Humans categorize individuals into social groups to manage vast amounts of social information. This categorization creates ingroups and outgroups, leading to intergroup bias – more positive evaluations of ingroup members. Age and race are primary categories readily used due to their perceptual salience and automatic processing. Automatic intergroup bias toward age and race groups can have significant negative consequences. This research aims to expand understanding of moderating factors by focusing on ingroup-outgroup salience with multiply categorizable targets. Since individuals belong to multiple social groups, the ingroup-outgroup status of a target depends on the salient category. For example, a young White person might favor other White people when racial identity is salient, but favor other young people when age identity is salient. Therefore, manipulating the salient ingroup-outgroup distinction should moderate automatic age and race bias. Previous studies have shown that social categorization moderates automatic social evaluation, but most manipulated the categorization of stimuli presented during the bias measurement (e.g., Implicit Association Test, Evaluative Priming Task), or involved a categorization practice phase before the bias measure. This leaves open the question of whether direct categorization manipulation is necessary for these effects. Other research used a minimal group paradigm, where categorization practice and potential cooperative contexts might influence results. This study uniquely manipulates ingroup-outgroup salience by directing participants' attention to their own ingroup identity and contrasting outgroup, without manipulating stimulus categorization or inducing a cooperative context. The hypothesis is that this manipulation is sufficient to change automatic intergroup bias, providing strong evidence for the role of ingroup-outgroup distinction salience.

Existing research demonstrates that social categorization significantly influences automatic social evaluation. However, methodologies vary considerably. Some studies directly manipulate the categorization of social stimuli during automatic bias measurement, for instance, by instructing participants to categorize faces by race or another social category in an Implicit Association Test. Others indirectly manipulate categorization by using distractor items or blocked presentation during the automatic evaluation measure. A different approach uses a minimal group paradigm, assigning participants to fictitious teams to manipulate ingroup-outgroup status. This usually involves a learning phase where participants repeatedly categorize photos of people according to their team membership. Subsequently, they complete an automatic bias measure, revealing more positive evaluations of ingroup members regardless of race. The learning phase may have induced positive attitudes toward ingroup members and negative attitudes toward the outgroup members through evaluative learning. All of these previous methods either directly involved the categorization of stimuli presented during the automatic bias measurement or involved a practice categorization task or a group-building phase. This current research explores a novel manipulation focusing on ingroup-outgroup distinction salience without these confounding elements.

Two experiments were conducted using variations of a social identity manipulation adapted from social identity research. **Experiment 1:** 74 female first-year psychology students participated. Two participants were excluded for being over 40; one for data loss due to technical problems. The final sample included 71 participants aged 19–38 (M = 23.90, SD = 3.95). Participants were randomly assigned to one of two conditions: White-Black salience or young-old salience. In the White-Black salience condition, participants described how they, as a White person, differed from Black people; in the young-old salience condition, they described how they, as a young person, differed from old people. Following this, an Evaluative Priming Task (EPT) measured automatic age and race bias using photos of women varying in age and race as primes, and positive and negative nouns as targets. Social identification (Inclusion of Ingroup in the Self scale) and self-reported evaluations (feeling thermometers) were also assessed. **Experiment 2:** This experiment aimed to determine whether the writing activity was necessary for the effect, replicating the ingroup-outgroup manipulation but adding a “without attribute description” condition. 171 students participated. After exclusions (non-White participants, participants over 40, participants who didn’t select an option, participants who refused to list attributes, repeated participants), 159 participants (94 female, 65 male) aged 16–31 (M = 20.87, SD = 2.66) remained. In this experiment, participants were informed that data would be compared between White and Black participants (or young and old participants), and they indicated their group membership. The ‘with attribute description’ condition replicated Experiment 1's writing task. The ‘without attribute description’ condition proceeded directly to the EPT, which was identical to Experiment 1's EPT, except photos of males were used for male participants. Measures of frequency of thoughts about group membership and self-stereotyping were also included.

**Experiment 1:** A 2 (ingroup-outgroup salience) × 2 (evaluation score) mixed ANOVA revealed a significant interaction effect. Participants showed higher race bias when White-Black distinction was salient, and higher age bias when young-old distinction was salient. Self-reported evaluations showed a different pattern, potentially suggesting social desirability bias or response correction effects. Automatic measures, therefore, are emphasized as more valuable in investigating primary categories like age and race. **Experiment 2:** A 2 (ingroup-outgroup salience) × 2 (type of manipulation) × 2 (evaluation score) mixed ANOVA showed a significant interaction between ingroup-outgroup salience and evaluation score, replicating Experiment 1's findings. The three-way interaction was not significant, indicating that the writing activity did not significantly influence results. Separate ANOVAs for the 'with' and 'without attribute description' conditions both showed significant interactions between ingroup-outgroup salience and evaluation score, supporting the robustness of the main finding. Additional measures showed that frequency of thoughts about group membership was affected by the salience manipulation, aligning with the automatic bias results, while self-stereotyping wasn’t affected. The results showed that a simple shift in ingroup-outgroup distinction salience is sufficient to moderate automatic intergroup bias. Automatic race bias was higher when White-Black distinction was salient and age bias was higher when young-old distinction was salient, in both manipulation types.

The findings demonstrate that ingroup-outgroup distinction salience moderates automatic intergroup bias, regardless of whether participants were asked to describe typical group attributes. The manipulation of simply drawing attention to the participant’s ingroup identity in contrast to the respective outgroup was sufficient to shift automatic evaluations of subsequently presented, unrelated social targets. This extends previous research which typically manipulated the categorization of the stimuli presented in the automatic bias measure or involved a preceding categorization practice phase or group building phase. This study shows that such additional procedures are not necessary for these effects. The discrepancy between automatic and self-reported evaluations highlights the importance of employing automatic measures when investigating primary social categories. The results suggest that even a subtle shift in ingroup-outgroup salience can influence automatic biases, potentially implying that these shifts can generalize across contexts.

This research demonstrates that a simple shift in ingroup-outgroup distinction salience significantly moderates automatic age and race biases toward multiply categorizable targets. This expands our understanding of the determinants of automatic intergroup bias and emphasizes the importance of considering ingroup-outgroup salience in future research on prejudice. Future research could explore whether subliminal ingroup priming has similar effects, further investigate reduction versus augmentation effects of salience manipulations with larger sample sizes, and explore the role of ingroup identification strength on the magnitude of these effects.

The study primarily focused on young White participants, limiting the generalizability of the findings to other demographic groups. The use of primarily student samples may introduce biases related to educational level or social environment. The lack of a control group without a salience manipulation makes it difficult to directly compare the magnitude of bias reduction or augmentation. While the study effectively demonstrates the moderating role of ingroup-outgroup salience, it does not fully address the mechanisms underlying these effects.