The discrimination of discrete and continuous amounts in African grey parrots (Psittacus erithacus)

A wealth of research in infants and animals demonstrates discrimination of quantities, in some cases nonverbal numerical perception, and even elementary calculation capacities. We investigated the ability of three African grey parrots (Psittacus erithacus) to select the largest amount of food between two sets, either discrete food items (experiment 1) or as volume of a food substance (experiment 2). The two amounts were presented simultaneously and were visible at the time of choice. Parrots were tested several times for all possible combinations between 1 and 5 seeds or 0.2 and 1 ml of food substance. In both conditions, subjects performed above chance for almost all combinations. Accuracy was negatively correlated with the ratio, that is performance improved with greater differences between amounts. Therefore, these results with both individual items and volume discrimination suggest that parrots use an analogue of magnitude, rather than object-file mechanisms to quantify items and substances.     

奖惩线索对停止信号任务中抑制能力和心率、皮肤电的影响

采用不同类型强化刺激(中性刺激,奖励刺激,惩罚刺激,以及奖励、惩罚刺激并存)来改变可获得奖励和惩罚的强度和频度,分别考察不同类型强化条件对停止信号任务中抑制能力、心率和皮肤电的影响.结果显示:与奖惩混合条件相比,在奖励条件下,被试的反应速度快,但正确抑制率明显低于惩罚条件和奖惩混合条件;在奖励条件下,被试在任务完成过程中的心率明显高于反馈条件、惩罚条件和奖惩混合条件.四种条件下被试的皮肤电活动无差异.     

DEMAND EQUATIONS FOR QUALITATIVELY DIFFERENT FOODS UNDER FIXED‐RATIO SCHEDULES: A COMPARISON OF THREE DATA CONVERSIONS

Concurrent schedules were used to establish 6 hens' preferences for three foods. The resulting biases suggested wheat was preferred over honey‐puffed and puffed wheat, and puffed wheat was the least preferred food. The hens then responded under fixed‐ratio schedules for each food in 40‐min (excluding reinforcer time) sessions, with the response requirement doubling each session until no reinforcers were received. At the smaller ratios, the less preferred the food, the faster the hens' overall response rates (mainly as a result of shorter postreinforcement pauses) and the more reinforcers they received. The relations between the logarithms of the number of reinforcers obtained (consumption) and the response ratio (price) were well fitted by curvilinear demand functions. Wheat produced the smallest initial consumption (ln L), followed by honey‐puffed and puffed wheat, respectively. The response requirement at which the demand functions predicted maximal responding (P_max) were larger for wheat than for the other foods. Normalizing consumption and price, as suggested by Hursh and Winger (1995), moved the data for the three foods towards a single demand function; however, the P_max values were generally largest for puffed wheat. The results of normalization, as suggested by Hursh and Silberberg (2008), depended on the k value used. The parameter k is related to the range of the data, and the same k value needs to be used for all data sets that are compared. A k value of 8.0 gave significantly higher essential values (smaller α values) for puffed wheat as compared to honey‐puffed wheat and wheat, and the P_max values, in normalized standard price units, were largest for puffed wheat. Normalizing demand by converting the puffed and honey‐puffed wheat reinforcers to wheat equivalents (by applying the bias parameter from the concurrent‐schedules procedure) maintained separate demand functions for the foods. Those for wheat had the smallest rates of change in elasticity (a) and, in contrast to the other analyses, the largest P_max values. Normalizing demand in terms of concurrent‐schedule preference appears to have some advantages and to merit further investigation.     

