The psychological literature about consciousness has been analyzed. It is argued that: 1) Only the higher symbolic cognitive powers like the ability to keep secrets, knowledge of self or self-consciousness, a long-term view on the future, the ability to determine long-term goals, and to freely plan future behavior, add positive fitness-value to consciousness. Without these higher intellectual abilities consciousness will have only negative fitness value and no positive one. The intellectual powers mentioned may therefore be considered as prerequisites for consciousness. (...) Consciousness may therefore only be expected in those animal species that show these capacities in their behavior. So far these capacities have only been described for the anthropoid apes and humans. For the time being, they are therefore the only species in which consciousness may be expected. (shrink)

It is argued that the emotional feeling comprises the following two emotional qualia. (1) A nucleus feeling or primary emotional quale, which is the phenomenological counterpart of the end product of appraisal by the central nervous system. (2) The experience of being urged to emotion-related reflection or secondary emotional quale, which is the phenomenological counterpart of the brain's decision to inhibit pre-programmed emotional behaviour, and to initiate emotion-related reflections. Different brain modules regulate these two qualia, and thus each can be (...) experienced independently of the other. The primary emotional quale is related to activation of the amygdala, it is emotion specific, and neutral with respect to affect. The secondary emotional quale is related to activation of the orbito-prefrontal cortex (O-PFC), and includes affective aspects.It is argued that emotional behaviour is regulated by the following three neural mechanisms, two of which two are directly related to the two qualia. (1) An evolutionary ancient system (amygdala-system), which comprises the amygdalae and subcortical nuclei, and which activates pre-programmed emotional behaviour. (2) An evolutionary recent system (PFC-system), comprising the prefrontal cortex, which inhibits pre-programmed emotional behaviour, activates emotional reflection, generates and evaluates behavioural alternatives. In contrast to the pre-programmed behaviour, the behavioural alternatives are more likely to serve long-term goals. (3) A default mechanism, which gives rise to default (i.e., “just do something”) behaviour. The first two systems are mutually competitive, while the third mechanism takes over if either the competition between the first two mechanisms, or the decision process of the PFC-system, takes too long. This default mechanism involves the function of the medial-prefrontal cortex (M-PFC). (shrink)

The Müller-Lyer illusion is the natural consequence of the construction of the vertebrate eye, retina and visual processing system. Due to imperfections in the vertebrate eye and retina and due to the subsequent processing in the system by ever increasing receptive fields, the visual information becomes less and less precise with respect to exact location and size. The consequence of this is that eventually the brain has to calculate a weighted mean value of the information, which is spread out over (...) a population of neurons. In the case of the Müller-Lyer illusion this inevitably leads to extension of one and reduction of the other line. The arguments presented explain several published experimental results concerning the Müller-Lyer illusion and shed new light upon the philosophical neutrality of observation sentences. (shrink)