role of mood at the learning stage has its counterpart during retrieval, effective recall depending on ... 2) Hypnosis was employed to induce emotional states.
Revista de Psicología Social, 1986, 1, 79-82 © 1986 Re y. Psic. Soc.
Affective state dependence in a recognition task M. J. Blanco, F. Valle-Inclán, J. Lamas Universidad de Santiago de Compostela Introduction
The relationship berween memory and mood (in this article we shall use the terms «mood», «emotion» and «affective state» indiscriminately) has traditionally been investigated in the context of theories of affective quality or affective intensity (Rapaport, 1942; Dutta and Kanungo, 1975). According ro affective quality theories, the recall index (usually che proportion of stimuli correctly remembered) vares with the affective quality. of che stimuli and/or the state oflearnings, where as intensity theories maintain that the variables controlling the recall index are che emotional intensity and/or the state of learning. In recent years research on retrieval processes (Craik, 1981) has led ro che idea that the role of mood at the learning stage has its counterpart during retrieval, effective recall depending on the congruence or similarity between the affective states during learning and retrieval. The generic name given ro chis interaction is affective-state-dependent retrieval, Most research on affective state dependence has been carried out with tree recall tasks and has supported the hypothesis of affective state dependence (e.g. Bower el al, 1978; Bower, 1981; Laird et al, 1982). Affective state dependence has nervetheless failed to appear in experiments with recognition tasks (e.g. Macht el al, 1977; Bartlett and Santrock, 1979) or cued recall (e.g. Bartlett and Santrock, 1979; Bartlett et aL, 1982). The present communication describes a study of affetive state dependence carried out using a recognition test. Affective state dependence is usually explained in terms of the theory proposed by Bower (Bower, 1981; Bower and Cohen, 1982; Gilligan and Bower, 1984), which conceives of memory as a network of associations among semantic concepts and schemata, patterns of action and emotions, like an electric network with tiny «voltage sources» or nodes. The nodes corresponding ro emotions differ from concept nodes in three basic aspects. Firstly, certain emotion nodes have innate associations with facial musculature and the autonomous nervous system. Secondly, the activation of emotion nodes persists for longer than that of concept nodes due to feedback from the facial musculature and the autonomous nervous system. Thirdly, there is a difference berween che two kinds of node as regards the amount of excitation that they broadcast over the network once their «discharge threshold» has been topped. When an emotion node is excited ro aboye a certain threshold, the excitation is transmited to the emotional response patterns and other memory structures with wich it is connected, among them the events or items learnt while under the influence of this emotion. In short, the representation of an event in memory integrates the affective state experienced at the time of the event together with other features of che learning context (e.g. laboratory, experimenter, etc.). Certain authors refer to chis context as the «cognitive environment» or learning «set» (e.g. Tulving, 1983). For che retrieval process, Bower's theory accepts the basic postulares of generation-discrimination models (e.g. Anderson and Bower, 1972), according to which recall involves two processes, generation (search) and discrimination. According to Bower's theory, affective state dependence appears when one or more emotion nodes emit more excitation than che concept nodes. If this occurs, the emotion node «directs» che search process towards the iterns or events learnt under che influence of the corresponding affective state, making them more accesible than others. The theory thus assumes that the affective state effect is localized in the search process, and predicts that in recognition tasks (which involve no search) there
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will be no affective state dependence. In contrast with Bower's theory, the specific encoding principie enunciated by Tulving and Thomson (1973) predicts that affective state dependence may affect both free tecali and recognition tasks. According to Tulving and Thomson, there is no theoretical difference between tecali and recognition, where as differences between the two are established by two-process theories. The study of context dependence thus constitutes a mean of deciding between the two types of theory (Baddeley, 1982). The present communication reports the results of an experiment on affective state dependence in recognition tasks which differed from previous experiments of this kind in three ways. 1) The retention interval was varied. It seemed likely that the similitude between the learning set or cognitive environment at the time of learning and the environment at the time of retrieval might be greater for short retention intervals than for long, making it possible that for short intervals the effectiveness of affective state as a cue for recall might be obscured by the effects of non-affective cues. 2) Hypnosis was employed to induce emotional states. Hypnotic induction procedures have been the subject of much discussion concerning experimental demands (e.g. Orne, 1962), and the theoretical and methodological aspects of the problem, which he outside the proper limits of this paper, have been discussed by Bower et al, (1978) and Bower (1981). In the experiment described here, the absence of experimental demand was checked by a group of judges who saw a video recording of the experimental session. One of the advantages of the hypnotic procedure as against other more common techniques for inducing emotional states (Velten's technique, for example) is that it enables emotional states of greater intensity to be obtained. 3) The usual list of words was replaced by photographs of faces. In an experiment of this kind Gellerman and Bower (in Bower and Cohen, 1982) found no affective state dependence, even though faces might be supposed more subject to this kind of dependence than verbal material. Method
Design A 2 x 2 x 2 factorial design was employed (retention interval x state during learning x state during retrieval), measurement of the !atter two factors being repeated. The short retention interval was 20 minutes and the long interval 24 hours. Affective states (sadness or happiness) were induced by posthypnotic suggestion.
