Maren, S. & Quirk, G.J. (November 2004). Neuronal Signalling of Fear Memory. Nature Reviews Neuroscience, 5, 844-850.
Plasticity within the CNS is necessary for the representation of new information, and can range from synthesis and insertion of synaptic proteins to whole-brain synchronization of neuronal activity. Pavlovian fear conditioning is an especially interesting phenomenon since such fear memories are acquired rapidly and are long-lasting. Research first noticed conditioning-induced changes in the midbrain, thalamus, and cortex; however, it was unclear whether or not these were primary sites of plasticity or were simply downstream from other plastic sites. Eventually the lateral nucleus of the amygdala (LA), receiving direct projections from the auditory thalamus, was posited to be vital for auditory fear conditioning. The dorsal subdivision of the nucleus (LAd) seems to be the first site in the auditory pathway to show associative plasticity that is not fed forward passively from upstream sites, is not dependent on downstream sites, and is crucial for conditioned behavior. And LA neurons appear to drive plasticity at both thalamic and cortical levels.
Fear memories are useful to anticipate and respond to dangers within the environment. However, when signals for aversive events no longer predict those events, fear to those signals subsides. This is an inhibitory learning process known as extinction. It appears that although fear subsides after extinction, the fear memory is not erased. Extinction seems to be highly context dependent and sometimes short-lived. Fear responses can be spontaneously recovered over time. It seems biology has deemed it better to fear than not to fear. It is more likely that additional memories which interfere with pre-existing excitatory responses are learned in the extinction process. Again the amygdala seems to be essentially involved here. Further, the mPFC, which has an inhibitory influence on both the LA and the CE (the main output regions of the amygdala) through a rich network of inhibitory interneurons embedded in the amygdala, appears to be a major participant, and is perhaps modulated by context via hippocampus.
Friday, September 5, 2008
Emotion Circuits in the Brain
LeDoux, J.E. (2000). Emotion Circuits in the Brain. Annual Reviews in Neuroscience, 23, 155-184.
Emotion research was largely lost for some time in the wake of the cognitive revolution. However, people soon realized a purely cognitive view of the brain -- leaving out emotions, motivations, and the like -- is likely to paint an unrealistic view of real minds. Unfortunately, attempts to dig into emotions once again were hamstrung by the limbic system concept, a flawed and inadequate theory of the emotional brain: cognition does not only reside in the neocortex and emotions do not only reside within the limbic system (a moving target itself).
Emotion research began its official resurgence with a bottoms-up examination of fear conditioning, with a bulk of the work focused on the auditory modality. Research soon named amygdala as centrally important, a site where transmission of information about the CS and US converged and output projections controlled fear reactions. On the input side, CS sensory inputs terminate in the lateral amygdala (LA), coming from both the auditory thalamus and the auditory cortex, although plasticity seems to occur initially through the thalamic pathway. US information also seems to converge in the amygdala, receiving inputs from the spino-thalamic tract, cortical areas that process somatosensory stimuli including nociceptive stimuli, the parabrachial area, and the spinal cord. On the outbound side, the central nucleus of the amygdala (CE) projects to autonomic (hypothalamus) and defensive motoric (periaqueductal gray) centers. Methodologies used have largely been single unit recordings, long-term potentiation (LTP) studies, and pharmacological experiments which block LTP. Studies have focused on two types of fear learning: simple fear conditioning (a benign tone comes to evoke a fear response) and contextual fear conditioning (fear responsivity to environmental cues). Research agrees that the amygdala seems to be required for Pavlovian fear conditioning to occur, although the site of long-term fear memory storage is still unknown: it may very well exist in the amygdala, but it may also be distributed across multiple structures or transferred off to cortical areas over time. However, plasticity within the amygdala is probably not required for learning cognitive aspects of fear.
Human studies have echoed many of the results from animal literature. Additionally, they have found perceptual deficits of the emotional meaning of faces in patients with amygdalar damage. The amygdala also appears activated more strongly in the presence of fearful and angry faces than of happy ones. Further, when the activity of the amygdala during fear conditioning is cross-correlated with other regions of the brain, the strongest relations are seen in subcortical areas, emphasizing the importance of the direct thalamo-amygdala pathway in the human brain. Although a fear conditioning approach cannot account for all aspects of human fear and anxiety disorders, it may be especially elucidating for PTSD, panic disorders, and phobias. Difficulty in extinguishing fear memories witnessed in human disorders may also involve the medial prefrontal cortex circuitry.
Future research needs to integrate both cognition and emotion. How fear processing in the amygdala can influence perceptual, attentional, and memory functions of the cortex, and vice versa, is begging for additional research, although it is known that the amygdala does receive input from cortical sensory processing regions and projects back to these both directly and indirectly. How conscious emotional feelings are manifest is also relatively unexplored, although the models posit that feelings may arise from interactions between the amygdala and prefrontal working memory areas, sensory processing areas in cortex, long-term memory systems in the temportal lobe, and arousal systems which maintain global projections.
Tuesday, August 19, 2008
Our 100th Post!
Congratulations to all those who posted, i.e. Jeff and I. Maybe we can recruit some more people to join in! Stay tuned.
Wednesday, August 13, 2008
An Illustration of DBT
Linehan, M.M. (1998). An Illustration of Dialectical Behavior Therapy. In Session: Psychotherapy in Practice, 4, 2, 21-44.
In addition to providing illustrative transcripts from dialectical behavior therapy (DBT) sessions, the bulk of the read, this paper also summarizes DBT's theoretical perspective, its various treatment stages and targets, as well as treatment strategies. DBT was developed to treat clients meeting criteria for borderline personality disorder (BPD) whose behavioral patterns are commonly problematic and stressful for clients and therapists alike, not the least of which is suicidality. DBT theorizes that BPD individuals lack interpersonal, self-regulation, and distress-tolerance skills, and what skills they do possess are often undermined by behaviors which block the use of the capabilities the client does have. As such, outcomes are typically unpredictable, even for patients who resist the tempting urge to quit and remain in treatment.
