Introduction to Psychology – Interim exam 4

The motor system includes the components of the central and peripheral nervous system along with the muscles, joints and bones that enable movement. Motor control is the study of how body movements are planned by the brain and performed by the body. Woodworth stated that there were two phases: an impulse phase in which the brain calculates the necessary movements and a control phase where vision is the key to accuracy.

The degrees of freedom of a joint is the number of ways it can move. The degrees of freedom problem refers to the choice of how to move the body when there are countless possible ways to do so. There are several theories of movement planning:

1. Equilibrium point hypothesis (mass-spring model)
   This is a theory of motor control that emphasizes how the problem of control can be simplified by taking into account muscle properties. The muscle tension determines the movement. If one muscle increases tension, another muscle decreases tension (because most muscles are arranged in an agonist/antagonist system) and this causes the correct movement.
2. Dynamical systems
   Muscles and joints work together in a certain way. Movement is determined by the physical properties of the body (e.g: the difference between walking and running is determined by speed and transitions automatically). The dynamical systems cause movement to be performed correctly.
3. Optimal control theory
   This is a theory of motor control that states that movement that is the most efficient and the most optimal is selected. The most efficient movement is the movement that causes the least amount of torque change at the joints. This system uses forward models. This predicts the relationship between actions and their consequences. The body tries to predict sensory feedback (e.g: we can type relatively quickly and this wouldn’t be possible if we didn’t predict feedback, because we move too quickly to first process it and then act according to the perceived feedback). The control policy provides a set of rules that determine what to do given a particular goal. It takes as input the current state estimate and has a motor command as output. Aspects of the control policy seem to be located in the basal ganglia.

The associative chain theory states that the end of one particular action is associated with stimulating the start of the next action in the sequence, much like a chain. This theory explains how sequences of action arise from linking together associations between individual action components. This theory becomes problematic when one action has to produce multiple other actions. Langley stated that there is a hierarchy of actions, most clearly shown in language production and speech. Parallel processing is the ability to divide the process of solving a problem into multiple parts and work simultaneously on each part. Estes states that each node of the hierarchy corresponds to a particular action schema.

The use of hierarchical structures becomes problematic when explaining how currently desired units can be activated whilst others can be suppressed (e.g: when opening a locker, you don’t need to close the locker while you are taking things out of the locker). This is explained using recurrent networks. These are a type of artificial neural network with connections between units arranged so to obtain a cycle of activation. This design allows a temporal context to be designed into the computation. In this hierarchy, patterns of activation and inhibition work in a manner of interactive activation. This is a term used to describe the pattern of network activity generated by excitatory and inhibitory interactions of feature detectors and object representations (e.g: when one unit of the schema is activated, the other units at the same level are inhibited).

The frontal cortex is responsible for action planning. Apraxia is a neurological condition typically resulting from brain damage where a person loses the ability to perform activities that they are physically able and willing to do. Ideomotor apraxia is the inability to pantomime tool use and gesture when verbally instructed to do so.

The term cognitive sandwich describes the view that perception and action are like slices of bread that surround cognition. The ideomotor theory relates how thinking about the results of action can give rise to producing the action. Common coding is a theory of perception and action production which holds that both production and perception share certain representations of actions in the world. Planning of action happens automatically when you see something. This is common coding. The perception is tied closely to action planning.

There are several consequences of common coding.

1. Interference when production and perception use the same resources.
2. 1/3 power law of drawing
   We perceive things the same as movement changes.
3. People are quicker to recognize themselves perform actions than others.

Mirror neurons are neurons with the special property that they represent both the sensory aspects of perceiving actions as well as motor aspects of how to produce the actions. Mirror neurons exist in the frontal and parietal parts of the brain in monkeys. In humans, it is unclear where the mirror neurons exist, besides the parts homologous to the monkeys. One possible function of mirror neurons could be providing access to the goal of the movement. Another possible function of mirror neurons is imitation and learning motor actions from visual models. Motor primitives are the basic set of elemental movements that serve as building blocks for an animal’s repertoire of movements.

In the embodied view of cognition, perception and action are intimately connected. One consequence of embodied cognition is that we organize our environment in such a way to decrease the cognitive load. Gestures can convey a message, even without words. Gestures can be seen as a simulated action or simulated speech. One theory states that gestures result because ideas are being simulated in terms of perceptual and motor properties, regardless of whether the idea is about something physically spatial or only metaphorically spatial.

