Impression Formation, Primacy Effect, and Attribution

Topic focus: social beliefs and judgments, how impressions are formed, and how they influence interactions with people; connection to attributions and biases in judging others.
Core idea: first information about a person can set the trajectory for how we perceive and interpret all subsequent information.
The lecture frames this through examples and brief research-style demonstrations, then connects to broader cognitive processes and upcoming topics about maintenance of impressions.

Experimental Illustration: Warm vs. Cold Biography (Harold Kelly’s setup)

Setup: A speaker was brought into a class; all students watched the same talk with identical content, but each student received a biography describing the speaker as either a "warm" or a "cold" individual. The only difference between conditions was this one sentence.
Procedure: The presentation and Q&A session were identical for all participants.
Result: Participation differed dramatically by biography condition.
- Participants with the warm biography: 56\% participated in the class discussion.
- Participants with the cold biography: 33\% participated.
- These percentages show a sizable difference in engagement driven by a single adjective in the initial description.
Takeaway: The same event elicited different perceptions and behaviors simply due to the first impression created by the adjective in the bio.

Test/grading demonstrations: Different subjects rated the intelligence of a person taking a graded test based on early performance.
Group A (good first impression): first page had 10 correct out of 15; overall score across two pages was 15 out of 30.
Group B (poor first impression): first page had a worse performance (the transcript describes multiple groups with varying first-page results), and then the second page performance varied.
Despite equal final performance across conditions, those who saw a better first page tended to rate the person as more intelligent.
Quantitative example from Group A:
- First page: rac{10}{15} = rac{2}{3}
- Total: rac{15}{30} = rac{1}{2}
Core conclusion: First impressions color judgments of competence (e.g., intelligence) even when actual outcomes are the same, illustrating the primacy effect in impression formation.

Definition: The primacy effect refers to the tendency to remember and assign significance to the first information encountered, which weights subsequent judgments.
In impression formation: The first information creates a schema (a mental model) about the person.
Processing of later information: New information is interpreted through the existing schema to support or refine that initial impression.
Cognitive bias in action: Once an impression is formed, the mind tends to maintain it; people are not as open-minded as they think they are.
Summary: Early information systematically biases how later information is perceived and integrated.

Schema formation: The initial impression provides a cognitive framework (schema) for understanding the person.
Interpretive bias: Later observations are filtered with reference to this schema, which tends to reinforce the initial impression.
Impression maintenance: The mind works to preserve the initial impression, making it harder to update with contradictory information.
Closing note: This is a core idea in chapter three of the course; the instructor hints that the next class will cover how impressions are maintained over time.

Real-world relevance: First impressions can influence participation, engagement, evaluation, and opportunities in everyday settings (e.g., classrooms, meetings, interviews).
Connection to attribution theory: The material links impression formation and biases to how we make attributions about others’ behavior (e.g., why someone acted a certain way). The course frames this around Harold Kelley’s work on attribution.
Practical implications: Awareness of primacy effects can inform strategies for fair evaluation and interaction, encouraging deliberate reassessment when new information appears.
Ethical/philosophical considerations: First impressions can lead to unfair judgments and discrimination; there is a responsibility to mitigate bias and seek objective evidence before forming stable conclusions about others.

Examples in daily life: In classrooms, job interviews, social introductions, and performance reviews, early descriptions or impressions can shape how people are perceived and treated.
Educational linkage: The material ties to foundational principles in social psychology about perception, bias, and cognition, and to broader theories of attribution.
Course trajectory: The notes preview a future discussion on how impressions are maintained, suggesting an ongoing exploration of cognitive biases in social perception.

Impression formation: How we form judgments about others based on available information.
Primacy effect: The tendency for the first information encountered to have a disproportionate influence on subsequent judgments.
Schema: A mental framework or set of beliefs about a person that guides interpretation of later information.
Attribution (brief link): The process of inferring causes for others’ behavior; related biases can be influenced by initial impressions.
Closed-mindedness (implicit in the discussion): The idea that individuals may resist updating beliefs once an impression is formed.

Warm vs. cold biography participation difference: 56\% vs 33\% participation.
Sample test performance example (Group A): First page 10/15 correct; total 15/30.
- First-page accuracy: \frac{10}{15} = \frac{2}{3}
- Overall accuracy: \frac{15}{30} = \frac{1}{2}
Proportions on the first page for the other groups as described:
- Group with first page 5 correct: \frac{5}{15}
- Group with first page 7 correct: \frac{7}{15}
These numeric illustrations support the qualitative claim that good early information biases later judgments, even when performance is ultimately comparable.

The instructor mentions that on Wednesday the topic will be how impressions are maintained, continuing the discussion started in this chapter.