On the nature of the decision axis in signal-detection-based models of recognition memory

Most models of recognition memory involve a signal-detection component in which a criterion is placed along a decision axis. Older models generally assume a familiarity-decision axis, but newer models often assume a likelihood ratio axis instead because it allows for a more natural account of the ubiquitous mirror effect. In 3 experiments reported here, item strength was differentially manipulated to see whether a mirror effect would occur. Within a list, the items from 1 category were strengthened by repetition, but the items from another category were not. On the subsequent recognition test, the hit rate was higher for the strong category, but the false-alarm rates for the weak and strong categories were the same (i.e., no mirror effect was observed). This result suggests that the decision axis represents a familiarity scale and that participants adopt a single decision criterion that they maintain throughout the recognition test.     

Neurobiological and memory models of risky decision making in adolescents versus young adults

Predictions of fuzzy-trace theory and neurobiological approaches are examined regarding risk taking in a classic decision-making task--the framing task--as well as in the context of real-life risk taking. We report the 1st study of framing effects in adolescents versus adults, varying risk and reward, and relate choices to individual differences, sexual behavior, and behavioral intentions. As predicted by fuzzy-trace theory, adolescents modulated risk taking according to risk and reward. Adults showed standard framing, reflecting greater emphasis on gist-based (qualitative) reasoning, but adolescents displayed reverse framing when potential gains for risk taking were high, reflecting greater emphasis on verbatim-based (quantitative) reasoning. Reverse framing signals a different way of thinking compared with standard framing (reverse framing also differs from simply choosing the risky option). Measures of verbatim- and gist-based reasoning about risk, sensation seeking, behavioral activation, and inhibition were used to extract dimensions of risk proneness: Sensation seeking increased and then decreased, whereas inhibition increased from early adolescence to young adulthood, predicted by neurobiological theories. Two additional dimensions, verbatim- and gist-based reasoning about risk, loaded separately and predicted unique variance in risk taking. Importantly, framing responses predicted real-life risk taking. Reasoning was the most consistent predictor of real-life risk taking: (a) Intentions to have sex, sexual behavior, and number of partners decreased when gist-based reasoning was triggered by retrieval cues in questions about perceived risk, whereas (b) intentions to have sex and number of partners increased when verbatim-based reasoning was triggered by different retrieval cues in questions about perceived risk.     

Picture-word differences in decision latency: An analysis of single and dual memory models

Semantic and perceptual size decision times for pictorial and verbal material were analyzed in the context of a unitary memory model and several dual memory models. Experiment 1 involved a same-different categorical judgment task. The results showed that picture-picture response latencies were 185 msec faster than the corresponding word-word latencies, and word-picture and picture-word latencies equaled the mean of these two extremes. Similarity of subcategory for “same” judgments led to faster decision latency for all presentation conditions. Additionally, a linear relationship was found between picture-picture and word-word latencies for individual item pairs. Experiment 2 involved a comparison of pictures and words across a. categorical judgment and a size judgment task. Pictures produced faster decision latencies in both tasks, and the latency diflerence between pictures and words was comparable across tasks. These data fit the predictions of a unitary memory model. Several variants of a dual memory model are rejected and those which fit the data require assumptions about storage and/or transfer time values which result in a functional regression to the unitary memory model.     

Stereotypic biases in social decision making and memory: testing process models of stereotype use

Two information-processing mechanisms that could potentially contribute to judgmental discrimination against the members of stereotyped social groups were examined in two experiments, using a mock juror decision-making task. Both postulated mechanisms involve biased processing of judgment-relevant evidence. The interpretation hypothesis asserts that the activation of stereotypic concepts influences the perceived probative implications of other evidence. The selective processing hypothesis asserts that stereotype-consistent evidence is processed more extensively than is inconsistent evidence. Judgment and memory data from the first experiment supported the general notion that stereotype-based discrimination emerges from biased evidence processing. The specific pattern of results supported selective processing rather than interpretation biases as the critical process underlying observed judgmental discrimination. The second experiment corroborated this conclusion by showing that a manipulation that prevents selective processing of the evidence effectively eliminated biases in judgments and recall pertaining to stereotyped targets. Implications for a general understanding of stereotyping and discrimination are discussed.     

