Food hoarding behaviour in the golden hamster (Mesocricetus auratus): Effects of body weight loss and hoard-size discrimination

Two experiments investigated some of the factors that influence food hoarding behaviour in the golden hamster (Mesocricetus auratus). In Experiment 1, hamsters given limited access to food failed to increase the amount of food they consumed at each meal. Instead, they exhibited a significant increase in the amount of food taken to hoard during the limited access period, and this permitted hamsters who were allowed to retain their hoard to maintain body weight at levels comparable to free-feeding controls. Hamsters that were not allowed to retain hoarded food rapidly lost body weight. There was also an inverse correlation between body weight and amount of food taken to hoard in all hamsters given limited access to food, suggesting that body weight loss was one factor directly related to increased hoarding during periods of limited food accessibility. Experiment 2 investigated the effect of hoard-size discrimination on food hoarding in hamsters by artificially manipulating hoard size. The results suggested that hoarding behaviour could be influenced by artificially depleting and repleting the hoard, and this factor appears to influence hoarding in the absence of any significant changes in body weight. These results are discussed in relation to the kinds of adaptive feeding strategies that hamsters may utilize in their natural environment.     

The status of hoarding as a symptom of obsessive-compulsive disorder

Hoarding is considered by many to be a symptom of obsessive-compulsive disorder (OCD). Yet although it is observed in people with OCD, hoarding symptoms also appear in a number of other psychological and psychiatric conditions. The present studies were conducted using samples of OCD patients, patients with other anxiety disorders, and a non-clinical sample to further elucidate the relationship between hoarding and OCD. Across two investigations, we found that (a) whereas OCD patients had higher scores than the other groups on non-hoarding symptoms, this was not the case for hoarding symptoms; (b) hoarding tended to correlate more weakly with other OCD symptoms (e.g., washing, checking) than these other symptoms intercorrelated; (c) items measuring hoarding had the weakest factor loadings when a measure of OCD symptoms was submitted to factor analysis; (d) hoarding symptoms were not correlated with global OCD or anxiety severity, whereas other OCD symptoms were; and (e) hoarding did not show consistent relationships with OCD-related cognitive variables. These results do not support a specific relationship between hoarding and OCD; and they call into question hoarding's status as a specific symptom of OCD. Results are also discussed in terms of the importance of functional assessment of hoarding and OCD symptoms.     

Trait Versus Task-Induced Emotional Reactivity and Distress Intolerance in Hoarding Disorder: Transdiagnostic Implications

Evidence from analogue samples suggests that deficits in emotional functioning, namely elevated emotional reactivity and distress intolerance, are implicated in the development and maintenance of hoarding disorder. We aimed to extend previous research in this area by investigating emotional reactivity and distress intolerance in a sample of individuals diagnosed with hoarding disorder (n = 24) in comparison to clinical controls (n = 21) and nonclinical community controls (n = 26) using a combination of self-report, physiological, and behavioral measures. We found that trait distress intolerance was significantly and independently associated with greater hoarding severity. The hoarding and clinical control groups reported more trait emotional reactivity and distress intolerance than the community control group, but did not differ from each other on these traits. The hoarding group reported more subjective distress before beginning a frustrating behavioral task, but did not evidence more physiological arousal. Moreover, the hoarding group experienced similar increases in distress during the task and did not differ from either group in regard to time persisting on this task. The clinical control group, however, terminated the frustrating task significantly faster than the community control group, who tended to persist until the task timed out. Lastly, trait distress intolerance evidenced a small-to-moderate but nonstatistically significant independent relationship with task persistence time. Given the desynchrony between subjective distress and physiological arousal, we encourage researchers to utilize multimodal assessment in the future. We also suggest that clinicians start to use behavioral experiments, as has been done with other psychological disorders, to improve distress intolerance among persons who experience hoarding disorder.     

