Biological constraints in learning

Biological constraints on learning

Biological constraints on learning refer to any limitations on an organism's capacity to learn that are caused by the inherited sensory, response, or cognitive capabilities of members of a given species. Likewise Biological constraints are limitations on learning that result from biological factors rather than from experience.

What is BIOLOGICAL CONSTRAINT?

An observation that certain behaviors can be learned more easily than some other. It is part of the learning theory in psychology.

BIOLOGICAL CONSTRAINT: "Gorillas and chimps are able to learn different physical tasks and to communicate using the sign language, but due to biological constraint they are not able to learn to read or speak."

How do biological constraints affect classical and operant conditioning?

Classical conditioning principles, we now know, are constrained by biological predispositions, so that learning some associations is easier than learning others. Learning is adaptive: Each species learns behaviors that aid its survival. Biological constraints also place limits on operant conditioning. Training that attempts to override biological constraints will probably not endure because animals will revert to predisposed patterns.

Biological Constraints on Learning

The phenomena that are usually called biological constraints on learning indicated the intrusion of biological factors into standard, traditional conditioning situations. Breland and Breland (1961) were the first to recognize the importance of constraints in operant conditioning situations. They observed what they called instinctive drift, a tendency for "natural behaviors" of animals undergoing operant conditioning to intrude upon and interfere with the emission of the response being reinforced. The Brelands clearly recognized the fundamental importance of their observations, which they viewed as a "demonstration that there are definite weaknesses in the philoso­phy underlying these (conditioning] techniques" (Breland and Breland 1961, 684). However, their findings had little effect at the time. The later discoveries of taste aversion learning, autoshaping, and species-specific defense reactions had more impact.

Taste aversion learning was first reported by Garcia and Koelling (1966). In essence, taste aversion learning suggests that some stimuli are more associable than others, challenging the often implicit assumption of associationists that stimuli are generally equipotential (Seligman 1970). These studies show that many animals are more likely to associate intestinal illness with gustatory (or olfactory) stimuli than with external stimuli. Garcia and Koelling (1966) proposed that these results demon­strate that rats may have a genetically coded hypothesis: "The hypothesis of the sick rat, as for many of us under similar circumstances, would be 'it must have been something I ate'" (Garcia and Koelling 1966, 124).

The phenomenon of autoshaping was first reported by Brown and Jenkins (1968). Brown and Jenkins found that if they simply illuminated a light behind a pecking key for a few seconds, then presented food, the pigeons began to peck the key even though these pecks had no effect on the presentation of the reinforcer. Although they felt that an appeal to some species-specific disposition was necessary, and though Breland and Breland reported many similar findings in less constrained situations, Brown and Jenkins do not cite the Brelands. The implication that species-specific predispositions affect the key peck has been confirmed. Jenkins and Moore (1973) snowed that the topography of the pigeon's key peck depends on the rein-forcer used. Mauldin (1981; Kami! and Mauldin 1987) found that three different passerine species each used species-specific response topologies in an autoshaping situation.

There can be no doubt that these "biological constraints" on learning demon­strate that the evolutionary history of the species being studied can affect the out­come of a conditioning experiment. Whether the differences between taste aversion learning and other aversive conditioning are considered qualitative or quantitative, differences that seem most explicable in functional grounds do exist. The form of the response in a Skinner box depends on the natural repertoire of the animal, as do the results of avoidance learning experiments. However, the impact of these findings on the psychological study of animal learning has been limited.

In summary, then, three types of research indicate the need for a biological approach to learning: (1) studies of biological constraints, which clearly show that the evolutionary history of the species can affect the outcome of conditioning experi­ments in a variety of ways; (2) studies of specialized learning, which indicate that there can be significant variation in learning mechanisms that correlate with the ecologies of the species being studied; and (3) evidence from behavioral ecology, which shows that general forms of learning are of adaptive significance and may also, therefore, vary in ways that correlate with ecology.