DBT recommends splitting up therapy into different stages, each with unique goals. In Stage I, treatment tries to achieve self-control, with control over one's suicidal behaviors being most important. In Stage II, clients try to experience emotions without resistance and to form and maintain connections to people, places, and activities, even if they are somehow associated with past trauma. Stage III focuses on reducing residual problematic patterns that interfere with clients achieving other important goals. When successful, Stage IV achieves a lasting sense of completeness and the capacity for sustained joy.
DBT's treatment strategies include: (1) dialectical strategies which combine acceptance with change, synthesize opposites, and move the client from "either-or" thinking to "both-and" thinking; (2) core strategies of client validation and problem-solving; (3) communication strategies which balance warm responsiveness to the client's wishes with irreverence; and (4) case management strategies which help the therapist tackle the difficult problems of suicidality with team support and aim to ultimately teach the client how to effectively interact with their world, rather than teaching the environment how to interact with them.
In addition to providing illustrative transcripts from dialectical behavior therapy (DBT) sessions, the bulk of the read, this paper also summarizes DBT's theoretical perspective, its various treatment stages and targets, as well as treatment strategies. DBT was developed to treat clients meeting criteria for borderline personality disorder (BPD) whose behavioral patterns are commonly problematic and stressful for clients and therapists alike, not the least of which is suicidality. DBT theorizes that BPD individuals lack interpersonal, self-regulation, and distress-tolerance skills, and what skills they do possess are often undermined by behaviors which block the use of the capabilities the client does have. As such, outcomes are typically unpredictable, even for patients who resist the tempting urge to quit and remain in treatment.
DBT recommends splitting up therapy into different stages, each with unique goals. In Stage I, treatment tries to achieve self-control, with control over one's suicidal behaviors being most important. In Stage II, clients try to experience emotions without resistance and to form and maintain connections to people, places, and activities, even if they are somehow associated with past trauma. Stage III focuses on reducing residual problematic patterns that interfere with clients achieving other important goals. When successful, Stage IV achieves a lasting sense of completeness and the capacity for sustained joy.
DBT's treatment strategies include: (1) dialectical strategies which combine acceptance with change, synthesize opposites, and move the client from "either-or" thinking to "both-and" thinking; (2) core strategies of client validation and problem-solving; (3) communication strategies which balance warm responsiveness to the client's wishes with irreverence; and (4) case management strategies which help the therapist tackle the difficult problems of suicidality with team support and aim to ultimately teach the client how to effectively interact with their world, rather than teaching the environment how to interact with them.
Tuesday, August 12, 2008
Functional analytic psychotherapy
Kohlenberg, R.J. & Tsai, Mavis. Functional analytic psychotherapy. Journal of Psychotherapy Integration, 4, 175-201.
Functional analytic psychotherapy (FAP) is a radical behaviorist approach to psychotherapy. As such, it views everything we do as behavior and believes these behaviors are the result of contingencies of reinforcement we have experienced in past relationships. The therapy emphasizes the importance of the client-therapist relationship since it creates a functionally similar environment [to the "real world"] which can evoke problematic behavior (deemed CRB1's) that can then be observed and responded to with reinforcement, shaping, and interpretations. Improvements witnessed in-session (deemed CRB2's) can be praised and reinforced immediately, and the clinician's reinforcement can be assessed for effectiveness. Further, its emphasis on contextualism leads therapists to develop a comprehensive understanding of the meaning of a client's behaviors and forces practitioners to remain open-minded about an intervention's potential effectiveness given the context. As such, FAP commonly embraces and enhances concepts and techniques from different therapies, such as psychoanalysis and cognitive therapy. Practitioners of FAP are encouraged to tailor their use of therapeutic techniques depending on: what will evoke the client's problems in the session, whether the client's problems are rule-governed or contingency-shaped, and what will be naturally reinforcing of the client's target behaviors.
Tuesday, July 29, 2008
Acceptance and commitment therapy
Harris, R. (August 2006). Embracing your demons: an overview of acceptance and commitment therapy. Psychotherapy in Australia, 12, 4, 2-8.
Acceptance and Commitment Therapy (ACT) is one of the "third-wave" behavioral therapies which emphasizes mindfulness and is intended to be used with a broad range of clinical conditions. The goal of ACT is to create a rich and meaningful life, while accepting the pain that inevitably goes with it. Western psychology has typically operated under the "healthy normality" assumption which states that by their nature, humans are psychologically healthy. That is, they will naturally be happy and content, and suffering is seen as abnormal. However, research shows that psychiatric disorders are exceedingly commonplace, as is nonclinical psyshological suffering, despite our high standards of living. ACT assumes, rather, that psychological processes of a normal human mind are often destructive. They posit that there is a dark side of language and cognition which sits at the root of this suffering. We often struggle with our thoughts and feelings, hoping to change them, avoid them, ameliorate them, and get rid of suffering. In doing so, ACT points at that some of these tactics often create extra suffering for ourselves. These "emotional control strategies" commonly become costly, life-distorting, or harmful. In ACT, there is no attempt to reduce, change, avoid, suppress, or control these private experiences. Instead, mindfulness is encouraged.
ACT commonly employs six techniques: (1) Cognitive Defusion: Learning to perceive thoughts, images, emotions, and memories as what they are, not what they appear to be. (2) Acceptance: Allowing them to come and go without struggling with them. (3) Contact with the present moment: Awareness to the here and now experience with openness, interest, and receptiveness. (4) Observing the self: Accessing a transcendent sense of self, a continuity of consciousness which is changing. (5) Values: Discovering what is most important to one's true self. (6) Committed Action: Setting goals according to values and carrying them out responsibly.
