### abstract ###
researchers frequently argue that within-subjects designs should be avoided because they result in research hypotheses that are transparent to the subjects in the study
this conjecture was empirically tested by replicating several classic between-subjects experiments as within-subjects designs
in two additional experiments  psychology students were given the within-subjects versions of these studies and asked to guess what the researcher was hoping to find i e the research hypothesis  and members of the society for judgment and decision making sjdm were asked to predict how well students would perform this task
on the whole  students were unable to identify the research hypothesis when provided with the within-subjects version of the experiments
furthermore  sjdm members were largely inaccurate in their predictions of the transparency of a within-subjects design
### introduction ###
in the field of psychology  there is a long-standing controversy over the appropriate use of between- and within-subjects designs
within-subjects designs have greater power and less variability  but many researchers eschew their use for two reasons
first  it has been argued that within-subjects designs render our research hypotheses transparent  CITATION
that is  in a within-subjects design  subjects will be aware of the purposes of our experiment and may behave accordingly  thus posing a threat to the internal validity of the experiment
second  some have argued that life is more similar to a between-subjects design  CITATION
therefore  between-subjects designs increase the generalizability of the experimental findings
however  others have argued that between-subjects designs pose their own risks
parducci  CITATION  and birnbaum  CITATION  contend that  particularly with subjective judgments  the between-subjects design should be abandoned because it results in the confounding of context and stimulus
the most famous demonstration of this principle was provided by birnbaum  CITATION   who showed that in a between-subjects design subjects rated the number  NUMBER  as being significantly larger than  NUMBER 
theoretically  in a between-subjects design  the two conditions are identical except for the manipulation of a single stimulus
in this case  the stimulus to be manipulated was the number being rated   NUMBER  or  NUMBER 
however  birnbaum argues that subjective judgments cannot be made in isolation  they require a context
in a within-subjects design  the context is specified  the two or more conditions are compared to each other
in a between-subjects design  the subjects are left to construct their own context to evaluate the stimulus
when this is the case  it is very likely that different contexts will be invoked for different stimuli
in this example   NUMBER  is likely to bring to mind other single-digit numbers for comparison  thus leaving the impression that  NUMBER  is a relatively large number
in contrast   NUMBER  is likely to bring to mind other triple-digit numbers for comparison  leaving the impression that  NUMBER  is a relatively small number
thus  in a between-subjects design both the stimuli and the context vary between conditions  confounding the results
although the relative merits may be theoretically debated  what is more troubling is that hypotheses tested in these two designs often do not result in the same conclusions  CITATION
for example  in between-subjects comparisons  manipulations of base rates do not affect judgments of probability  leading to the conclusion that base rates are ignored  CITATION
however  in within-subjects comparisons  base rates have large  significant effects on judgments of probability  leading to the conclusion that base rates are not ignored  CITATION
despite the concerns about using between-subjects designs to evaluate subjective judgments raised by birnbaum and others  it appears that the within-subjects design has fallen out of favor in many areas of psychology
in particular  within judgment and decision making there exist many findings supported almost exclusively by between-subjects data
examples include the hindsight bias  CITATION   research on reason-based choice  CITATION   availability  CITATION   support theory  CITATION  and many classic demonstrations of heuristics and biases  CITATION
researchers in these areas have frequently argued that between-subjects designs are more appropriate
one of the main reasons cited for the superiority of between-subjects designs is the belief that within-subjects designs are transparent  CITATION
although this appears to be a popular reason for rejecting the within-subjects design  this assertion has never been empirically tested
thus  this gap in the literature inspired the two specific aims of this research
the first aim was to determine if classic examples of between-subjects designs could be replicated using within-subjects designs