Memories of reward and nonreward regulate the extinction and reacquisition of both excitatory and inhibitory associations

The memories of the unconditioned stimulus (US) and its absence (No US), symbolized as S^R and S^N, respectively, may be retrieved on US or No US trials giving rise to four types of associations, S^R → US, S^R → No US, S^N → US, and S^N → No US. Here, following acquisition under partial reward (PRF), rats were shifted either to different schedules of PRF (Experiment 1) or extinction (Experiments 1 and 2). Inhibitory S^R → No US associations formed in acquisition survived extinction and shifts to one, but not another type of PRF schedule (Experiments 1 and 2). Excitatory S^R → US associations also survived extinction (Experiment 2). These findings, as well as the acquisition findings of Experiment 2, are consistent with the sequential model but not with the only other two theories said to be able to explain PRF findings, the frustration hypothesis of Amsel and the attention hypothesis of Mackintosh [see Haselgrove, M., Aydin, A., & Pearce, J. M. (2004). A partial reinforcement extinction effect despite equal rates of reinforcement during Pavlovian conditioning. Journal of Experimental Psychology: Animal Behavior Processes, 30, 240–250]. Also, the reacquisition findings obtained here are inconsistent with two views applied to several learning phenomena, the rule-learning view and the position-item view.     

Negative reinforcer magnitude manipulations for treating escape-maintained problem behavior

The purpose of the current study was to evaluate the effects of different magnitudes of escape for compliance relative to the magnitudes of escape for problem behavior in a concurrent-schedule arrangement. Three individuals who exhibited escape-maintained problem behavior participated. A large differential magnitude condition (240-s escape for compliance, 10-s escape for problem behavior) was compared to equal (30-s escape for compliance and problem behavior) and moderate differential magnitude (90-s escape for compliance, 10-s escape for problem behavior) conditions. The authors also evaluated the impact of correcting for reinforcer access time (i.e., time on escape intervals) on intervention interpretation. For all participants, problem behavior decreased during only the large differential magnitude condition, and including reinforcer access time in the overall session time did not affect interpretation of treatment outcomes. Providing larger escape magnitudes for compliance relative to problem behavior may facilitate treatment involving concurrent-reinforcement schedules for escape-maintained problem behavior.     

Effects of reward magnitude frames on measures of delay discounting in a hypothetical money scenario

The current study analyzed the effects of three frames of reward magnitude—quantity, volume, and duration—on the rate at which college students discounted hypothetical, delayed monetary rewards. Hypothetical scenarios were presented using the fill-in-the-blank discounting questionnaire and participants made choices between immediate and delayed hypothetical monetary rewards. Scenarios framed the monetary choices as (a) quantity of dollar bills, (b) height (inches) of a stack of dollar bills, and (c) duration of time spent in a hypothetical cash machine to collect dollar bills. For each scenario, participants' subjective values were used to calculate the area under the curve (AuC). Framing resulted in a moderate effect size: The duration frame yielded significantly smaller AuC values compared to the quantity and volume frames. Thus, the framing of reward magnitude was a significant variable in controlling discounting rates for hypothetical, delayed monetary rewards. Subsequent investigations should be aware of the independent effects of the reward magnitude frames on delay discounting rates.     

虚拟和真实金钱奖赏幅度对海洛因戒断者风险决策的影响

已有研究表明海洛因成瘾者风险决策能力受损, 但少有研究关注不同幅度金钱奖赏对戒断期海洛因成瘾者风险决策的影响以及这种影响是否会受到金钱奖赏类型的调节。因此, 本研究使用气球模拟风险任务(BART), 通过两个实验探究不同幅度虚拟和真实金钱奖赏对海洛因戒断者风险决策的影响。结果显示, 在虚拟奖赏情景下, 海洛因戒断者未爆破气球按键次数和爆破气球个数均显著大于正常组被试, 以及两组被试在25分奖赏条件下的未爆破气球按键次数和爆破气球个数均显著大于1分奖赏; 而在真实奖赏情景下, 海洛因戒断者未爆破气球按键次数和爆破气球个数均显著小于正常组被试, 以及两组被试在25分奖赏条件下的未爆破气球按键次数和爆破气球个数均显著小于1分奖赏。研究结果表明, 金钱奖赏类型和金钱奖赏幅度会影响被试的风险决策行为。在虚拟奖赏情景下, 两组被试的风险偏好水平随着奖赏幅度的增加显著升高, 但是戒断期海洛因成瘾者的风险偏好水平高于正常组被试; 而在真实奖赏情景下, 两组被试的风险偏好水平随着奖赏幅度的增加显著降低, 同时戒断期海洛因成瘾者的风险偏好水平低于正常组被试。     

