Tipultech logo

Approach and avoidance motivation

Author: Dr Simon Moss


The distinction between approach and avoidance motivation has been applied to explain a variety of interesting phenomena. For example, when individuals attempt to highlight their qualities, rather than conceal their deficiencies, during social interactions, their satisfaction with the conversation rises (e.g., Srachman & Gable,2006). In addition, when individuals press upwards from below a table, their creativity tends to improve (e.g., Friedman & Forster,2002).

Organisms have evoled to aproach pleasurable opportunities and to avoid painful experiences. These two broad motivations are referred to as approach and avoidance motivation and are both considered vital for survival (Elliot, & Covington, 2001). For example, avoidance manifests itself in the startle, salivary, and blink reflex, and has been examined even in single celled organisms that withdrawe from intense light (see Elliot & Covington, 2001, for a review). Avoidance appears to have evolved, therefore, to protect organisms from harm. In contrast, the approach system is more closely related to hedonistic activities, such as the consumption of food and sexual pleasure. Such activities promote the growth of organisms.

Consequences of approach and avoidance motivation

Evaluations of products

As Labroo and Nielsen (2010) showed, after individuals approach a negative outcome, they evaluate this alternative more positively. In one study, participants were exposed to a can of red curry grasshopper--a product that most individuals perceive as aversive. Some individuals were told to imagine pulling the object towards themselves, representing approach. Some individuals were told to imagine pushing the object away, representing avoidance. Furthermore, some respondents were told to consider five benefits of this product, a form of approach that does not involve a physical movement.

Participants were then asked to evaluate the extent to which they perceive the product as desirable and the amount of money they would pay to purchase this can. As hypothesized, when participants imagined pulling the object towards themselves, they were more inclined to evaluate the product favorably and pay a sizeable amount. Presumably, this approach movement is associated with reward--and this sense of reward biases evaluations.

Consistent with this conclusion, if participants were also informed that physical movements can bias evaluations, they perceived the can as aversive even after they imagined pulling the object towards themselves. That is, they were able to correct this bias. Merely listing the benefits of this product, however, did not improve evaluations.

Mathematics performance and attitudes

As Kawakami, Steele, Cifa, Phills, and Dovidio (2008) showed, if people learn to associate mathematics with an approach motivation, their mathematics abilities and attitudes improve. To illustrate, in one study, a series of images appeared on a screen. These images related to either mathematics, such as calculators and equations, or arts, such as guitars or poetry. Some participants were told to press a joystick towards themselves whenever images that relate to mathematics appeared and to press the joystick away from themselves otherwise. Because people tend to shift positive items towards themselves, this movement epitomizes approach instead of avoidance. These participants, therefore, should learn to associate mathematics with approach. In the control condition, participants were told to press a joystick away from themselves whenever images that relate to mathematics appeared and to press the joystick towards themselves otherwise.

Next, participants completed an implicit association task to assess their attitudes towards mathematics. In particular, this task gauges the degree to which people associate mathematics with either positive words, such as happy, or with personal pronouns, such as me or myself. Participants who shifted the joystick towards themselves in response to mathematics symbols were, subsequently, more likely to exhibit positive attitudes towards mathematics. This pattern of findings, however, was observed only in participants who previously did not perceive themselves as mathematical.

The second study replicated these findings. In addition, this study showed that associations between mathematics and approach motivation also enhanced persistence and performance on a subsequent mathematics quiz.

Conflict between approach and avoidance motivation

In most studies, researchers compare the consequences of an approach motivation with the consequences of an avoidance motivation. Fewer studies have explored the consequences that unfold when both an approach and avoidance motivation are primed simultaneously. Conceivably, when both of these motivations are primed concurrently--or when both of these motivations are inhibited concurrently--people feel uncertain how to proceed. As this sense of certainty diminishes, their motivation and persistence may decrease as well.

Robinson, Wilkowski, and Meier (2007) uncovered some evidence that a conflict between an approach and avoidance motivation impairs certainty and motivation. Relative to introverted individuals, extraverted individuals are more likely to adopt an approach motivation. In addition, compared to people who seem emotionally stable, individuals who report elevated levels of neuroticism are more likely to adopt an avoidance motivation. Therefore, if people exhibit high levels of both extraversion and neuroticism, they should experience an approach and avoidance orientation concurrently, compromising certainty and motivation. Likewise, if people report low levels of extraversion and neuroticism, they should experience neither of these orientations, also translating to uncertainty.

