Visual feature learning in artificial grammar classification

The Artificial Grammar Learning task has been used extensively to assess individuals' implicit learning capabilities. Previous work suggests that participants implicitly acquire rule-based knowledge as well as exemplar-specific knowledge in this task. This study investigated whether exemplar-specific knowledge acquired in this task is based on the visual features of the exemplars. When a change in the font and case occurred between study and test, there was no effect on sensitivity to grammatical rules in classification judgments. However, such a change did virtually eliminate sensitivity to training frequencies of letter bigrams and trigrams (chunk strength) in classification judgments. Performance of a secondary task during study eliminated this font sensitivity and generally reduced the contribution of chunk strength knowledge. The results are consistent with the idea that perceptual fluency makes a contribution to artificial grammar judgments.     

The effects of rational and experiential information processing of expert testimony in death penalty cases

Past research examining the effects of actuarial and clinical expert testimony on defendants' dangerousness in Texas death penalty sentencing has found that jurors are more influenced by less scientific pure clinical expert testimony and less influenced by more scientific actuarial expert testimony (Krauss & Lee, 2003; Krauss & Sales, 2001). By applying cognitive-experiential self-theory (CEST) to juror decision-making, the present study was undertaken in an attempt to offer a theoretical rationale for these findings. Based on past CEST research, 163 mock jurors were either directed into a rational mode or experiential mode of processing. Consistent with CEST and inconsistent with previous research using the same stimulus materials, results demonstrate that jurors in a rational mode of processing more heavily weighted actuarial expert testimony in their dangerousness assessments, while those jurors in the experiential condition were more influenced by clinical expert testimony. The policy implications of these findings are discussed.     

Different time course for the memory facilitating effect of bicuculline in hippocampus, entorhinal cortex, and posterior parietal cortex of rats

Several lines of evidence indicate that gamma-aminobutyric acid (GABA) type A (GABA(A)) receptors regulate memory consolidation. Here we studied the effect on consolidation of the selective antagonist of GABA(A) receptors, bicuculline, given into several regions of the cortex at different times after one-trial step-down inhibitory avoidance (0.5 mA, 2-s footshock). Rats were bilaterally implanted with cannulae aimed at the CA1 region of the dorsal hippocampus, entorhinal cortex or posterior parietal cortex, three areas known to be involved in the memory consolidation of this task. At different times after training, bicuculline (0.5 microg/side) was infused into the above mentioned structures. Bicuculline increased memory retention when administered either immediately or 1.5h after training into CA1, and both immediately and 3h after training in the entorhinal or parietal cortex. Thus, in agreement with previous findings using other drugs, the response was biphasic in these latter structures. This suggests that GABAergic mechanisms normally downregulate, memory processing by inhibiting on-going activities necessary for consolidation at the times in which bicuculline was effective in each structure. Based on previous findings, in the hippocampus, such activity involves a number of receptors and signaling pathways in the first 1.5h after training. In the entorhinal and parietal cortex memory-related activities include the participation of protein kinase A and extracellularly regulated kinase (ERK) twice, right after training and then again 3h later.     

The elusive nature of self-measurement: the self-construal scale versus the twenty statements test

In the present study, the authors compared 2 frequently used measures to operationalize the construct of the self, namely, the Self-Construal Scale (SCS; T. M. Singelis, 1994) and the Twenty Statements Test (TST; M. Kuhn & T. S. McPartland, 1954), in a sample of 324 male and female undergraduate psychology students of diverse ethnocultural backgrounds. Results demonstrated low intercorrelations between the 2 measures, suggesting that the qualitative and quantitative measures did not evaluate the same construct. A factor analysis of the SCS scale revealed 3 constructs-an independent construct, an interdependent construct, and a power distance or hierarchy construct. Implications for future research included the need for ongoing work in identifying and measuring the constructs of the self.     

