Efeitos de estímulos emocionais sobre a ocorrência de falsas memórias : investigação por meio do paradigma da equivalência de estímulos

Abstract

False memories can be defined as recollections that do not correspond to the facts experienced by subjects. Cognitive research have pointed out that the referred phenomenon is, to some extent, determined by semantic relations among stimuli. Based on these studies, behavior analysts have proposed experimental analogous of false memories using the stimulus equivalence paradigm to establish symbolic relations. The current master’s thesis was composed by one preliminary study and two main studies. The preliminary study aimed to assess the valence and arousal of pictures depicting facial expressions, and to select the meaningful stimuli that were employed on the class formation procedures of Studies 1 and 2. Study 1 aimed to analyze possible effects of emotional stimuli with different valences (positive, neutral and negative) on the occurrence of false memories. For this purpose, a systematic replication of Aggio’s (2014) Study 3, using lists of symbolically related stimuli through the stimulus equivalence paradigm was carried out. The main experimental manipulations of Study 1, in the present thesis, were the control of valence and arousal magnitudes attributed to the emotional stimuli; the use of emotional stimuli in the class formation procedure, which contained the unrelated distracting stimuli; and the randomization of list order presentation. Study 1 was structured in four phases, which encompassed 1) the establishment of six equivalence classes; 2) a false memories test with a memorization task and a recognition test, held one week after the beginning of Phase 1; 3) class merger and maintenance test, and 4) stimuli assessment through a semantic differential. Results showed that the false memories effect, under symbolic control, occurred only in relation to the positive stimuli list. It was hypothesized that the stability of the equivalence classes was an intervening variable. In order to verify the aforementioned hypothesis and search for new evidences regarding the effects of emotional valence on the establishment of false memories, a second study was proposed. The Study 2 had the same procedure as Study 1, with the exception of two changes: the reduction of the time interval employed between the first and the second phase, and the insertion of baseline review blocks of the six equivalence classes before the false memories test. These changes were adopted in order to increase the probability that the equivalence relations were stable and strengthened at the moment of the false memories test. Results showed the occurrence of the false memories effect in positive and neutral lists. These results suggest that stimuli with negative emotional valence can reduce the probability of false memories occurrence.