Consistent with these arguments, when people exhibited high levels of both extraversion and neuroticism--or low levels of both extraversion and neuroticism--their certainty and motivation was compromised. They seemed more anxious during an interview. They behaved less assertively. And their performance on a go-no go task was impaired, reflecting an inability to differentiate stimuli that are relevant to their goals from stimuli that are irrelevant.

Neural underpinnings

Behavioral measures

The approach and avoidance systems are associated with a distinct profile of brain regions and emotional states, facilitating different behavioural outcomes. For example, Friedman, and Forster (2005) examined the effects of priming approach and avoidance motivation. Their participants completed one of two tasks. One task involved completing a maze where the goal was to help a mouse approach a piece of cheese. The alternative task was exactly the same, but the goal was framed differently: the goal was to complete the maze to rescue the mouse from an owl. After completing either task, participants completed another activity in which they were required to identify the centre of a horizontal line. Participants who completed the approach tasks, were more inclined to perceive the centre toward the left hand side of the line, which is more indicative of right brain hemispheric activation. In contrast, the avoidance task was associated with increased left hemispheric activation.

According to Fiore and Scholler (1998), the right brain hemisphere perhaps evolved to overcome the constraints or limitations of the left hemisphere. For example, the left hemisphere might facilitate the focus on immediate, concrete details, partly to identify potential threats, and is characterised by localized processing and negative affective states (Derryberry & Reed, 1994). The right hemisphere, in contrast, is associated with creative thought, perhaps to facilitate growth, and is characterized by global processing and positive affective states (Forster & Higgins, 2005 & Friedman & Forster, 2005).

An approach motivation tends to be associated with activation of the left, instead of the right, hemisphere especially when time is limited. For example, in one study, reported by Roskes, Sligte, Shalvi, and De Dreu (2011), either an approach motivation or an avoidance motivation was activated. Specifically, participants completed a computer task in which they shifted a mouse through a mazed. To evoke an approach motivation, their task was to locate the cheese. To evoke an avoidance motivation, their task was to escape an owl that was hovering nearby. Next, they were asked to bisect a series of 8 lines and granted either 1.5 or 4 seconds to complete this task.

If an approach rather than avoidance motivation was elicited, participants tended to bisect the lines towards the right, reflecting considerable activation of the left hemisphere. This tendency was observed, however, only when participants were granted merely 1.5 seconds to bisect the lines. Presumably, when time is not limited, participants can override their natural association between an approach motivation and left hemispheric processing.

EEGs and neuroimaging

EEG measures confirm the proposition that approach motivation corresponds to the left hemisphere and avoidance motivation corresponds to the right hemisphere. This proposition evolved from previous studies, which seemed to show that positive emotions are underpinned by the left hemisphere and negative emotions are underpinned by the right hemisphere.

To illustrate, in one study, conducted by Tomarken, Davidson, and Henriques (1990), participants watched films, intended to evoke various emotions. EEG patterns revealed that activation was higher in the left hemisphere when positive emotions were evoked. In most participants, activation was higher in the right hemisphere when negative emotions were evoked--as gauged by elevated levels of alpha power (8-13 Hz band) in the left hemisphere, which is inversely related to cortical activity (see also Davidson, Ekman, Saron, Senulis, & Friesen, 1990).

Nevertheless, further studies challenged the proposition that positive emotions coincide with activation of the left hemisphere and negative emotions coincide with activation of the right hemisphere. To illustrate, anger, which is a negative emotion, but often evokes an approach motivation, usually coincides with activation of the left hemisphere (Harmon-Jones & Allen, 1998;; Harmon-Jones, Lueck, Fearn, & Harmon-Jones, 2006). Similarly, worry, which is a negative emotion, but related to problems solving and thus possibly approach, also coincides with activity in the left hemisphere, as EEG studies verify (Heller, Schmidtke, Nitschke, Koven, & Miller, 2002).

Accordingly, the left and right hemisphere might correspond to approach and avoidance motivations respectively. Approach and avoidance motivation frequently, but not invariably, relates to positive and negative emotions respectively. Consistent with this proposition, Sutton and Davidson. (1997) showed that individuals who demonstrated preferential activation of the left hemisphere often exhibited a disposition to approach, but did not report more positive emotions. Likewise, individuals who demonstrated preferential activation of the right hemisphere typically exhibited a disposition to avoid, but did not report more negative emotional states.