Acceptance and Commitment Therapy (ACT) is one of the "third-wave" behavioral therapies which emphasizes mindfulness and is intended to be used with a broad range of clinical conditions. The goal of ACT is to create a rich and meaningful life, while accepting the pain that inevitably goes with it. Western psychology has typically operated under the "healthy normality" assumption which states that by their nature, humans are psychologically healthy. That is, they will naturally be happy and content, and suffering is seen as abnormal. However, research shows that psychiatric disorders are exceedingly commonplace, as is nonclinical psyshological suffering, despite our high standards of living. ACT assumes, rather, that psychological processes of a normal human mind are often destructive. They posit that there is a dark side of language and cognition which sits at the root of this suffering. We often struggle with our thoughts and feelings, hoping to change them, avoid them, ameliorate them, and get rid of suffering. In doing so, ACT points at that some of these tactics often create extra suffering for ourselves. These "emotional control strategies" commonly become costly, life-distorting, or harmful. In ACT, there is no attempt to reduce, change, avoid, suppress, or control these private experiences. Instead, mindfulness is encouraged.
ACT commonly employs six techniques: (1) Cognitive Defusion: Learning to perceive thoughts, images, emotions, and memories as what they are, not what they appear to be. (2) Acceptance: Allowing them to come and go without struggling with them. (3) Contact with the present moment: Awareness to the here and now experience with openness, interest, and receptiveness. (4) Observing the self: Accessing a transcendent sense of self, a continuity of consciousness which is changing. (5) Values: Discovering what is most important to one's true self. (6) Committed Action: Setting goals according to values and carrying them out responsibly.
Sunday, July 27, 2008
Relapse Prevention for Alcohol and Drug Problems
Witkiewitz, K. & Marlatt, G.A. (2004). Relapse Prevention for Alcohol and Drug Problems. American Psychologist, 59, 4, 224-235.
Relapse prevention (RP) is a cognitive-behavioral approach with the goal of identifying and preventing high-risk situations such as substance abuse, obsessive-compulsive behavior, sexual offending, obesity, and depression. Relapse is seen as both an outcome and as a transgression in the process of behavior change. An initial setback (lapse) may either translate into a return to the previous problematic behavior (relapse) or into the individual turning again towards positive change (prolapse). That individuals commonly experience lapses, and even relapses, is not contested. However, an understanding of this phenomenon continues to evolve.
Relapse is thought to be multi-determined, especially by self-efficacy, outcome expectancies, craving, motivation, coping, emotional states, and interpersonal factors. High self-efficacy, negative outcome expectancies, potent availability of coping skills following treatment, positive affect, and functional social support are expected to predict positive outcome. Craving has not historically been shown to serve as a strong predictor.
The article proposes a new reconceptualization of relapse as a multidimensional, complex system. Such a nonlinear dynamical system is believed to be able to best predict the data witnessed, which commonly includes cases where small changes introduced into the equation seem to have large effects. The model also introduces concepts of self-organization, feedback loops, timing/context effects, and interplay between tonic and phasic processes. The effectiveness and efficacy of RP for various goals is also discussed in the article.
(I, Doug Girard, am the author of this article, Relapse Prevention, and I release its content under the terms of the GNU Free Documentation License, Version 1.2 and later.)
Relapse prevention (RP) is a cognitive-behavioral approach with the goal of identifying and preventing high-risk situations such as substance abuse, obsessive-compulsive behavior, sexual offending, obesity, and depression. Relapse is seen as both an outcome and as a transgression in the process of behavior change. An initial setback (lapse) may either translate into a return to the previous problematic behavior (relapse) or into the individual turning again towards positive change (prolapse). That individuals commonly experience lapses, and even relapses, is not contested. However, an understanding of this phenomenon continues to evolve.
Relapse is thought to be multi-determined, especially by self-efficacy, outcome expectancies, craving, motivation, coping, emotional states, and interpersonal factors. High self-efficacy, negative outcome expectancies, potent availability of coping skills following treatment, positive affect, and functional social support are expected to predict positive outcome. Craving has not historically been shown to serve as a strong predictor.
The article proposes a new reconceptualization of relapse as a multidimensional, complex system. Such a nonlinear dynamical system is believed to be able to best predict the data witnessed, which commonly includes cases where small changes introduced into the equation seem to have large effects. The model also introduces concepts of self-organization, feedback loops, timing/context effects, and interplay between tonic and phasic processes. The effectiveness and efficacy of RP for various goals is also discussed in the article.
(I, Doug Girard, am the author of this article, Relapse Prevention, and I release its content under the terms of the GNU Free Documentation License, Version 1.2 and later.)
Thursday, July 10, 2008
Theory-based research for understanding dynamic psychotherapy
Luborsky, L., Barber, J.P., & Crits-Christoph, P. (1990). Theory-based research for understanding the process of dynamic psychotherapy. Journal of Consulting and Clinical Psychology, 58, 3, 281-287.
This article reviews empirical support for 6 basic theoretical assumptions central to psychodynamic psychotherapy. (1) A therapeutic alliance must develop. The strength of therapeutic alliance (the collaborative and affective bond between therapist and client) is shown to predictive of positive outcomes. (2) Patients display transference. Trends from existing studies show central relationship patterns exist which are largely consistent over time and may be projected onto the therapist. (3) Accurate interpretations of transference by the clinician lead to increased benefits for the client. Findings are inconsistent on this point, specifically on the relation between increased number of transference interpretations and outcomes. Mediators may exist, such as how the patient responds to the interpretation. (4) The patient will benefit more from more accurate interpretations. Accurate interpretations correlate with "better" sessions. Accuracy of interpersonal aspects of interpretation predicted outcomes best. (5) Increased insight about themselves and their relationships with others leads to better outcomes. Gaining an understanding about the therapist and others is associated with outcomes. An understanding of self and parents does not seem to be as well correlated. (6) Improved patients show greater change in their transference patterns. Results are consistent with the theory that transference still exists but is under better control and mastery. Patients' expectations of how others will respond becomes less negative and their mental health improves.
