Forced-choice and free-choice trials in response priming with moving primes

Basically, we conducted a response priming experiment with moving row-of-dots-primes (motion direction: leftwards, rightwards, neutral [to the center or the boarders of the screen; inwards or outwards, respectively]; see Bermeitinger, 2013). In forced-choice trials, the target was a directional arrow (<< or >>) which has to be classified (leftwards or rightwards). In free-choice trials, the target was an ambigous arrow composition (<> or ><) and subjects should freely choose the left or right response.

Hypothesis: positive compatibility/congruency effects (PCE) with the shorter stimulus onset asynchrony (SOA) and reduced, perhaps even negative compatibility/congruency effects (NCE) with the longer SOA. (SOA was varied between subjects, short SOA = 147 ms, longer SOA = 360 ms.) In general, we expected the same pattern of results in forced-choice and free-choice trials.

Further, we set out to determine whether there are differences in the responses to trials with compatible neutral primes (i.e., inwards motions and >< targets; outwards motions and <> targets) and to trials with incompatible neutral primes (i.e., inwards motions and <> targets; outwards motions and >< targets).

Last but not least, we analyzed differences between >< and <> targets, focusing on leftwards and rightwards prime motions in free-choice trials. According to Cole and Kuhn (2010), responses should be faster or slower depending on the number of attentional turns needed between prime and response. For <> targets, we thus expected faster and more likely prime-congruent (than prime-incongruent) responses. In contrast, a >< target should result in faster and more probable prime-incongruent responses.

Results:
In forced-choice trials:
Compatible trials = primes and targets move/point in the same direction;
incompatible trials: primes and targets move/point in opposite directions;

In free-choice trials, congruency was determined by the responses given, i.e. congruent response = left/right button press after leftwards/rightwards motion; incongruent response = left/right button press after rightwards/leftwards motion.

Compatibility/congruency effect = response time in incompatible/incongruent trials - response time in compatible/congruent trials.

Stimulus Onset Asynchrony (SOA) = time from the beginning of the prime display to the beginning of the target display

We found (non-significant) PCEs in the short SOA (for forced-choice and free-choice trials) and (significant) NCEs in the longer SOA (for forced-choice and free-choice trials).
There were no congruency effects regarding neutral conditions (i.e. <> and outwards motion; >< and inwards motion).
For directional motions in free-choice trials, we found (non-significantly) faster prime-congruent than prime-incongruent responses after >< targets and the reverse (significant) result after <> targets (which is contrary to Cole & Kuhn, 2010).

本实验主要通过移动点列原初刺激（运动方向：向左，向右，中性[向中心或屏幕边缘；分别向内或向外]；参见 Bermeitinger，2013 年的研究）进行响应启动实验。在强制选择试验中，目标为一个方向箭头（<< 或 >>），需对其进行分类（向左或向右）。在自由选择试验中，目标为一个模糊的箭头组合（<< 或 >>），受试者应自由选择左或右的反应。

假设：较短刺激 onset 同步时间（SOA）下存在正向兼容/一致性效应（PCE），而较长 SOA 下则存在减少，甚至可能为负向兼容/一致性效应（NCE）。(SOA 在受试者之间有所变化，短 SOA 为 147 毫秒，长 SOA 为 360 毫秒。)总体而言，我们预期强制选择和自由选择试验的结果模式相同。

此外，我们旨在确定对兼容中性原初刺激（即，向内运动和 >> 目标；向外运动和 << 目标）的试验与对不兼容中性原初刺激（即，向内运动和 << 目标；向外运动和 >> 目标）的试验的反应是否存在差异。

最后但同样重要的是，我们分析了 << 和 >> 目标之间的差异，重点在于自由选择试验中的左右原初运动。根据 Cole 和 Kuhn（2010 年）的研究，反应速度应根据原初与反应之间所需的注意力转向次数而快慢不一。对于 << 目标，我们因此预期更快的、更有可能的原初一致性反应。相反，>> 目标应导致更快的、更有可能的原初不一致性反应。

结果：

在强制选择试验中：
兼容试验：原初和目标运动/指向同一方向；
不兼容试验：原初和目标运动/指向相反方向；

在自由选择试验中，一致性通过所给的反应来确定，即一致性反应 = 左/右按钮按下后跟随向左/向右运动；不一致性反应 = 左/右按钮按下后跟随向右/向左运动。

兼容/一致性效应 = 不兼容/不一致性试验的反应时间 - 兼容/一致性试验的反应时间。

刺激 onset 同步时间（SOA）= 原初显示开始至目标显示开始的时间

我们发现（非显著性）PCE 在短 SOA 下（强制选择和自由选择试验）和（显著性）NCE 在长 SOA 下（强制选择和自由选择试验）。

关于中性条件（即 << 和向外运动；>> 和向内运动），没有发现一致性效应。

在自由选择试验中的方向运动中，我们发现（非显著性）在 >> 目标之后，原初一致性反应比原初不一致性反应更快，而在 << 目标之后（这与 Cole & Kuhn，2010 年的研究结果相反），则出现了显著性相反的结果。