Personality and Assessment

The book argues that global personality trait measures have limited predictive utility for behavior across different situations, with correlations typically falling in the .20 to .30 range—a limit Mischel termed the 'personality coefficient' . It rejects the assumption that broad dispositions directly cause cross-situationally consistent behavior, and it rejects the methodological dominance of questionnaire-based assessment as a substitute for observing what people actually do. Crucially, the book does not deny that behavior is coherent or that individual differences matter. It relocates the source of coherence from stable traits to the person's cognitive-affective construal of situations, foreshadowing the if-then behavioral signatures and cognitive-affective processing system that Mischel and colleagues would later formalize .

The book coined the 'personality coefficient,' defined as the correlation between .20 and .30 persistently found when any questionnaire-inferred personality dimension is related to an external criterion sampled in a different medium . The concept crystallized the trait psychologist's predictive problem and gave the field a quantitative marker for the limits of dispositional assessment. Funder later noted that the personality coefficient was ahead of its time because it anticipated the modern emphasis on effect sizes over significance testing . Today the term is standard shorthand in discussions of trait predictive validity and remains a reference point in debates about the ceiling on personality-behavior correlations, even as meta-analytic techniques have refined estimates of those limits.

The book was published in 1968 and within a year the person-situation debate dominated personality and social psychology . Critics from the trait tradition, notably Block, defended personality theory against Mischel's conclusions, while others argued that the book's message was overextended into a general situationist doctrine. A 2009 retrospective special issue marking the book's 40th anniversary brought together authors on opposing sides: Funder reflected on its impact on personality-social psychology relations, Roberts argued some critiques of traits were unfounded, while Andersen and Thorpe credited the book with providing intellectual background for relational-self work . The debate's residue includes the persistent misreading that Mischel denied personality altogether—a simplification the book's own nuanced treatment of construal and situations does not support .

Personality and Assessment is the opening move in a constructive project that Mischel developed over subsequent decades. The book's emphasis on the acquired meaning of stimuli, the situation as perceived, and the person as a cognitive-affective being who construes and transforms social input provided the conceptual seed for the cognitive-affective processing system (CAPS) formalized in Mischel and Shoda's 1995 work . The if-then behavioral signatures that became central to CAPS were explicitly foreshadowed in the 1968 book, which called for a 'truly dynamic personality psychology' . The later work thus extends the critique into a positive theory of how cognitive-affective mediating units generate stable within-person patterns of situation-behavior relations.

The most common misreading treats the book as arguing that personality does not exist or that situations alone determine behavior. Funder has documented how the book's oversimplified bottom line was transformed into a putative social psychology lesson that people underestimate situational power—a lesson enshrined in introductory textbooks' treatment of the fundamental attribution error . This misreading persists because the book's provocative framing and its focus on predictive failures made it easy to recruit for situationist arguments, even though Mischel's own position was interactionist and emphasized the person's construal of situations. The 1996 reissue's preface notes that the book outlined the need to encompass the situation while focusing on acquired meaning and the individual as a cognitive-affective being, a nuance lost in the sloganized version .

The second half of the book moves from critique to constructive alternative, outlining a social learning and cognitive approach to personality assessment and behavior change. Mischel argued that useful prediction and modification of behavior require attention to the specific situations in which behavior occurs, the individual's past behavior in similar contexts, and the cognitive and attentional processes that mediate between stimulus and response . This alternative was informed by his Peace Corps selection research, which first disillusioned him about trait approaches, and it pointed toward the social-cognitive reconceptualization he would publish in 1973 . The book thus pairs its demolition of trait pretensions with a programmatic case for studying persons in situations rather than persons in the abstract.