Locus of control and the perception of freedom in an agent of reinforcement

Internals and externals observed a staged videotape presentation that portrayed a “teacher” and a “learner” engaging in a 20-item anagrams task. For externals, any variability (10, 50, and 90% schedule) in the reinforcing behavior of the “teacher” (agent of reinforcement) resulted in significantly greater perceived freedom than when no variability (0 and 100% schedule) occurred in behavior. For internals, perceived freedom was a negative linear function of the amount of reinforcement administered. Internals indicated that they could influence the behavior of the “teacher” in all reinforcement conditions, whereas externals indicated that they could influence only the “teachers” in the variable reinforcement conditions. It was concluded that greater freedom is attributed to a person whose behavior is perceived as congruent with the person's inner disposition.     

Profiling Hoarding Within the Five-Factor Model of Personality and Self-Determination Theory

This study investigated the dispositional profile associated with hoarding symptoms by applying a personality and motivational trait perspective. A community sample oversampling high hoarding symptoms (N = 649, ages 18–74 years) completed an online questionnaire assessing hoarding, the five-factor model of personality, and general causality orientations drawn from self-determination theory. Personality aspects (10 traits), a level of measurement intermediate to factors (5 traits) and facets (30 traits), were assessed to provide greater specificity than a factor-level approach. Hoarding was correlated with neuroticism and conscientiousness. Aspects predicting hoarding were industriousness (C), orderliness (C), withdrawal (N), and assertiveness (E). Hoarding was significantly related to impersonal and control orientations, albeit with only slight (1.4%) incremental validity for general causality orientations above personality aspects in predicting hoarding. These findings may not generalize to a clinical treatment sample, and possible configurative interactions between traits were not assessed. This study extended the existing literature by reporting aspect-level personality and general causality orientation correlates of hoarding. These data may inform preventative monitoring and intervention programs, as well as predicting meaningful personality characteristics of hoarding clients.     

Pharmacological and physiological aspects of sexual exhaustion in male rats

The present article reviews the current findings on the interesting phenomenon of sexual satiety. Knut Larsson in 1956 reported on the development of sexual exhaustion in the male rat after repeated copulation. We have studied the process and found the following results. (1) One day after 4 hours of ad libitum copulation, two-thirds of the population showed complete inhibition of sexual behavior, while the other third displayed a single ejaculatory series from which they did not recover. (2) Several pharmacological treatments, including 8-OH-DPAT, yohimbine, naloxone and naltrexone, reverse this sexual satiety, indicating that the noradrenergic, serotonergic and opiate systems are involved in this process. Indeed, direct neurochemical determinations showed changes in various neurotransmitters during sexual exhaustion. (3) Given enough stimulation, by changing the stimulus female, sexual satiety was prevented, suggesting that there are motivational components of the sexual inhibition that characterizes sexual exhaustion. (4) The GABA antagonist bicuculline, or the electrical stimulation of the medial preoptic area, did not reverse sexual exhaustion. These data suggest, on the one hand, that sexual exhaustion and the postejaculatory interval (which is shortened by bicuculline administration) are not mediated by similar mechanisms and, on the other, that the medial preoptic area does not regulate sexual satiety. (5) The androgen receptor density in brain areas closely related to the expression of masculine sexual behavior, such as the medial preoptic nucleus, was drastically reduced in sexually exhausted animals. Such reduction was specific to certain brain areas and was not related to changes in the levels of androgens. These results suggest that changes in brain androgen receptors account for the inhibition of sexual behavior present during sexual exhaustion. (6) The recovery process of sexual satiety after 4 hours of ad libitum copulation reveals that, after 4 days, only 63% of the males are able to show sexual behavior while after 7 days all animals display copulatory activity.     

A bioinspired model of short-term satiety of hunger influenced by food properties in virtual creatures

The behavior of the human is continually changed as a consequence of various drives which human is predisposed also of your survival instinct. Among the basic drives of the human, there are the physiological needs and is precisely the hunger that motivates the food intake to get the energy that the body requires via food. The regulation of hunger allows to stop the food intake by means of the homeostatic and hedonic control which are influenced by the food properties. The process that consists of ending the food intake is known as short-term satiety and is important because it limits the amount of food intake; Otherwise, an over-consumed affect the organism functioning negatively. In this paper, we propose a conceptual model for the generation of short-term satiety behaviors based on neuroscientific evidence for virtual creatures. The conceptual model proposed is implemented in a distributed system-a virtual creature endowed with this implementation is placed in a virtual environment to analyze its behavior. The analysis shows how the virtual creature modifies its hunger level (behavior) based on food’s properties. The results show the execution of the process when the creature interacts with the environment.     