Developmental origins of sociality in brown-headed cowbirds (Molothrus ater)

Five variables were studied relating to the emergence of sociality in hand-reared cowbirds (Molothrus ater): proximity, sex assortment, reactions to adults, head-down displays, and vocalizations. The authors were especially interested in female sociality because adult female birds influence male courtship, song content, and use through proximity, attention, and displays. The authors found that young female birds failed to show same-sex affiliation typical of the species at any point in the study. Brief introduction of adults did not affect social patterns. Adults used more head-down displays than juveniles, who used more displays with familiar peers. Directed and undirected singing emerged concurrently; directed singing was positively correlated with earlier hatching. This is the first demonstration of the need for early learning in the development of female sociality.     

Simultaneous training on two hippocampus-dependent tasks facilitates acquisition of trace eyeblink conditioning

A common cellular alteration, reduced post-burst afterhyperpolarization (AHP) in CA1 neurons, is associated with acquisition of the hippocampus-dependent tasks trace eyeblink conditioning and the Morris water maze. As a similar increase in excitability is correlated with these two learning paradigms, we sought to determine the interactive behavioral effects of training animals on both tasks by using either a consecutive or simultaneous training design. In the consecutive design, animals were trained first on either the trace eyeblink conditioning task for six sessions, followed by training on the water maze task for six sessions, or vice versa. The simultaneous design consisted of six or 11 training days; animals received one session/day of both trace eyeblink conditioning and water maze training. Separate groups were used for consecutive and simultaneous training. Animals trained on both tasks simultaneously were significantly facilitated in their ability to acquire the trace eyeblink conditioning task; no effect of simultaneous training was seen on the water maze task. No effect was seen on acquisition for either task when using the consecutive training design. Taken together, these findings provide insight into how the hippocampus processes information when animals learn multiple hippocampus-dependent tasks.     

Book reviews

Laughing Gods, Weeping Virgins: Laughter in the History of Religion. Ingvild Sæud Gilhus, 1997 London, New York: Routledge 173 pp., £45.00 (hb) ISBN 0–415–16197–5

Questioning the Secular State: The Worldwide Resurgence of Religion in Politics. David Westerlund, ed., 1996 London: Hurst & Companyμ xii +428 pp., £14.95 ISBN 1–85065–241–4 (pb.)

Religion and Resistance Politics in South Africa. Lyn S. Graybill, 1996 Westport, Connecticut: Praeger/Greenwood Press 157 pp., £44.95 (hb) ISBN 0–275–95141–3

Engaged Buddhism: Buddhist Liberation Movements in Asia Christopher S. Queen & Sallie B. King, eds., 1996 Albany, NY: State University of New York Press 446 pp., US$24.95 ISBN 0–7914–2844–3

Religious Pluralism and Christian Truth. Joseph S. O'Leary, 1996 Edinburgh: Edinburgh University Press xiii + 269 pp., £45.00 ISBN 0–7486–0727–7

Church, State and Religious Minorities. Tariq Modood, ed., 1997 London: Policy Studies Institute 96 pp., £10.95 ISBN 0 85374 724 5

The Coming Deliverer: Millennial Themes in World Religions. Fiona Bowie, ed., 1997 Cardiff: University of Wales Press 264 pp., £9.95 (pb) ISBN 0–7083–1338–8

Zoroastrians in Britain. John R. Hinnells, 1996 Oxford, Clarendon Press xiv + 336 pp., £42.00 (hb) ISBN 0–19–826193–4

From the Holy Mountain: A Journey in the Shadow of Byzantium. William Dalrymple, 1997 London, Harper Collins 484 pp., illustrated, £18.00 ISBN 0–0025–5509–3

Jerusalem Today: What Future for the Peace Process?. Ghada Karmi, edv 1996 Reading: Ithaca Press xix +191 pp., £25.00 ISBN 0–86372–204–0

Judaism Since Gender. Miriam Peskowitz & Laura Levitt, eds., 1997 London: Routledge 229 pp., £14.99 (pb), £45.00 (hb) ISBN 0–415–91461–2 (pb), ISBN 0–415–91460–4 (hb)

Muslim Communities in the New Europe. Gerd Nonneman, Tim Niblock & Bogdan Szajkowski, eds., 1996 Reading: Ithaca Press 346 pp, £35.00 (hb) ISBN 0–86372–192–3