This article reviews empirical support for 6 basic theoretical assumptions central to psychodynamic psychotherapy. (1) A therapeutic alliance must develop. The strength of therapeutic alliance (the collaborative and affective bond between therapist and client) is shown to predictive of positive outcomes. (2) Patients display transference. Trends from existing studies show central relationship patterns exist which are largely consistent over time and may be projected onto the therapist. (3) Accurate interpretations of transference by the clinician lead to increased benefits for the client. Findings are inconsistent on this point, specifically on the relation between increased number of transference interpretations and outcomes. Mediators may exist, such as how the patient responds to the interpretation. (4) The patient will benefit more from more accurate interpretations. Accurate interpretations correlate with "better" sessions. Accuracy of interpersonal aspects of interpretation predicted outcomes best. (5) Increased insight about themselves and their relationships with others leads to better outcomes. Gaining an understanding about the therapist and others is associated with outcomes. An understanding of self and parents does not seem to be as well correlated. (6) Improved patients show greater change in their transference patterns. Results are consistent with the theory that transference still exists but is under better control and mastery. Patients' expectations of how others will respond becomes less negative and their mental health improves.
Prolonged Exposure Treatment for PTSD following 9/11
Kazi, A., Freund, B., & Ironson, G. (2008). Prolonged Exposure Treatment for Posttraumatic Stress Disorder following the 9/11 attack with a person who escaped from the Twin Towers. Clinical Case Studies, 7, 100-116.
This article chronicles the progress of one 9/11 survivor through the cognitive-behavioral therapy intervention of prolonged exposure (PE) therapy to address her PTSD and depressive symptomatology. This treatment consists of (1) imaginal exposure, and (2) in vivo exposure. It is designed to elicit emotional processing until the detrimental traumatic memories and avoidances have habituated (desensitized). After 15 sessions this client improved 75% as measured by a composite index. However, there was residual symptomatology 6 months after therapy ended but measures remained sub-clinical. Progress through treatment can be seen as waxing and waning, but trending towards improvement. Still, in this type of therapy clients must be stressed before they are to feel better. With the prevalence of PTSD at 8% in the US population, clinicians are calling more and more for effective treatment regimes. PE may be a promising candidate.
This article chronicles the progress of one 9/11 survivor through the cognitive-behavioral therapy intervention of prolonged exposure (PE) therapy to address her PTSD and depressive symptomatology. This treatment consists of (1) imaginal exposure, and (2) in vivo exposure. It is designed to elicit emotional processing until the detrimental traumatic memories and avoidances have habituated (desensitized). After 15 sessions this client improved 75% as measured by a composite index. However, there was residual symptomatology 6 months after therapy ended but measures remained sub-clinical. Progress through treatment can be seen as waxing and waning, but trending towards improvement. Still, in this type of therapy clients must be stressed before they are to feel better. With the prevalence of PTSD at 8% in the US population, clinicians are calling more and more for effective treatment regimes. PE may be a promising candidate.
Wednesday, June 18, 2008
Statistical Functions
Zimmerman, D. W., & Zumbo, B. D. (1992). Parametric alternatives to the student t test under violation of normality and homogeneity of variance. Perceptual and Motor Skills, 74, 835-844.
*Rank order tests are effective only under violations of normality; modified t-tests are far better under conditions of violated homogeneity of variance
Clinch, J. J. & Keselman, H. J. (1982). Parametric alternatives to the analysis of variance. Journal of Educational Statistics, 7, 215-231.
*Different tests were compared under various assumption violations via Monte Carlo methods; the ANOVA F test did worst, while the Brown/Forsyth method did best overall
Tomarken, A. J. & Serlin, R. C. (1986). Comparison of ANOVA alternatives under variance heterogeneity and specific noncentrality structures. Psychological Bulletin, 99, 90-99.
*ANOVA F test alternatives were compared on Type I error rates and power under variance heterogeneity; the Welch test did best in all cases except when extreme means were paired with high variances, where the Brown/Forsyth method did better
Wilcox, R. R. (1998). How many discoveries have been lost by ignoring modern statistical methods? American Psychologist, 53, 300-314.
*Many nonsignificant research results could have been significant if modern statistical methods had been used; new methods also create more accurate confidence intervals
*Rank order tests are effective only under violations of normality; modified t-tests are far better under conditions of violated homogeneity of variance
Clinch, J. J. & Keselman, H. J. (1982). Parametric alternatives to the analysis of variance. Journal of Educational Statistics, 7, 215-231.
*Different tests were compared under various assumption violations via Monte Carlo methods; the ANOVA F test did worst, while the Brown/Forsyth method did best overall
Tomarken, A. J. & Serlin, R. C. (1986). Comparison of ANOVA alternatives under variance heterogeneity and specific noncentrality structures. Psychological Bulletin, 99, 90-99.
*ANOVA F test alternatives were compared on Type I error rates and power under variance heterogeneity; the Welch test did best in all cases except when extreme means were paired with high variances, where the Brown/Forsyth method did better
Wilcox, R. R. (1998). How many discoveries have been lost by ignoring modern statistical methods? American Psychologist, 53, 300-314.
*Many nonsignificant research results could have been significant if modern statistical methods had been used; new methods also create more accurate confidence intervals
Alternatives to Null Hypothesis Significance Testing
Abelson, R. P. (1985). A Variance Explanation Paradox: When a Little Is a Lot. Psychological Bulletin. 97 (1), 129-34.
*Using percent variance to explain the influence of situational factors is misleading
Prentice, D. A., & Miller, D. T. (1992). When small effects are impressive. Psychological Bulletin, 112, 160-164.
*Interpretation of effect size requires careful consideration of the topic being researched
Bem, D. J., & Honorton, C. (1994). Does Psi Exist? Replicable Evidence for an Anomalous Process of Information Transfer. PSYCHOLOGICAL BULLETIN. 115 (1), 4.
*An example of meta-analysis in action, arguing that psi exists (and is replicable)
Kirsch, I. & Sapirstein, G. (1998). Listening to Prozac but hearing placebo: A meta-analysis of antidepressant medication. Prevention & Treatment, 1
*An example of meta-analysis in action, arguing that SSRI’s work through placebo effect
Krueger, J. (2001). Null Hypothesis Significance Testing: On the Survival of a Flawed Method. AMERICAN PSYCHOLOGIST. 56, 16-26.