Neuroimaging studies, using fMRI or PET, have confirmed this argument (see Murphy, Nimmo-Smith, & Lawrence, 2003). That is, approach motivation tends to be related to activation of the left hemisphere, where avoidance motivation tends to be related to activation of the right hemisphere. Nevertheless, in addition to hemispheric differences, other regions seem to differentially relate to approach and avoidance motivation. Approach motivation seems to coincide with activation of the medial prefrontal cortex as well as the nucleus accumbens (Wager, Phan, Liberzon, & Taylor, 2003). Avoidance motivation seems to coincide with activation of the amygdala and anterior cingulate cortex (Wager, Phan, Liberzon, & Taylor, 2003).

Antecedents to approach versus avoidance motivation

Availability of resources and confidence

According to Schnelle, Brandstatter, and Knopfel (2010), the key determinants of whether individual adopt an approach goal, like "I will attempt try to pass the exam", instead of an avoidance goal, like "I will try not to fail an exam", depends on the resources they can access. That is, sometimes, individuals can access many personal, social, and material resources to facilitate their performance. Personal resources include concentration, discipline, and skills. Social resources include support and advice from friends. Material resources include equipment, for example. When resources are scarce, the prospect of failure is amplified, and avoidance goals are more likely. When resources are abundant, this problem dissipates, confidence soars, and approach goals prevail.

Schnelle, Brandstatter, and Knopfel (2010) conducted several studies to examine and to verify this contention. In the first study, participants completed a measure that assesses the extent to which participants feel they can access resources, like family support, discipline, concentration, resistance to stress, and energy, relative to other university students.

Next, they completed a measure that specifies the degree to which they pursue various approach or avoidance goals at university. For example, participants were asked whether they want to "Get to know new fellow students" or "(Not) miss out on getting to know new fellow students". Similarly, they were asked whether they "want to be prepared for all the lectures" or "(Not) want to be unprepared for all the lectures".

As predicted, if participants reported access to more resources, like family support or concentration ability, they were more inclined to pursue approach rather than avoidance goals. The second study was similar, but assessed participants three times over four months as well as evaluated their level of neuroticism (see five factor model). Resources at one time predicted approach goals later, even after controlling neuroticism.

In the third study, resource availability was manipulated experimentally. In essence, participants were instructed to read about a student who could either access scarce or abundant resources. They were asked to consider life from the perspective of this student. For example, to emphasize that resources were limited, they were told she is unable to receive financial support from her parents, busy with other commitments, dubious about her studies, distracted by TV, and unable to concentrate effectively. To emphasize that resources were abundant, other participants were told that she did not experience these problems. Next, they were asked to specify the extent to which they would like to pursue various approach and avoidance goals.

Again, resource availability increased the likelihood of approach goals. Similar results emerged in the final study. In this stduy, availability of time was manipulated to prime scarce or extensive resources. This study showed that outcome expectancy--that is, expectation of success on a test of ability--mediated the association between resource availability and approach orientation.

Economic cycles

During times of economic contraction, an avoidance orientation is more salient. People are motivated to prevent losses and problems. In contrast, during times of economic growth, an approach orientation is more salient. People tend to be motivated to seek gain rather than to avoid problems.

To illustrate, in one study, conducted by Millet, Lamey, and Van den Bergh (2012), some participants imagined they were listening to a news bulletin that highlighted the economic contraction of recent times will endure over the next few years. The other participants imagined they were listening to a news bulletin that highlighted the economy would soon grow. Next, they were asked to indicate the degree to which they feel emotions that often coincide with avoidance, such as fear, and emotions that often coincide with approach, such as curiosity, interest, and eagerness. Images of economic contraction evoked feelings of fear and images of economic growth evoked feelings of curiosity. A second showed that images of contraction, but not images of growth, also diminished the willingness of individuals to gamble.

A final study showed that actual economic contraction over the last 80 years decreased gambling but increased the purchasing of insurance. When individuals attempt to avoid losses, they are more inclined to refrain from gambling but more inclined to seek security. These finding, therefore, are consistent with the premise that economic contraction evokes an avoidance motivation, consistent with the finding that recessions decrease the tendency of individuals to purchase expensive labels (Lamey, Deleersnyder, Dekimpe, & Steenkamp, 2007). They are also likely to prefer conservative parties during these periods.

