Differential effects of forward or simultaneous conditioned stimulus-unconditioned stimulus intervals on the defensive behavior system of the Norway rat (Rattus norvegicus)

To test several predictions derived from a behavior-systems approach, the authors assessed Pavlovian fear conditioning in rats after 30 trials of forward, simultaneous, or unpaired training. Direct evidence of conditioned fear was collected through observation of flight and freezing reactions during presentations of the conditioned stimulus (CS) alone. The authors also tested the CS's potential to reinforce an instrumental escape response in an escape-from-fear paradigm. On the one hand, rats that received forward training showed conditioned freezing, but no conditioned flight was observed. On the other hand, rats that received simultaneous training showed conditioned flight, but no conditioned freezing was observed. Rats that received either forward or simultaneous pairings showed instrumental learning of the escape-from-fear response. Implications for several theories of Pavlovian conditioning are discussed.     

Practice variability and transfer of training: the role of self-efficacy generality

Practice variability has been shown to enhance transfer of training. The purpose of the present study was to examine the role of self-efficacy generality as a motivational mechanism in explaining the relationship between practice variability and transfer. Undergraduate students (N = 82) were randomly assigned to 1 of 2 training conditions (constant or variable) for a computer decision-making task. Measures of self-efficacy (intensity and generality) and transfer (near and far) were assessed. The results provided support for some of the hypothesized relationships. Specifically, practice variability led to increased self-efficacy generality. Both self-efficacy intensity and generality influenced far transfer performance, although only self-efficacy generality served as a mediator between practice variability and far transfer.     

MMPI-2 and MCMI-III scores among dutch inpatient substance abusers: Assessing correspondence and cross-cultural equivalence

The Millon Clinical Multiaxial Inventory (MCMI-II and MCMI-III) and the Minnesota Multiphasic Personality Inventory (MMPI-2) were applied to 263 Dutch inpatient substance abusers with multiple psychiatric diagnoses, and the results compared with those of 306 North-American substance abusers studied by Ward (1995). We looked for structural similarity both across groups (per instrument) and across the two instruments (per sample), using principal components analysis and congruence analysis. The component structure found by Ward was partly replicated in the Dutch group, thus cross-validating the use of the two instruments with these patients. Moreover, as found by Ward, the MMPI-2 content and supplementary scales of the Dutch sample proved to be important determinants of the first three MMPI-2 components, adding to convergent validity. Questions remained about the influence of the (dis)continuity of MCMI-II and MCMI-III on the replicability of the MCMI components.     

Inhibition and working memory: effect of acute sleep deprivation on a random letter generation task]

The literature contains inconsistent data on the effects of acute sleep deprivation on the superior cognitive functions. The primary purpose of this study is to determine the effectiveness of inhibition, one of the functions of the working memory executive centre (EC), over an extended, 36-hour waking period. Inhibition is a cognitive mechanism whereby individuals ignore non-relevant information recorded in their working memory. We also tested the effects of a 36-hour period of acute sleep deprivation on simple reaction time. Twelve young, healthy volunteers (M = 21.5 years, sigma = 2.3) performed a random generation task involving letters and a simple reaction time psychomotor test over four sessions held at 10-hour intervals. Each participant was assigned a "constant routine." Participants were kept awake in a prone position within a room whose environment was held strictly constant (light, noise, temperature, meals, etc.). This control procedure provided assurance that any variation in participant performance was solely caused by sleep deprivation. The random generation task, nearly two minutes in length, consisted in verbally producing a sequence of 100 letters in a random fashion (i.e. by inhibiting, for example, alphabetical order) and by keeping to a set rhythm. Our assumption was that capacity for inhibition diminished as the number of hours of sleep deprivation increased. The simple reaction test, 10 minutes in length, involved pressing a button as swiftly as possible to cause a black square to disappear from a screen. In this case our assumption was that acute sleep deprivation alters simple reaction time. Analysis of variance (ANOVA) through repeated measures using the "sessions" factor as an intra-subject variable showed no significant changes in randomization indices of the random generation task, contrary to analysis of average simple reaction times. Participants' reaction times deteriorated over the first two minutes of the test during the night they were deprived of sleep. It would seem that the contradictory results of previous studies of the effects of acute sleep deprivation on the inhibition function would be due to errors in factor identification. In conclusion, the inhibition function, as measured during the performance of a brief task, seems to remain intact during an extended, 36-hour waking period. Simple reaction time assessed by means of a brief psychomotor test is affected during a night of sleep deprivation. The working-memory inhibition executive function shows greater resistance to acute sleep deprivation than does psychomotor reaction time for the performance of short tasks.     

