Casino gambling increases heart rate and salivary cortisol in regular gamblers.

BACKGROUND: Although the effects of gambling on cardiovascular parameters have been documented, no data exists describing the effect of gambling on stress hormone secretion. Our study investigated the effect of gambling on heart rate and salivary cortisol in a casino environment. METHODS: Ten male gamblers participated in both an experimental and control session. In the experimental session, gamblers played a game of blackjack using their own money. Gamblers played cards in the same setting during the control condition; however, the game was played for accumulation of points rather than money. Heart rate and endocrine parameters were recorded at baseline, 30 min, and 60 min following commencement of each session, and again at completion of the game. RESULTS: Heart rate increased significantly from baseline to 30 min in the experimental session and remained elevated for the remainder of the recording period. Salivary cortisol was raised at 30 min and further elevated at 60 min during gambling, then returned to control levels following completion of the game. CONCLUSIONS: These data indicate that gambling in a "real life" situation produces increases in salivary cortisol levels that accompany increased cardiovascular activity. Such effects may contribute to the development of gambling addiction.

Estimating unconscious processes: implications of a general class of models.

Jacoby and his colleagues (e.g., L. L. Jacoby, J. P. Toth, & A. P. Yonelinas, 1993) have shown how the mnemonic contributions of conscious recollection and unconscious familiarity can be separated using a process-dissociation procedure based on a comparison of tasks in which consciously recollected material is to be included in vs. excluded from the responses. However, the estimate of unconscious familiarity depends on the assumptions of the model. This article describes a more general class of models in which the ratio of overlap between conscious and unconscious processes remains fixed and shows that this class of models (which includes the redundancy and exclusivity models as extreme cases) yields improbable results.

Implicit learning of a nonverbal sequence in younger and older adults.

Two experiments examined age-related differences in implicit serial learning using the M. J. Nissen and P. Bullemer (1987) task. Younger adults and 2 samples of older adults who differed in educational attainment, occupational status, and verbal ability were given a 10-trial repeating sequence embedded in 100-trial blocks. On each trial, participants pressed a key that matched a designated spatial location. Implicit learning was inferred from the difference in RT between a random sequence trial block and the immediately preceding block with the repeating sequence. Results indicated that negative transfer effects were comparable for the younger and higher ability older adults, but lower ability older adults showed less evidence of implicit learning. On an explicit task, younger and higher ability older adults were more accurate than the lower ability older adults. The implications of these findings for current views on implicit learning in adulthood are discussed.

On learning complex procedural knowledge.

Lewicki, Czyzewska, and Hoffman (1987) demonstrated learning without awareness in a visual search task. Rules determined target location on every seventh trial on the basis of target locations in the preceding six trials. Learning was demonstrated by negative transfer effects when the rules were changed. When questioned afterwards, the subjects could not describe the rules and denied awareness of them. This experiment was designed to replicate that of Lewicki et al. and to test several hypotheses about this apparent learning without awareness. Transfer conditions were included to determine whether rule learning was primarily perceptual or motor. The present assessment of awareness was based on an objective definition of awareness, rather than a subjective definition as in Lewicki et al.'s study. Their effect was replicated, and the transfer conditions revealed that learning relied on perceptual aspects of the task. The objective measure of awareness provided further evidence that subjects were unaware of the rules.

Varieties of positive and negative priming.

Numerous recent investigations have focused on a particular relation between the roles a stimulus plays in successive displays: when a stimulus ignored by a subject on one occasion is to be attended on a succeeding occasion, reaction time to that stimulus is slowed relative to a control condition. But this is but one possible case ofnegative priming. There are other ways in which negative priming might occur, and there are several varieties of positive priming as well. All these possibilities were explored in the present experiment.

Implicit serial learning: questions inspired by Hebb (1961).

Implicit serial learning occurs when indirect measures such as transfer reveal learning of a repeating sequence even when subjects are not informed of the repeating sequence, are not asked to learn it, and do not become of aware of it. This phenomenon is reminiscent of an experiment by Hebb (1961), who studied the repetition of sequences in a serial recall task. Two experiments investigated the relation between implicit serial learning and ideas about learning forwarded by Hebb and others who used his method. The experiments showed that implicit serial learning occurs even when the repeating sequence is intermixed with randomly generated sequences instead of being repeated continuously, that the organization of the sequence into regularly or irregularly grouped subsequences determines the extent of learning, and that the repetition effect observed does not depend on subjects' ability to recognize the repetition.

On imaging and seeing: repetition priming and interactive views of imagery.

The interaction between perceptual and imaginal processes was investigated, with the use of the repetition-priming paradigm. The idea is that the overlap between processes employed in imagery and processes employed in perception will be reflected in the amount of transfer from one encounter with an item that engages perception or imagery and a second encounter that engages perception or imagery. The greater the overlap between perception and imagery, the greater the transfer between them should be. The results showed that perceptual and imaginal processes transferred maximally to themselves; that is, maximum transfer occurred when an item was processed in the same way on both encounters. Further, prior use of perceptual processes transferred to the use of imaginal processes, but not vice versa. These results are discussed as they relate to the interactive view of imagery, which holds that imagery relies on many of the same mental structures and processes as perception.

Is there a search in fixed-set memory search?

