Generation and context memory

Generation enhances memory for occurrence but may not enhance other aspects of memory. The present study further delineates the negative generation effect in context memory reported in N. W. Mulligan (2004). First, the negative generation effect occurred for perceptual attributes of the target item (its color and font) but not for extratarget aspects of context (location and background color). Second, nonvisual generation tasks with either semantic or nonsemantic generation rules (antonym and rhyme generation, respectively) produced the same pattern of results. In contrast, a visual (or data-driven) generation task (letter transposition) did not disrupt context memory for color. Third, generating nonwords produced no effect on item memory but persisted in producing a negative effect on context memory for target attributes, implying that (a) the negative generation effect in context memory is not mediated by semantic encoding, and (b) the negative effect on context memory can be dissociated from the positive effect on item memory. The results are interpreted in terms of the processing account of generation. The original, perceptual-conceptual version of this account is too narrow, but a modified processing account, based on a more generic visual versus nonvisual processing distinction, accommodates the results.     

How to Assess a Model's Testability and Identifiability

Formal definitions are given of the following intuitive concepts: (a) A model is quantitatively testable if its predictions are highly precise and narrow. (b) A model is identifiable if the values of its parameters can be ascertained from empirical observations. (c) A model is redundant if the values of some parameters can be deduced from others or if the values of some observables can be deduced from others. Various rules of thumb for nonredundant models are examined. The Counting Rule states that a model is quantitatively testable if and only if it has fewer parameters than observables. This rule can be safely applied only to identifiable models. If a model is unidentifiable, one must apply a generalization of the Counting Rule known as the Jacobian Rule. This rule states that a model is quantitatively testable if and only if the maximum rank (i.e., the number of linearly independent columns) of its Jacobian matrix (i.e., the matrix of partial derivatives of the function that maps parameter values to the predicted values of observables) is smaller than the number of observables. The Identifiability Rule states that a model is identifiable if and only if the maximum rank of its Jacobian matrix equals the number of parameters. The conclusions provided by these rules are only presumptive. To reach definitive conclusions, additional analyses must be performed. To illustrate the foregoing, the quantitative testability and identifiability of linear models and of discrete-state models are analyzed. Copyright 2000 Academic Press.     

The interplay of memory and judgment processes in effects of aging on hindsight bias

Hindsight bias is the phenomenon that after people are presented with the correct answer to a question, their judgment regarding their own past answer to this question is biased toward the correct answer. In three experiments, younger and older adults gave numerical responses to general-knowledge questions and later attempted to recall their responses. For some questions, the correct answer was provided during recall (Experiment 1) or before recall (Experiments 2 and 3). Multinomial model-based analyses show age differences in both recollection bias and reconstruction bias when the correct judgment was in working memory during the recall phase. The authors discuss implications for theories of cognitive aging and theories of hindsight bias.     

Adult age differences in distinctive processing: the modality effect on false recall

Age differences in distinctive processing were investigated by examining the effects of study presentation modality on false recall in younger and older adults using the Deese/Roediger and McDermott paradigm. Participants were presented with study words either visually or auditorily. Older adults did not show the typical reduction in false recall after visual, compared to auditory, study presentation (R.E. Smith & R.R. Hunt, 1998). The authors interpret these results as evidence of reduced distinctive processing on the part of older adults.     

Exploring the role of attention during memory retrieval: Effects of semantic encoding and divided attention

Research on attention and memory suggests that semantic encoding leads to retrieval that is highly susceptible to divided attention. Three experiments tested this proposition and showed that dividing attention did not selectively affect semantically encoded items. Participants encoded a list of words in one of two ways: semantically or phonetically. Later, memory was assessed using either a standard recognition test (Experiment 1) or a rhyme recognition test (Experiments 2 and 3). The participants took the memory test either alone (full attention) or while simultaneously performing a secondary task (divided attention). Recognition accuracy was reduced by divided attention on both recognition tests, and semantically and phonetically encoded words were equally affected.     

The sounds of dominance.

A study was conducted to determine the effects of vocal cues on judgements of dominance in an interpersonal influence context. Physical measures of human vocal cues and participant ratings of dominance were obtained from videotapes of actors delivering short influence messages. After controlling for linguistic and visual content of messages, results indicated that mean amplitude and amplitude standard deviation were positively associated with dominance judgments, whereas speech rate was negatively associated with dominance judgments. An unexpected interaction revealed that mean fundamental frequency (F₀) was positively associated with dominance judgments for male speakers but not significantly associated with dominance judgments for female speakers. F₀ standard deviation was not significantly associated with dominance judgments. Results support the conclusion that dominance judgments are inferred from multiple sources of information and that some vocal markers of dominance are more influential than others.     

