The role of memory representation in the vigilance decrement

Working memory load is critically important for the overall level of performance on vigilance tasks. However, its role in a key aspect of vigilance—sensitivity decrement over time—is unclear. We used a dual-task procedure in which either a spatial or a nonspatial working memory task was performed simultaneously with a spatial vigilance task for 20 min. Sensitivity in the vigilance task declined over time when the concurrent task involved spatial working memory. In contrast, there was no sensitivity decrement with a nonspatial working memory task. The results provide the first evidence of a specific role for working memory representation in vigilance decrement. The findings are also consistent with a multiple resource theory in which separate resources for memory representation and cognitive control operations are differentially susceptible to depletion over time, depending on the demands of the task at hand.     

Gummed-up memory: Chewing gum impairs short-term recall

Several studies have suggested that short-term memory is generally improved by chewing gum. However, we report the first studies to show that chewing gum impairs short-term memory for both item order and item identity. Experiment 1 showed that chewing gum reduces serial recall of letter lists. Experiment 2 indicated that chewing does not simply disrupt vocal–articulatory planning required for order retention: Chewing equally impairs a matched task that required retention of list item identity. Experiment 3 demonstrated that manual tapping produces a similar pattern of impairment to that of chewing gum. These results clearly qualify the assertion that chewing gum improves short-term memory. They also pose a problem for short-term memory theories asserting that forgetting is based on domain-specific interference given that chewing does not interfere with verbal memory any more than tapping. It is suggested that tapping and chewing reduce the general capacity to process sequences.     

Chewing gum while studying: Effects on alertness and test performance

Recent research has demonstrated chewing gum can enhance various cognitive processes associated with learning, but most studies have used cognitive functioning tasks (e.g., selective attention and working memory) as outcomes. Across two experiments, we investigated effects of chewing gum on self‐reports of alertness and test performance following study of realistic educational materials. In Experiment 1 (n = 40), adult participants who chewed gum while studying a 20‐min physiology lesson outperformed a nonchewing condition on subsequent terminology and comprehension tests, but did not report higher levels of postlesson alertness as hypothesised. In Experiment 2 (n = 39), adult participants who chewed gum while studying a 9‐min lesson on a mental mathematics strategy outperformed a nonchewing condition on a subsequent problem‐solving test, whereas also reporting higher levels of postlesson alertness. The results provide initial support for chewing gum while studying realistic educational materials across a range of topics and study durations.     

Chewing gum and context‐dependent memory: The independent roles of chewing gum and mint flavour

Two experiments independently investigated the basis of the chewing gum induced context‐dependent memory effect. At learning and/or recall, participants either chewed flavourless gum (Experiment 1) or received mint‐flavoured strips (Experiment 2). No context‐dependent memory effect was found with either flavourless gum or mint‐flavoured strips, indicating that independently the contexts were insufficiently salient to induce the effect. This is found despite participants’ subjective ratings indicating a perceived change in state following administration of flavourless gum or mint‐flavoured strips. Additionally, some preliminary evidence for a non‐additive facilitative effect of receiving gum or flavour at either learning and/or recall is reported. The findings raise further concerns regarding the robustness of the previously reported context‐dependent memory effect with chewing gum.     

Keep your eyes open: dispositional vigilance moderates the relationship between operational police stress and stress symptoms

Background: Vigilant coping is characterized by a deep processing of threat-related information. In many cases, vigilant coping increases stress symptoms, whereas avoidant coping decreases negative affect. However, vigilance may be beneficial when stress-eliciting situations involve a risk of injury or escalation as is usually the case in police operations. Design: We investigated the roles of vigilance and cognitive avoidance in police operations in a cross-sectional survey. Methods: The participants were 137 students (104?men, M_age?=?28.54, SD?=?8.04) from the Federal University of Applied Administrative Sciences; 76 of them were already police officers (work experience: M?=?12.59?years), and 61 were police officer candidates who had completed a 3- to 6-month police internship. Participants completed a paper-and-pencil survey and reported their operational stress, dispositional vigilance and cognitive avoidance in police operations, and stress symptoms. Results: We found that vigilance was negatively associated with stress symptoms and moderated the relationship between operational stress and stress symptoms. Cognitive avoidance, on the other hand, just missed the level of statistical significance in our test of whether it was positively associated with stress symptoms. Conclusions: Our findings demonstrate that vigilance may protect against the negative consequences of stress in police operations.     

Illusion decrement and transfer of illusion decrement in real- and subjective-contour Poggendorff figures

The reduction in illusion magnitude with visual inspection and the transfer of such illusion decrement to a noninspected figure were examined in real- and subjective-contour Poggendorff figures. For both types of figures, illusion magnitude decreased significantly, and in a similar manner, during a 5-min inspection period. Postinspection tests showed that inspecting either a real- or subjective-contour figure resulted in a reduction in illusion magnitude for the other, noninspected figure. These findings suggest that real- and subjective-contour Poggendorff figures share a similar global organization and are thus probably processed in a similar manner. These characteristics make subjective-contour figures a useful tool for separating illusion-producing mechanisms into structural and strategy components.     