We discuss the hypothesis that structural factors in the fixed-set memory-search task may contribute to the standard linear set-size effect typically observed in this task. We constructed a lexical decision task that contained the same structural factors as the memory-search task. Two structural factors are discussed: (1) the priming of the probe by the memory set, and (2) the confounding of repetitions per item with set size. Our experiment demonstrated that these structural factors play a role in the set-size effect. The implications of these effects for the memory-search task and for models proposed to account for memory-search data are discussed.

True but not false memories produce a sensory signature in human lateralized brain potentials.

False memories (e.g., recognition of events that did not occur) are considered behaviorally and subjectively indistinguishable from true memories. We report that brain activity differs when true and false memories are retrieved. Strongly associated lists of words were presented to one or the other cerebral hemisphere at study. This led to lateralized brain activity for these words during a centrally presented recognition test, reflecting their lateralized encoding. This activity was absent for nonstudied but strongly associated words falsely recognized as studied items. These results indicate that studied words leave sensory signatures of study experiences that are absent for false memories. In addition, hemifield effects emerged, including a slower reaction time (RT) for false recognition of nonstudied words whose associated lists were presented to the left hemifield (i.e., right hemisphere). These false recognition responses were accompanied by frontal slow wave activity, which may reflect a differential ability of the two hemispheres with respect to semantic processing.

Negative priming from activation of counting and addition knowledge.

In two experiments, subjects were presented with digit pairs (e.g., 32) and asked to respond to the rightmost number. Negative priming, that is, slowed processing, was evident when the rightmost number was a counting-string (e.g., 43 following 12) or addition-sum (e.g., 65 following 32) associate of the number pair from the preceding trial. The studies are the first to demonstrate negative priming with counting and arithmetical memory representations and suggest the obligatory activation of these representations with the presentation of number pairs. The results are also consistent with the view that negative priming often occurs at the semantic level.

Is there implicit memory without attention? A reexamination of task demands in Eich's (1984) procedure.

The relation between memory and attention has been of long-standing interest. Eich (1984) made an important discovery of implicit but not explicit memory for contextually determined homophones (e.g., taxi-FARE) presented in a channel to be ignored within a selective listening procedure. However, his slow rate of presentation of shadowing task materials may have allowed frequent attention shifts to the allegedly ignored channel. With a direct replication of Eich's timing parameters, we reproduced his results, but when the attended channel was presented twice as fast as Eich's, implicit memory for the to-be-ignored words vanished. Our results contradict claims of extensive semantic processing of unattended auditory information in this task.

Is there cross-format transfer in implicit invariance learning?

Three experiments investigated cross-form transfer in the invariance learning paradigm introduced by McGeorge and Burton (1990). The results suggest that the transfer observed by McGeorge and Burton depended on subjects' ability to use a response strategy discovered by Wright and Burton (1995). When that strategy was denied to subjects (Experiments 1 and 2), no cross-form transfer was observed; when the strategy was made available (Experiment 3), cross-form transfer re-emerged. These results suggest that this form of learning, like many other forms of implicit learning and memory, is hyperspecific.

The relationship between the Wechsler Memory Scale-Revised (WMS-R) Attention index and putative measures of Attention.

Although the Wechsler Memory Scale-Revised (WMS-R; Wechsler, 1987) is one of the more frequently used measures of memory and attention, its Attention/Concentration Index (ACI) has been minimally researched. If the ACI is to be used as a measure of "attention," the need exists to determine if it is related to other measures theoretically argued to be sensitive to attention deficits. The present study evaluated the relationship between the WMS-R ACI and other putative measures of attention by comparing individuals labeled as Attention Impaired [ACI at least 15 points < General Memory Index (GMI)] versus those labeled as Memory Impaired (GMI at least 15 points < ACI). Contrary to expectations, the Attention Impaired group scored equal to the Memory Impaired group on all measures theorized to be sensitive to attention deficits (Trails A and B time, Trails B errors, Rey AVLT interference list), except for statistically weaker performance on Trails A errors. In contrast but as expected, the Memory Impaired group scored statistically worse on all memory tests (Rey AVLT, all TPT variables). The groups also did not differ on tests argued not to be differentially affected by either attention or memory (WAIS-R FIQ, Category Test). It is concluded that the WMS-R Attention Index is not related to deficits on other measures sensitive to attention, further emphasizing the need to identify more clearly specific attention constructs.

Norms for word lists that create false memories.

Roediger and McDermott (1995) induced false recall and false recognition for words that were not presented in lists. They had subjects study 24 lists of 15 words that were associates of a common word (called the critical target or critical lure) that was not presented in the list. False recall and false recognition of the critical target occurred frequently in response to these lists. The purpose of the current work was to provide a set of normative data for the lists Roediger and McDermott used and for 12 others developed more recently. We tested false recall and false recognition for critical targets from 36 lists. Despite the fact that all lists were constructed to produce false remembering, the diversity in their effectiveness was large--60% or more of subjects falsely recalled window and sleep following the appropriate lists, and false recognition for these items was greater than 80%. However, the list generated from king led to 10% false recall and 27% false recognition. Possible reasons for these wide differences in effectiveness of the lists are discussed. These norms serve as a useful benchmark for designing experiments about false recall and false recognition in this paradigm.