Valence from effort

Individuals might learn to avoid actions that are difficult to implement. Task difficulty, therefore, might sometimes evoke an avoidance motivation

Specifically, Morsella, Feinberg, Cigarchi, Newton, and Williams (2010) proposed a hypothesis called valence from effort. According to this hypothesis, individuals have evolved to feel motivated to complete challenging goals but with minimal effort, primarily to conserve finite resources such as food. Therefore, they naturally associate challenging goals with positive states. However, they naturally associate difficult actions or means to achieve these goals, such as awkward maneuvers, with negative states.

To illustrate, as many studies have shown, challenging rather than easy or impossible goals are perceived as more desirable (e.g., Friedman, Tarpy, & Kamelski, 1968). For example, in one study participants needed to complete either an easy or difficult cognitive task to earn a sandwich. Hungry participants were especially likely to enjoy the sandwich if they had completed a difficult, rather than, easy task (Biner, Hua, Kidd, & Spencer, 1991).

Nevertheless, as Morsella, Feinberg, Cigarchi, Newton, and Williams (2010) showed, challenging rather than easy means or actions to fulfill a goal are perceived as undesirable. In one study, participants had to shift a rectangle from one location on a screen to another location on a screen, using a mouse pointer. When the rectangle was shifted, another shape or pattern was uncovered. Participants rated the extent to which they liked this shape or pattern.

In one condition, the pointer was difficult to maneuver, demanding considerable effort. In the other condition, the pointer was easy to maneuver, like a typical mouse. When the mouse was easier to maneuver, ratings of the pattern were more positive. Presumably, the seamless action evoked positive states, biasing perceptions of the pattern.

In a second study, on each trial, participants had to decide whether two shapes or patterns were identical, after they were rotated. Therefore, to complete this task, participants had to rotate these patterns mentally. In one condition, the shapes did not need to be rotated appreciably. In another condition, the shapes did need to be rotated considerably. Participants then rated the extent to which they like the figures.

If the shapes had to be rotated considerably, representing appreciable effort, participants were more inclined to specify unfavorable ratings. A difficult mental action, in this instance, seemed to evoke negative feelings.


When individuals experience anger, an approach motivation is more likely to be evoked. That is, anger is associated with an escalation of energy, mobilized to achieve some goal. For example, if people tend to associate a brand with anger or rage, such as an angry bull, they tend to be more inclined to purchase this product. That is, this brand elicits an approach motivation.

For example, in one study, conducted by Veling, Ruys, and Aarts (2012), participants were exposed to photographs of a novel notebook, paired with a person displaying either an angry or neutral expression, embedded within another task. Next, participants were informed they could take the notebook. Unbeknownst to participants, the notebook was fixed to a tray. The force that participants exerted to tug the notebook from the tray was recorded and was assumed to represent approach motivation. If the notebook was associated with an angry expression, people tended to tug harder.

The second study was similar besides four modifications. First, the advertised product was a bottle of water instead of a notebook. Second, to gauge approach motivation, participants indicated the amount of money they would pay to purchase this bottle. Third, the facial expressions appeared either visibly or subliminally. Finally, whether the bottle could be purchased was also manipulated& that is, only some participants were told they could purchase the water. Participants were inclined to pay more money for the bottle of water when the brand was associated with anger, rather than neutral expressions, but only if this product could be purchased. This pattern of observations was observed even when the expressions were presented subliminally--that is, too rapidly to be recognized consciously.

Individual characteristics

Many studies have shown that individual characteristics affect the likelihood that people will adopt an approach or avoidance orientation. In general, traits that orient attention to negative features of the environment, such as fear of failure (Elliot & Sheldon, 1997), behavioral inhibition (Elliot and Thrash, 2002 & see reinforcement sensitivity theory), and neuroticism (Elliot, Sheldon, & Church, 1997), evoke an avoidant rather than approach orientation.


Apart from the maze task, many other protocols have been introduced to manipulate these systems. For example, in some studies (e.g., Friedman & Forster,2002), participants are instructed to contract their biceps to prime an approach motivation and instructed to contract their triceps to prime an avoidance motivation. That is, biceps are contracted when individuals shift positive stimuli towards themselves, whereas triceps are contracted when individuals push negative stimuli away from themselves--and hence should represent approach and avoidance respectively. Consistent with this premise, bicep contraction is more likely than tricep contraction to enhance creativity, and this ability is assumed to manifest an approach motivation.