Decision making is the cognitive process of choosing between alternative possible actions. The normative approach to decision making attempts to establish ideal ways of deciding what will give the best decision possible. Descriptive approaches aim to describe how decisions are actually taken as against how they should be made. A risk in decision making is the possibility of a negative outcome. A riskless decision involves choices where the outcomes of the choices are known with certainty. Single attribute decision problems involve alternatives that vary in only one dimension. The multi-attribute decision problem is a decision task in which the alternatives vary in many dimensions or aspects. The expected value is the long-term average value of a repeated decision, which is determined by probability and the size of the outcome.

The expected value theory works like a charm for decisions that involve money, but it does not comply with human behaviour. Human behaviour seems to follow risk aversion. This is avoiding risky choices even when a higher expected value than riskless alternatives. Risk seeking is a preference for risky choices even when riskless alternatives of a higher value are available. Risk aversion is mostly used when choices are phrased positively. Risk seeking is mostly used when choices are phrased negatively. Utility is the subjective value of an option. Subjective probability is how likely a person believes an outcome to be irrespective of the objective probability.

The prospect theory is a decision theory stressing relative gains and losses (e.g: 10$ means more to a poor person than to an extremely rich person). This theory uses loss aversion. This is that there is a greater dislike of losing utility than liking for gaining the same degree of utility (e.g: losing $10 would feel worse than winning$10 would feel good). Loss aversion is shown in the endowment effect, the tendency to over-value a possessed object and to require more money to sell it than to buy it in the first place (e.g: people don’t want to sell something precious to them for the price which they bought it for). The status quo bias is a tendency to prefer the current state of affairs and this also shows loss aversion.
Objective probabilities are transformed into subjective probabilities, also called decision weights. People tend to overweight small probabilities (e.g: the chance of dying because of a shark attack) and underweight big probabilities (e.g: the chance of dying because of heart disease). Framing effects in decision making occur when irrelevant features of a situation affect the decisions that are made (e.g: something being described positively or negatively). Invariance is the principle that choices should not be affected by how the options are described.

There are two major probabilities often used in making probability judgements:

1. Availability heuristic
   Things that come to mind more quickly are thought to occur more often.
2. Representativeness heuristic
   Representative or typical instances tend to be judged more likely to occur than unrepresentative instances.

The conjunction fallacy is the mistaken belief that the conjunction of two events is more likely than either one of A and B. The extension rule states that if the extension of a set, A, includes the extension of a set, B, then the probability of A must be greater than or equal to the probability of B. Frequencies can correct thinking in conjunction tasks. The base rate of an event is the overall probability of the event in a population.

An affect heuristic involves substituting feelings for target attributes in decision problems. People tend to form emotional responses to the initial component to which they were exposed. People with damage to the ventromedial frontal cortices of the brain don’t have emotional responses to risky decision options which warn them of danger.

The multi-attribute theory (MAUT) states that when considering two options an expected value (but then with weights instead of money) table should be made. There are, however, also other options. MAUT requires a lot of cognitive effort. When someone uses elimination by aspects, one aspect is chosen and all options that did not meet some criterion level are eliminated (e.g: all holidays above a certain price). This is a cognitively less demanding procedure than MAUT. Satisficing is a technique where the first option that meets the set criteria is chosen. The MAUT approach is a compensatory technique (e.g: a good rating on one thing can compensate a bad rating on another) and the other approaches are not compensatory. When choices are difficult, people tend to use a more demanding approach to the decision.

The two-system approach to thinking states that there are two modes of thought. System 1 is a hypothetical system that carries out rapid intuitive thinking. System 2 is a hypothetical system that carries out deliberate thinking. System two will be more involved in careful analytical decision making that seeks to combine many types of information in a rule-governed procedure. System 1 will be more involved in decision making based on heuristics and biases.

Fast and frugal heuristics are heuristics that are fast and easy to execute as they require little effort. The recognition heuristic is a heuristic where the choice is based on something you recognize. Too much knowledge of a domain can make a heuristic unworkable.

