The period marks the emergence of information-processing ideas in perception, treating perceptual decision making as information transfer under uncertainty. Researchers quantized how the amount of information needed to discriminate among alternatives shapes reaction times and processing efficiency, introducing an information-theoretic view to psychophysics. The approach highlighted how stimulus-response compatibility and cross-modal processing influence perceptual-motor performance, while empirical work on size and distance evidenced distortions and constancies that oriented future theories. Together, these efforts fostered a unifying framework that connected perception across modalities and laid the groundwork for later computational and cognitive models.