Exploring the temporal dynamics of social facilitation in the Stroop task

The importance of social context in affecting attention has recently been highlighted by the finding that the presence of a passive, nonevaluative confederate can improve selective attention. The underlying mechanism, however, remains unclear. In this paper, we argue that social facilitation can be caused by distractor inhibition. Two distinct sources of evidence are provided from an experiment employing the Stroop task with and without social presence. First, analysis of the response time (RT) distribution indicates that interference is reduced at relatively long RTs. This is consistent with an inhibitory mechanism, whose effects build up slowly. Further support is provided by showing that social facilitation is prevented by using short response-to-stimulus intervals that are thought to reduce cognitive control processes.     

Trait predictors of placebo responses in itch

This study investigated trait predictors of placebo responses in the context of inflammatory skin reactions. This was a randomized, cross-over, experimental study using a deceptive placebo protocol. A healthy sample of volunteers (N = 48) completed online personality measures, then attended two laboratory sessions in which short-term inflammatory skin reactions were induced. One was a control session and the other the ‘treatment’ session in which a placebo cream was administered with the suggestion of a reduced skin reaction. A placebo response was defined as smaller skin reactions in control vs. treatment sessions. The traits ego resiliency and neuroticism were selected as possible predictors of placebo responses. Traits were selected in consideration of the two-faceted transactional model of placebo responsiveness and in light of empirical and psychometric considerations ego resiliency emerged as a consistent predictor of placebo responses in itch (p < .05). This is the first study to identify trait predictors of placebo responses in inflammatory skin reactions. Ego resiliency may typify greater placebo responsiveness; however, this may only be in certain contexts. Matching treatment approaches to bio-behavioural response tendencies may be useful clinically if the placebo component of traditional treatments can be enhanced.     

Maternal depression and locus of control orientation as predictors of dyadic play behavior

Maternal locus of control orientation and depression were examined in relation to joint negotiation and coordination of mother-child play at 20 months. Subjects were 51 high-social-risk mothers and children. Mothers completed the I-E Scale and the Beck Depression Inventory prenatally and at 20 months; mother-child interaction was videotaped in a laboratory playroom at 20 months. Tapes were coded using the Control-Autonomy Balance Scales to evaluate maternal control and sensitivity and child engagement and autonomy. Analyses of dyadic play behavior indicated that maternal controllingness was related to an external locus of control orientation. Child engagement during play was related to the resolution of mild maternal depression.     

Principles that are invoked in the acquisition of words, but not facts

A controversial question is whether language acquisition is the result of domain-general or domain-specific principles. Focusing on word-learning, Markson and Bloom (Nature 385(6619) (1997) 813) recently argued that the ability to learn and retain new words (count nouns) is the result of abilities that are not specific to language. In the current experiment, we replicate their empirical finding, but challenge their domain-general interpretation by highlighting a crucial distinction between the principles involved in learning a count noun, as compared to learning a fact. The current results confirm that learning count nouns and facts involve (at least) two common components: establishing a mapping to a designated individual, and retaining this mapping over time. However, these results go further to document that the processes invoked in the acquisition of words differ from those invoked in the acquisition of facts. Children spontaneously and systematically extended a novel count noun exclusively to other members of the same category, but revealed no such systematicity when extending a fact. This illustrates that there are principles that are invoked in learning a novel count noun that are not invoked in learning a fact.     

The reduction of claustrophobia--I.

The purpose of this study was to investigate the process of change during three interventions for claustrophobia, with particular reference to cognitive changes. Forty-eight participants, recruited from the community through the local media, were randomly assigned to one of four groups: pure exposure, exposure to the sensations of anxiety (interoceptive exposure), modification of negative cognitions, or a control group. All interventions were given over three sessions. The exposure group proved superior to the control on a wide range of measures. In the cognitive group, scores of reported fear and panic, declined significantly. The interoceptive group made some modest gains. An analysis of the timing of fear reduction and of treatment generalization, provides some indications of the mechanism of change.     

Olfactory conditioning by association with histidine-free or balanced amino acid loads in rats

An histidine-devoid but otherwise balanced amino acid mixture depressed food intake from 2 hr after its gastric intubation. It induced conditioned aversion to an odour incorporated in a protein-free diet presented for 6 h following intubation. In other rats, a balanced amino acid mixture established conditioned preference for odour presented in the same diet for 6 h following intubation. The degree of preference was considerably less than the degree of aversion.     

Book reviews

ROBINSON, J. O. The psychology of Visual Illusion. London: Hutchinson University Library. 1972. Pp. 285. £ 3.00.

CARROLL, JOHN B. and FREEDLE, Roy O. (Eds). Language Comprehension and the Acquisition of Knowledge. New York: John Wiley. 1972.

PEARSON, R. The Avian Brain. London: Academic Press. 1972. Pp 624. £ 10.00.

KORNBLUM, S. (Ed.). Attention and Perfomance IV. New York and London: Academic Press. 1973. Pp. xxx+771. $ 18.50.

WASON, P. C. and JOHNSON-LAIRD, P. N. Psychology of Reasoming: Reasosming: Structure and Content. London: B. T. Batsford Limited. 1972. Pp 26.4. £ 3.50.

GILBERT, R. M. and MILLENSON, J. R. (Eds). Reinforcement: Behavioural Analysis. New York: Academic Press. 1972. Pp. xiii+288. £ 6.35.

STRONGMAN, K. T. The Psychology of Emotion. London: Wiley. 1973. Pp. 191. £ 3.50.

MYERS, R. D. (Ed.). Methods in psychobiology. Vol. 2. London and New York: Academic Press. 1972. Pp. xii+398. £ 6.50.

NILSSON, N. J. Problem-Solving Methods in Artificial Intelligence. New York: McGraw-Hill. 1971. Pp. 255. POund 5.40.

SHEEHAN, P. W. (Ed.). The function and Nature of Imagery. New York: Acadmic Press. 1972. Pp. $ 22.50.

CLARKE, E. and DEWHURST, K. An Illustrated of Brain Furction. Oxford: Sandford Publication. 1972. Pp. 154. £ 5.50.

SCHACHTER, S. Emotion, Obesity and Crime. New York: Academic Press. 1971. Pp. 195. £ 3.50.

MCGUIGAN, F. J. and LUMSDEN, D.B. (Eds). Contemporary Appraches to Conditioning and Learning. Washingotn, D. C.: v. H. Winston and Sons. 1973. Pp. xii+231. £ 6.50.

BECK, J. Surface Colour Perception. Ithaca and London: Cornell University Press. 1972.Pp. £ 11.50.