Llamas use social information from conspecifics and humans to solve a spatial detour task

Animal Cognition - Learning by observing others (i.e. social learning) is an important mechanism to reduce the costs of individual learning. Social learning can occur between conspecifics but also...     

Predictive pointing movements and saccades toward a moving target

The authors investigated whether and, if so, how velocity information is used to control predictive manual pointing movements and saccades. Participants (N = 6) intercepted an occluded moving target as if it were still visible. They kept their eyes fixated while the target moved. The target traveled over a fixed distance and changed its velocity on the way. The presentation time of the final velocity was varied. Both the eye and the hand overshot the slow target and undershot the fast target, particularly when the duration of the final velocity was short. Thus, responses were biased in the direction of the target's initial velocity. The error seemed to arise because participants did not take their latency into account when aiming at the target. Instead, they strategically aimed farther ahead when the target was fast. Amplitude was also more related to the position of velocity change than to final velocity duration. Both findings suggest that target velocity is not extrapolated but that individuals add an increment to the position of velocity change.     

Book reviews

Weiskrantz, L. (1986). Blindsight: A case study and implications. Oxford University Press. Pp. 187. ISBN 0-19-852129-4. £19.50.

Humphreys, G. W. & Riddoch, M. J. (1987). to see but not to see: A case study of visual agnosia. Hove and London: Lawrence Erlbaum Associates Ltd. Pp. 124. ISBN 0-83677-064-9. £12.95.

Downing, J. A. (1988). Advances in psychology: Cognitive psychology and reading in the USSR. Amsterdam: North Holland; Elsevier Science Publishers. Pp. 471. ISBN 0-444-70374-8. $108.00.

John Beech & Ann Colley (Eds.) (1987). Cognitive approaches to reading. Chichester: John Wiley. Pp. xii + 315.

James Wertsch (Ed.) (1985). Culture, communication and cognition: Vygotskian perspectives. Cambridge: Cambridge University Press. Pp. 379. ISBN 0-521-25214-8. £27.50 (Hardback).

Fodor, J. A. (1987). Psychosemantics: The problem of meaning in the philosophy of mind. Cambridge, MA: M.I.T. Press. Pp. xiii, 1-171. ISBN 0-262-06106-6.

Richardson, K. (1988). Understanding Psychology. Milton Keynes: The Open University Press. Pp. 114. ISBN 0-335-09842-8. Paperback £7.95.

Stanovich, Keith E. (Ed.) (1988). Children's reading and the development of phonological awareness. Detroit: Wayne State University Press. Pp. 177. ISBN 0-8143-1909-2. $20.00.

Allport, A., MacKay, D.G., Prinz, W., & Scheerer, E. (Eds.), (1987). Language perception and production: Relationships between listening, speaking, reading, and writing. London: Academic Press. Pp. xiii + 497. ISBN 0-12-052750-2. £32.00

Light, L. L. & Burke, D. M. (eds.) (1988). Language, Memory and Aging. Cambridge: Cambridge University Press. Pp. 280. ISBN-0-521-32942-6. £27.50

Friedman, S.L., Scholnick, E.F., and Cocking, R. R. (1987). Bleuprints for thinking: The role of planing in cognitive development. Cambridge: Cambridge University Press. Pp. xv + 559. ISBN 0-521-25605-4. £40.00.     

An islet of social ability in Asperger Syndrome: judging social attributes from faces

We asked adults with Asperger Syndrome to judge pictorial stimuli in terms of certain social stereotypes to evaluate to what extent they have access to this type of social knowledge. Sixteen adults with Asperger Syndrome and 24 controls, matched for age and intelligence, were presented with sets of faces, bodies and objects, which had to be rated on a 7-point scale in terms of trustworthiness, attractiveness, social status, and age, or, in the case of objects, price. Despite impaired performance on two important aspects of social cognition (second-order mentalizing and face recognition) the social judgements of the individuals with Asperger Syndrome were just as competent and consistent as those of their matched controls, with only one exception: there was a trend for them to be less able to judge the attractiveness of faces if they were the same sex. We explain this difference in terms of a weakness in mentalizing, specifically the ability to take a different point of view: While all other stereotypic attributions could be made from an egocentric point of view, judging the attractiveness of faces of one's own sex requires taking the perspective of someone of the opposite sex, a challenge for people with mentalizing problems. We conclude that individuals with Asperger Syndrome show preserved aspects of social knowledge, as revealed in the attribution of stereotypes to pictures of people. These findings suggest that there are dissociable subcomponents to social cognition and that not all of these are compromised in Asperger Syndrome.     

Misleading postevent information and working memory capacity: an individual differences approach to eyewitness memory

The present study examines how individual differences in working memory capacity relate to the effect of misleading postevent information on memory for the original event. Participants were shown a film of a crime event and were then asked to unscramble a narrative that included misinformation regarding some of the film's details. Additionally, the working memory capacity of the participants was measured using the operation‐word span task. Finally, in a free recall test, participants recalled fewer correct details in the misinformation condition compared to the control condition. This effect was negatively correlated with working memory capacity. Copyright © 2002 John Wiley & Sons, Ltd.     

On the timescale of stimulus-based action-effect learning

When performing an action, people pick up associations between their actions and the resulting consequences of that action, a phenomenon that has been termed response (R)-effect (E) learning. In the present study, we investigated incidental R-E learning in a forced-choice-that is, a stimulus (S)-based-acquisition mode. Specifically, the study examined at which timescale R-E learning evolves-that is, how many encounters are actually needed to form stable R-E associations. The learning of R-E associations was assessed in a subsequent test phase via effect-based response priming. Experiment 1 tested 4 different numbers of S-R-E repetitions for a 2-2-2 S-R-E mapping. Experiment 2 disentangled the contributions of S-E and R-E associations to the facilitating impact of effect-based response priming by means of a 4-2-4 S-R-E mapping. Experiment 3 investigated whether R-E associations can be picked up even when a given E cannot be unequivocally predicted based on the antecedent S in case of inconsistent S-R-E couplings. Together, the results of the present study clearly show that R-E learning occurs in a stimulus-based action mode and that it evolves very rapidly after only 12 S-R-E repetitions. Moreover, the present findings suggest that at least in this initial phase of learning, complete S-R-E consistency seems to be relevant for R-E learning.     

The solitaire illusion: An illusion of numerosity

A new illusion in which the apparent number of elements of two kinds is determined by their spatial arrangement is described. The illusion is such that one large cluster appears to contain more elements than several small clusters, clustering being determined by Gestalt principles. The illusion was found both in adults and in children of 8 years.     

Egocentrism, allocentrism, and Asperger syndrome

In this paper, we attempt to make a distinction between egocentrism and allocentrism in social cognition, based on the distinction that is made in visuo-spatial perception. We propose that it makes a difference to mentalizing whether the other person can be understood using an egocentric ("you") or an allocentric ("he/she/they") stance. Within an egocentric stance, the other person is represented in relation to the self. By contrast, within an allocentric stance, the existence or mental state of the other person needs to be represented as independent from the self. We suggest here that people with Asperger syndrome suffer from a disconnection between a strong na?ve egocentric stance and a highly abstract allocentric stance. We argue that the currently used distinction between first-person and third-person perspective-taking is orthogonal to the distinction between an egocentric and an allocentric stance and therefore cannot serve as a critical test of allocentrism.