Consequentialism states that choices are being made based on the possible consequences of an action. There are heuristics that oppose the consequentialism, such as ‘do not harm’ or ‘fairness’. In terms of consequences, omission and commission can have the same results, yet people tend to go for the omission, because it is easier to do nothing than to do something. Doing nothing makes sure that people don’t feel responsible for their actions. This is called the omission bias. Most people also see punishment as a mean for retribution, not thinking of the consequences. Sometimes consequentialism is breached because of the fairness heuristic, simply because something is not fair.

Naturalistic decision making refers to making real-life decisions in the field (e.g: in case of an emergency). Critical incident analysis is gaining information about naturalistic decision making by analysing detailed recalls of recent important decisions. Recognition primed decision was most common in naturalistic decision making. This is expert knowledge-based decision making in which cues in the situation are recognized as indicating particular actions (e.g: a firemen sees a cue for an explosion and immediately flees). Real-life decision making by experts do not actually involve conscious decision making between alternatives and is more of a ‘one-option’ decision making.

Neuroeconomics is the study of neural processes underlying economic decisions. Animal study shows that decisions that activate the reward system more are preferred over decisions that activate the reward system weakly. Activity in dopamine neurons is linked to reward size. Choices of delayed rewards are governed by the lateral prefrontal cortex. Short-term decisions are driven by the limbic system.

Old people make poorer financial choices than middle-aged people, although old people have more experience, because of the decline of cognitive functioning. This can be related to the decline of fluid intelligence over the years. Old people are generally also more positive and this also changes the decisions they make. Young people felt worse after anticipating a loss and showed more activity in the insula than older people.

When making decisions under uncertainty, people tend to be influenced more by perceived risk than by objective risk. Consumers may benefit from greater awareness of how even important choices about taking out loans may be swayed by presentational factors which are irrelevant to making good decisions.

Syntax refers to the rules governing the ways words can be combined to create meaningful sentences. Content words are words that provide meaning to the sentence. Language production refers to a number of processes by which we convert thought into language output, in the form of speech, sign language or writing. Social cognition refers to the ways in which people make sense of themselves and of others in order to function effectively in a social world. Speech production proceeds in a top-down manner, also known as conceptually driven.

Language is important for information sharing and promoting social interaction. Language can be used through writing and speech. Mental lexicon is our store of knowledge about words and their uses. Linguistic universals are linguistic features said to be found in all languages. There are several linguistic universals, such as consonants, vowels, negatives, questions and so on. Tonal languages are languages that use changes in tone to alter the meaning of the word, in addition to vowels and consonants. Hockett’s design features for human language consists of a set of properties. Some are shared with animals, but only human language uses the full set. It includes things such as rapid fading, interchangeability and feedback. Functional reference refers to the use by animals of a specific call to stand for a specific object or threat.

Language is a structured system which uses a finite set of sounds to construct words, sentences and conversations. There are several components of language:

1. Phonemes
   Phonemes are the basic sounds that makeup speech within a language. Phones are the basic speech sounds. Phonemes are the smallest meaningful sound unit within a language. Allophones are different phones that are treated as the same phone within a language. The reduction in discrimination between allophones may serve to reduce the ambiguity in the incoming speech signal. Phonotactic rules describe which sounds can go together in a given language.
2. Morphemes
   Morphemes are the meaning units of a language. A free morpheme is a morpheme that can stand alone as a word and a bound morpheme is a morpheme that cannot form a word on its own, but forms a word when attached to a free morpheme. Content words can be changed by adding a morpheme as suffix or prefix (e.g: dependence becomes independence by adding the morpheme prefix ‘in’). Function words provide a grammatical structure that shows how content words relate to each other within a sentence.
3. Semantics and the lexicon
   A word is the smallest unit of grammar that can be meaningfully produced on its own. It can consist of one or more morphemes. Semantics refers to the meaning of words and morphemes and the relationship between the words we use and the object they refer to in the world.
4. Syntax
   The productivity of language refers to the ability to generate novel utterances (e.g: people can create new sentences). Syntax describes the rules that determine the construction of phrases, which is a group of words referring to a particular idea. Slang describes an informal pattern of speech that is considered to be non-standard. Syntax describes descriptive grammar, how language is used and not prescriptive grammar, how language should be used. Sentences follow a hierarchical structure and are made up of the noun phrase and the verb phrase. Recursion refers to the ability to extend sentences infinitely by embedding phrases within sentences (e.g: sentences can become as long as you like as long as the syntax is correct).
5. Discourse
   Discourse refers to multi-sentence speech and includes dialogue, conversation and narrative. Pragmatics refers to the understanding of the communicative function of language and the conventions that govern language use. Linguistic competence is our ability to construct sentences and communicative competence refers to our ability to communicate a message effectively and is driven by social conventions. Conversations are not possible when the participants don’t follow implicit social conventions.