Is Emotional Magnitude Spatialized? A Further Investigation

Accumulating evidence suggests that different magnitudes (e.g., number, size, and duration) are spatialized in the mind according to a common left–right metric, consistent with a generalized system for representing magnitude. A previous study conducted by two of us (Holmes & Lourenco, 2011 ) provided evidence that this metric extends to the processing of emotional magnitude, or the intensity of emotion expressed in faces. Recently, however, Pitt and Casasanto ( 2018 ) showed that the earlier effects may have been driven by a left–right mapping of mouth size rather than emotional magnitude, and they found no evidence for an emotional magnitude mapping when using words as stimuli. Here, we report two new experiments that further examine these conclusions. In Experiment 1, using face stimuli with mouths occluded, we replicate the original finding: Less emotional faces were associated with the left and more emotional faces with the right. However, we also find that people can reliably infer the sizes of the occluded mouths, and that these inferred mouth sizes can explain the observed left–right mapping. In Experiment 2, we show that comparative judgments of emotional words yield a left–right mapping of emotional magnitude not attributable to stimulus confounds. Based on these findings, we concur with Pitt and Casasanto that faces pose challenges for isolating the forces driving spatialization, but we suggest that emotional magnitude, when assessed using unconfounded stimuli in a sufficiently sensitive task, may indeed be spatialized as originally proposed. Suggestions for further research on the spatialization of emotional magnitude are discussed.     

Elimination of position-biased responding in individuals with autism and intellectual disabilities

Five individuals with autism or other developmental disabilities participated in paired-stimulus preference assessments during repeated baseline probes. All subjects initially showed a pronounced bias by typically selecting the stimulus placed in either the left or right position. Biased responding for 3 subjects was eliminated when training trials were conducted in which a stimulus of known lesser quality was presented as one of the choices. Reinforcer-quality training was unsuccessful for 2 subjects, as was a condition in which reinforcer magnitude was modified to favor unbiased responding. These subjects' biased responding was eliminated only when a correction procedure (repetition of error trials) was implemented.     

REINFORCER MAGNITUDE ATTENUATES: APOMORPHINE'S EFFECTS ON OPERANT PECKING

When given to pigeons, the direct‐acting dopamine agonist apomorphine elicits pecking. The response has been likened to foraging pecking because it bears remarkable similarity to foraging behavior, and it is enhanced by food deprivation. On the other hand, other data suggest the response is not related to foraging behavior and may even interfere with food ingestion. Although elicited pecking interferes with food capture, it may selectively alter procurement phases of feeding, which can be isolated in operant preparations. To explore the relation between operant and elicited pecking, we provided pigeons the opportunity to earn different reinforcer magnitudes during experimental sessions. During signaled components, each of 4 pigeons could earn 2‐, 4‐, or 8‐s access to grain for a single peck made at the end of a 5‐min interval. In general, responding increased as a function of reinforcer magnitude. Apomorphine increased pecking for 2 pigeons and decreased pecking for the other 2. In both cases, apomorphine was more potent under the component providing the smallest reinforcer magnitude. Analysis of the pattern of pecking across the interval indicated that behavior lost its temporal organization as dose increased. Because apomorphine‐induced pecking varied inversely with reinforcer magnitude, we conclude that elicited pecks are not functionally related to food procurement. The data are consistent with the literature on behavioral resistance to change and suggest that the effects of apomorphine may be modulated by prevailing stimulus—reinforcer relationships.