An Approach to Environmental Psychology

The book argues that environmental psychology lacked a theory around which research could be organized, leaving the field unable to compare effects of color, heat, light, and sound across studies. Mehrabian and Russell propose that environmental stimuli are linked to behavioral responses by intervening emotional responses—pleasure, arousal, and dominance (PAD). By measuring the impact of any environment on these three dimensions, the effects of diverse stimulus components within or across sense modalities can be compared on a common scale. This framework transforms environmental psychology from a catalog of disconnected findings into a testable causal chain.

The model proposes that any environment induces an emotional state characterized by three dimensions: pleasure (well-being and satisfaction), arousal (excitement and alertness), and dominance (feeling of control and freedom to act). Environmental stimuli are assessed for their combined impact on these dimensions, then linked to approach-avoidance behaviors such as exploration, affiliation, and performance. An additional concept, information rate, compares environments with stimulation in multiple sense modalities. The authors provide extensive sets of measures for investigating the theory and implementing it in everyday environments.

Information rate. The authors introduced this concept to compare the effects of different environments, each with stimulation in many sense modalities. Rather than treating a room's lighting, sound, temperature, and spatial configuration as separate variables, information rate provides a single dimension along which environments can be ranked. This allows researchers to ask whether a high-information-rate environment (complex, novel, unpredictable) produces different emotional and behavioral effects than a low-information-rate environment, regardless of which specific sensory channels are involved. The concept addresses the field's central methodological problem: how to compare apples and oranges across studies.

The PAD framework became widely adopted in consumer behavior, tourism, and retail research. A literature review of store atmosphere studies found that most studies make reference to the PAD model as the standard for measuring emotions in shopping environments. Tourism researchers have used the PAD scale to measure emotional responses to environmental and architectural stimuli, with some arguing it is more suitable than alternatives like PANAS for studying environmental experience. Recent work has applied PAD to evaluate environmental protection posters, situational atmosphere preferences, and retail store atmosphere, with studies confirming significant correlations among the three dimensions.

The reviewer praised the attempt to provide a theoretical framework to the environment and behavior field, calling such a framework sorely needed. The review highlighted the authors' conceptual framework of interaction effects—environmental factors and personality jointly shaping intervening emotional responses of arousal, pleasure, and dominance, which in turn affect approach-avoidance responses of exploration, affiliation, and performance. The reviewer also credited the authors for applying concepts from mainstream psychology to environment and behavior issues, positioning the book as a bridge between environmental research and established psychological theory.

Not universally. Since 1980, James Russell—Mehrabian's co-author—dropped dominance from the PAD scale, arguing it seemed more like a cognitive dimension, an antecedent or consequence of emotion rather than part of core affect. Russell found dominance belonged more to the concept of an emotional episode than to core affect itself. Mehrabian, however, continued to include dominance in his version of the scale. Other researchers have noted that dominance is completely lacking from rival frameworks like Plutchik's, and that the PAD data captures more information about emotional aspects of experience than those alternatives.