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

ecently found that pigeons’ post-reinforcement waiting contributes substantially to relative
response rates in choice procedures: longer waits, and thus fewer responses, with longer delays to
reinforcement. Computer simulations of wait-and-respond (WR) models on simple concurrent
variable-interval schedules reproduced typical findings such as power matching. Here we report
on the results of WR models applied to concurrent-chain schedules and problems such as
reinforcement delay, self-control, and preference for variable times to reinforcement.
1005.3 A selectionist model of choice, A. Machado, Universidade do Minho, Braga, Portugal
I will present a selectionist model of choice that is based on three assumptions. First, reponses
replicate at the end of epochs whose length is inversely related to the overall reinforcement rate.
Second, each response replicates in proportion to its local reinforcement rate. These assumptions
imply that whereas overall reinforcement rate sets the tempo of learning, a Weber-like fraction in
the domain of reinforcement rate sets its direction. And third, responses of one class may mutate
into responses of another. The model accounts for a variety of results concerning steady-state
choice behavior and the speed of acquisition of preference.
1005.4 Behavioral versions of human decision making research, T. Sakagami, Keio University,
Tokyo, Japan
Experimental economists have pointed out several crucial differences between economic and
cognitive approaches in decision making studies. We conducted a behavioral version of the
experiments for the certainty effect using Indonesian and Japanese students as subjects. Both
populations previously showed the effect in paper and pencil questionnaires. The students were
requested to respond to a computer display on a Web page containing two differently colored
alternatives. Points could either be earned (Gain trials) or lost (Loss trials). Results revealed that a
majority of participants showed the shift of preference from riskless to risky choice that is
characteristic of the effect.
1005.5 Procedural aspects of experiments on choice behavior, J.C. Todorov, Universidade de
Brasília, Brasília, DF, Brazil
A review of studies on choice behavior involving human and animal subjects will be presented to
show the importance of careful planning of contingencies and recording and reporting of results.
In studies related to the matching law and infra-human subjects, with two concurrent schedules of
variable-interval reinforcement, some critical definitions are the consequences for changeovers,
the discriminability of the different stimuli associated with the schedules of the concurrent pair,
and the discriminability of the different operand associated with the four operants in the situation.
When humans are used as subjects and procedural aspects are neglected there is the danger of
concluding erroneously that species differences are present.
1006 INVITED SYMPOSIUM
Scientific reasoning - Current research
Convener and Chair: M. Bullock, USA
1006.1 Scientific reasoning: From formal models to classroom instruction, D. Klahr 1 , Z. Chen 2 ,
1 Carnegie Mellon University, Pittsburgh, PA, USA; 2 University of California, Davis, CA, USA
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