Congregation and Community. Nancy Tatom Ammerman, 1997 New Brunswick: Rutgers University Press xvi + 434 pp., US$55.00 (hb), US$24.00 (pb) ISBN 0–81352–334–6 (hb), ISBN 0–81352–335–4 (pb)

Against the Stream: The Adoption of Traditional Christian Faiths by Young Adults. Richard P. Cimino, 1997 Lanham, Maryland: University Press of America & Religion Watch 128 pp., US$46,00 (hb), US$26,00 (pb) ISBN 0–7618–0574–5 (hb), ISBN 0–7618–0575–3 (pb)

Polygamous Families in Contemporary Society. Irwin Altman & Joseph Ginat, 1996 Cambridge: Cambridge University Press xv + 512 pp., £55.00 (hb), £19.95 (pb) ISBN 0–521–56169–8 (hb), 0–521–56731–9 (pb)

Fertility, Class and Gender in Britain: 1860–1940. Simon Szreter, 1996 Cambridge: Cambridge University Press 710 pp., £50.00 ISBN 0–521–34343–7

Implicit Religion in Contemporary Society. Edward I. Bailey, 1997 Kampen, Netherlands: Kok Pharos Publishing House; Weinheim, Germany: Deutscher Studien Verlag 302 pp., Dfl.69.00, £23.00 ISBN (Kok) 90–390–0581–8; ISBN (DSV) 3–89271–694–3

Geography of Religions in Russia. Alexei D. Krindatch, 1996 Decatur, Georgia: Glenmary Research Center 72 pp., 47 maps, US$29.95 (Paper/Spiral Bound) ISBN 0–914422–25–1

Believing in Australia: A Cultural History of Religions". Hilary M. Carey, 1996 St Leonards, N.S.W.: Allen & Unwin xviii + 270p., £16.95 (pb) ISBN 1–86373–950–5

Icelandic Spiritualism: Mediumship and Modernity in Iceland. William H. Swatos, jr. & Loftur Reímar Gíssurarson, 1997 New Brunswick: Transaction Publishers 269 pp., US$32.95 (hb) ISBN 1–56000–273–5

The Channeling Zone: American Spirituality in an Anxious Age. Michael F. Brown, 1997 Cambridge, Massachusetts & London, England: Harvard University Press 214 pp., £14.50 (hb) ISBN 0–674–10882–5

Listening People, Speaking Earth: Contemporary Paganism. Graham Harvey, 1997 London: Hurst & Co. 250 pp., £27.50 (hb), £9.95 (pb) ISBN 1–85065–271–6 (hb), ISBN 1–85065–272–4 (pb)     

Myelin breakdown mediates age-related slowing in cognitive processing speed in healthy elderly men

Background

To assess the hypothesis that in a sample of very healthy elderly men selected to minimize risk for Alzheimer’s disease (AD) and cerebrovascular disease, myelin breakdown in late-myelinating regions mediates age-related slowing in cognitive processing speed (CPS).

Materials and methods

The prefrontal lobe white matter and the genu of the corpus callosum myelinate later in brain development (late-myelinating white matter; LMWM) and are more vulnerable to breakdown due to the effects of normal aging. An in vivo MRI biomarker of myelin integrity (transverse relaxation rates; R₂) of LMWM was obtained for 38 very healthy elderly adult men (mean age = 66.3 years; SD = 6.0; range = 55–76). To evaluate regional specificity, we also assessed a contrasting early-myelinating region (splenium of the corpus callosum; SWM), which primarily contains axons involved in visual processing. CPS was assessed using the Trail Making Test.

Results

LMWM R₂ and CPS measures were significantly correlated (r = .515, p = .0009), but no significant association between R₂ and CPS was detected in the splenium (p = .409). LMWM R₂, but not SWM R₂, was a significant mediator of the relationship between age and CPS (p = .037).

Conclusions

In this very healthy elderly sample, age-related slowing in CPS is mediated by myelin breakdown in highly vulnerable late-myelinating regions but not in the splenium.