There are strong universals in turn-taking patterns across languages and suggest a common pattern whereby the gaps between turns, and overlaps, are minimized. Grice described four conversation rules or maxims:

1. Maxim of quantity
   The speaker should provide enough information in order to be understood, but not too much information.
2. Maxim of quality
   The speaker should provide accurate information.
3. Maxim of relevance
   The speaker should provide information that is relevant to the current topic of conversation.
4. Maxim of manner
   Ambiguity and vagueness should be avoided.

If the maxims are violated, more cognitive processing is required to determine the response. Violation of the maxims provides the basis of humour (e.g: sarcasm is the violation of the maxim of quality). Connotations refer to the non-literal aspects of word meaning and reflect social and cultural factors that affect the literal processing of word meaning.

Aphasia is the term given to a group of speech disorders that occur following brain injury. Disfluency is hesitation or disruption to the normal fluency of speech. Dysfluency is an abnormal disruption to fluency as a result of brain damage. About 6 in 100 words are affected by disfluency. The use of pauses varies with context, task demands and from individual to individual. A clause is a part of a sentence containing a subject and verb. If people want to find out whether someone is lying, it is better to look at the speech than at other cues.

Parapraxes are slips of the tongue or other actions originally thought to reflect unconscious motives. Errors rarely jump across phrase boundaries. Morpheme exchange mostly happens within clauses. The lexical bias refers to the tendency for phonological speech errors to result in real words. Syntax has a large influence in speech errors, as content words get exchanged with content words, function words with function words and so on.

The tip of the tongue state is a temporary inability to access a word from memory. In the TOT state, the target word is a known word. A feeling-of-knowing is a subjective sense of knowing that we know a word and is an example of meta-memory. Bilinguals produce more cross-language intrusion errors when using their non-dominant language, while very few intrusions occurred when they spoke in the dominant language.

There are a number of stages to speech production:

1. Conceptualization
   The process by which a thought forms and is prepared to be conveyed through language.
2. Formulation of the linguistic plan
   In this stage, the concept or proposition must be translated so that the thought becomes language.
3. Articulation of the plan
   In this stage, the sounds of the word are accesses and the motor program for speech output is planned and articulated.

A lemma is an abstract word form that contains syntactic and semantic information about the word. A lexeme is the basic lexical unit that gives the word’s morpho-phonological properties.

Garret’s model is a serial theory. Serial theories propose that speech production progresses through a series of stages or levels, with different types of processing being completed and each level. According to Garret’s hierarchical model, speech is produced via a series of stages, proceeding in a top-down manner. According to this model, speech production consists of five steps:

1. Conceptual/inferential level
   The meaning to be conveyed is selected
2. Functional level
   Content words are selected and assigned to syntactic roles
3. Positional level
   Content words are placed in order and function words are selected
4. Phonological level
   Speech sounds are selected
5. Articulation level
   Sounds are prepared for speech

This model does not predict errors that occur across levels. Non-plan internal errors occur when the intrusion is external to the planned content of the utterance (e.g: saying something wrong, because you happen to see it right now). Levelt’s model consists of six stages:

1. Conceptual preparation
   The process leading up to the activation of a lexical concept.
2. Lexical selection
   A lemma or abstract word is retrieved from the mental lexicon. All related items are activated.
3. Morphological encoding
   Once the lemma is selected, morphemes are selected. TOT’s can occur here, because the lemma is available, but not yet the phonological form.
4. Phonological coding
   Syllables are computed here.
5. Phonetic encoding
   The sounds are selected.
6. Articulation
   The speech is made ready for output.

There is monitoring until the sixth stage. This model explains errors as the failure of monitoring. Dell’s model uses the concept of spreading activation in a lexical network to show how competing activation across different levels might predict speech errors. Processing is interactive in this model and processing is parallel. There are four levels in Dell’s model: semantic level, a syntactic level, a morphological level and a phonological level. Lexical access involves six steps:

1. Semantic units are activated by an external source.
2. Activation spreads throughout the network
3. The word unit with the highest level of activation if selected and linked to the syntactic frame for the sentence.
4. The phonological information is activated.
5. Activation continues to spread, but phonological units linked to the selected word become more highly activated.
6. The most active phonological units are selected.