Subjects Experiments were carried out on 10 subjects (seven women and three men), all of them first year psychology students aged 18-19 years. Ah l ten had scored 12 out 12 on the Harvard Group Scale of Hypnotic Susceptibility (Shor and Orne, 1962) and had already taken part in individual hypnotic sessions prior ro the present experiment. Ah l were volunteers and none was remunerated for taking part in the experiment. The subjects were divided into two groups of five, one of which performed the recognition task 20 minutes after the stimuli were presented, and the other 24 hours later. Stimuli The stimuli were twenty 2 x 3 cm black-and-white photographs of faces selected at random from among the identity card photos of students who had graduated. The photos were presented on 10x 15 cm cards of various colours (black, white or green), the colour of the card being used as a posthypnotic signai ro trigger affective states.
Procedure Ahl sessions involved single subjects and took place in the same room. A two-way mirror in one wall and a video camera in one comer were explained as necessary for experimental objectivity. The hypnotist was the same in ah l sessions. The other two experimenters remained in an adjacent room observing the session through the mirror and controlling the video equipment. The learning phase began with a brief hypnotic induction procedure during which the subject received the suggestion that he or she would feel happy on seeing 10 white cards and sad on seeing 10 black cards. Posthypnotic amnesia was verified after the subject was roused. After a short interval 80
(never longer than 5 minutes) the 20 cards were presented in rwo blocks differentiated by their colour. The effect of the order in which the two blocks were presented was controlled for, and the order of the cards within each block was random. No limit was placed on the time for which the cards were presented, but it never exceeded 5 seconds. The subject's task was ro examine the faces carefully and say whether he knew the person portrayed or not (ah l these answers were negative). Once the cards had been presented, hypnotic trance was induced to «cancel» the earlier suggestions. Five of the subjects were asked to return 20 minutes later for a second session, and the other five 24 hours later, but neither group was informed that the second session would involve recognizing the photos they had just been shown. The second session began like the first with a brief hypnotic induction procedure, but this time it was suggested to the subject that he or she would feel happy (five subjects) or sad (the other five) on seeing green cards. After being roused, the subject was presented with 40 green cards, one by one, 20 of which bore a photograph seen during the first session and 20 a new photograph. The subject's task was ro reply «Yes» or «No» ro question «Have you seco this face before?». A week after the second session both were repeated with the same subjects, but using a different set of 40 photographs and inducing the contrary affective state during the recognition session;. Results The independent variable was the proportion of successes or correct guesses («Yes» answers when presented with photographs that had been seco in the learning session). The results were analysed by 3-way analysis of variance corresponding ro the design described in the Methods section. Table 1 shows the proportion of successes for each experimental condition. The analysis of variance revealed no significant effect of the retention time, though the percentage of successes with the longer time was slightly greater than with the shorter (59% as against 56.5%). Nor were significant effects observed ro be associated with either the affective state during learning or the affective state during retrieval or any interaction between these variables and the retention time. The only significant effect detected by the statistical analysis was that of the interaction between the two affective states [F(1.8)=10.8; p