Opponent-Process Theory

The Opponent-Process Theory of Motivation

(Solomon and Corbit, 1974)

The concepts of habituation and sensitization have been extended to emotions and motivated behavior.

Common characteristics of emotional reactions

1. Emotional reactions are biphasic; a primary reaction is followed by an opposite after-reaction

2. The primary reaction becomes weaker with repeated stimulations

3. The after-reaction is strengthened

The Opponent-Process Theory is a homeostatic theory

The theory assumes that neurophysiological mechanisms involved in emotional behavior serve to maintain emotional stability.

Richard Solomon’s OPPONENT PROCESS THEORY

      New stimulus events, esp. those arousing strong emotions, disrupt a person’s equilibrium.

      This disruption triggers an opposite (opponent) response (process) that eventually restores equilibrium.

      If the event occurs repeatedly, the opponent process becomes stronger and eventually suppresses the initial reaction to the stimulus, creating habituation.

      e.g., development of drug tolerance and addiction

      e.g., engagement in high risk/arousal activities such as skydiving

      e.g., accidental drug overdoses

      NOTE:  Opponent process explanations based on habituation and sensitization cannot explain many of the behaviors  and mental processes that are the focus of psychology.

      Learned associations between certain environmental stimuli and certain opponent responses affect our thoughts and behaviors as well. 

      CLASSICAL CONDITIONING is one type of associative learning that builds associations between various stimuli as well as between stimuli and responses

Richard Solomon developed a motivational theory based on opponent processes. Basically he states that every process that has an affective balance, (i.e. is pleasant or unpleasant), is followed by a secondary, "opponent process". This opponent process sets in after the primary process is quieted. With repeated exposure, the primary process becomes weaker while the opponent process is strengthened.

The most important contribution is Solomon's findings on work motivation and addictive behavior, though it does not fit the "economist's standard model", and how there are growing suspicions that addiction is a much broader phenomenon than first believed. According to opponent-process theory, drug addiction is the result of an emotional pairing of pleasure and the emotional symptoms associated with withdrawal. At the beginning of drug or any substance use, there are high levels of pleasure and low levels of withdrawal. Over time, however, as the levels of pleasure from using the drug decrease, the levels of withdrawal symptoms increase, thus providing motivation to keep using the drug despite a lack of pleasure from it.

Opponent-Process Theory:

Opponent-process theory is a psychological and neurological model that accounts for a wide range of behaviors, including color vision. This model was first proposed in 1878 by Ewald Hering, a German physiologist, and later expanded by Richard Solomon, a 20th-century psychologist.

The opponent-process theory was first developed by Ewald Hering. He noted that there are color combinations that we never see, such as reddish-green or yellowish-blue. Opponent-process theory suggests that color perception is controlled by the activity of three opponent systems. In the theory, he postulated about three independent receptor types which all have opposing pairs: white and black, blue and yellow, and red and green.

These three pairs produce combinations of colors for us through the opponent process. Furthermore, according to this theory, for each of these three pairs, three types of chemicals in the retina occur, in which two types of chemical reactions exist. These reactions would yield one member of the pair in their building up phase, or anabolic process, whereas they would yield the other member while in a destructive phase, or a catabolic process.

The colors in each pair oppose each other. Red-green receptors cannot send messages about both colors at the same time. This theory also explains negative afterimages; once a stimulus of a certain color is presented, the opponent color is perceived after the stimulus is removed because the anabolic and catabolic processes are reversed. For example, red creates a positive (or excitatory) response while green creates a negative (or inhibitory) response. These responses are controlled by opponent neurons, which are neurons that have an excitatory response to some wavelengths and an inhibitory response to wavelengths in the opponent part of the spectrum.

According to this theory, color blindness is due to the lack of a particular chemical in the eye. The positive after-image occurs after we stare at a brightly illuminated image on a regularly lighted surface and the image varies with increases and decreases in the light intensity of the background.

