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What Animals Never Operantly Coordinate Actions with Sensory Input: The Earliest Stages of Animal Behavior Michael Lamport Commons Patrice Marie Miller Harvard Medical School We describe developmental stages of the least complex animals Several reasons for doing this are Understand the most basic task actions and how they are controlled Be more exact about how these basic units get combined to form more complex tasks Better understand evolution Commons et al have proposed the Model of Hierarchical Complexity (MHC) This model can be used to determine behavioral stage MHC orders tasks in terms of Hierarchical complexity A task action is defined as more hierarchically complex when the higher order action – is defined in terms of the actions at the next lower order – organizes these lower-order actions – in a non-arbitrary way Explains stages of development A Stage name and number corresponds to the order of hierarchical complexity of a task it correctly completes This paper will focus mainly on Stage 1 Stage 1 describes that organisms complete tasks in which they are required to either act or sense, but they do not complete tasks that coordinate the two First, we examine some Stage 1 tasks that animals might complete Second, we examine evidence for animals that never progress further than Stage 1 in any area Stage 0 – Calculatory Before Stage 1, however, we describe stage 0 At stage 0, both the detection of stimuli and the production of responses are exact There is no generalization – All examples have to have been programmed – Robots and computers respond this way For computers, only written programmed learning is possible – The exception are neural networks, especially stacked neural networks We would assert that there are no animals that function at this stage Stage 1 – Sensory or Motor The criterion for classifying action as Stage 1 is The organism engages in a single action at a time These actions are not coordinated with other actions There are coordinations of stimuli Both the detection of stimuli or the production of responses are somewhat flexible But the relationship between them is not For example, when water moves, mollusks open their shells reflexively If something touches their membrane, the shells close There is very little variability in these responses Many subtypes of zooplankton behavior is confined to Stage 1 Zooplankton are floating or weakly swimming They rely on water currents to move great distances Microzooplankton are usually less than 200 mm Protozoa are a eukaryote subclass plankton They are mobile and heterotrophic – They use organic substrates to get carbon for growth and development – Most protozoans are around 001–005 mm but up to 05 They are predators upon unicellular or filamentous algae, bacteria, and microfungi Possible Stage 1 behaviors seen in such organisms A Taxis is an organism’s directed physical action in response to a specific stimulus A taxis can be a directional response or a non-directional response (kinesis) Phototaxis: flagellate protozoans of the genus Euglena move towards a light source Chemotaxis: Cells such as the free-living amebas or the wandering cells of the Metazoa may detect the direction of a potential food source through the chemicals that the food sheds Other kind of Taxis behaviors include: anemotaxis (stimulation by wind), barotaxis (pressure), galvanotaxis (electrical current), geotaxis (gravity), hydrotaxis (moisture), phototaxis (light), rheotaxis (fluid flow), thermotaxis (temperature changes) and thigmotaxis (physical contact) Example 2: Phagocytosis Phagocytosis: a way of obtaining nutrients that involves an organism completely surrounding a food particle Amoebae: food object surrounded by their pseudopods In another protozoan, called a ciliate, there is a specialized groove in the cell where phagocytosis takes place Example 3: Reflexes The most complex stage 1 system are reflexes A reflex is a biologically-based system linking stimulus to response This may be mediated by a reflex arc only a few neurons long Here, the stimulus and the response are coordinated – But the coordination is automatic – It is simply due to the neural connection For animals without neurons, we do not believe there can be true reflexes Some modification of a reflex is possible For example, habituation of a reflex can occur Habituation may be due simple process as neural fatigue Likewise with sensitization What about stimulus generalization? Stimulus generalization results from similarity of the original eliciting stimulus to other stimuli As a stimulus becomes less and less similar, it is less likely to elicit the same response For simple, physical stimuli the degree of similarity can be measured quantitatively rather than in hierarchical terms So, behavior remains at stage 1 Is respondent conditioning also Stage 1? One stimulus precedes closely before another stimulus It can come to elicit the same or similar response Pairing of the unconditioned and stimulus to be conditioned is not a task that the animal must actively solve This is so even though the stimuli must be salient The two stimuli are arbitrarily paired, either by an accident of nature or by an experimenter This does not constitute an increase in the hierarchical complexity of the task that must be solved The organism does not temporally or in some other way organize actions in order to more adequately accomplish this Stage 2 – Circular Sensory- Motor Even very primitive animals differentially respond to stimuli, for example, rejecting non-food items They do not change their behavior based on this environmental consequences feedback following those responses Every encounter with a food or a non-food object is like a new encounter Such animals may not operantly hunt for prey or forage Some animals change their behavior in response to consequences The consequences lead to them to Stage 2 behavior in which they coordinate action with sensory input Coordinating perception and action or two or more actions At Stage 2, animals coordinate operant action with perception or they coordinate two or more actions Hunting behavior is controlled by consequences (eg most predatory fish, insects) are performing at this stage Corrette (1990) observed prey capture in the praying mantis They coordinated capture and strike movements Coordinating of multiple behaviors such as looking, reaching and grasping require Stage 2 circular sensory and motor action Conclusion We have described stage of actions by various simple organisms The first two orders of hierarchical complexity adequately described the tasks they accomplish Simple one-celled organisms that were not part of groups of cells, functioned at stage 1 Some multiple cell organisms that operantly conditioned functioned at stage 2 Some animals such as mammals probably never function only at stage 1