Hoarding and its relation to obsessive-compulsive disorder

Although hoarding is observed in some patients with obsessive-compulsive disorder (OCD), it has not been shown to share a specific relation with OCD. Across two studies, we found that (a) whereas the classic OCD symptoms of checking, rituals, and contamination intercorrelated consistently strongly with one another, hoarding related only moderately to both these OCD symptoms and to depression; (b) OCD patients were distinguished from both other patients and non-patients by classic OCD symptoms, but not by hoarding; and (c) whereas OCD symptoms showed consistent relations with Negative Affect, hoarding largely was uncorrelated with this dimension. These results do not support a specific OCD-hoarding relation but rather call into question the trend of considering it a specific symptom of OCD.     

囤积症的行为心理特征及相关因素

囤积症是指过度获取和不能丢弃那些没有用处或失去价值的物品。这种行为通常会给患者本人及其家庭成员带来感情、躯体、财务、社会甚至法律方面的负面影响。对于囤积症的行为特征、心理特征及相关因素,学界已有大量的研究。近期,囤积症已被纳入DSM-5,这将有助于确定有持续性丢弃困难的个体,并对其予以帮助与干预。     

The prevalence of compulsive hoarding and its association with compulsive buying in a German population-based sample

The aims of the study were to estimate the prevalence rate of compulsive hoarding, and to determine the association between compulsive hoarding and compulsive buying in a nationally representative sample of the German population (N = 2307). Compulsive hoarding was assessed with the German version of the Saving Inventory-Revised (SI-R; Frost, R.O., Steketee, G., & Grisham, J. (2004). Measurement of compulsive hoarding: saving inventory-revised. Behaviour Research and Therapy, 42, 1163-1182.). The point prevalence of compulsive hoarding was estimated to be 4.6%. Individuals with compulsive hoarding did not differ significantly from those without compulsive hoarding regarding age, gender, and other sociodemographic characteristics. Significant correlations were found between the compulsive hoarding and the compulsive buying measures. Participants with compulsive hoarding reported a higher propensity to compulsive buying than respondents without hoarding. About two thirds of participants classified as having compulsive hoarding were also defined as suffering from compulsive buying. In summary, these results suggest that compulsive hoarding may be relatively prevalent in Germany and they confirm the close association between compulsive hoarding and compulsive buying through the investigation of a large scale representative sample.     

Signal duration and suppression of operant responding by free reinforcement

Pigeons were trained on a VI (variable interval) schedule of food presentation with a superimposed schedule of response-independent food. Substantial suppression of the operant response rate occurred when the free food was presented without a signal. When the free food was preceded by a short (4 sec) signal, the degree of suppression was similar to that with unsignaled free food. But when the signal was lengthened to 12 sec, the degree of suppression was substantially reduced. Experiment 3 assessed the effect of signal duration using a baseline schedule of delayed reinforcement, in which contingent reinforcers were themselves preceded by a signal. The signal preceding the free reinforcers was then either the same as or different from this contingent signal. Signal duration effects occurred only when the two types of signals were different. These differences as a function of signal duration have implications for both “context-blocking” and “comparator” interpretations of the effects of noncontingent reinforcement in both Pavlovian and operant procedures.     

Stock optimizing in choice when a token deposit is the operant.

Each of 2 monkeys typically earned their daily food ration by depositing tokens in one of two slots. Tokens deposited in one slot dropped into a bin where they were kept (token kept). Deposits to a second slot dropped into a bin where they could be obtained again (token returned). In Experiment 1, a fixed-ratio (FR) 5 schedule that provided two food pellets was associated with each slot. Both monkeys preferred the token-returned slot. In Experiment 2, both subjects chose between unequal FR schedules with the token-returned slot always associated with the leaner schedule. When the FRs were 2 versus 3 and 2 versus 6, preferences were maintained for the token-returned slot; however, when the ratios were 2 versus 12, preference shifted to the token-kept slot. In Experiment 3, both monkeys chose between equal-valued concurrent variable-interval variable-interval schedules. Both monkeys preferred the slot that returned tokens. In Experiment 4, both monkeys chose between FRs that typically differed in size by a factor of 10. Both monkeys preferred the FR schedule that provided more food per trial. These data show that monkeys will choose so as to increase the number of reinforcers earned (stock optimizing) even when this preference reduces the rate of reinforcement (all reinforcers divided by session time).     