Habituation vs. Sensitization Habituation

Habituation vs. Sensitization Habituation

Habituation

• Decrease in strength of behavior • Typically low-intensity stimuli • Stimulus-specific generalization • < neurotransmitter Sensitization

• Increase in strength of behavior • Typically highintensity stimuli • Nonspecific generalization • > neurotransmitter

Dual process theory

Dual process theory

According to the dual-process theory, which explains responses that occur as a result of two different processes, habituation and sensitization are opposite dynamics that relate to our reaction to stimuli.

Habituation, which may result in a habit or learning, is a decreased response to stimulus as opposed to its antithesis in sensitization: a heightened response to stimulus.

These two reactions are results of different processes, the S-R system and the state of arousal system, and originate in different areas of the human brain. When we habituate, we no longer respond to either the negative or the positive factors of the stimulus. We adapt in a way that we perform a function without stimulus response. Habituation is the result of changing neurons that moderate our level of response. Sensitization occurs when the state of arousal is greater in the excitation of stimulus response. Since habituation and sensitisation stimulus responses have two different results and function through two different systems (S-R and state), they are not said to be related to each other.

An example of habituation is eating in shift-workers who have a set time for their hunger stimulus that is not the same as that of regular workers. The shift-workers' schedules habituate their bodies to change the original bio-clock stimulus. Keep in mind that habituation can be either short or long term differentiating between short-term habituation and long-term habituation.

Sensitization is the excitation of sensory response towards a stimulus. In the example of animal trainers, sensitization is the best conduit to instill trust and motivation in the animal who is being behaviorally conditioned. Hence, a piece of food is often used as a reward for performing the expected response as part of the heightened sensitization process.

Conclusion:

Learning that occurs as the result of the presentation of a single stimulus. 1.  Habituation:   Decrease in the strength of a response following repeated presentations of a single stimulus.  Stimulus initially results in a STARTLE RESPONSE (orientation, increased awareness & attention, fight or flight) which dissipates after a few trials. Alternative Explanations       a.  muscle fatigue:  muscles unable to respond?  change stimulus or intensity of stimulus       b.  sensory adaptation: fatigue of sensory system?  reintroduce stimulus when not expected  2.  Sensitization:   Increase in the strength of a response following repeated presentations of a stimulus -- "opposite" of habituation. 3.  Groves & Thompson (1970) dominant theory of how HABITUATION & SENSITIZATION works is called the DUAL PROCESS THEORY proposed by GROVES & THOMPSON (1970)  • DUAL PROCESS THEORY hypothesizes that there are 2 processes that underlie the increase in responsiveness seen in SENSITIZATION and the decrease in responsiveness seen in HABITUATION. • There's the SENSITIZATION PROCESS and the HABITUATION PROCESS and these processes are not mutually exclusive -- that is, they can BOTH be activated at the same time. a. HABITUATION NEURAL PROCESSES occur in what Groves & Thompson call the S-R SYSTEM which is analogous to the REFLEX ARC.  EVERY presentation of a stimulus activates this system. b. SENSITIZATION NEURAL PROCESSES occur in the STATE SYSTEM which determine's the Animal's general level of responsiveness or "AROUSAL".  Only arousing events activate this system. The S-R SYSTEM works together with the STATE SYSTEM and the net result is behavior. .  The outcome -- whether we habituate or sensitize -- will depend upon which is stronger in any given set of circumstances. 3.  Davis (1974) Rats in an apparatus with movable floors called stabilimeter chambers, repeated pairings of loud tone (110dB) = habituation, loud tone over 60db background noise = habituation, loud tone over 80db background noise = sensitization. Results support GROVES & THOMPSON (1970) THE LOUDER BACKGROUND NOISE CHANGED THE AROUSAL LEVEL OF RATS = INCREASED NOISE, INCREASED AROUSAL, INCREASED RESPONDING They would say that when the rats were tested with a relatively quiet background noise, there wasn't much to produce changes in the STATE SYSTEM so the S-R SYSTEM won out and the rats habituated. When the rats were tested in a loud background noise, the background noise probably increased arousal (the STATE SYSTEM) and the rats increased responding, that is they sensitized.

What is habituation

What is habituation?

