Re‐examination of Oostenbroek et al. (2016): evidence for neonatal imitation of tongue protrusion

The meaning, mechanism, and function of imitation in early infancy have been actively discussed since Meltzoff and Moore's (1977) report of facial and manual imitation by human neonates. Oostenbroek et al. (2016) claim to challenge the existence of early imitation and to counter all interpretations so far offered. Such claims, if true, would have implications for theories of social‐cognitive development. Here we identify 11 flaws in Oostenbroek et al.'s experimental design that biased the results toward null effects. We requested and obtained the authors’ raw data. Contrary to the authors’ conclusions, new analyses reveal significant tongue‐protrusion imitation at all four ages tested (1, 3, 6, and 9 weeks old). We explain how the authors missed this pattern and offer five recommendations for designing future experiments. Infant imitation raises fundamental issues about action representation, social learning, and brain–behavior relations. The debate about the origins and development of imitation reflects its importance to theories of developmental science.     

Self-reported psychosocial factors among in vitro fertilization patients interviewed alone or with the partner

The purpose of this study was to compare the sociodemographic and psychosocial characteristics reported by female in vitro fertilization (IVF) patients interviewed alone or with the partner in heterosexual couples. During 12 months (2011–2012), all patients undergoing IVF or intracytoplasmic sperm injection at one public reproductive medicine unit, in Portugal, were interviewed on the day of the diagnosis of pregnancy, being recruited 221 women interviewed with the partner and 92 interviewed alone. Interviewers collected data on sociodemographic and obstetric characteristics; and anxiety, depression, social support and partner relationship were collected by self-administered questionnaires. χ² test was used to assess the independent association between the categorical variables and being interviewed alone or with the partner. For continuous variables, mean or median differences were compared by the t-test or the Mann–Whitney test, according to data distribution. No statistically significant differences were found in the self-reporting of depression, anxiety, social support and partner relationship or in sociodemographic and obstetric characteristics between women interviewed alone or with the partner. Although women interviewed alone were older and more frequently had children than women interviewed with the partner, no significant associations were observed. Thus, having a male partner present in the research setting during a self-administered questionnaire seems not to influence women’s responses to psychosocial measures. Other outcomes and settings need to be evaluated to support evidence-based guidelines for research on infertility.     

Action observation network in childhood: a comparative fMRI study with adults

Very little is known about the action observation network and the mirror neuron system (AON/MNS) in children and its age‐related properties compared with those observed in adults. In the present fMRI study we explored the activation of areas belonging to the AON/MNS in children and adults during observation of complex hand‐grasping actions, as compared to observation of simple grasping acts executed with the left and the right hand, seen from a first person perspective. The results indicate that during the action observation tasks in children there was activation of a cortical network similar to that found in adults, including the premotor cortex, the posterior part of the inferior frontal gyrus and the posterior parietal lobe. However, the activation in children was more widespread and showed a higher inter‐subject variability compared with adults. Furthermore, the activated network seems more lateralized to the left hemisphere in adults and more bilateral in children, with a linear growth of lateralization index as a function of age. Finally, in children the activation in the anterior intraparietal cortex (AIP) of each hemisphere was higher during observation of the contralateral hand (hand identity effect) and during the observation of complex actions relative to simple grasping acts, confirming the role of AIP for action‐related hand identity previously described in adults. These results support the assumption that structure and size of action representations are sensitive to mechanisms of development and show physiological plasticity. These properties of the AON/MNS could constitute a powerful tool for spontaneous reorganization and recovery of motor deficits after brain injury in children and in adults, as well as for specific rehabilitation programmes.     

Temporal generalization gradients following an interdimensional discrimination protocol

We investigated the effects of interdimensional discrimination training in the temporal generalization gradient. In a matching-to-sample task, pigeons learned to choose key S after a T–s houselight sample and key NS in the absence of the houselight sample. For one group of pigeons, T?=?20?s; for another, T?=?10?s. Subsequently, houselight duration was varied to obtain temporal generalization gradients. Results showed that (a) proportion S increased as houselight duration ranged from 0?s to T?s and then remained high for houselight durations longer than T; (b) the gradients were well described by negative-exponential functions; (c) these non-flat gradients were present from the beginning of testing, and; (d) the average gradients obtained with T?=?20?s and T?=?10?s overlapped when plotted in relative time. We conclude that temporal control does not require explicit discrimination training along the temporal dimension, and that temporal generalization gradients obtained with an interdimensional protocol show the scalar property of timing. We discuss how these findings challenge current models of timing.     

