Contents

132 PART II: Descriptive MethodsOther Biases An observer’s expectancies regarding the outcome of a study maynot be the only source of observer bias. You might think that using automatedequipment such as video cameras would eliminate observer bias. Although automationreduces the opportunity for bias, it does not necessarily eliminate it.Consider the fact that, in order to record behavior on film, the researcher mustdetermine the angle, location, and time of filming. To the extent that these aspectsof the study are influenced by the researcher’s personal biases, such decisionscan introduce systematic errors into the results. For example, Altmann(1974) described an observational study of animal behavior in which the observersbiased the results by taking midday breaks, which coincided with atime of relative inactivity among the animals. Observations of the animals duringthese periods of inactivity were conspicuously absent for the observationalrecords, which biased the results to make the animals appear more active thanthey were. In addition, the use of automated equipment generally only postponesthe process of classification and interpretation, and it is perfectly possiblefor the effects of observer bias to be introduced when narrative records arecoded and analyzed.Controlling Observer Bias Observer bias is difficult to eliminate, but it can be reducedin several ways. As we mentioned, the use of automatic recording equipmentcan help, although the potential for bias is still present. Probably the mostimportant factor in dealing with observer bias is the awareness that it might be present.That is, an observer who knows about this bias will be more likely to take stepsto reduce its effect. One important way researchers reduce observer bias is tolimit the information provided to observers. When observers and coders do notknow the hypotheses of a study they cannot form expectations about behavior.In a manner of speaking, observers can be kept “blind” regarding certainaspects of the study. Observers are blind when they do not know the reasonsfor the observations or the goals of the study. For example, when trained codersanalyzed the videotapes of interactions between mothers and children frommaltreating and nonmaltreating families, they were not aware of which typeof family they were observing (Valentino et al., 2006). As you might imagine,observers’ expectancies regarding maltreating families might influence theirinterpretation of behaviors, just as staff members in Rosenhan’s (1973) studyinterpreted pseudopatients’ behavior according to their diagnostic label. Usingblind observers greatly reduces the possibility of introducing systematic errorsdue to observer expectancies.SUMMARYResearchers rarely observe all behavior that occurs. Consequently, researchersmust use some form of behavior sampling such as time and situation sampling.An important goal of sampling is to achieve a representative sampleof behavior. External validity refers to the extent to which observations froma study can be generalized to describe different populations, settings, andconditions; external validity is enhanced when a representative sample isobtained. Observational methods can be classified as direct observation or