Retrieval-induced forgetting,delay, and sleep

Retrieval-induced forgetting (RIF) refers to the finding that retrieval of a subset of previously studied material can cause forgetting of related unpractised material. Prior work on the role of delay between practice and test for RIF reported mixed results. Whereas some studies found RIF to be a relatively transient phenomenon, others found RIF to persist over time. We examined whether the persistence of RIF can depend on whether wakefulness or sleep follows retrieval practice. We employed a variant of the retrieval-practice paradigm with short (20 minutes) and long (12 hours) delay conditions. In all conditions participants studied a perceptually categorised list followed by retrieval practice on some of the items from some of the categories. Participants studied and practised the material in the morning or the evening. RIF was present in the short-delay conditions, and it was present in the long-delay condition if the delay included nocturnal sleep; if the long delay was filled with diurnal wakefulness, RIF was absent. Results show that whether delay eliminates RIF or not can depend on whether sleep or wake follows retrieval practice. Connections of the results to recent findings about the role of delay and sleep for RIF are discussed.     

Contribution of Religiousness in the Prediction and Interpretation of Mystical Experiences in a Sensory Deprivation Context: Activation of Religious Schemas

M. A. Persinger (2002) claimed that transcranial magnetic stimulation with weak, complex magnetic fields evokes mystical experiences. However, in a double-blind experiment, P. Granqvist, M. Fredrikson, P. Unge, A. Hagenfeldt, S. Valind., et al. (2005) found no effects of field exposure on mystical experiences (N = 89), though a minority of participants reported spontaneous mystical experiences. Following the conclusion of null effects from magnetic field exposure, the setup of this experiment, including pre-experimental assessments of religiousness and sensory deprivation, can be viewed as a prime/setting for such experiences. The authors analyzed subsets of experimental data from P. Granqvist and colleagues with emphasis on the contribution of religiousness in the prediction and interpretation of mystical experiences. They found that a higher degree of religiousness predicted a higher occurrence of mystical experiences with a religious quality, but not of mystical experiences without such a quality. The authors discuss findings in terms of the experimental setup serving as a prime/setting activating the religious schemas of religious participants.     

One night of sleep is insufficient to achieve sleep-to-forget emotional decontextualisation processes

Neutral memories unbind from their emotional acquisition context when sleep is allowed the night after learning and testing takes place after two additional nights of sleep. However, mood-dependent memory (MDM) effects are not abolished after a restricted sleep episode mostly featuring non rapid-eye-movement (NREM) or rapid-eye-movement (REM) sleep. Here, we tested whether (1) one night of sleep featuring several NREM-REM sleep cycles is sufficient to suppress MDM effects and (2) a neutral mood is a sufficiently contrasting state to induce MDM effects, i.e. interfere with the recall of information learned in happy or sad states. Results disclosed MDM effects both in the post-learning sleep and wake conditions, with better recall in congruent than incongruent emotional contexts. Our findings suggest that the emotional unbinding needs several consecutive nights of sleep to be complete, and that even subtle mood changes are sufficient to produce MDM effects.     

Bouts of responding on variable-interval schedules: effects of deprivation level

Rats obtained food pellets on a variable-interval schedule of reinforcement by nose poking a lighted key. After training to establish baseline performance (with the mean variable interval set at either 60, 120, or 240 s), the rats were given free access to food during the hour just before their daily session. This satiation operation reduced the rate of key poking. Analysis of the interresponse time distributions (log survivor plots) indicated that key poking occurred in bouts. Prefeeding lengthened the pauses between bouts, shortened the length of bouts (less reliably), and had a relatively small decremental effect on the response rate within bouts. That deprivation level affects mainly between-bout pauses has been reported previously with fixed-ratio schedules. Thus, when the focus is on bouts, the performances maintained by variable-interval schedules and fixed-ratio schedules are similarly affected by deprivation.     

Dichotic listening and sleep deprivation: vigilance effects

Twelve sleep-deprived and 13 non-deprived Navy cadets were tested with the dichotic listening procedure for effects of sleep deprivation on hemispheric asymmetry and sustained attention. Consonant-vowel syllables were presented to the subjects in three different conditions, a divided (non-forced) attention condition, a forced right ear and a forced left ear attention condition. In the two forced attention conditions the subjects were instructed to focus attention only on the right or left ear stimulus. The results showed an expected right ear advantage for both groups during the non-forced and forced right attention conditions, indicating superior left hemisphere processing. During the forced left attention condition, the sleep-deprived subjects showed no ear advantage at all, while the non-deprived subjects showed an expected left ear advantage. The results are discussed within a theoretical framework of a dual process model, where sleep deprivation disrupts the ability to sustain attention, caused by a temporary failure of the right hemisphere's top-down (instruction-driven) processing to override the left hemisphere's bottom-up (stimulus-driven) processing.     

