The list-strength effect: Strength-dependent competition or suppression?

Abstract

If several items are associated with a common cue, the cued recall of an item is often supposed to decrease as a function of the increase in strength of its competitors' associations with the cue. Evidence for such a list-strength effect has been found in prior research, but this effect could have been caused both by the strength manipulations and by retrieval-based suppression, because the strengthening and the output order ofthe items were confounded. The experiment reported here employed categorizable item lists; some categories in each list contained strong items only,some contained weak items only, and some contained both strong and weak items. Strengthening was accomplished by varying the exposure time of the items. The testing sequence of the items from each category was controlled by the use of category-plus-first-letter cues. When the typical confounding of strengthening and output order was mimicked,list-strength effects were found, which is consistent with prior research. However, when this confounding was eliminated, the list-strength effects disappeared: The recall of neither strong nor weak items varied with the strengths of the other category exemplars. This pattern of results indicates that the list-strength effect is not the result of strength-dependent competition, but is caused by output-order biases and a process of suppression.The cued recall ofan item decreases as the number of items associated with the same cue increases. Corresponding evidence has been provided by a number of studies in quite different experimental paradigms (see Watkins, 1978, for a review). This finding is generally seen as support for the assumption that memories associated with a common cue compete for access to conscious recall when that cue is presented.Often, this competition is assumed to be strength dependent; that is, the cued recall of an item is supposed to decrease as a function of the increase in strength of its competitors' associations with the cue. Evidence for this strength dependence arises particularly from studies on retroactive and proactive interference (Barnes & Underwood, 1959;Briggs, 1957), although the results from studies on part-set cuing have been interpreted similarly (Roediger, 1974;Rundus, 1973). This evidence for strength dependence appears to be so compelling that the concept has been incorporated as a fundamental property into many memory models (Mensink & Raaijmakers, 1988;Raaijmakers & Shiffrin, 1981;Rundus, 1973).The concept of strength dependence, however, is far less well empirically established than it would seem. Recently, Anderson, Bjork, and Bjork (1994) emphasized this point by arguing that previous interference studies, which seemingly provide evidence for strength dependence, confounded the manipulation of the strengths of Thanks are extended to M. Anderson, A. Glenberg, H. L. Roediger III. and one anonymous referee for their comments on an earlier draft of this manuscript. The author's address is Institut fur Psychologie, Universitat Regensburg, 93040 Regensburg, Germany (e...

Part-list cuing in amnesic patients: Evidence for a retrieval deficit

“…Rather, it is consistent with the view that interference and part-list cuing are mediated by different mechanisms (Anderson et al, 2000;D. R. Basden & B. H. Basden, 1995;Bäuml, 1997Bäuml, , 2002Ciranni & Shimamura, 1999). On the basis of this view, the present results together with those from prior research indicate that there is more than just one form of retrieval failure and that amnesic patients may show a deficit with respect to one form of retrieval failure but show no deficit with respect to another.…”

“…Thus, it might well be the case that amnesics exhibit a normal increase in competition arising from the encoding of additional material but are more susceptible to incongruencies between learning and test. Such a finding would further underscore the fact that retrieval failure can be caused by different mechanisms (Anderson, E. L. Bjork, & R. A. Bjork, 2000; D. R. Basden & B. H. Basden, 1995;Bäuml, 1997Bäuml, , 2002Ciranni & Shimamura, 1999). If so, amnesics may show intact retrieval processes in some situationsbut may be impaired in others.…”

Decrease of Precurrent Behavior as Training Increases: Effects of Task Complexity

“…Results from Experiment 3 showed that increases in the number of different responses to be learned in the total set, per pair, and per position, were associated to decreases in performance, corroborating those found in the literature concerned with task complexity, despite their theoretical and procedural differences (e.g., Bauml, 1997;Brehmer, 1992;Coren & Ward, 1989;Ebbinghaus, 1885Ebbinghaus, /1964Kerstholt, 1992;Payne, 1982;Postman, 1972;Ratcliff, Clark, & Shiffrin, 1990;Simon , 1972Simon , , 1974Sundstrom, 1987). It may be relevant to notice that the measure of performance adopted in the present experiment, that is, the area of the function, which can be interpreted as the total duration of precurrent response necessary to learn each current response, is similar to those used in the first experimental investigations of memory (cf.…”

“…Despite the lack of consensus or agreement concerning the best way of theorizing about task complexity, the effects of one variable has been systematically mentioned in investigations following different theoretical traditions. Increases in the number of responses to be learned (or that are possible) in a given situation have been associated with decreases in performance in several different experimental contexts: (a) The increase in the number of items to be memorized in serial learning tasks increased the time to learn each item (ct. Ebbinghaus, 1885Ebbinghaus, /1964; for opposite results, see Deese, 1958); (b) according to information theory, the number of response alternatives, or possible stimuli in the situation, determines the complexity of different tasks (e.g., Coren & Ward, 1989;Simon , 1972Simon , , 1974; (c) decision making research has suggested that the number of choice alternatives is one of the variables that influences task complexity (e.g., Brehmer, 1992;Kerstholt, 1992;Payne, 1982;Sundstrom, 1987); (d) the cued recall of an item decreases as the number of items associated with the same cue increases (e.g., Bauml, 1997;Ratcliff, Clark, & Shiffrin, 1990); and (e) the increase in the number of responses associated with a given stimulus in paired-associates tasks reduced performance in transfer tasks, when compared to the increase in the number of stimuli associated to the same responses (e.g., Postman, 1972).…”

Retrieval induces forgetting, but only when nontested items compete for retrieval: Implication for interference, inhibition, and context reinstatement.

“…As we have discussed in the Introduction, Jakab and Raaijmakers might have obtained equivalent retrieval-induced forgetting regardless of competitor strength because they used category cued recall as their final test, which did not allow one to control output order. When participants are free to output items within a category in any order, they are likely to recall the stronger Rp+ items before the weaker Rp-items, and output interference from the Rp+ items can then impair retrieval of the Rp-items (Bäuml, 1997). Thus, whether competition dependent retrieval-induced forgetting occurs may depend on the nature of the final recall test.…”