Furthermore, in some studies, participants are encouraged to highlight positive characteristics or conceal negative characteristics to prime approach and avoidance respectively. In a study reported by Srachman and Gable (2006), participants were instructed to either emphasize highlight their strengths orconceal their limitatins during social interactions. When instructed to highlight their strengths, participants were more likely to experience positive affective states, which tends to reflect an approach motivation (e.g., Srachman & Gable,2006).

Juxtapositions with other theories

Approach and avoidance seem to align with promotion and prevention focus, in the context of regulatory focus theory, as well as align with behavioral activiation and behavioral inhibition, in the context of reinforcement sensitivity theory. The principal differences amongst these dichotomies is merely the contexts in which they have been examined and the measures or manipulations that are applied.


Biner, P. M., Hua, D. M., Kidd, H. J., & Spencer, P. M. (1991). Incentive strength, need state, instrumental task difficulty, and the magnitude of goal valence. Personality and Social Psychology Bulletin, 17, 442-448.

Davidson, R. J. (1999). Neuropsychological perspectives on affective styles and their cognitive consequences. In T. Dalgleish & M. J. Power (Eds.), Handbook of cognition and emotion (pp. 103-123). New York: Wiley. .

Davidson, R. J., Ekman, P., Saron, C. D., Senulis, J. A., & Friesen, W. V. (1990). Approach-withdrawal and cerebral asymmetry: Emotional expression and brain physiology I. Journal of Personality and Social Psychology, 58, 330-341. .

Derryberry, D. & Reed, M. A. (1998). Anxiety and attentional focusing: Trait, state and hemispheric influences. Personality and Individual Differences, 25, 745-761.

Egloff, B., Weck, F., & Schmukle, S. C. (2008). Thinking about anxiety moderates the relationship between implicit and explicit anxiety measures. Journal of Research in Personality, 42, 771-778.

Elliot, A. J. (1999). Approach and avoidance motivation and achievement goals. Educational Psychologist, 34, 169-189.

Elliot, A. J. (2008). Approach and avoidance motivation. In A. J. Elliot (Ed.), Handbook of approach and avoidance motivation (pp. 3-14). New York: Psychology Press.

Elliot, A. J., & Church, M. A. (1997). A hierarchical model of approach and avoidance achievement motivation. Journal of Personality and Social Psychology, 72, 218-232.

Elliot, A. J. & Covington, M. V. (2001). Approach and avoidance motivation. Educational Psychology Review, 13, 73-92.

Elliot, A. J., Maier, M. A., Moller, A. C., Friedman, R., & Meinhardt, J. (2007). Color and psychological functioning: The effect of red on performance attainment. Journal of Experimental Psychology: General, 136(1), 154-168.

Elliot, A. J., & McGregor, H. A. (2001). A 2 X 2 achievement goal framework. Journal of Personality and Social Psychology, 80, 501-519.

Elliot, A. J., & Sheldon, K. M. (1997). Avoidance achievement motivation: A personal goals analysis. Journal of Personality and Social Psychology, 73, 171-185.

Elliot, A. J., & Sheldon, K. M. (1998). Avoidance personal goals and the personality-illness relationship. Journal of Personality and Social Psychology, 75, 1282-1299.

Elliot, A. J., Sheldon, K. M., & Church, M. A. (1997). Avoidance personal goals and subjective well-being. Personality and Social Psychology Bulletin, 23, 915-927.

Elliot, A. J., & Thrash, T. M. (2002). Approach-avoidance motivation in personality: Approach and avoidance temperaments and goals. Journal of Personality and Social Psychology, 82, 804-818.

Fiore, S.M., & Schooler, J.W. (1997). Right hemisphere contributions to creative problem solving: Converging evidence for divergent thinking. In. M. Beeman and C. Chiarello (Eds.) Right Hemisphere Language Comprehension (pp. 349-372). Hillsdale, NJ: Lawrence Erlbaum.

Forster, J. & Higgins, E. T. (2005). How global versus local perception fits regulatory focus. Psychological Science, 16, 631-636.