Can Inattention/Overactivity Be an Institutional Deprivation Syndrome?

Elevated rates of attention deficit and overactivity have been noted previously in samples of institution-reared children. This study examined the hypothesis that inattention/overactivity(I/O) might constitute a specific deprivation syndrome. One hundred and sixty five children adopted at varying ages (e.g., 0–42 months of age) into the UK following severe early deprivation were compared with 52 within-UK adoptees who did not suffer deprivation. The children were rated by teachers and parents on levels of I/O, conduct difficulties, and emotional difficulties using the Revised Rutter Scales. Data were collected at age 6 for the entire sample and at age 4 for the UK adoptees and for the subsample of Romanian children who entered the UK before the age of 2 years. Mean level analyses suggested a significant effect of duration of deprivation on I/O, but not on conduct or emotional difficulties. The effects of duration of deprivation were specific to I/O and were not accounted for by low birth weight, malnutrition, or cognitive impairment. Levels of I/O correlated with attachment disturbances. Furthermore, the effects of duration of deprivation on I/O did not attenuate over time. We conclude that I/O may well constitute an institutional deprivation syndrome, but that the type of attention deficit and overactivity exhibited by these children may present a different clinical picture from that of ordinary varieties of attention deficit disorder or hyperkinetic syndrome.     

Variable-interval reinforcement schedule value influences responding following REM sleep deprivation

The effects of rapid-eye movement sleep deprivation (REMSD) in rats were studied in relation to variable-interval (VI) reinforcement schedule value. Initially, lever pressing was maintained on a VI 30-s schedule of food pellet delivery. After a baseline was established, rats were repeatedly exposed to 96 hr of REMSD and control conditions of an equivalent duration. Responding decreased following REMSD but not after exposure to control conditions. Lever pressing was then maintained on a VI 15-s schedule of food pellet delivery and exposure to the REMSD and control conditions was repeated. Under this condition following repeated REMSD exposures, rates of lever pressing became similar to baseline responding. A VI 30-s schedule of food pellet delivery was then reinstated and REMSD and control conditions were repeated. Lever pressing following exposure to the REMSD condition decreased for 3 of 4 rats. Results suggest that VI schedule value influences the effects of REMSD on responding.     

Psychological impact of coronavirus-related social isolation in Colombia after a year of lockdown

Several repercussions of the COVID-19 pandemic and its subsequent isolation period have been reported worldwide. In this paper, we analyze the behavioral and emotional effects of 1 year of coronavirus-related lockdown in Colombia. A cross-sectional correlational design was used on a sample of 1853 participants from different regions, and with different levels of education, income, and employment situations. We applied the fear of coronavirus scale, the use of preventive behaviors scale, and a scale to measure pleasant and unpleasant emotions based on the circumplex model of affect. Our data shows that women, participants who were unemployed during the lockdown, and participants that study or work in legal, computational, or related fields, have been more affected in terms of unpleasant emotions. In addition, we observed a trend towards a relation between higher income and educational levels with lower degrees of fear, higher degrees of pleasant emotions, and a greater use of preventive behaviors related to the pandemic.     

Examining the between- and within-person effects of relative deprivation: Results from a 7-year longitudinal panel sample

Despite the extensive literature on relative deprivation theory, few studies have examined the longitudinal effects of individual- and group-based relative deprivation (IRD and GRD, respectively) on individual- and group-based outcomes, nor has research investigated the between-person and within-person effects of these constructs. Using two random intercept cross-lagged panel models, we address these oversights by estimating the between-person and average annual within-person associations IRD and GRD have with psychological distress and collective action support in a nation-wide longitudinal panel sample (N = 64,607). As expected, IRD and GRD were more strongly associated with psychological distress and collective action support, respectively, at the between-person level and contemporaneously at the within-person level. However, contrary to expectations, temporary departures in IRD and GRD predicted within-person increases in collective action support and psychological distress, respectively. These results raise questions about how and when people respond to inequality and provide the foundations for future longitudinal research.