Food priming: A therapeutic tool to increase the percentage of meals bought by chronic mental patient

In a motivating ward environment for schizophrenics, three methods of maximizing food as an effective reinforcer were tested. On the basis of pre-treatment measures, patients were classified as (1) “non-chronic meal missers” who served as control patients (Group A), (2) “chronic meal missers” because they had no tokens (Group B), or (3) “chronic meal missers” because they chose not to eat but had tokens (Group C). One of the following three experimental treatments was then administered when a patient missed a meal : (1) visual food priming (observing others eat), (2) oral food priming (sampling one teaspoon of each type of food for that meal), and (3) free meal (being offered a free meal when it was missed). Oral and visual food priming were found to be equally effective in increasing the percentage of meals bought by patients. A post-treatment follow-up for Group B found that this increase was even greater during the follow-up phase. The percentage of meals bought by patients in the free meal condition of Group B decreased during the treatment phase but was significantly above pre-treatment measures during the follow-up phase, suggesting that complete reinforcer sampling may also be an effective technique for increasing the percentage of meals bought.     

Punished and Nonpunished Responding in A Multiple Schedule in Humans: A Brief Report

Four male subjects responded on a multiple schedule in which responding was maintained by a random interval 20-sec (RI20) schedule of point presentation. Responding was suppressed in alternating components by an added variable ratio 30 (VR30) schedule of point subtractions. Each component was accompanied by distinctive stimulus lights. Subjects were exposed to the multiple schedule from the initial session. Two subjects experienced four 50-min sessions daily (Experiment 1) and the other two subjects participated in one 50-min session daily (Experiment 2). Once responding in the punished components had stabilized, responding in the nonpunished components continued to increase across sessions. Nonpunished responding did not stabilize even after as many as 36 sessions. These results are discussed in the context of previous studies using animals which employed multiple schedules with punished and nonpunished response contingencies.

     

An Ecological Momentary Assessment Study Investigating the Function of Hoarding

This study examined the function of hoarding behaviors and the relations between hoarding and a series of cognitive and affective processes in the moment using ecological momentary assessment. A matched-groups design was used to compare college students with higher hoarding symptoms (n = 31) and matched controls (n = 29). The two groups did not differ in what function they reported acquiring served, and positive automatic reinforcement was the most commonly reported function in both groups. Engaging in hoarding-relevant behaviors did not predict change in positive or negative affect when controlling for previous affect. Emotional reactivity and experiential avoidance in the moment were both elevated in the higher hoarding group compared to controls, while momentary mindfulness and negative affect differentiation were lower. Overall, these findings support the importance of emotion regulation processes in hoarding. They also suggest individuals may not be successfully regulating affect in the moment with hoarding behaviors, despite efforts to do so. It may be useful to evaluate processes such as striving for positive affect in hoarding disorder in the future.     

Physiological drives investigated by means of injections into the cerebral ventricles of the rat

A technique is described for permanently implanting a cannula in the lateral ventricle of the rat, and the effects on certain physiological drives of various substances injected by this route were investigated.

Food intake was significantly reduced by intraventricular glucose, while intra-ventricular fructose, insulin, glucagon and a lipid-mobilizing agent were without effect. Drinking was elicited by hypertonic saline and suppressed by hypotonic solutions. The intake of salt was not effected by intraventricular low-sodium solutions. Intraventricular procaine, but not alcohol, induced an akinetic state. Intraventricular glucose failed to relieve hypoglycaemic coma.

The significance of some of these findings is discussed in relation to the hypothalamic regulation of hunger.     