*Critics and defenders of NHST use Bayesian ideas; the real issue at stake is replicability
Seaman, M. A., & Serlin, R. C. (1998). Equivalence Confidence Intervals for Two-Group Comparisons of Means. PSYCHOLOGICAL METHODS. 3 (4), 403-411.
*Equivalence confidence intervals can and should replace NHST for determining if two group means are practically equivalent
Duckworth, W.M. and Stephenson, W.R. Resampling methods: Not just for statisticians anymore. Invited paper presented at JSM 2003, San Francisco, CA.
*Explores how to teach resampling methods (jackknife and bootstrap) to psychologists
*Using percent variance to explain the influence of situational factors is misleading
Prentice, D. A., & Miller, D. T. (1992). When small effects are impressive. Psychological Bulletin, 112, 160-164.
*Interpretation of effect size requires careful consideration of the topic being researched
Bem, D. J., & Honorton, C. (1994). Does Psi Exist? Replicable Evidence for an Anomalous Process of Information Transfer. PSYCHOLOGICAL BULLETIN. 115 (1), 4.
*An example of meta-analysis in action, arguing that psi exists (and is replicable)
Kirsch, I. & Sapirstein, G. (1998). Listening to Prozac but hearing placebo: A meta-analysis of antidepressant medication. Prevention & Treatment, 1
*An example of meta-analysis in action, arguing that SSRI’s work through placebo effect
Krueger, J. (2001). Null Hypothesis Significance Testing: On the Survival of a Flawed Method. AMERICAN PSYCHOLOGIST. 56, 16-26.
*Critics and defenders of NHST use Bayesian ideas; the real issue at stake is replicability
Seaman, M. A., & Serlin, R. C. (1998). Equivalence Confidence Intervals for Two-Group Comparisons of Means. PSYCHOLOGICAL METHODS. 3 (4), 403-411.
*Equivalence confidence intervals can and should replace NHST for determining if two group means are practically equivalent
Duckworth, W.M. and Stephenson, W.R. Resampling methods: Not just for statisticians anymore. Invited paper presented at JSM 2003, San Francisco, CA.
*Explores how to teach resampling methods (jackknife and bootstrap) to psychologists
Controversy in Null Hypothesis Significance Testing
Macdonald, R. R. (1997). On statistical testing in psychology. BRITISH JOURNAL OF PSYCHOLOGY. 88 (2), 333-348.
*Criticisms of NHST apply to Neyman-Pearson approach, but not the Fisherian approach
Huberty, C. J. (1993). Historical Origins of Statistical Testing Practices. Journal of Experimental Education. 61 (4), 317-33.
*Textbooks in psychology confuse the use and interpretation of p-values and alpha-levels
Gigerenzer, G. (1993). The superego, the ego, and the id in statistical reasoning. In G. Keren & C. Lewis (Eds.), A handbook for data analysis in the behavioral sciences: Methodological issues (pp. 311-339). Hillsdale, NJ: Lawrence Erlbaum Associates.
*Textbooks present an incoherent “hybrid logic,” mixing Neyman-Pearson and Fisher
Kaiser, H. (1960). Directional statistical decisions. Psychological Review. 67, 160-167.
*When using two-sided tests, it makes no sense to use a non-directional test
Greenwald, A. G. (1975). Consequences of prejudice against the null hypothesis. Psychological Bulletin, 82, 1-20.
*The false ideas that null results are useless or more likely to be due to incompetence prevents (or at least slows) scientific progress
Rosenthal, R. (1979). The “File Drawer Problem” and tolerance for null results. Psychological Bulletin, 86, 638-641.
*Research that results in null results are rarely published, making a field of research look more “significant” than it might actually be
Rozeboom, W. W. (1960). The fallacy of the null-hypothesis significance test. Psychological Bulletin. 57, 416-28.
*Using statistical tests to make “decisions” is naïve and rejection criteria are arbitrary, calling for a use of confidence intervals and (if possible) Bayesian statistics
Bakan D. (1966). The test of significance in psychological research. Psychological Bulletin. 66 (6), 423-37.
*Statistical results are often misinterpreted, calling for Bayesian methods
Hunter, J. E. (1997). Needed: A Ban on the Significance Test. PSYCHOLOGICAL SCIENCE -CAMBRIDGE-. 8 (1), 3-7.
*NHST breaks down when H0 is false and most studies purposely use H0's they know to be false, causing the error rate (Type I and II) of NHST to be around 60%
Cohen, J. (1994). The Earth Is Round (p <.05). AMERICAN PSYCHOLOGIST. 49 (12), 997.
*The logic of NHST is flawed and backwards; we need to better understand our data
Cohen, J. (1990). Things I Have Learned (So Far). American Psychologist. 45 (12), 1304-12.
*Informed judgment from the researcher is indispensable; power analysis can help
Loftus, G. R. (1996). Psychology Will Be a Much Better Science When We Change the Way We Analyze Data. CURRENT DIRECTIONS IN PSYCHOLOGICAL SCIENCE. 5 (6), 161-170.
*Null hypotheses are rarely possible, making “significance” useless; power is under-attended and the dichotomy of effects/non-effects is artificial
Harris, R. J. (1997). Reforming significance testing via three-valued logic. In Harlow, L.L., Mulaik, S.A., & Steiger, J.H. (Eds.) What if there were no significance tests? Hillsdale, NJ: Erlbaum.
*Three-valued logic can establish directionality and address Type III error
Wilkinson, L. (1999). Statistical Methods in Psychology Journals: Guidelines and Explanations. AMERICAN PSYCHOLOGIST. 54 (8), 594-604.
*APA decided not to ban NHST, instead urging researchers to distinguish between statistical and theoretical significance, and also use modern statistical graphics
Abelson, R. P. (1997). On the Surprising Longevity of Flogged Horses: Why There Is a Case for the Significance Test. PSYCHOLOGICAL SCIENCE -CAMBRIDGE-. 8 (1), 12-15.