Relation and lexical priming during the interpretation of noun-noun combinations

This research indicates that recent exposure to a similar combination (e.g., oil moisturizer or surgery treatment) influences the processing of a subsequent combination (e.g., oil treatment) by increasing the availability of the lexical entries for the modifier and head noun, and by altering the availability of the relation used to link the two nouns. The amount of lexical and relational priming obtained depends on whether the modifier or head noun is in common between the prime and target. The head noun prime yields more lexical priming than does the modifier prime and this finding suggests that the head noun is more strongly activated than the modifier. In contrast, relation priming is obtained only from the modifier prime and this finding is consistent with the CARIN theory (C. L. Gagné & E. J. Shoben, 1997) but inconsistent with schema-based theories of conceptual combination (e.g., G. L. Murphy, 1988; E. J. Wisniewski, 1996).     

Verifying simple arithmetic sums and products: Are the phonological loop and the central executive involved?

In two experiments, we investigated the role of the phonological loop and the central executive in the verification of the complete set of one-digit addition (Experiment 1) and multiplication (Experiment 2) problems. The focus of the present study was on the contradictory results concerning the contribution of the phonological loop in the verification of true problems (e.g., 8 + 4 = 12 or 4 x 6 = 24) reported until now. The results revealed that this slave system is not involved in verifying simple arithmetic problems, in contrast to the central executive. Furthermore, our results indicated that the split effect is due to the use of two different arithmetic strategies.     

Innate versus learned recognition of conspecifics in great spotted cuckoos Clamator glandarius

When birds raised by another species become adults, they (if they are non-brood-parasitic species) usually attempt to mate with birds of their foster species rather than with birds of their own species, a phenomenon called sexual imprinting. Avian brood parasites lay their eggs in nests of other species (the hosts) that rear the young, but the problem of sexual imprinting among brood parasites has generally been neglected, and brood parasites have been considered as an exception among birds. Here, we show, with data from field observations and field experiments, firstly, that adult great spotted cuckoos Clamator glandarius sometimes maintain contact with both older nestling and fledgling cuckoos. Adult cuckoos visited parasitized nests during the last days of the nestling period (5 observations) and, when parasitic chicks left the nest, adult cuckoos maintained contact with the young (14 observations). Adults and fledgling cuckoos communicated vocally (5 observations), and an adult great spotted cuckoo even fed a parasite fledgling in two cases. Secondly, when experimentally cross-fostered in nests of magpie Pica pica hosts outside the parasite breeding range (thus avoiding visual and acoustic communication with adult cuckoos), young cuckoos did not learn to recognize their own species when only one cuckoo chick was introduced per nest, but they learnt to recognize conspecifics when two cuckoos were reared together. This means that young great spotted cuckoos apparently must learn to recognize conspecifics, that is, recognition is not innate. Social interactions between adult brood parasites and young have also been reported in other brood parasites; thus, brood parasites are probably not an exception to the general phenomenon of imprinting, and young brood parasites may need to be imprinted on conspecifics, although more studies on other brood parasite species are needed to confirm this. Received: 7 January 1999 / Accepted after revision: 27 February 1999     

Espbase: A microsoft access tool for selecting symbol and icon sets for usability

The ESPbase provides a tool for storing symbols and icons along with information about their characteristics. Information about a wide range of symbol characteristics is included on the database to facilitate the selection of symbol sets for research and design. The database includes information about the graphical characteristics and functions of symbols. It also includes ratings of symbol concreteness, complexity, familiarity, and meaningfulness. Symbols and icons can be accessed on the basis of each of these characteristics or any combination of characteristics. This makes it easier to select symbols on the basis of usability and design requirements. It also means that symbols can be easily selected for research while controlling their characteristics on a number of dimensions.     

Cognitive Bias in Spider-Phobic Children: Comparison of a Pictorial and a Linguistic Spider Stroop

The relation between spider fear in children and cognitive processing bias toward threatening information was examined. It was investigated whether spider fear in children is related to a cognitive bias for threatening pictures and words. Pictorial and linguistic Stroop stimuli were administered to 28 spider phobic and 30 control children aged 8–12. Spider-phobic children showed a moderate bias for threatening words. Surprisingly, no bias was found for spider pictures, while the spider-phobic children judged the pictures as more aversive. Moreover, in a recent similar study in adults (Kindt & Brosschot, 1997), a strong relation between spider phobia and bias toward threat words and pictures was found. Several explanations are given to account for this divergence.