28th International Congress of Psychology August 8 ... - U-netSURF

often, consciously or subconsciously, discriminate daughters against sons. Female-biased
infanticide is one of the extreme cases, but usually it shows as the excess-female mortality
resulting from neglect. Although there is no evidence of excess-female mortality in current
Japanese societies, it was evident during the period from about 1900 to 1935. I will summarize the
patterns of differential parental investment towards sons and daughters published so far and will
describe in detail the excess-female mortality in pre-war time Japan.
5010.4 Reproductive variance and family decisions, X.T. Wang, University of South Dakota,
Vermillion, SD, USA
From an evolutionary perspective, risks should be viewed as reproductive uncertainties in terms of
variations in reproductive fitness. In field studies conducted in the US and China, we found that
families with higher perceived wealth invested more in daughters than sons whereas this pattern
was reversed in the lower perceived-wealth families. In contrast, real-wealth affected the overall
parental investment reflected by the rate of breastfeeding. In addition, children with a low
paternity uncertainty, who were perceived as physically resembling the father, were more likely to
be breastfed. These results are explained in the framework of Bounded Risk Distributions (Wang,
2002).
5011 INVITED SYMPOSIUM
Suggestion and belief: Placebos, hypnosis, and false memories
Convener and Chair: I. Kirsch, UK
Co-convener: G. Mazzoni, UK
5011.1 The effects of suggestion and belief on perception, memory, health, and cognition, I.
Kirsch, G. Mazzoni, University of Plymouth, Plymouth, UK
Suggestion is defined as the provision of information that is new to the recipient and that pertains
to events within the experience of the individual. Types of suggestion include those produced by
placebos, hypnosis, and misinformation about the past. Suggestions can produce profound changes
perception, memory, health, and cognition. These changes are mediated by alteration of beliefs
and typically involve changes response expectancy, which is a particular type of belief. The power
of belief is illustrated by the placebo effect in the treatment depression, which has been found to
account for almost all of the effects of antidepressant medication.
5011.2 Theories of the placebo effect, S. Stewart-Williams, Massey University, Palmerston
North, New Zealand
A wide variety of placebo effects have been demonstrated, including placebo-induced analgesia,
sedation, physiological arousal, and even relief from depression. The two main approaches to this
fascinating phenomenon are expectancy theory and classical conditioning. Typically, these are
pitted against one another. In this talk, I argue that this way of construing the issue does not
adequately address the complex relationship between conditioning and expectancy. A review of
the literature suggests that some conditioned placebo effects are mediated by expectancy; however,
some placebo effects involve expectancy but not conditioning, and others involve conditioning but
not expectancy.
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