*NHST can be used effectively in combination with other methods; enforcing a complete ban on it would be throwing away a tool that can be useful in a number of situations
Greenwald, A. G., Gonzalez, R., Harris, R. J., & Guthrie, D. (1996). Effect Sizes and p Values: What Should Be Reported and What Should Be Replicated? PSYCHOPHYSIOLOGY. 33 (2), 175-183.
*The interpretation of p-values in terms of replicability is widely mistaken
Harris, R. J. (1997). Significance Tests Have Their Place. PSYCHOLOGICAL SCIENCE -CAMBRIDGE-. 8 (1), 8-11.
*Three-valued logic can help NHST; using confidence intervals as an alternative runs into the same problems as NHST, while providing less information than a p-value would
Jones, L. V., & Tukey, J. W. (2000). A Sensible Formulation of the Significance Test. PSYCHOLOGICAL METHODS. 5, 411-414.
*Yet another iteration of the virtues of three-valued logic applied to NHST
*Criticisms of NHST apply to Neyman-Pearson approach, but not the Fisherian approach
Huberty, C. J. (1993). Historical Origins of Statistical Testing Practices. Journal of Experimental Education. 61 (4), 317-33.
*Textbooks in psychology confuse the use and interpretation of p-values and alpha-levels
Gigerenzer, G. (1993). The superego, the ego, and the id in statistical reasoning. In G. Keren & C. Lewis (Eds.), A handbook for data analysis in the behavioral sciences: Methodological issues (pp. 311-339). Hillsdale, NJ: Lawrence Erlbaum Associates.
*Textbooks present an incoherent “hybrid logic,” mixing Neyman-Pearson and Fisher
Kaiser, H. (1960). Directional statistical decisions. Psychological Review. 67, 160-167.
*When using two-sided tests, it makes no sense to use a non-directional test
Greenwald, A. G. (1975). Consequences of prejudice against the null hypothesis. Psychological Bulletin, 82, 1-20.
*The false ideas that null results are useless or more likely to be due to incompetence prevents (or at least slows) scientific progress
Rosenthal, R. (1979). The “File Drawer Problem” and tolerance for null results. Psychological Bulletin, 86, 638-641.
*Research that results in null results are rarely published, making a field of research look more “significant” than it might actually be
Rozeboom, W. W. (1960). The fallacy of the null-hypothesis significance test. Psychological Bulletin. 57, 416-28.
*Using statistical tests to make “decisions” is naïve and rejection criteria are arbitrary, calling for a use of confidence intervals and (if possible) Bayesian statistics
Bakan D. (1966). The test of significance in psychological research. Psychological Bulletin. 66 (6), 423-37.
*Statistical results are often misinterpreted, calling for Bayesian methods
Hunter, J. E. (1997). Needed: A Ban on the Significance Test. PSYCHOLOGICAL SCIENCE -CAMBRIDGE-. 8 (1), 3-7.
*NHST breaks down when H0 is false and most studies purposely use H0's they know to be false, causing the error rate (Type I and II) of NHST to be around 60%
Cohen, J. (1994). The Earth Is Round (p <.05). AMERICAN PSYCHOLOGIST. 49 (12), 997.
*The logic of NHST is flawed and backwards; we need to better understand our data
Cohen, J. (1990). Things I Have Learned (So Far). American Psychologist. 45 (12), 1304-12.
*Informed judgment from the researcher is indispensable; power analysis can help
Loftus, G. R. (1996). Psychology Will Be a Much Better Science When We Change the Way We Analyze Data. CURRENT DIRECTIONS IN PSYCHOLOGICAL SCIENCE. 5 (6), 161-170.
*Null hypotheses are rarely possible, making “significance” useless; power is under-attended and the dichotomy of effects/non-effects is artificial
Harris, R. J. (1997). Reforming significance testing via three-valued logic. In Harlow, L.L., Mulaik, S.A., & Steiger, J.H. (Eds.) What if there were no significance tests? Hillsdale, NJ: Erlbaum.
*Three-valued logic can establish directionality and address Type III error
Wilkinson, L. (1999). Statistical Methods in Psychology Journals: Guidelines and Explanations. AMERICAN PSYCHOLOGIST. 54 (8), 594-604.
*APA decided not to ban NHST, instead urging researchers to distinguish between statistical and theoretical significance, and also use modern statistical graphics
Abelson, R. P. (1997). On the Surprising Longevity of Flogged Horses: Why There Is a Case for the Significance Test. PSYCHOLOGICAL SCIENCE -CAMBRIDGE-. 8 (1), 12-15.
*NHST can be used effectively in combination with other methods; enforcing a complete ban on it would be throwing away a tool that can be useful in a number of situations
Greenwald, A. G., Gonzalez, R., Harris, R. J., & Guthrie, D. (1996). Effect Sizes and p Values: What Should Be Reported and What Should Be Replicated? PSYCHOPHYSIOLOGY. 33 (2), 175-183.
*The interpretation of p-values in terms of replicability is widely mistaken
Harris, R. J. (1997). Significance Tests Have Their Place. PSYCHOLOGICAL SCIENCE -CAMBRIDGE-. 8 (1), 8-11.
*Three-valued logic can help NHST; using confidence intervals as an alternative runs into the same problems as NHST, while providing less information than a p-value would
Jones, L. V., & Tukey, J. W. (2000). A Sensible Formulation of the Significance Test. PSYCHOLOGICAL METHODS. 5, 411-414.
*Yet another iteration of the virtues of three-valued logic applied to NHST
Thursday, June 5, 2008
Balancing work and family
Pleck, J.H. (1999). Balancing work and family. Scientific American Presents: Men's Health.
With women's move into the workplace over the last few decades, men's roles have changed as well. Men spend much less of their lives working than they did in the past. Father's are not only becoming more available, but more engaged in the family as well. However, these effects are countered by an increase in divorce rates and an increase in the number of unmarried fathers. The family is far more psychologically central to men than work, as is the case for women. Fathers tend to carry their emotions home with them from work, whereas mothers keep their family experiences insulated from the workplace. There also still exist gross gender differences in the nature of behavioral interaction with children. However, despite changing roles, companies have not caught up in their sympathy for their male employees' work-family problems, so social change is still lagging.