Friedman, H., Tarpy, R. M., & Kamelski, P. (1968). The preference of rats for a more difficult task. Psychonomic Science, 13, 157-158.

Friedman, R. S., & Forster, J. (2002). The influence of approach and avoidance motor actions on creative cognition. Journal of Experimental Social Psychology, 38, 41-55.

Friedman, R. S. & Forster, J. (2005). Effects of motivational cues on perceptual asymmetry: Implications for creativity and analytical problem solving. Journal of Personality and Social Psychology, 88, 263-275.

Harmon-Jones, E., & Allen, J. J. B. (1998). Anger and frontal brain activity: EEG asymmetry consistent with approach motivation despite negative affective valence. Journal of Personality and Social Psychology, 74, 1310-1316. .

Harmon-Jones, E., Lueck, L., Fearn, M., & Harmon-Jones, C. (2006). The effect of personal relevance and approach-related action expectation on relative left frontal cortical activity. Psychological Science, 17, 434-440. .

Heller, W., Schmidtke, J. I., Nitschke, J. B., Koven, N. S., & Miller, G. A. (2002). States, traits, and symptoms: Investigating the neural correlates of emotion, personality, and psychopathology. In D. Cervone & W. Mischel (Eds.), Advances in personality science (pp. 106-126). New York: Guilford Press.

Kawakami, K., Steele, J. R., Cifa, C., Phills, C. E., & Dovidio, J. F. (2008). Approaching math increases math=me and math=present. Journal of Experimental Social Psychology, 44, 818-825. doi:10.1016/j.jesp.2007.07.009

Labroo, A. A., & Nielsen, J. H. (2010). Half the thrill is in the chase: Twisted inferences from embodied cognitions and brand evaluation. Journal of Consumer Research, 37, 143-158.

Millet, K., Lamey, L., & Van den Bergh, B. (2012). Avoiding negative vs. achieving positive outcomes in hard and prosperous economic times. Organizational Behavior and Human Decision Processes, 117, 275-284. doi:10.1016/j.obhdp.2011.11.008

Morsella, E., Feinberg, G. H., Cigarchi, S., Newton, J. W., & Williams, L. E. (2010). Sources of avoidance motivation: Valence effects from physical effort and mental rotation. Motivation and Emotion35(3), 296-305.

Murphy, F. C., Nimmo-Smith, I., & Lawrence, A. D. (2003). Functional neuroanatomy of emotions: A meta-analysis. Cognitive, Affective & Behavioral Neuroscience, 3, 207-233.

Robinson, M. D., Wilkowski, B. M., & Meier, B. P. (2007). Approach, avoidance, and self-regulatory conflict: An individual differences perspective. Journal of Experimental Social Psychology, 44, 65-79.

Roskes, M., Sligte, D., Shalvi, S., & De Dreu, C. K. W. (2011). The right side? Under time pressure, approach motivation leads to right-oriented bias. Psychological Science, 22, 1403-1407. doi: 10.1177/0956797611418677

Schnelle, J., Brandstatter, V., & Knopfel, A. (2010). The adoption of approach versus avoidance goals: The role of goal-relevant resources. Motivation and Emotion, 34, 215-229.

Srachman, A., & Gable, S. L. (2006). What you want (and do not want) affects what you see (and so not see): Avoidance social goals and social events. Personality and Social Psychology Bulletin, 32, 1446-1458.

Sutton, S. K., & Davidson, R. J. (1997). Prefrontal brain asymmetry: A biological substrate of the behavioral approach and inhibition systems. Psychological Science, 8, 204-210.

Tomarken, A. J., Davidson, R. J., & Henriques, J. B. (1990). Resting frontal brain asymmetry predicts affective responses to films. Journal of Personality and Social Psychology, 59, 791-801.

Veling, H., Ruys, K. I., & Aarts, H. (2012). Anger as a hidden motivator: associating attainable products with anger turns them into rewards. Social Psychological and Personality Science, 3, 438-445. doi: 10.1177/1948550611425425

Wager, T. D., Phan, K. L., Liberzon, I., & Taylor, S. F. (2003). Valence, gender, and lateralization of functional brain anatomy in emotion: A meta-analysis of findings from neuroimaging. NeuroImage, 19, 513-531.

Academic Scholar?
Join our team of writers.
Write a new opinion article,
a new Psyhclopedia article review
or update a current article.
Get recognition for it.

Last Update: 5/22/2016