The experience of self-awareness and its relation to level of self-consciousness: An experiential sampling study

The present research studied self-awareness by utilizing experiential sampling methodology, which allows for the random sampling of individuals' thoughts and feelings as they go about their normal daily activities. Neither Study 1 nor 2 found a relation between private or public self-awareness and negative affect. However, attention to private self-aspects was generally more positive and less ruminative for low as opposed to high private self-conscious subjects, and awareness of oneself as a social object was generally more positive but less important for low as opposed to high public self-conscious subjects. What may have accounted for the negative relation between private self-consciousness and average affect was that low private self-conscious subjects were more likely to attend to their private self-aspects if they were pleasant than if they were unpleasant, while high private self-conscious subjects' degree of private self-awareness was unrelated to whether the content of this state was pleasant or not. These findings are consistent with the hypothesis that low private self-conscious individuals engage in a more selective type of self-attention when in the private self-aware state than do high private self-conscious individuals. Regarding the relation between self-awareness and social context, both studies found that the presence of others results in a heightened public self-awareness. However, even though subjects were more attentive to public self-aspects when with others than when alone, in general, they were more attentive to their “private self” than to their “public self”. Results are discussed in terms of current self-awareness theory.     

Consideration of the BDNF gene in relation to two phenotypes: hoarding and obesity

The gene coding for the brain derived neurotrophic factor (BDNF) has emerged as an interesting candidate for multiple brain and brain disorder-related phenomena. The primary aim of the present investigation was to consider the relationship between the BDNF Val66Met variant and two phenotypes: compulsive hoarding as a symptom dimension of obsessive-compulsive disorder (OCD), and body mass index (BMI). We examined the BDNF gene in a large (N=301) clinical sample of probands with OCD. Participants were classified as hoarding or nonhoarding using a strict, multimeasure grouping approach. Results revealed that the Val/Val genotype was linked with hoarding classification and more severe hoarding behaviors, as well as greater BMI levels. Hoarding status was also associated with greater BMI scores, with individuals in the hoarding group being far more likely to be classified as obese compared with the nonhoarding group. Our findings may provide a distinct avenue through which hoarding and BMI could be linked. These findings are suggestive of a complex gene, body weight, and psychopathology relationship wherein a primitive, survival "thrifty gene" strategy may be conserved and represented in a subgroup of humans manifesting severe hoarding symptoms.     

Hoarding behaviour and the defence of body weight in adult rats, following undernutrition during different periods of early development

In Experiment I, male rats, previously undernourished by underfeeding their mothers during lactation, weighed less as adults than progeny of mothers underfed during gestation, or than normally-nourished control rats. Daily 16 h food deprivation of the adults induced weight loss and elicited hoarding of food pellets. Deprivation-induced weight losses at criterion for hoarding did not differ significantly among the groups, and the critical weight at which hoarding began was thus significantly lower in the lactationally-undernourished group than in the controls. Thus adult rats, previously undernourished during their suckling period, appear to defend their body weights in a manner similar to controls, although at a lower level. Lactationally-undernourished rats also hoarded significantly fewer pellets than controls. Similar results were obtained when the rats were partially satiated before hoarding tests, suggesting that hoarding scores were unlikely to have been significantly affected by competition with feeding. Foetal undernutrition had weaker, and less consistent effects than lactational undernutrition on the ad libitum weight of the adult, and on the critical weight for hoarding. In Experiment II, severe undernutrition after weaning did not affect adult body weight, the weight loss necessary to induce hoarding, or the number of pellets hoarded. It is concluded that the pre-weaning period is specifically sensitive to the effects of undernutrition on body weight regulation and on hoarding. The data on hoarding do not support the view that a period of undernutrition at any time in early life increases the rat's responsiveness towards food.     

Assessment and treatment of hoarding in an individual with dementia

The authors used a reinforcer assessment to evaluate possible interventions for hoarding in an older individual with dementia. The most preferred condition from the assessment (sorting activity) was compared to a staff developed treatment involving item removal and redirection. Hoarding was reduced during both interventions with a greater reduction in the sorting condition. The behavioral reductions were maintained during schedule thinning of social interactions and follow-up.