Memory strength and the decision process in recognition memory

We investigated the role that memory strength plays in the decision process by examining the extent to which strength is used as a cue to dynamically modify recognition criteria. The study list consisted of strong and weak items, with strength a function of study duration or repetition. The recognition test list was divided into two consecutive blocks; strong items appeared in one block, weak items in the other. If the change in item strength across blocks leads to a shift in criterion, the false alarm rate should change accordingly. In four experiments, the false alarm rates did not change across blocks, even when the difference between the strong and the weak items was magnified and marked with semantic cues. However, the strength of the items in the first test block affected the false alarm rate. Thus, strength cues influence initial criterion placement but fail to induce criterion shifts following permanent and even dramatic changes in item strength. These null findings are contrasted with those in a fifth experiment, in which accuracy feedback produced dynamic criterion shifts.     

An evolutionary approach to support decision making with linear decision models

In this paper we consider decision problems that can be described as linear decision models. These models have been traditionally solved using linear programming, fuzzy linear programming, multiple-objective linear programming or ‘what-if’ analysis. Using these approaches, one encounters a number of difficulties. We propose an ‘evolutionary approach’ to overcome these difficulties. In the proposed approach the decision maker does not have to precisely specify the model (i.e. the objective functions, the RHS values, etc.) at the beginning of the solution procedure. In fact, the model evolves as the solution procedure proceeds.     

Triadic decision making in lexical memory

Word and category recognition was investigated in the context of other stimuli, where the semantic distance relationships among the stimuli were derived from multidimensional scaling. On each trial, three horizontal strings of letters were presented. In the word condition, a positive response was required when the three strings formed three words; in the category condition, a positive response was required when the three strings formed words belonging to the same category. The results indicated that: (a) category decisions take about 150-200 msec longer than do word decisions, (b) word decisions are facilitated by a common categorical membership but semantic distances within the category are relatively unimportant, and (c)within-category semantic distances systematically altered response time for the category condition. It was hypothesized that semantic distance relationships may be sensitized for categorical decisions, but that only large semantic distances function effectively for word decisions.     

Impulsive decision making and working memory

Decision making that favors short-term over long-term consequences of action, defined as impulsive or temporally myopic, may be related to individual differences in the executive functions of working memory (WM). In the first 2 experiments, participants made delay discounting (DD) judgments under different WM load conditions. In a 3rd experiment, participants high or low on standardized measures of imupulsiveness and dysexecutive function were asked to make DD judgments. A final experiment examined WM load effects on DD when monetary rewards were real rather than hypothetical. The results showed that higher WM load led to greater discounting of delayed monetary rewards. Further, a strong direct relation was found between measures of impulsiveness, dysexecutive function,and discounting of delayed rewards. Thus, limits on WM function, either intrinsic or extrinsic, are predictive of a more impulsive decision-making style.     

Performance and process in collective and individual memory: the role of social decision schemes and memory bias in collective memory

To assess performance and processes in collective and individual memory, participants watched two job candidates on video. Beforehand, half the participants were told they would be tested on their memory of the interviews, and the other half were asked to make a decision to hire one of the candidates. Afterwards, participants completed a recognition memory task in either a group or individual condition. Groups had better recognition memory than individuals. Individuals made more false positives than false negatives and groups exaggerated this. Post-hoc analysis found that groups only exaggerated the tendency towards false positives on items that reflected negatively on the job candidate. There was no significant difference between instruction conditions. When reaching consensus on the recognition task, groups tended to choose the correct answer if at least two members had the correct answer. This method of consensus is discussed as a factor in groups' superior memory performance.     

Attention and implicit memory in the category-verification and lexical decision tasks

Prior research on implicit memory appeared to support 3 generalizations: Conceptual tests are affected by divided attention, perceptual tasks are affected by certain divided-attention manipulations, and all types of priming are affected by selective attention. These generalizations are challenged in experiments using the implicit tests of category verification and lexical decision. First, both tasks were unaffected by divided-attention tasks known to impact other priming tasks. Second, both tasks were unaffected by a manipulation of selective attention in which colored words were either named or their colors identified. Thus, category verification, unlike other conceptual tasks, appears unaffected by divided attention, and some selective-attention tasks, and lexical decision, unlike other perceptual tasks, appears unaffected by a difficult divided-attention task and some selective-attention tasks. Finally, both tasks were affected by a selective-attention task in which attention was manipulated across objects (rather than within objects), indicating some susceptibility to selective attention. The results contradict an analysis on the basis of the conceptual-perceptual distinction and other more specific hypotheses but are consistent with the distinction between production and identification priming.     