Word substitutions occur because a semantically related, but incorrect, choice achieves a higher activation than the target word.

Neurolinguistics is the study of the relationship of brain function to language processing. The lateralization of function refers to the asymmetric representation of a cognitive function in the cerebral hemispheres of humans and higher primates. Language is processed on the left and spatial processing is on the right. When a cognitive function is lateralized, one cortical hemisphere is dominant for that function. The dichotic listening task is one where different stimuli are presented to each ear. There is a right-ear advantage for verbal stimuli. The right hemisphere is involved in the emotional aspects of speech, prosody and aspects of non-literal speech.

The Wernicke-Geschwind model is a simplified model of language function used as the basis for classifying aphasia disorders. It notes a number of key areas for language. The model proposes that we repeat a heard word by processing of the following sequence of brain areas. Following processing of the word in the auditory cortex, information about word meaning is processed in Wernicke’s area and the output is sent to Broca’s area. Broca’s area prepares the speech output and a motor program for output is then articulated via the motor cortex.

Aphasia refers to a language deficit as the result of brain injury. Crossed aphasia refers to language dysfunction following right hemisphere damage in a right-handed individual. Aphasic disorders can be classified according to whether they are fluent, non-fluent or pure. In pure disorders, a particular facet of language is affected, while other language functions remain intact. The fluent disorders are characterized by fluent, but meaningless speech and the non-fluent disorders are characterized by non-fluent, but meaningful speech. There are several types of aphasia:

1. Broca’s aphasia
   This is an acquired language disorder characterized by non-fluent speech, reduced speech output and problems with grammar processing. Patients with Broca’s aphasia often also show telegraphic speech.
2. Global aphasia
   This is an acquired language disorder involving extreme impairment of language function.
3. Non-fluent aphasia
   This is aphasia when the patient’s speech output is reduced, laboured or absent.
4. Wernicke’s aphasia
   This is fluent aphasia, characterized by fluent, but meaningless output and repetition errors.
5. Fluent aphasia
   Aphasia when the patient’s speech is fluent, but not meaningful.
6. Conduction aphasia
   This is aphasia when the patient has a specific difficulty affecting the repetition of speech. This occurs when the connection between Broca’s area and Wernicke’s area is damaged, called the arcuate fasciculus.
7. Anomic aphasia
   This is aphasia when the patient has a specific difficulty with word retrieval. Patients with this know the meaning of words, but seem to experience a TOT state a lot.

Writing requires access to the orthographic form of a word rather than its phonological form. Composition is a process by which ideas are turned into symbols. The Hayes and Flower model of writing proposes a cognitive model of writing that focuses on three main domains affecting the writing process: task environment, long-term memory and the immediate cognitive aspects of the writing process. They also propose three general stages of writing: planning, translating and reviewing.

Emotion refers to a number of mental states that are relatively short-lived and are associated with an eliciting event. There are four key features of emotions:

1. Emotions are bounded episodes elicited when an event occurs that is of relevance to the organism’s needs, goals or well-being.
2. Emotions prepare the organism to act so as to deal with an event.
3. Emotions affect most or all bodily systems.
4. Emotions establish control precedence over behaviour.

Emotions provide us with essential feedback on the execution of our plans relative to our goals. Emotions have not been studied a lot, because it was first seen as irrational and it is difficult to study. The amygdala (fear), the orbitofrontal cortex (anger) and the cingulate cortex (sadness) are involved in emotions. The insula has been linked to disgust. The default network is a network of brain regions that is active when the person is not focused on the external environment. The salience network is involved in monitoring the external and internal environment to allow detection of salient stimuli.

Emotions are to some extent culture-dependent. Display rules are social conventions governing how, when and with whom emotions may be expressed in society. There are core emotions that are universal. The core emotions are anger, disgust, fear, happiness and sadness. Emotional leakage refers to the unintended expression of emotion or a failure to mask emotion. Masked emotions are associated with more inconsistent expressions and an increased blink rate. The emotional responses someone has when depressed is culturally determined, as being depressed also means not being able to regulate the emotional expression in line with the cultural norms.