With women's move into the workplace over the last few decades, men's roles have changed as well. Men spend much less of their lives working than they did in the past. Father's are not only becoming more available, but more engaged in the family as well. However, these effects are countered by an increase in divorce rates and an increase in the number of unmarried fathers. The family is far more psychologically central to men than work, as is the case for women. Fathers tend to carry their emotions home with them from work, whereas mothers keep their family experiences insulated from the workplace. There also still exist gross gender differences in the nature of behavioral interaction with children. However, despite changing roles, companies have not caught up in their sympathy for their male employees' work-family problems, so social change is still lagging.
Sunday, May 25, 2008
Child care quality matters
Love et al. (August 2003). Child care quality matters: how conclusions may vary with context. Child Development, 74, 4, 1021-1033.
A report from the NICHD concluded that more time spent in a variety of nonmaternal care arrangements leads to more externalizing behavior problems, regardless of child care quality. Authors were skeptical and tested the generalizability of these findings with 3 other studies. These new findings suggest that quality of child care is an important factor influencing children's development, and that quality may be an important moderator of the amount of time in care.
A report from the NICHD concluded that more time spent in a variety of nonmaternal care arrangements leads to more externalizing behavior problems, regardless of child care quality. Authors were skeptical and tested the generalizability of these findings with 3 other studies. These new findings suggest that quality of child care is an important factor influencing children's development, and that quality may be an important moderator of the amount of time in care.
Friday, May 9, 2008
Cultural variation in infant's sleeping arrangements
Morelli, G.A., Rogoff, B., Oppenheim, D., & Goldsmith, D. (1992). Cultural variation in infant's sleeping arrangements: Questions of Independence. Developmental Psychology, Vol. 28, No. 4, 604-613.
Cultural practices differentiate infant sleep arrangements. In the middle-class US population, a common goal is to have infants sleep in their own rooms as soon as possible, consonant with the culture's importance on independence. In the Mayan population, it is not uncommon for children to sleep with their parents or other siblings well on into childhood, reflecting their culture's value on interpersonal relations. Changes are not prescribed by the authors; instead, broader cultural perspective is offered for American readers.
Cultural practices differentiate infant sleep arrangements. In the middle-class US population, a common goal is to have infants sleep in their own rooms as soon as possible, consonant with the culture's importance on independence. In the Mayan population, it is not uncommon for children to sleep with their parents or other siblings well on into childhood, reflecting their culture's value on interpersonal relations. Changes are not prescribed by the authors; instead, broader cultural perspective is offered for American readers.
Wednesday, May 7, 2008
Seasonal changes of hippocampus volume in parasitic cowbirds
Clayton, N.S., Reboreda, J.C., & Kacelnik, A. (1997). Seasonal changes of hippocampus volume in parasitic cowbirds. Behavioral Processes, 41, 237-243.
This study compared a set of phylogenetically closely related species with striking differences in natural behavior, offering the opportunity for seeking neural differences in association with these behavioral changes. Notable differences exist in these South American cowbirds of the genus Molothrus related to parasitic nesting. In one species, the birds are especially active during the breeding season, searching and locating potential hosts' nests. In another two species, only females are active during the breeding season in locating potential hosts' nests (sexual dimorphism). A fourth species is non-parasitic and no sexual differences are known with respect to spatial memory use in either season. Results show that the first species shows significantly larger relative hippocampal volume in the breeding season. The sexual dimorphic species show significantly larger relative hippocampal volume in the breeding season, but only in females. The evidence suggests seasonal variation in neuroanatomy associated with specific changes in behavior, namely spatial memory demands, as opposed to purely seasonal fluctuations per se.
This study compared a set of phylogenetically closely related species with striking differences in natural behavior, offering the opportunity for seeking neural differences in association with these behavioral changes. Notable differences exist in these South American cowbirds of the genus Molothrus related to parasitic nesting. In one species, the birds are especially active during the breeding season, searching and locating potential hosts' nests. In another two species, only females are active during the breeding season in locating potential hosts' nests (sexual dimorphism). A fourth species is non-parasitic and no sexual differences are known with respect to spatial memory use in either season. Results show that the first species shows significantly larger relative hippocampal volume in the breeding season. The sexual dimorphic species show significantly larger relative hippocampal volume in the breeding season, but only in females. The evidence suggests seasonal variation in neuroanatomy associated with specific changes in behavior, namely spatial memory demands, as opposed to purely seasonal fluctuations per se.
Continuous flash suppression reduces negative afterimages
Tsuchiya, N. & Koch, C. (August 2005). Continuous flash suppression reduces negative afterimages. Nature Neuroscience, Vol. 8, No. 8, 1096-1101.
Continuous flash suppression (CFS) is a tool that can be used to reliably suppress vivid images from conscious awareness for long periods of time. Here, different patterned images ("Mondrians") are flashed rapidly into one eye while input to the corresponding location in the other eye remains fixed, the latter typically remaining unseen often for durations greater than ten times what can be achieved with binocular rivalry or other masking methods, even though the image remains present on the retina for several minutes. Interestingly, researchers discovered that negative afterimages or "photogenes", effects lingering in view after termination of the visual stimulus, also seem to be diminished with exposure to CFS. Though it is widely believed that afterimages originate among retinal neurons, this evidence supports the conclusion that the weakened afterimage must be due to interference from sites at or beyond binocular convergence, such as the lateral geniculate nucleus (LGN) or cortex. Specifically, it must be an area which receives input from both eyes but does not correspond directly to the neuronal correlates of perceptual awareness. The results hint at differences between concepts of attention and awareness.
