the elements were separated randomly into two frames. In Experiment 2, visible persistence was measured with 34 percent contrast and duration set near threshold levels for each subject (as determined in Experiment 1). Young subjects had greater persistence for both low and high spatial frequency information. Similar results were found for Experiment 3 where duration was set to 29 msec, and contrast was set near threshold. In Experiment 4, both duration and contrast were set to a constant value as has been the case in previous studies investigating individual differences in visible persistence. Longer persistence was found for high spatial frequency information. Elderly subjects had longer persistence but more so for the high spatial frequency condition. Those results demonstrated that the stimuli and procedure used in the present study yield "typical" age and spatial frequency effects under "typical" test conditions. Within a certain critical interval, contrast and duration combine to determine temporal summation (e.g., Legge, 1977). Under the typical test conditions that generate age effects in visible persistence, the greater temporal sensitivity of young subjects under a given level of contrast would lead to more complete temporal summation and hence shorter visible persistence. The failure to obtain longer visible persistence for elderly adults in Experiments 2 and 3 when the salience of the image is equated across age and spatial frequency suggests that previously reported visible persistence age effects are the result of age differences in the rate of temporal summation.
Grover Gilmore (Advisor)
112 p.
spatial frequency-dependent visible persistence temporal summation

Recommended Citations

Citations

  • Persanyi, M. W. (1995). Individual differences in spatial frequency-dependent visible persistence: The role of temporal summation [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1057952547

    APA Style (7th edition)

  • Persanyi, Mary. Individual differences in spatial frequency-dependent visible persistence: The role of temporal summation. 1995. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1057952547.

    MLA Style (8th edition)

  • Persanyi, Mary. "Individual differences in spatial frequency-dependent visible persistence: The role of temporal summation." Doctoral dissertation, Case Western Reserve University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=case1057952547

    Chicago Manual of Style (17th edition)

case1057952547
376
© 1995, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.