Some psychologists argue that their role as scientists is to present facts as objectively as possible. Others believe that because psychologists are human, they cannot possibly be value free, even if they try to be. Some even argue that psychologists should take stands on value-laden issues. For example, if research shows that day care in the first year of life is harmful to children's development, shouldn't psychologists support reforms to improve day care or to give parents up to a year of paid leave after the child is born?

The debate over the place of values in psychology continues. But psychologists have generally come to agree that another type of personal objectivity is desirable when doing research. Psychological studies are most useful when they are conducted without bias or prejudice toward any particular group of people-especially bias based on sex or gender and bias based on culture and ethnicity.

For decades, society has had a strong gender bias, a preconceived notion about the abilities of women and men that prevented individuals from pursuing their own interests and achieving their potential. Like other women, women in psychology have faced barriers in the academic world and in their careers.

Gender bias also has had a less obvious effect within psychology. For too long, the female experience has been subsumed under the male experience. Conclusions are often drawn about females' attitudes and behaviors from research done with males as the only participants. In addition, the gender differences that are found are often unduly magnified (Denmark & others, 1988). Small statistical differences might disappear if the study were repeated or might reflect methodological problems.

Researchers interested in reducing gender bias have raised some new questions (Tetreault, 1997):

• How might gender bias influence the choice of hypotheses, participants, and research design? For example, the most widely known theory of moral development was proposed by a male (Lawrence Kohlberg) in a male-dominant society (the United States), and males were the main participants in research used to support the theory for many years.
• How might research on topics of primary interest to females, such as relationships, feelings, and empathy, challenge existing theory? For example, in the study of moral development, Kohlberg's highest level has often been portrayed as based on a principle of "justice for the individual." However, more recent theorizing notes that individuality and autonomy tend to be male concerns and suggests that a principle based on relationships and connections with others be added to our thinking about high-level moral development (Gilligan, 1982, 1996).
• How has research that has exaggerated gender differences between females and males influenced the way people think about females? For example, some researchers believe that gender differences in mathematics have often been exaggerated and have been fueled by societal bias (Hyde & Mezulis, 2002; Hyde & Plant, 1995). Such exaggeration of differences can lead to negative expectations for females' math performance.

The realization that psychological research needs to include more people from diverse ethnic groups has also been building. Historically, when the scores of people from ethnic minority groups have varied from the norm or average, they have been viewed as confounds, or "noise" in the data. Consequently, researchers have deliberately excluded minority group members from the samples they have selected. We might reasonably conclude that people's real lives are perhaps more varied than research data have indicated in the past.

Researchers also have tended to overgeneralize about members of ethnic groups. A researcher might describe a research sample like this: "The participants were 20 Latinos and 20 Anglo-Americans." A more complete description of the Latino group might be something like this: "The 20 Latino participants were Mexican Americans from low-income neighborhoods in the southwestern area of Los Angeles. Twelve were from homes in which Spanish is the dominant language spoken, 8 from homes in which English is the main language spoken. Ten were born in the United States, 10 in Mexico. Ten described themselves as Mexican American, 5 as Mexican, 3 as American, 2 as Chicano, and 1 as Latino." Ignoring such diversity can lead to stereotyping.

Many psychological findings have been based on research with male, middle-socioeconomic status European-Americans. Taking into account the expectations, attitudes, and behaviors of both women and men and of diverse ethnic groups can only enrich psychological theory and practice.

1		The belief that women perform less well than men in the area of mathematics may be an example of bias.