Mothers' speech to their 1-year-old infants in home and laboratory settings

The speech of mothers and their 1-year-old infants was compared in the home and in the laboratory playroom. The home and laboratory settings were similar for measuring the number of actual words that infants spoke and were similar for measuring the complexity of the mother's speech, including the number of different words, the type-token ratio, and the length of the utterances. Infants vocalized at similar rates in the two settings, but mothers spoke at a faster rate in the laboratory playroom. The usefulness of a preliminary warm-up period was supported by the finding that for the second half of the sessions, mothers slowed their rate of speech and increased the complexity of their speech.     

Signal-controlled responding

Pigeons' key pecks were reinforced with grain, then extinguished. An 8-second tone preceded the availability of peck-dependent grain 1 second after tone offset. When a tone signalled grain and an 8-second clicking sound did not, three pigeons pecked during a high percentage of tone periods, but they pecked during a low percentage of click periods. When the roles of the tone and clicking sound were reversed, performance reversed. For other birds, when a key peck during the tone cancelled the availability of grain (omission procedure), the tendency to key peck during the tone decreased some, but still remained high. A third group of pigeons received the omission procedure with the addition that the tone could not end unless 2 seconds had elapsed without a key peck. The pigeons continued to respond in a high percentage of tone periods. The experiments favor an explanation based on the pairing of the tone with a reinforced response, such as Pavlovian conditioning.     

Evaluative verbalization and delay maintenance behavior in children

An experiment is presented which examined the influence of verbalizations on children's tendencies to postpone immediate gratification in terms of increased delayed reward. Children's verbalizations were varied in terms of their evaluative valence and whether they focused upon the reward itself or the delay task. During a delay task children in experimental groups periodically verbalized evaluative statements that were either positive (I like …) or negative (I don't like …) and which focused upon either the reward itself (… the tokens) or the delay behavior (… to wait). Children who focused on reward, under conditions of either positive or negative evaluation, postponed immediate gratification less than control subjects who made no verbalization. Children who evaluated delay behavior positively postponed immediate gratification longer than silent subjects, though children who negatively evaluated delay behavior did not differ from subjects who did not verbalize. The results are interpreted in terms of the influence of evaluative valence and focus as parameters of plans for delay behavior.     

Hypnotic time distortion and free-recall learning — an attempted replication

Summary Krauss, Katzell and Krauss (1974) have presented evidence suggesting that hypnosis can be used to facilitate free-recall learning. Specifically, they report that hypnotised individuals, given special time-distortion instructions, can recall as much in three minutes as waking control subjects can in ten minutes. The present study was an attempt to replicate and extend this main finding of Krauss et al. The results of the present study failed to replicate Krauss et al.'s finding; in fact, the hypnotised subjects did rather worse than waking control groups; also no relationship was found between recall scores and depths of hypnosis. Marked discrepancies were noticed between the scores of the waking control groups used in the present study, and those used by Krauss et al. It was concluded that any facilitatory effect of hypnotic time distortion on free-recall learning still awaits a definitive demonstration.     

Book reviews

Johnson-Laird, P. N. and Wason, P. C. (Eds). Thinking: Readings in Cognitiwe Science. Cambridge: Cambridge University Press. 1977. Pp. xii+615. ISBN 0 521 21756 3. £17.50. (Also paperback ISBN 0 521 29267 0. £5.95.)

Marks, L. E. The Unity of the Senses. Interrelations among the Modalities. London: Academic Press. 1978. Pp. 289. ISBN 0 12 472960 6. £11.35.

Callaway, E., Tueting, P. and Koslow, S. H. (Eds). Event-Related Brain Potentials in Man. New York: Academic Press. 1978. Pp. ix+630. ISBN 0 12 155150 4. £22.00.

Clifford, B. R. and Bull, R. The Psychology of Person Identification. London: Routledge & Kegan Paul. 1978. Pp. 254. ISBN 0 7100 8867 1. £7.95.

Albert, M. A. and Obler, L. K. The Bilingual Brain. New York: Academic Press. 1978. Pp. 302. ISBN 0 12 048750 0. £12.65.

Welch, R. B. Perceptual Modification: Adapting to Altered Sensory Environments. London: Academic Press. 1978. Pp. 346. ISBN 0 12 741850 4. £15.90.

Wales, R. J. and Walker, E. (Eds). New Approaches to Language Mechanisms. Amsterdam: North-Holland. 1976. Pp. 296. ISBN 0 7204 0523 8. $19.75.

Lomax, E. M. R. Science and Patterns of Child Care. San Francisco: Freeman. 1978. Pp. 247. ISBN 0 7167 0296 7. Hardback £5.50; paperback £3.70.

Armington, J. C., Krauskopf, J. and Wooten, B. R. (Eds). Visual Psychophysics and Physiology New York: Academic Press 1978 Pp 488 ISBN 0 12 062260 0. $29.50.

Williams, M. Brain Damage, Behaviour and the Mind. Chichester: Wiley. 1979. Pp. 187. ISBN 0 471 99704 8. £8.50.     

Newborns' central vision: Whole or hole?

We studied visual detection in 150 infants, 1- to 7-days old, by presenting single lines varying in width and location. We found that newborns detected a line only 8′ wide in the central visual field. Peripherally, they appeared to detect lines of 33′, 33′, and 1°6′ at 10°, 20°, and 30°, respectively. Thus, both the central retina and the peripheral retina appear to function at birth.     

The role of short-term working memory in mental arithmetic

A series of experiments explored the role of information storage in working memory in performing mental arithmetic. Experiment 1 assessed the strategies people report for solving auditorily presented multidigit problems such as 325 + 46. As expected, all subjects reported breaking down the problems into a series of elementary stages, though there were considerable individual differences with regard to the order of their execution. Strategies of this type necessitate both the temporary storage of information and the mobilization of long-term knowledge. Experiments 2 and 3 examined the effects of delaying the output of individual partial results on calculation accuracy and showed that interim information is forgotten if it is not utilized immediately. Experiment 4 showed that forgetting the initial information is also a source of error and suggested that forgetting increases as a function of the number of calculation stages intervening between initial presentation and subsequent utilization of information. Two simple quantitative models were derived from a general task analysis, one of which assumed a decay process in working storage and the other no decay. The decay model gave a reasonable fit to data from Experiments 2–4, and in doing so it coped appreciably well with the effects of a large variety of task variables (e.g., carrying, the provision of written notes, calculation strategy, output order). The decay model is a tractable analysis of a complex task, and it is suggested that similar analyses may prove fruitful for other problem-solving activities which involve the use of working memory.     

Hyperactivity from fluorescent lighting — Fact or fancy: A commentary on the report by O'Leary,Rosenbaum, and Hughes

The following commentary is designed to explain the experimental differences between the foregoing negative article by O'Leary, Rosenbaum, and Hughes and the original articles in this field, whose results were positive. These differences fall under the general categories of subjects, lights, measurements, and design.