Illusion decrement and transfer of illusion decrement in obtuse- and acute-angle variants of the Poggendorff illusion

Illusion-decrement and transfer-of-illusion-decrement procedures were used to examine the contribution of the obtuse- and acute-angle components of the Poggendorff pattern to the standard Poggendorff illusion. In the first four experiments, subjects were required to scan between the oblique lines of the Poggendorff pattern during the inspection phase of the decrement procedure. However, because of a possible confound associated with this procedure, a different decrement technique was used in Experiment 5. The results of Experiment 5 confirm and extend MacKay and Newbigging's (1977) finding that similar amounts of transfer to the standard pattern are obtained from the obtuse- and acute-angle patterns as from the standard pattern itself: In showing that the acute- and obtuse-angle components both contribute to the illusion, these findings question the plausibility of those theories of the Poggendorff illusion which do not assign any significant role to the acute-angle component. Furthermore, the potential confound associated with the decrement procedure of Experiments 1-4 suggests that the results of other studies obtained with similar procedures need to be reevaluated.     

Processing strategy moderates the cultivation effect

This study tested the hypothesis that processing strategy moderates the effect of television viewing on social perceptions (cultivation effect). One hundred twenty‐two male and female students provided estimates of the prevalence of crime, occupations, affluence, and marital discord under one of three conditions. Some participants were induced to process heuristically (heuristic group) through instructions to provide their estimates spontaneously with little elaboration. Other participants were induced to process systematically (systematic group) through an accuracy motivation/task importance manipulation. A third (control) group received instructions to simply answer the questions. The results indicated that processing strategy moderated the cultivation effect such that cultivation effects were noted in the heuristic and control groups but not in the systematic group. These results are consistent with the notion that the cultivation effect can be explained in part as the result of heuristic processing through lack of source discounting, and they provide support for the heuristic processing model of cultivation effects.     

Differentiation and decrement in the Mueller-Lyer illusion

Two experiments were conducted to test the hypothesis that decrement of the Mueller-Lyer illusion with inspection is due to learning to differentiate the test element from the accessory lines. In one experiment, the test element is predifferentiated for the observer by means of configurational variations and in the other by restriction of attention. Although the initial magnitude of the illusion is found to be inversely proportional to the amount of predifferentiation, the slopes of the decrement curves are not affected.     

Task difficulty moderates the revelation effect

Tasks that precede a recognition probe induce a more liberal response criterion than do probes without tasks—the “revelation effect.” For example, participants are more likely to claim that a stimulus is familiar directly after solving an anagram, relative to a condition without an anagram. Revelation effect hypotheses disagree whether hard preceding tasks should produce a larger revelation effect than easy preceding tasks. Although some studies have shown that hard tasks increase the revelation effect as compared to easy tasks, these studies suffered from a confound of task difficulty and task presence. Conversely, other studies have shown that the revelation effect is independent of task difficulty. In the present study, we used new task difficulty manipulations to test whether hard tasks produce larger revelation effects than easy tasks. Participants (N = 464) completed hard or easy preceding tasks, including anagrams (Exps. 1 and 2) and the typing of specific arrow key sequences (Exps. 3–6). With sample sizes typical of revelation effect experiments, the effect sizes of task difficulty on the revelation effect varied considerably across experiments. Despite this variability, a consistent data pattern emerged: Hard tasks produced larger revelation effects than easy tasks. Although the present study falsifies certain revelation effect hypotheses, the general vagueness of revelation effect hypotheses remains.     

Exemplar effect in Mueller-Lyer decrement

Coren and Girgus in 1972 had each of their subjects inspect one of four Mueller-Lyer variants with the two segments set equal. In six interspersed Average Error test trials with the initial setting at zero illusion, the variants showed similar decremental rates. In 1962 Day had observed decrement when the test trials began with the segments equal; Eysenck and Slater in 1958 found no decrement when the test trials started with the segments clearly dissimilar. Present subjects addressed figures having either equal or unequal segments, and, over six trials, with and without inspection periods, came to approach the presented figures as exemplars.     

Exploring a recognition-induced recognition decrement

Four experiments were performed to explore a recognition decrement that is associated with the recognition of a word from a short list. The stimulus material for demonstrating the phenomenon was a list of words of different syntactic types. A word from the list was recognized less well following a decision that a word of the same type had occurred in the list than following a decision that such a word had not occurred in the list. A recognition decrement did not occur for a word of a given type following a positive recognition decision to a word of a different type. A recognition decrement did not occur when the list consisted exclusively of nouns. It was concluded that the phenomenon may reflect a criterion shift but, probably, does not reflect a list strength effect, suppression, or familiarity attribution consequent to a perceived discrepancy between actual and expected fluency.     

Eye movements and decrement in the Oppel-Kundt illusion

Two groups of 15 Ss each observed the Oppel-Kundt illusion, in which a divided extent appears longer than an undivided extent. The group which made saccadic eye movements over the figure showed significant decrement of the illusion, while the group which maintained steady fixation showed no decrement. These results support an interpretation which maintains that information from eye-movement errors provides data as to the nature and extent of the illusion, thus leading to decrement.