Continuous flash suppression (CFS) is a tool that can be used to reliably suppress vivid images from conscious awareness for long periods of time. Here, different patterned images ("Mondrians") are flashed rapidly into one eye while input to the corresponding location in the other eye remains fixed, the latter typically remaining unseen often for durations greater than ten times what can be achieved with binocular rivalry or other masking methods, even though the image remains present on the retina for several minutes. Interestingly, researchers discovered that negative afterimages or "photogenes", effects lingering in view after termination of the visual stimulus, also seem to be diminished with exposure to CFS. Though it is widely believed that afterimages originate among retinal neurons, this evidence supports the conclusion that the weakened afterimage must be due to interference from sites at or beyond binocular convergence, such as the lateral geniculate nucleus (LGN) or cortex. Specifically, it must be an area which receives input from both eyes but does not correspond directly to the neuronal correlates of perceptual awareness. The results hint at differences between concepts of attention and awareness.
Tuesday, May 6, 2008
Sign Language in the Brain
Hickok, G., Bellugi, U. & Klima, E.S. (June 2001). Sign Language in the Brain. Scientific American.
Because sign language relies heavily upon visual-spatial contrast, one might expect sign language to be supported by systems in the right hemisphere rather than the traditional left hemisphere language systems. However, this does not appear to be the case. A deaf signer with damage to Wernicke's area is likely to have comprehension difficulties and one with damage to Broca's area may have difficulty producing signs, just like normal speakers. And signers with right hemisphere damage continued to be fluent and accurate in their production of signs, used normal grammar, and comprehended signs with ease. One exception of the left hemisphere's monopoly on language production is creation of a coherent discourse, where right hemisphere damage may lead to rambling as it tends to be involved in more global-level processes. Generally speaking, sign language abilities of lifelong signers appear to be independent of their nonlinguistic spatial skills. Thus, it is likely that signers maintain unique early stages of processing compared to regular speakers, but thereafter neural organization is quite similar, being translated into a format optimized for linguistic processing and being routed to central linguistic systems.
Because sign language relies heavily upon visual-spatial contrast, one might expect sign language to be supported by systems in the right hemisphere rather than the traditional left hemisphere language systems. However, this does not appear to be the case. A deaf signer with damage to Wernicke's area is likely to have comprehension difficulties and one with damage to Broca's area may have difficulty producing signs, just like normal speakers. And signers with right hemisphere damage continued to be fluent and accurate in their production of signs, used normal grammar, and comprehended signs with ease. One exception of the left hemisphere's monopoly on language production is creation of a coherent discourse, where right hemisphere damage may lead to rambling as it tends to be involved in more global-level processes. Generally speaking, sign language abilities of lifelong signers appear to be independent of their nonlinguistic spatial skills. Thus, it is likely that signers maintain unique early stages of processing compared to regular speakers, but thereafter neural organization is quite similar, being translated into a format optimized for linguistic processing and being routed to central linguistic systems.
Monday, May 5, 2008
Marijuana use as a coping response
Preston, P. (2006). Marijuana use as a coping response to psychological strain: racial, ethnic, and gender differences among young adults. Deviant Behavior, 27, 397-420.
Besides tobacco and alcohol, marijuana is the most frequently used and abused substance. This study used data taken from the National Household Survey of Drug Abuse (from all 50 states), and examined 4601 subjects between the ages of 18-25 who used marijuana within the past year. Their dependent variable was marijuana use frequency, defined as either recreational or chronic, with chronic being greater than 12 times per month. Independent variables measured included strain, economic strain, norms favorable to drug use, number of friends who use drugs, and attitudes towards risky behavior. Results were also examined through the lenses of gender, ethnicity, marital status, employment status, and education.
Results indicate that social learning factors have the strongest effect on chronic marijuana use, operationalized as the number of friends who use drugs and a personal approval of drug use. Strain (operationalized as social nervousness) had the next strongest effect. Self control had a weak effect overall. High school dropouts and the unmarried were found to be particularly at risk for becoming chronic users. Strain appeared to have a stronger effect on minority groups, possibly suggesting fewer alternative coping strategies in this population. Minority women experience a "double-whammy", more likely than their nonminority counterparts to be chronic users and also more likely to be affected by social learning and self control variables.
Besides tobacco and alcohol, marijuana is the most frequently used and abused substance. This study used data taken from the National Household Survey of Drug Abuse (from all 50 states), and examined 4601 subjects between the ages of 18-25 who used marijuana within the past year. Their dependent variable was marijuana use frequency, defined as either recreational or chronic, with chronic being greater than 12 times per month. Independent variables measured included strain, economic strain, norms favorable to drug use, number of friends who use drugs, and attitudes towards risky behavior. Results were also examined through the lenses of gender, ethnicity, marital status, employment status, and education.
Results indicate that social learning factors have the strongest effect on chronic marijuana use, operationalized as the number of friends who use drugs and a personal approval of drug use. Strain (operationalized as social nervousness) had the next strongest effect. Self control had a weak effect overall. High school dropouts and the unmarried were found to be particularly at risk for becoming chronic users. Strain appeared to have a stronger effect on minority groups, possibly suggesting fewer alternative coping strategies in this population. Minority women experience a "double-whammy", more likely than their nonminority counterparts to be chronic users and also more likely to be affected by social learning and self control variables.
Love in Infant Monkeys
Harlow, H.F. (June 1959). "Love in Infant Monkeys", Scientific American.
Harlow used baby rhesus monkeys to yield insights into the origin of the infant's love for its mother and concluded that bodily contact comfort is a decisive variable in this relationship. For example, newborn monkeys preferred a surrogate "cloth" mother to a "wire" mother, and sought out the cloth mother in times of emotional stress. Other variables were also explored. A mother's rocking motion appeared to enhance affection, but less so than simple contact. Heat of the mother did not appear to be an important variable. Other visual, auditory, and olfactory stimulation may also play a role. Additionally, a critical period to attachment formation seems to be evident.
Harlow used baby rhesus monkeys to yield insights into the origin of the infant's love for its mother and concluded that bodily contact comfort is a decisive variable in this relationship. For example, newborn monkeys preferred a surrogate "cloth" mother to a "wire" mother, and sought out the cloth mother in times of emotional stress. Other variables were also explored. A mother's rocking motion appeared to enhance affection, but less so than simple contact. Heat of the mother did not appear to be an important variable. Other visual, auditory, and olfactory stimulation may also play a role. Additionally, a critical period to attachment formation seems to be evident.
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