Testing enhances both encoding and retrieval for both tested and untested items

ABSTRACT

In forward testing effects, taking a test enhances memory for subsequently studied material. These effects have been observed for previously studied and tested items, a potentially item-specific testing effect, and newly studied untested items, a purely generalized testing effect. We directly compared item-specific and generalized forward testing effects using procedures to separate testing benefits due to encoding versus retrieval. Participants studied two lists of Swahili–English word pairs, with the second study list containing “new” pairs intermixed with the previously studied “old” pairs. Participants completed a review phase in which they took a cued-recall test on only the “old” pairs or restudied them. In Experiments 1a, 1b, and 2, the review phase was given either before or after the second study list. Testing benefited memory to the same degree for both “new” and “old” pairs, suggesting that there were no pair-specific benefits of testing. The larger benefit from testing when review was given before rather than after the second study list suggests that the memory enhancement was due to both testing-enhanced encoding and testing-enhanced retrieval. To better equate generalized testing effects for “new” and “old” pairs, Experiment 3 intermixed them in the review phase. A statistically significant pair-specific testing effect for “old” items was now observed. Overall, these results show that forward testing effects are due to both testing-enhanced encoding and retrieval effects and that direct, pair-specific forward testing benefits are considerably smaller than indirect, generalized forward testing benefits.

KEYWORDS:

• Test-potentiated learning
• Forward testing effect
• Retrieval practice
• Retrieval-induced facilitation
• Testing effect

Acknowledgement

We thank Christina Mastricovo, Marsha Kaddo Mouawad, Nik Tamburello, and Geoffrey Saunders for their assistance in collecting data, and W. Trammell Neill for his very helpful comments on drafts of this manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1 When participants are not encouraged to integrate the to-be-tested items and the untested items, and the final test is administered in the same session as the review, many studies (e.g., Anderson, Green, & McCulloch, 2000; Chan, 2009) have obtained an inhibitory indirect generalized testing effect for the untested items when they are semantically related to the tested item. (See Anderson, 2003; Raaijmakers & Jakab, 2013, for reviews of inhibitory indirect generalized testing effects.) In the present research, the tested and untested items are unrelated.

2 When no restudy follows the review test, the data are mixed when the retention interval for the final test is short (typically 5 minutes or less). Although Carpenter, Pashler, Wixted, and Vul (2008, Experiment 3), Carrier and Pashler (1992), and Rowland and DeLosh (2014a, Experiment 3) have reported a positive testing effect at a short retention interval, some researchers have obtained null item-specific effects of testing (e.g., Carpenter & DeLosh, 2006; Coppens, Verkoeijen, & Rikers, 2011) or have obtained reverse, inhibitory testing effects (e.g., Jang, Wixted, Pecher, Zeelenberg, & Huber, 2012; Roediger & Karpicke, 2006b; Toppino & Cohen, 2009).

3 Due to a programming error, the retention interval was not extended long enough. This limitation is addressed in our Experiment 2.

4 Because memory for untested words in both tested and untested lists that were studied after the first review test would benefit to the same degree from any testing-enhanced encoding that might occur, the superior free recall of untested items that were studied in tested lists versus untested lists must be due to testing-enhanced retrieval processes.

5 Many experiments that have employed retrieval incentives (monetary gains or electric shock avoidance) have reported null (Weiner & Walker, 1966; Wickens & Simpson, 1968) or very small effects (Loftus & Wickens, 1970; Weiner, 1966) of incentive on memory performance. Also, as far as we can ascertain, Loftus and Wickens’s (1970) conclusion that their retrieval-incentive effect was statistically significant seems to have been based on averaging across some conditions that included a confounding of encoding incentive with retrieval incentive (and the effect of encoding incentive alone was large). Moreover, those experiments that have demonstrated a small non-null effect of incentive have manipulated incentive within participants. According to Weiner (1966), “between-participants designs are less likely to yield an expected motivational effect than a within-participants design” (p. 15). Because we manipulated test and restudy between participants in Experiments 1a, 1b, and 2, even if there were a contribution of increased retrieval effort to our testing effects, it was likely to be quite minimal.