Abstract As the population of a society ages and evolves, the cognitive capacity and life-long learning ability of its older adults is extremely significant. Our research mainly aims at demonstrating whether the interpolated testing could effectively improve older adults’ abilities to learn and retain new information. In other words, to see whether the Forward Testing Effect (FTE) can be applied to older adults. Early research in younger adults and older children indicates that the Forward Testing Effect in learning individual items is primarily due to the reduction of the Proactive Interference (PI). The research with regard to younger children indicates that they cannot reduce the PI so that they do not have FTE in their early years when they are just learning. But this cannot explain why people have the Forward Testing Effect during complex learning, which is also attributed to the reduction of Mind Wondering (MW). However, other research demonstrates that learning engagement plays a role to make a great difference between the Proactive Interference and Mind Wandering of older adults and that of younger adults. Will older adults experience FTE when learning simplified things? How about more complex matters?
Our research uses three experiments to answer the questions in a progressive manner. All of the participants of older adults were randomly separated into two groups by computer. The tested group was then given interim tests and the other group, the control group, went without any test until the last list or segment. The latter will of course have a memory test for all the things they have gone through the process of learning. The size of these groups was determined according to the Effect size in previous studies. The number of participants in each experiment was 30, 32, and 49. In the first experiment both groups were each given five lists of words. The test group was given an interim test after studying each of the five lists., while the control group was required to solve the math problem after studying each list, they only took an interim test on list 5. With experiment 2 the participants had five lists of common supermarket items to learn. The test group was also given an interim test after studying each of the five lists. But the control group only had to study lists 1-4, then they were given an interim test after studying the fifth list. In the third experiment the participants were instructed to study a four-segment lecture video where the instructions and experiment procedures were the same as those in experiment 2. The participants in first experiment were older British adults over 60 years of age. In experiment 2 and 3 older Chinese adults over the age of 60 participated.
As the result of Experiments 1 shows, the test group (M = 5.87, SD = 1.21) recalled about twice as many List 5 words correctly as the math group (M = 3.20, SD = 2.01) in the List 5 interim test, difference = 2.67 words, 95% CI = [1.02, 4.32], t(28) = 3.31, p = .003, Cohen’s d = 1.21, indicating that interpolated tests facilitate older adults’ learning of new single items. For the test group, a repeated measures ANOVA, with List (2-5) as within-subjects variable, showed that PI linearly increased across lists, F(1, 14) = 8.15, p = .01, ηp2 = .37, indicating that interim tests could not completely prevent the build-up of PI across lists for older adults. Of critical importance, the math group (M = 3.40, SD = 1.59) experienced about third times as much PI as the test group (M = 1.20, SD = 1.21) in the List 5 interim test, difference = 2.20 words, 95% CI = [1.14, 3.20], t(28) = 4.26, p < .001, Cohen’s d = 1.56, indicating that interim tests prevent the build-up of PI for older adults. As the result of Experiments 2 shows, the test group (M = 5.13, SD = 1.41) recalled about twice as many words correctly as the restudy group (M = 2.38, SD = 1.63) in the List 5 interim test, difference = 2.76 words, 95% CI = [1.64, 3.88], t(29) = 5.03, p < .001, Cohen’s d = 1.80. A repeated measures ANOVA showed that, for the test group, PI linearly increased across Lists 2-5 interim tests, F(1, 14) = 20.70, p < .001, ηp2 = .60. In the List 5 interim test, the restudy group (M = 3.06, SD = 2.11) committed about third times as much PI as the test group (M = 0.93, SD = 0.96), difference = 2.13, 95% CI = [0.91, 3.35], t(29) = 3.57, p = .001, Cohen’s d = 1.30. As the result of Experiments 3 shows, the test group (M = 6.32; SD = 3.11) recalled about twice as many items correctly as the restudy group (M = 3.50; SD = 2.17) in the Segment 4’s interim test, difference = 2.82 items, 95% CI = [1.28, 4.36], t(47) = 3.68, p = .001, Cohen’s d = 1.05, revealing that interpolated testing enhances older adults’ learning of new complex materials.
The results show the FTE could effectively rise older adult’s learning and memorizing abilities for the new information. The test groups have a higher score than math and restudy groups whether to learn single items or complex materials. The results support an integrated theory of interference reduction and learning engagement, which can comprehensively explain the FTE difference between younger children, older children, younger adults, and older adults. Therefore, we can use Forward Testing Effect as a comprehensive method to modify the older adults’ learning and memorizing condition. It has a significant meaning in preventing and relieving the older adult from Alzheimer's disease.