Components of working memory and somatic markers in decision making

According to Damasio’s somatic marker hypothesis, affective reactions ordinarily guide and simplify decision making. In an earlier study, we used a modified version of the gambling task developed by Bechara and colleagues so that we could explore the relations among decision making, working memory (WM) load, and formation of somatic markers. This prior work found that an increased WM load produced by secondary tasks interfered with the development of somatic markers and led to poorer gambling task performance. In the present study, we tested whether secondary tasks affect the executive functions of WM, verbal buffering, or both. Our findings indicate that verbal buffering alone does not interfere with gambling task performance or the development of somatic markers. Interference with the executive functions of WM is necessary to disrupt gambling performance and somatic markers.     

Applying artificial neural network models to clinical decision making

Because psychological assessment typically lacks biological gold standards, it traditionally has relied on clinicians' expert knowledge. A more empirically based approach frequently has applied linear models to data to derive meaningful constructs and appropriate measures. Statistical inferences are then used to assess the generality of the findings. This article introduces artificial neural networks (ANNs), flexible nonlinear modeling techniques that test a model's generality by applying its estimates against "future" data. ANNs have potential for overcoming some shortcomings of linear models. The basics of ANNs and their applications to psychological assessment are reviewed. Two examples of clinical decision making are described in which an ANN is compared with linear models, and the complexity of the network performance is examined. Issues salient to psychological assessment are addressed.     

Using response time modeling to distinguish memory and decision processes in recognition and source tasks

Receiver operating characteristic (ROC) functions are often used to make inferences about memory processes, such as claiming that memory strength is more variable for studied versus nonstudied items. However, decision processes can produce the ROC patterns that are usually attributed to memory, so independent forms of data are needed to support strong conclusions. The present experiments tested ROC-based claims about the variability of memory evidence by modeling response time (RT) data with the diffusion model. To ensure that the model can correctly discriminate equal- and unequal-variance distributions, Experiment 1 used a numerousity discrimination task that had a direct manipulation of evidence variability. Fits of the model produced correct conclusions about evidence variability in all cases. Experiments 2 and 3 explored the effect of repeated learning trials on evidence variability in recognition and source memory tasks, respectively. Fits of the diffusion model supported the same conclusions about variability as the ROC literature. For recognition, evidence variability was higher for targets than for lures, but it did not differ on the basis of the number of learning trials for target items. For source memory, evidence variability was roughly equal for source 1 and source 2 items, and variability increased for items with additional learning attempts. These results demonstrate that RT modeling can help resolve ambiguities regarding the processes that produce different patterns in ROC data. The results strengthen the evidence that memory strength distributions have unequal variability across item types in recognition and source memory tasks.     

Recognition and source memory as multivariate decision processes

Recognition memory, source memory, and exclusion performance are three important domains of study in memory, each with its own findings, its specific theoretical developments, and its separate research literature. It is proposed here that results from all three domains can be treated with a single analytic model. This article shows how to generate a comprehensive memory representation based on multidimensional signal detection theory and how to make predictions for each of these paradigms using decision axes drawn through the space. The detection model is simpler than the comparable multinomial model, it is more easily generalizable, and it does not make threshold assumptions. An experiment using the same memory set for all three tasks demonstrates the analysis and tests the model. The results show that some seemingly complex relations between the paradigms derive from an underlying simplicity of structure.     

Selective perception without confounding contributions of decision and memory

Previous research has demonstrated that decision processes and short-term memory limitations contribute to the observed limitation in the span of apprehension in tachistoscopic experiments. The present study addresses the question of whether perceptual factors also contribute to this limitation. Observers were asked to indicate which of four target letters occurred in a four-item test display. The irrelevant background items were either highly confusable or completely nonconfusable with the target letters. The target detection task is designed to bypass short-term memory limitations. In order to eliminate differences in decision processing, the location of the target letter was indicated either slightly before or shortly after the display presentation. The indicator was either an arrow cue or a pattern mask. Performance decreased with increases in the delay of the arrow cue only when the background items were confusable. The pattern mask yielded standard masking functions, but performance with the nonconfusable background items improved more rapidly with increases in processing time than did performance with the confusable background items. These results conform to the hypothesis that attention operates at the perceptual stage of processing. The results were accurately described by a quantification of attentional effects in a general information processing model.