A new variable interval schedule with constant hazard rate and finite time range

We propose a new variable interval (VI) schedule that achieves constant probability of reinforcement in time while using a bounded range of intervals. By sampling each trial duration from a uniform distribution ranging from 0 to 2 T seconds, and then applying a reinforcement rule that depends linearly on trial duration, the schedule alternates reinforced and unreinforced trials, each less than 2 T seconds, while preserving a constant hazard function.     

The differentiation of response numerosities in the pigeon

Two experiments examined how pigeons differentiate response patterns along the dimension of number. In Experiment 1, 5 pigeons received food after pecking the left key at least N times and then switching to the right key (Mechner's Fixed Consecutive Number schedule). Parameter N varied across conditions from 4 to 32. Results showed that run length on the left key followed a normal distribution whose mean and standard deviation increased linearly with N; the coefficient of variation approached a constant value (the scalar property). In Experiment 2, 4 pigeons received food with probability p for pecking the left key exactly four times and then switching. If that did not happen, the pigeons still could receive food by returning to the left key and pecking it for a total of at least 16 times and then switching. Parameter p varied across conditions from 1.0 to .25. Results showed that when p= 1.0 or p=.5, pigeons learned two response numerosities within the same condition. When p=.25, each pigeon adapted to the schedule differently. Two of them emitted first runs well described by a mixture of two normal distributions, one with mean close to 4 and the other with mean close to 16 pecks. A mathematical model for the differentiation of response numerosity in Fixed Consecutive Number schedules is proposed.     

Testing the Δ-∑ hypothesis in the suboptimal choice task: Same delta with different probabilities of reinforcement

In a concurrent-chain procedure, pigeons choose between 2 initial-link stimuli; one is followed by terminal link stimuli that signal reliably whether food will be delivered after a delay; the other is followed by terminal link stimuli that do not signal whether food will be delivered after the delay. Pigeons prefer the former alternative even when it yields a lower overall probability of food. Recently, we proposed the Delta-Sigma (∆-∑) hypothesis to explain the effect: Preference depends on the difference (∆) between the reinforcement probabilities associated with the terminal link stimuli, and the overall probability of reinforcement (∑) associated with the alternative. The hypothesis predicts that, for constant ∑, animals should prefer alternatives with greater ∆ values regardless of the specific probabilities of reinforcement that determine ∆. In 2 experiments, we tested this prediction by comparing a ∆ = .5 against a ∆ = 0 alternative, with the former obtained with different pairs of reinforcement probabilities across conditions. The results supported the hypothesis when the 2 probabilities defining ∆ were significantly greater than 0, but not when one of them was close to 0. The results challenge our theoretical accounts of suboptimal choice and the variables considered to determine pigeons’ preference.     

When repetitive consumption leads to predictions of faster adaptation

Hedonic adaptation can explain why individuals enjoy their products less over time. One key feature of hedonic adaptation is its dependence on consumption repetition. Our research investigates when the perception of repetitive consumption leads consumers to predict faster hedonic adaptation (i.e., less enjoyment). We conducted four studies testing the impact of repetition on predicted enjoyment (Studies 1A and 1B), the interaction between repetition and assortment variety (Study 2), and the interaction between repetition and attention drawn by the product (Study 3). Results show that repetition leads consumers to predict less future enjoyment, weakens the effect of assortment variety on hedonic adaptation prediction, and strengthens the effect of attention drawn by product on hedonic adaptation prediction. Our results also show that consumers who predict less future enjoyment with a product are less likely to purchase this product. Overall, the findings advance knowledge on hedonic adaptation by presenting the impact of the most relevant feature of hedonic adaptation (i.e., consumption repetition) when it is made salient for consumers, and its interaction with common contextual cues.     

Covert orienting to the locations of targets and distractors: Effects on response channel activation in a flanker task

The role of covert orienting of attention in response channel activation was examined using the flanker interference and precueing paradigms. Four experiments assessed the influence of distractors on the discrimination of a target colour patch under cueing conditions (three with non-informative, exogenous cues and one with informative, endogenous cues) that modulated attention at the flanker or target locations. Across all of the experiments, the amount of interference generated by the distractors was not modulated by the facilitation and inhibition of return induced by spatial attention precues. These results are consistent with previous reports of patients with neglect, which demonstrated that flanker interference proceeds at unattended locations (Audet, Bub, & Lecours, 1991; Cohen, Ivry, Rafal, & Kohn, 1995), and they suggest that response channel activation can occur independently from spatial attention.