Stimulus control in the use of landmarks by pigeons in a touch-screen task

Pigeons were tested in a search task on the surface of a monitor on which their responses were registered by a touch-sensitive device. A graphic landmark array was presented consisting of a square outline (the frame) and a colored “landmark.” The unmarked goal, pecks at which produced reward, was located near the center of one edge of the frame, and the landmark was near it. The entire array was displaced without rotation on the monitor from trial to trial. On occasional no-reward tests, the following manipulations were made to the landmark array: (a) either the frame or the landmark was removed; (2) either one edge of the frame or the landmark was shifted; and (3) two landmarks were presented with or without the frame present. On these two-landmark tests, the frame, when present, defined which was the “correct” landmark. When the frame was absent, the “correct” landmark was arbitrarily determined. Results showed that pecks of 2 pigeons were controlled almost solely by the landmark, pecks of 3 were controlled primarily by the landmark but the frame could distinguish the correct landmark, and 1 bird's behavior was controlled primarily by the frame. Stimulus control in this search task is thus selective and differs across individuals. Comparisons to other search tasks and to other stimulus control experiments are made.     

Zuckerkandl结节在甲状腺手术中对上甲状旁腺的定位与保护

探讨Zuckerkandl结节（ZT）在甲状腺手术中对上甲状旁腺的定位与保护作用.对我院2011年10月至2013年1月在我院行甲状腺手术患者351例进行回顾分析,结果显示,ZT在左侧叶甲状腺的发生率为89.0％（268/301）,右侧叶中的发生率为87.3％（254/291）,共计5例患者出现术后甲状旁腺功能一过性下降,未有永久性甲状旁腺功能损失患者出现.ZT为甲状腺手术中探查上甲状旁腺提供了新的途径与解剖标志,值得引起甲状腺外科医生的关注.     

助推目标实现：时间标记的动力效应

时间标记是指日常生活中所有突出的独特性事件。个体在经历当下的时间标记或期待未来的时间标记时, 其追求目标的动机水平得到提高, 并表现出更多的目标相关行为, 即时间标记具有一种动力效应。时间标记可能增加了个体对不同时间自我之间的分离感, 继而通过自我效能感、保持一致的自我形象、损失规避及缩小差距等心理过程提高追求目标的动机。未来研究应进一步探讨时间标记在动力效应中的角色定位及动力效应的持续时间、探究时间标记动力效应的普适性、检验可能的心理机制并在实践领域开展时间标记助推行为决策的应用研究。     

回溯式时距估计的计时机制

回溯式时距估计是以记忆为主要成分, 且事后才知要对两个相继事件之间的间隔时间或某一事件持续时间的长短进行估计。可分为近时和远时的回溯式时距估计, 两者的计时机制与记忆有关, 但各有侧重：前者侧重短时或长时记忆, 直接证据来源于即时回忆单一或多个认知任务以估计时间, 间接证据则聚焦于物理、生理、心理因素的影响; 后者侧重自传体记忆, 可从问卷或访谈的测量方式以及主客体特征的影响两个方面来寻找证据。今后需以整合的观点深入探究回溯式时距估计的计时机制, 拓展回溯式时距估计行为测量的研究, 并开展对回溯式时距估计神经生物学基础的探讨。     

Target localization after saccades and at fixation: Nontargets both facilitate and bias responses

ABSTRACT

The image on our retina changes every time we make an eye movement. To maintain visual stability after saccades, specifically to locate visual targets, we may use nontarget objects as “landmarks”. In the current study, we compared how the presence of nontargets affects target localization after saccades and during sustained fixation. Participants fixated a target object, which either maintained its location on the screen (sustained-fixation trials), or displaced to trigger a saccade (saccade trials). After the target disappeared, participants reported the most recent target location with a mouse click. We found that the presence of nontargets decreased response error magnitude and variability. However, this nontarget facilitation effect was not larger for saccade trials than sustained-fixation trials, indicating that nontarget facilitation might be a general effect for target localization, rather than of particular importance to post-saccadic stability. Additionally, participants’ responses were biased towards the nontarget locations, particularly when the nontarget-target relationships were preserved in relative coordinates across the saccade. This nontarget bias interacted with biases from other spatial references, e.g., eye movement paths, possibly in a way that emphasized non-redundant information. In summary, the presence of nontargets is one of several sources of reference that combine to influence (both facilitate and bias) target localization.     

The orientation of young and older adults' mental representations of their home town with familiar and new landmarks

Familiarity with an environment produces refined mental representations in adults of all ages, but it is not clear whether these representations tend to have a north-up orientation and whether familiarity facilitates the learning of new spatial information, especially in ageing. Thirty-two young and 32 older adults studied a map of their home town that included familiar and new fictitious landmarks, then performed pointing tasks, some aligned with the cardinal points south–north (SN), and others counter-aligned, north–south (NS). A measure of visuo-spatial working memory (VSWM) and a questionnaire on pleasure in exploring were also administered. The results showed that performance was better when pointing SN than NS (alignment effect), whereas pointing performance for familiar landmarks was similar for SN and NS alignments (no alignment effect). No interaction involving age was found. VSWM emerged as a significant predictor of pointing performance. Spatial mental representations of familiar environments are elaborate and flexible as regards familiar landmarks, in both young and older adults; and a familiar layout does not seem to enhance older adults' spatial memory as regards new landmarks.