Clore and Ortony propose that human emotions are characterized by four components:

1. Cognitive
   Mentally register the significance of the emotion. Appraisal refers to the ways in which people interpret or explain to themselves the meaning of events.
2. Motivational-behavioural
   Our actions in response to the emotion.
3. Somatic
   This involves the autonomic nervous system, which regulates internal organs and the central nervous system, which consists of the brain and the spinal cord. The characteristic of the somatic part of emotion is the physiological responses that occur along with emotion.
4. Subjective-experiential
   This involves the personal experience of the emotion.

There are several theories on the relationship between emotion and cognition. There are two early theories of emotion and cognition:

1. James-Lange theory
   This theory holds that the experience of emotion follows the physiological changes associated with that state. An emotion arises from bodily feedback. Emotion is the perception of bodily changes. The facial feedback hypothesis proposes that feedback from the facial muscles can influence emotional state.
2. Cannon-Bard theory
   This theory holds that the emotional experience and the physiological changes arise concurrently from the stimulus events. The two events are independent.

The catharsis myth is the mistaken idea that aggressive behaviour is an effective means of reducing aggressive feelings. There are also other theories of emotions, based on the James-Lange and the Cannon-Bard theories:

1. Two-factor theory
   This theory holds that two factors create emotion. Physiological arousal and our interpretation of it (e.g: if we see a bear we have the physiological arousal of fear, but our interpretation of the situation causes us to feel the emotion fear). This theory states that physical arousal is necessary in order to feel an emotion.
2. Affective-primacy: Zajonc’s theory
   This theory holds that cognition is not necessary for emotion. Cognition can influence emotion at a later stage of processing, the initial emotional response can be unaffected by cognition. The mere exposure effect refers to the tendency for people to develop a preference for a stimulus with repeated exposure to it. This effect shows that people can develop a preference (some sort of emotional response) without cognition. This theory refers to cognition as conscious cognition.
3. Cognitive primacy: Lazarus’s theory
   This is an appraisal theory, a theory that states that emotions result from our interpretations of, or reactions to, events. This theory holds that cognitive appraisal is fundamental to emotional experience and that you cannot separate out the cognitive aspect of the emotion. He suggested three types of cognitive appraisal: the primary appraisal is an initial assessment of a situation, the secondary appraisal involves an assessment of the resources we have available to us in dealing with the particular situation and reappraisal involves continual monitoring the situation until it’s resolved.

The multi-level theories of emotion propose that both preattentive and conscious cognitive processes are involved in emotion. This states that sometimes we feel an emotion before cognition and sometimes we feel emotion after cognition.

Emotions have an effect on cognition. Attentional bias refers to the tendency for emotional stimuli to capture or draw attention. Emotional content is likely to draw the attention of an individual. This has been demonstrated in the emotional Stroop task. The visual search tasks require an active search of a visual array, usually for a particular object or stimulus feature. Pre-attentive visual search is faster for emotional information compared to neutral information.

Presence of an emotional stimulus heightens contrast sensitivity in perception. Emotion also increases an individual’s field of view. Emotion has an influence on perception.

Memory for emotional events is generally better than for events that do not arouse emotions, but these memories are not error-free. Extreme emotions can have a negative effect on cognition. There is a confidence-accuracy disparity. Confidence is not a useful predictor for the accuracy of a memory. The most common error in memory recall is source error. People tend to misattribute the source of information. The best predictor of later recall accuracy was the strength of the emotional response of the person at the time of the event. Self-monitoring describes the extent to which a person is concerned with self-presentation and how others perceive them. The idea of encoding specificity refers to the idea that memory is facilitated when there is overlap between the conditions at encoding and those at retrieval. Tunnel memory refers to the enhancement of memory of central details with reduced memory for peripheral details. This effect mostly applies to negative events.

Mood congruency refers to the tendency to recall events consistent with the current mood state. This effect is often explained in terms of network models. Network models of memory treat memories as items related in a network which can affect each other through activation. State-dependent memory refers to the facilitation of memory when the mental or physiological state at encoding and retrieval matches. Emotion-congruent memory is stronger for positive emotions than for negative emotions. This does not fit with a network model. Thought congruity is the tendency for thoughts and judgements to be consistent with mood state.