The early multi-level models

1.4.1a. Leventhal’s hierarchical emotion processing model

Leventhal (1979, 1984) proposes that emotions are based upon operations performed at three levels of processing which are hierarchically organised, each of which can, by itself, give rise to emotions (although often all the levels influence emotions). The

sensory-motor, schematic and conceptual levels proposed by Leventhal are proposed to be constructed on the basis of various (emotional) experiences an individual has throughout their development.

The sensory-motor level involves processing by largely innate, unconditioned, hardwired feature detectors, which gives rise to a reflex-like, uncontrolled reaction.

Leventhal proposes that through evolution, the sensory-perceptual mechanisms were tuned in such a manner as to quickly recognise potentially harmful or beneficial stimuli. Responses are generated without the interference of more controlled

processes, in order to save time. Emotions elicited through sensory-motor processing are mostly short-lived and are of a reflex-like nature. Even though this level is held to be able to give rise to full emotions however, most emotions observed in daily life cannot be accounted for by an innate disposition. Rather, according to Leventhal, many emotions are learned in order that a person is able to adapt to the environment.

The schematic level of processing is based on the past learning experiences of an organism, which give rise to representations of learned procedures. Events or stimulus patterns lead to the activation of stored records of emotional experiences, which can be considered as average, prototypical exemplars, or “schemata”, of the emotions which an organism has developed throughout its life. These schemata contain

combined information concerning the conditions of the emotion-eliciting event itself, as well as the physiological and behavioural responses together with the concomitant subjective feeling. Incoming information sharing features with a schema and/or a specific stored instance, automatically reactivates and generates the associated emotional response.

The conceptual level of processing is characterised by reflective, propositional processes, as opposed to the template matching-like processes which were specific to the first two levels. This level comprises capacities to abstract from and reason about the environment on the bases of propositional memory structures, which are

developed by comparisons between past experiences. Processes such as anticipating or problem-solving are typical for the conceptual level, and permit a more flexible, thoughtful response to emotional experiences compared to the processes involving the schematic and sensory-motor level. The formation of conceptual code in emotion

processing plays, according to Leventhal, a crucial role in the control of emotional responses. The main contribution of Leventhal’s model is the acknowledgement that each level, even a simple, more “primitive” level is capable of eliciting emotion by itself and that the main function of the conceptual level comprises the control of emotional responses.

1.4.1b. Öhman's “preparedness” model of emotion-generation

In contrast to Leventhal, Öhman proposes that lower level processes do not result in full-blown emotions by themselves, but rather activate higher level processes.

Öhman’s (1979, 1986, 1988, 1993) research, based on Pavlovian conditioning of fear-relevant stimuli, reveals that physiological responses can be activated pre-attentively, and that emotional learning can take place without the participant being aware of its source. Based upon this research evidence, Öhman argues that evolution has tuned the perceptual mechanisms in such a manner as to promptly generate a response as soon as a stimulus relevant to the organism is perceived, even at a very low level of analysis of the stimulus. According to this view, the perceptual systems detect relevant stimuli automatically and independently of the current attentional focus. As soon as a relevant stimulus is perceived, ongoing actions are interrupted and more conscious, i.e. controlled, processing mechanisms are activated to further analyse the situation's significance before directed action is taken. This “call” for controlled processing is, in the older versions of the model, accompanied by an unspecific physiological response, preparing the organism for subsequent, more directed emotional responses.

Research findings reported by Öhman and colleagues (see e.g. Öhman, 1988 for an overview of pertinent research) underscore the pre-attentive activation aspect in Öhman’s model. The research paradigm generally used in this work consisted of conditioning of emotionally relevant and irrelevant pictures to a light electric shock in an acquisition phase where the stimuli were presented optimally (i.e. clearly visible), followed by an extinction phase in which a sub-optimal presentation of the

conditioned pictures took place, using backward masking procedures in order to maximally exclude controlled or conscious processing of the pictures. During the extinction phase, phasic skin conductance activity in response to the pictures was recorded. These skin conductance response measures revealed increases in

sympathetic nervous system activity only for fear-relevant pictures, such as spiders and snakes (Öhman, 1986) and angry facial expressions (Öhman, Dimberg, &

Esteves, 1989). No such effects were found with the fear-irrelevant pictures, such as mushrooms and happy facial expressions. Öhman and Soares (1994) have been able to extend these findings to spider and snake phobias where the phobics show similar physiological responses when presented either optimally or suboptimally presented pictures with the object of their phobia. Furthermore, Flykt (1998) found that stimuli which are pointed towards the subject, such as a gun which was used as a cultural threat stimulus to put the preparedness hypothesis to a test, also show such effects even when the stimuli are presented with the backward masking procedure in an extinction phase. These effects do not occur when threat objects points away from the subject, or when a neutral stimulus points towards the subject. The perceived direction of a threat stimulus, i.e. towards the person or directed elsewhere, thus seems to equally possess “hard-wired” or highly overlearned significance related to threat which can be activated pre-attentively.

Recently, Öhman (1992, 1993) revised his view somewhat on the basis of other research, and considers the direct, automatic activation of the arousal-system as a response specific to biologically fear-relevant stimuli, whereas other threat-related stimuli (such as words) need to be consciously perceived in order for the arousal system to be activated. This suggestion adds to the knowledge obtained from e.g.

affective priming and emotional Stroop studies (as reviewed above) in proposing that whereas subliminally presented, and hence pre-attentively processed, affective stimuli might have been evaluated and have an effect on subsequent processing, these types of evaluations are not necessarily capable of activating the arousal system.

1.4.2. LeDoux’s dual route model: Neuroscientific evidence of different processing