Book reviews

Unfolding Islam. P. J. Stewart. xiii + 252 pp. hb., £24.00, London, Ithaca Press, 1994, ISBN 0 86372 194 X; pb. London, Garnet Publishing, 1995, ISBN 1 85964 046 X.

The Basics 2: Islam. Roland Machatschke, 1995. London, SCM Press, 89 pp., pb. £5.95, ISBN 0 334 02603 2.

Voices of Islam. John Bowker 1995. Oxford, Oneworld, 188 pp., pb. £8.95, ISBN 1 85168 095 0.

Abraham, A Symbol of Hope for Jews, Christians and Muslims. Kakl‐Josef Kuschel, 1995. London, SCM, xxix + 286 pp., pb. £14.95, ISBN 0 334 02567 2.

Petrus Alfonsi and his Medieval Readers. J Tolan, 1993. Gainesville, University Press of Florida, 288 pp., pb. £15.00, ISBN 0 8130 1239 2; hb, £31.00, ISBN 0 8130 1238 4.

Islamic Science and Engineering. Donald R. Hill, 1993. Edinburgh, Edinburgh University Press, 250 pp., pb. £16.95, ISBN 0 7486 0455 3.

Islam: the view from the edge. Richard W. Bulliet, 1994. New York, Columbia University Press, 236 pp., pb. $16.95, £11.95, ISBN 0 231 08219 3.

Pioneers of Islamic Revival. Ali Rahnema (Ed.), 1994. London, Zed Books, 279 pp., hb. £36.95, ISBN 1 85649 253 2; pb. £14.95, ISBN 1 85649 254 0.

Freiheit der Religion: Christentum und Islam unter dem Anspruch der Men‐schenrechte [Freedom of Religion; Christianity and Islam tinder the claims of human rights]. Johannes Schwartländer (Ed.), 1993. Mainz, Matthias Grünewald Verlag, 474 pp., DM 48.

Religion, Law and Society: A Christian‐Muslim Discussion. Tarek Mitri (Ed.), 1995. Geneva, WCC Publications and Kampen, Kok Pharos, 154pp, pb. £9.95, ISBN 2 8254 1148 5 (WCC) and 90 390 0514 1.

Muslims in Western Europe. J?rgen Nielsen, 1995 (2nd Edition). Edinburgh, Edinburgh University Press, 190 pp., £14.95, ISBN 0 7486 0617 3.

From Ta'izz to Tyneside: an Arab community in the north‐east of England during the early twentieth century. Richard I. Lawless, 1995. Exeter, University of Exeter Press, 292 pp., pb. n.p., ISBN 0 85989 460 6.

The New Middle East. Shimon Peres with Arye Naor, 1993. Shaftesbury, Element Books, 224 pp., hb. £16.99, ISBN 1 85230 519 3.

The Palestinians: the road to nationhood. David McDowall, 1994. London, Minority Rights Group, 215 pp., hb. £15.95, ISBN 1 873194 70 6.

Mahdism in West Africa: the Ijebu Mahdiyya movement. P.B. Clarke, 1995. London, Luzac Oriental, 224 pp., hb. £30.00, ISBN 1 898942 06 4.

Assaulting with Words: popular discourse and the bridle of Shari^cah. A. A. Ibrahim, 1994. Evanston, IL, Northwestern University Press, 208 pp., hb. 859.95, ISBN 0 8101 1081 4.

The Vanguard of the Islamic Revolution: the Jama't‐i Islami of Pakistan. Seyyed Vali Reza Nasr, 1994. London, I. B. Tauris, 301 pp., hb. n.p., ISBN 1 85043 862 3; pb. £14.95, ISBN 1 85043 864 1.     

The object advantage can be eliminated under equiluminant conditions

A key phenomenon supporting the existence of object-based attention is the object advantage, in which responses are faster for within-object, relative to equidistant between-object, shifts of attention. The origins of this effect have been variously ascribed to low-level “bottom-up” sensory processing and to a cognitive “top-down” strategy of within-object attention prioritization. The degree to which the object advantage depends on lower-level sensory processing was examined by differentially stimulating the magnocellular (M) and parvocellular (P) retino-geniculo-cortical visual pathways by using equiluminant and nonequiluminant conditions. We found that the object advantage can be eliminated when M activity is reduced using psychophysically equiluminant stimuli. This novel result in normal observers suggests that the origin of the object advantage is found in lower-level sensory processing rather than a general cognitive process, which should not be so sensitive to differential activation of the bottom-up P and M pathways. Eliminating the object advantage while maintaining a spatial-cueing advantage with reduced M activity suggests that the notion of independent M-driven spatial attention and P-driven object attention requires revision.