Hypothalamo-Pituitary-Adrenocortical Regulation Following Lesions of the Central Nucleus of the Amygdala

Previous reports indicate that the central nucleus of the amygdala (CeA) stimulates adrenocorticotropin and corticosterone secretion, suggesting a role for this region in central hypothalamo-pituitary-adrenocortical (HPA) stress regulation. To evaluate this hypothesis, this study assessed the impact of CeA lesion on the response of hypophysiotrophic paraventricular nucleus (PVN) neurons to acute restraint and chronic unpredictable stress exposure. In contrast to previous reports, CeA lesions did not affect corticosterone or ACTH secretion induced by acute stress. Acute restraint increased PVN corticotropin releasing hormone (CRH) mRNA expression, increased the number of parvocellular PVN neurons expressing the co-secretagogue arginine vasopressin (AVP), and induced cFOS mRNA expression in the parvocellular PVN. However, there was no additional effect of CeA lesion on any measure of PVN activation. Chronic unpredictable stress exposure induced long-term activation of the HPA axis, noted by thymic involution, adrenal hypertrophy and increased PVN CRH mRNA expression. Stress-induced changes in thymus and adrenal weights were not affected by CeA lesion. Further, CeA lesion rats did not differ from controls in post-stress CRH mRNA expression. However, basal CRH mRNA expression was increased in the PVN of CeA rats, suggesting that the CeA plays a role in long-term inhibition of the PVN. The results of these studies are not consistent with the hypothesis that the CeA is necessary for stress-induced pituitary-adrenocortical activation. Rather, this region may play a stressor-specific modulatory role in regulation of HPA function.     

Persuasion and the structure of affect.

Participants viewed eight PSAs, providing data on their cognitive and emotional responses to each, as well as judgments of the perceived effectiveness of the messages. They also responded to Carver and White's (1994) BIS/BAS scales designed to measure individual differences in the behavioral inhibition and behavioral activation systems. Consistent with dual‐systems theories of affect, the BIS scales predicted arousal of negative emotions, while BAS was associated with the elicitation of positive emotions. However, when predicting perceived message effectiveness, the positive affects showed variation in the sign and magnitude of the coefficients, as did the negative affects. This latter finding supports a discrete‐emotions perspective. Knowledge that the two affect structures are appropriate to different conceptual domains (i.e., elicitation vs. effect) should enable researchers to formulate more precise questions regarding the role of affect in persuasion.     

Using verification feedback to correct errors made on a multiple-choice test

A key educational challenge is how to correct students' errors and misconceptions so that they do not persist. Simply labelling an answer as correct or incorrect on a short-answer test (verification feedback) does not improve performance on later tests; error correction requires receiving answer feedback. We explored the generality of this conclusion and whether the effectiveness of verification feedback depends on the type of test with which it is paired. We argue that, unlike for short-answer tests, learning whether one's multiple-choice selection is correct or incorrect should help participants narrow down the possible answers and identify specific lures as false. To test this proposition we asked participants to answer a series of general knowledge multiple-choice questions. They received no feedback, answer feedback, or verification feedback, and then took a short-answer test immediately and two days later. Verification feedback was just as effective as answer feedback for maintaining correct answers. Importantly, verification feedback allowed learners to correct more of their errors than did no feedback, although it was not as effective as answer feedback. Overall, verification feedback conveyed information to the learner, which has both practical and theoretical implications.     

Using verification feedback to correct errors made on a multiple-choice test

A key educational challenge is how to correct students’ errors and misconceptions so that they do not persist. Simply labelling an answer as correct or incorrect on a short-answer test (verification feedback) does not improve performance on later tests; error correction requires receiving answer feedback. We explored the generality of this conclusion and whether the effectiveness of verification feedback depends on the type of test with which it is paired. We argue that, unlike for short-answer tests, learning whether one's multiple-choice selection is correct or incorrect should help participants narrow down the possible answers and identify specific lures as false. To test this proposition we asked participants to answer a series of general knowledge multiple-choice questions. They received no feedback, answer feedback, or verification feedback, and then took a short-answer test immediately and two days later. Verification feedback was just as effective as answer feedback for maintaining correct answers. Importantly, verification feedback allowed learners to correct more of their errors than did no feedback, although it was not as effective as answer feedback. Overall, verification feedback conveyed information to the learner, which has both practical and theoretical implications.