This study assesses the effect of visual versus audio observation/recording on both client and therapist verbal and non-verbal behavior in ongoing therapy. Three co-led, therapy groups were studied over six weekly sessions under counterbalanced observation conditions. Measures of verbal behavior, verbal productivity, and non-verbal behavior were taken along with independent measures of personality and self-reported inhibition. Results indicate that: (1) visual observation has significant negative and detrimental effects in comparison to audio observation on therapeutically meaningful verbal behavior, on self-exploratory verbal behavior, and on rate of verbal behavior; (2) there is an interaction effect for personality variables, with the more extroverted and less neurotic clients evidencing the greater suppression of verbal behavior under videotaping conditions; (3) physical distance between group members decreases significantly under videotaping conditions; and (4) self-reported inhibition does not relate to actual in-session behavior. The results indicate that observation and recording media have significant, differential and intrusive effects on desired, therapeutic client behavior in groups. (Author)