Decreases in responsiveness to a stimuli after repeated presentations of it

Properties of habituation?

1. large response decrements occur at first, followed by progressively smaller response decrements
2. Response recovers over time if no stimulus is presented (spontaneous recovery)
3. Relearning - Habituation is more faster when stimulus is presented again
4. Habituation = faster with weaker stimuli (helicopter story)
5. Increased freq. of stimuli = faster habituation
6. below-zero habituation = increases long term retention of habituation
7. Amount of generalization depends on similarity of stimuli
8. Restoration of habituated response by changing the nature of the eliciting stimulus = dishabituation

What is non-associative learning

What is non-associative learning?

1. Changes in elicited behaviour occurring as a result of repeated presentations of a stimuli
2. both increases/decreases in response can occur with repeated stimuli presentation
3. Decreases in responsiveness = habituation
4. Increases in responsiveness = sensitization
5. habituation + sensitization help organize and focus attention
6. Habituation occurs in all organisms from humans to single celled protozoa.
7. Properties of habituation and sensitization appear to be the same across organisms

LEARNING

LEARNING is the adaptive process through which experience modifies pre-existing behavior and understanding; relatively permanent change in behavior based on prior experiences

      plays central role in development of most aspects of human behavior

      humans and animals learn primarily by:

1.      experiencing events

2.      observing relationships between those events

3.      noting consistencies in the world around them

Three Types of Behavior

Reflexes: involuntary responses to stimuli

Instincts: stereotyped responses triggered by environmental stimuli

Learning: a relatively permanent change in behavior due to experience

Learning is traditionally divided into three categories: associative, nonassociative, and observational. More than one type of learning can operate simultaneously in the same situation.

Associative learning occurs when we form associations, or connec­tions, among stimuli and/or behaviors. Associative learning helps us to pre­dict the future based on past experience. In other words, if A happens, then B is likely to follow. The ability to anticipate the future provides enormous survival advantages, as animals gain time to prepare. Psychologists who have study learning describe two types of associative learn­ing: classical conditioning and operant conditioning. In classical conditioning, we form associations between pairs of stimuli that occur sequentially in time. If a child sees a bee for the first time and then gets slung, the child will form a connection between seeing bees and the pain of being stung. The next time a bee flies by, the child is likely to feel quite frightened. In operant conditioning, we form associations between behaviors and their consequences. If you study hard, you will get good grades. We will discuss each of these forms of associative learning in more detail in later sections.

Nonassociative learning involves changes in the magnitude of responses to a single stimulus rather than the formation of connections between stimuli. Two important types of nonassociative learning are habituation and sensitization. Habituation reduces our reactions to repeated experiences that already been evaluated and found to be unchanging and harmless. For example, you might sleep much better the second night than the first in the same hotel, because you have adapted to the new noises in that environ­ment. Sometimes, we habituate to things that we should, ideally, still be noticing. A major concern about exposing children to violent media is the possibility that their emotional responses to violent images will habituate, leading to higher tolerance for violent behavior.

In contrast to habituation, sensitization increases our reactions to a wide range of stimuli following exposure to one strong stimulus. Following an earthquake, people often experience exaggerated responses to move­ment, light, or noise. If you are awakened by a loud crash, even if you figure out it's just your roommate coming home late at night, it might be harder to get back to sleep due to your suddenly increased state of arousal. Every little sound now seems magnified.

In general, habituation occurs in response to milder stimuli, whereas sensitization occurs in response to stronger stimuli. Habituation ensures that we do not waste pre­cious resources monitoring low-priority stimuli. Sensitization is particularly useful in dangerous situations. After detecting one harmful stimulus, raising our overall level of responsive­ness should improve reaction time should other dangers arise.

Observational learning (also known as social learning or modeling), occurs when an organism learns by watching the actions of another. If your knowledge of table manners does not extend lo the many forks, knives, and spoons at a very fancy dinner, you might want to watch what others do before diving into your own food. Observational learning provides the advantage of transmitting information across generations wiihin families and cultures.