The interaction between specific and general information in category learning and representation: unitization and parallel interactive processing.

We investigated the effects of specific stimulus information on the use of rule information in a category learning task in 2 experiments, one presented here and an intercategory transfer task reported in an earlier article. In the present experiment photograph--name combinations, called identifiers, were associated with 4 demographic attributes. The same attribute information was shown to all participants. However, for one group of participants, half of the identifiers were paired with attribute values repeated over presentation blocks. For the other group the identifier information was new for each presentation block. The first group performed less well than the second group on stimuli with nonrepeated identifiers, indicating a negative effect of specific stimulus information on processing rule information. Application of a network model to the 2 experiments, which provided for the growth of connections between attribute values in learning, indicated that repetition of identifiers produced a unitizing effect on stimuli. Results suggested that unitization produced interference through connections between irrelevant attribute values.

Diagnostic hypothesis generation and human judgment.

Diagnostic hypothesis-generation processes are ubiquitous in human reasoning. For example, clinicians generate disease hypotheses to explain symptoms and help guide treatment, auditors generate hypotheses for identifying sources of accounting errors, and laypeople generate hypotheses to explain patterns of information (i.e., data) in the environment. The authors introduce a general model of human judgment aimed at describing how people generate hypotheses from memory and how these hypotheses serve as the basis of probability judgment and hypothesis testing. In 3 simulation studies, the authors illustrate the properties of the model, as well as its applicability to explaining several common findings in judgment and decision making, including how errors and biases in hypothesis generation can cascade into errors and biases in judgment.

Motivated to retrieve: how often are you willing to go back to the well when the well is dry?

Despite the necessity of the decision to terminate memory search in many real-world memory tasks, little experimental work has investigated the underlying processes. In this study, the authors investigated termination decisions in free recall by providing participants an open-ended retrieval interval and requiring them to press a stop button when they had finished retrieving. Three variables important to assessing one's willingness to search memory were examined: (a) the time spent searching memory after the last successful retrieval before choosing to quit (the exit latency); (b) task difficulty; and (c) individual differences in motivation, as measured by Webster and Kruglanski's (1994) Need for Closure Scale. A strong negative correlation was found between individual differences in motivation and participants' exit latencies. This negative correlation was present only when the retrieval task started out as relatively difficult.

Memory and language improvements following cognitive control training.

Cognitive control refers to adjusting thoughts and actions when confronted with conflict during information processing. We tested whether this ability is causally linked to performance on certain language and memory tasks by using cognitive control training to systematically modulate people's ability to resolve information-conflict across domains. Different groups of subjects trained on 1 of 3 minimally different versions of an n-back task: n-back-with-lures (High-Conflict), n-back-without-lures (Low-Conflict), or 3-back-without-lures (3-Back). Subjects completed a battery of recognition memory and language processing tasks that comprised both high- and low-conflict conditions before and after training. We compared the transfer profiles of (a) the High- versus Low-Conflict groups to test how conflict resolution training contributes to transfer effects, and (b) the 3-Back versus Low-Conflict groups to test for differences not involving cognitive control. High-Conflict training-but not Low-Conflict training-produced discernable benefits on several untrained transfer tasks, but only under selective conditions requiring cognitive control. This suggests that the conflict-focused intervention influenced functioning on ostensibly different outcome measures across memory and language domains. 3-Back training resulted in occasional improvements on the outcome measures, but these were not selective for conditions involving conflict resolution. We conclude that domain-general cognitive control mechanisms are plastic, at least temporarily, and may play a causal role in linguistic and nonlinguistic performance. (PsycINFO Database Record

Retrieval dynamics in self-terminated memory search.

Most free-recall experiments employ a paradigm in which participants are given a preset amount of time to retrieve items from a list. While much has been learned using this paradigm, it ignores an important component of many real-world retrieval tasks: the decision to terminate memory search. The present study examines the temporal characteristics underlying memory search by comparing within subjects a standard retrieval paradigm with a finite, preset amount of time (closed interval) to a design that allows participants to terminate memory search on their own (open interval). Calling on the results of several presented simulations, we anticipated that the threshold for number of retrieval failures varied as a function of the nature of the recall paradigm, such that open intervals should result in lower thresholds than closed intervals. Moreover, this effect was expected to manifest in interretrieval times (IRTs). Although retrieval-interval type did not significantly impact the number of items recalled or error rates, IRTs were sensitive to the manipulation. Specifically, the final IRTs in the closed-interval paradigm were longer than those of the open-interval paradigm. This pattern suggests that providing participants with a preset retrieval interval not only masks an important component of the retrieval process (the memory search termination decision), but also alters temporal retrieval dynamics. Task demands may compel people to strategically control aspects of their retrieval by implementing different stopping rules.

Measuring working memory is all fun and games: a four-dimensional spatial game predicts cognitive task performance.

We developed a novel four-dimensional spatial task called Shapebuilder and used it to predict performance on a wide variety of cognitive tasks. In six experiments, we illustrate that Shapebuilder: (1) Loads on a common factor with complex working memory (WM) span tasks and that it predicts performance on quantitative reasoning tasks and Ravens Progressive Matrices (Experiment 1), (2) Correlates well with traditional complex WM span tasks (Experiment 2), predicts performance on the conditional go/no go task (Experiment 3) and N-back (Experiment 4), and showed weak or nonsignificant correlations with the Attention Networks Task (Experiment 5), and task switching (Experiment 6). Shapebuilder shows that it exhibits minimal skew and kurtosis, and shows good reliability. We argue that Shapebuilder has many advantages over existing measures of WM, including the fact that it is largely language independent, is not prone to ceiling effects, and take less than 6 min to complete on average.

On the lawfulness of the decision to terminate memory search.

Nearly every memory retrieval episode ends with a decision to terminate memory search. Yet, no research has investigated whether these search termination decisions are systematic, let alone whether they are made consistent with a particular rule. In the present paper, we used a modified free-recall paradigm to examine the decision to terminate search. Data from two experiments revealed that the total time engaged in retrieval was a monotonically increasing function of the total number of items retrieved, whereas the time from final retrieval to search termination (exit latency) was a monotonically decreasing function of the total number of items retrieved. These findings were compared to the predictions of previously proposed stopping rules, using the Search of Associative Memory framework. Of the four rules examined, only one predicts the obtained data pattern.